Homebrew PCBs

Just finished a mini-project:

        http://www.delorie.com/pcb/r8c-1b-adapter/

This is a toner transfer board.  I used the wiping trick for etching,
a little different than last time.  I poured a bit of FeCl into a
small plastic tray, and dipped a sponge into it.  I wiped the copper
with the soaked sponge, but this time I occasionally squeezed out the
used FeCl and soaked up more (same tray, so not "perfectly" clean, but
at least cleaner).  The copper etched much faster this way (last time,
I poured the FeCl into the sponge, so there was no opportunity to
refresh it).

Question: I'm using Kester SP-44 flux, the no-clean type.  I use NC so
I don't have to worry about what's under parts, but I'd still like to
"pretty up" the exposed board by removing the spent flux.  Ideas?
What works on the flux, but doesn't damage the parts?  I've got
xylene, a water pic, and rubbing alcohol available to me.

DJ

----- Original Message ----- 

From: "DJ Delorie" <dj@...>
To: <Homebrew_PCBs@yahoogroups.com>
Sent: Sunday, November 26, 2006 11:54 PM
Subject: [Homebrew_PCBs] mini-project done, and cleaning no-clean flux


>
> Just finished a mini-project:
>
>        http://www.delorie.com/pcb/r8c-1b-adapter/
>
> This is a toner transfer board.  I used the wiping trick for etching,
> a little different than last time.  I poured a bit of FeCl into a
> small plastic tray, and dipped a sponge into it.  I wiped the copper
> with the soaked sponge, but this time I occasionally squeezed out the
> used FeCl and soaked up more (same tray, so not "perfectly" clean, but
> at least cleaner).  The copper etched much faster this way (last time,
> I poured the FeCl into the sponge, so there was no opportunity to
> refresh it).
>
> Question: I'm using Kester SP-44 flux, the no-clean type.  I use NC so
> I don't have to worry about what's under parts, but I'd still like to
> "pretty up" the exposed board by removing the spent flux.  Ideas?
> What works on the flux, but doesn't damage the parts?  I've got
> xylene, a water pic, and rubbing alcohol available to me.

Rubbing alcohol is basically IPA, so it should be OK. Xylene works OK as 
well, but the fumes aren't very nice.

Leon

"Leon Heller" <leon.heller@...> writes:
> Rubbing alcohol is basically IPA, so it should be OK.

Ok, thanks.

> Xylene works OK as well, but the fumes aren't very nice.

Yeah, I do that outside.  It's the same stuff I use to remove the
toner.  I just worry it will dissolve the SMD parts (for this board,
one cap and one crystal).

----- Original Message ----- 

From: "DJ Delorie" <dj@...>
To: <Homebrew_PCBs@yahoogroups.com>
Sent: Monday, November 27, 2006 2:52 AM
Subject: Re: [Homebrew_PCBs] mini-project done, and cleaning no-clean flux


>
> "Leon Heller" <leon.heller@...> writes:
>> Rubbing alcohol is basically IPA, so it should be OK.

I forgot to mention that it might contain oil of wintergreen, which will 
leave an oily residue. Pure IPA is best, and is easy to obtain from 
electronic suppliers.

Leon
--
Leon Heller, G1HSM
Suzuki SV1000S motorcycle
leon.heller@...
http://www.geocities.com/leon_heller

----- Original Message ----- 

From: "Leon Heller" <leon.heller@...>
To: <Homebrew_PCBs@yahoogroups.com>
Sent: Monday, November 27, 2006 7:56 AM
Subject: Re: [Homebrew_PCBs] mini-project done, and cleaning no-clean flux


> ----- Original Message ----- 
> From: "DJ Delorie" <dj@...>
> To: <Homebrew_PCBs@yahoogroups.com>
> Sent: Monday, November 27, 2006 2:52 AM
> Subject: Re: [Homebrew_PCBs] mini-project done, and cleaning no-clean flux
>
>
>>
>> "Leon Heller" <leon.heller@...> writes:
>>> Rubbing alcohol is basically IPA, so it should be OK.
>
> I forgot to mention that it might contain oil of wintergreen, which will
> leave an oily residue. Pure IPA is best, and is easy to obtain from
> electronic suppliers.

Another option that works well is plain hot water. I remember once visiting 
a company that used a dishwasher for cleaning their boards.

Leon

On Mon, 27 Nov 2006 11:12:16 +0100, Leon Heller  
<leon.heller@...> wrote:

>
> Another option that works well is plain hot water. I remember once  
> visiting
> a company that used a dishwasher for cleaning their boards.
> Leon


With some circuits you need de-ionized water. Many companies use ion  
exchangers for that, i believe the water softening ion exchanger in the  
dishwasher will not be enough.

ST

Leon Heller:

Was that company, by any chance, Scientific Audio Engineering
in Los Angeles California. They manufactured the famous
SAE audio equipment.

Roland F. Harriston
******************
Leon Heller wrote:
>
> > I forgot to mention that it might contain oil of wintergreen, which will
> > leave an oily residue. Pure IPA is best, and is easy to obtain from
> > electronic suppliers.
>
> Another option that works well is plain hot water. I remember once 
> visiting
> a company that used a dishwasher for cleaning their boards.
>
> Leon
>
> 



[Non-text portions of this message have been removed]

----- Original Message ----- 

From: "Roland Harriston" <rolohar@...>
To: <Homebrew_PCBs@yahoogroups.com>
Sent: Monday, November 27, 2006 11:51 AM
Subject: Re: [Homebrew_PCBs] mini-project done, and cleaning no-clean flux


> Leon Heller:
> 
> Was that company, by any chance, Scientific Audio Engineering
> in Los Angeles California. They manufactured the famous
> SAE audio equipment.

No, it was a company in Crawley, UK, IIRC.

Leon

Leon Heller:

Thanks for the response. SAE used to employ an ordinary dish washer
to clean PC boards after they came off  of the wave soldering machine.
I don't recall what kind of soap they used!

Roland F. Harriston

On Mon, 27 Nov 2006 14:22:05 +0100, Leon Heller  
<leon.heller@...> wrote:

>
>> Leon Heller:
>>
>> Was that company, by any chance, Scientific Audio Engineering
>> in Los Angeles California. They manufactured the famous
>> SAE audio equipment.

> No, it was a company in Crawley, UK, IIRC.
> Leon


I've heard it a few times now, many companies must do the same.

ST

On Mon, 27 Nov 2006 14:38:36 +0100, Roland Harriston <rolohar@...>  
wrote:

> Leon Heller:
> Thanks for the response. SAE used to employ an ordinary dish washer
> to clean PC boards after they came off  of the wave soldering machine.
> I don't recall what kind of soap they used!
> Roland F. Harriston


Detergent for manual dish washing (usually green) seems to work for people.
The dish washer stuff is quite agressive.

ST

Tektronix used to run test instrument guts thru a dishwasher when they did refurbs.

  ----- Original Message ----- 
  From: Roland Harriston 
  To: Homebrew_PCBs@yahoogroups.com 
  Sent: Monday, November 27, 2006 8:38 AM
  Subject: Re: [Homebrew_PCBs] Dish Washer PC Board Cleaning


  Leon Heller:

  Thanks for the response. SAE used to employ an ordinary dish washer
  to clean PC boards after they came off of the wave soldering machine.
  I don't recall what kind of soap they used!

  Roland F. Harriston



   

[Non-text portions of this message have been removed]

----- Original Message ----- 

From: "Syd H. Levine" <wireline@...>
To: <Homebrew_PCBs@yahoogroups.com>
Sent: Monday, November 27, 2006 3:47 PM
Subject: Re: [Homebrew_PCBs] Dish Washer PC Board Cleaning


> Tektronix used to run test instrument guts thru a dishwasher when they did 
> refurbs.

The old 541 scopes were dunked in a large vat of hot detergent.

Leon

"Leon Heller" <leon.heller@...> writes:
> I forgot to mention that it might contain oil of wintergreen, which will 
> leave an oily residue. Pure IPA is best, and is easy to obtain from 
> electronic suppliers.

Ok, the two alcohols I have are both 70% alcohol, with nothing else
but water.  They got off most but not all of the residue.  The water
pic didn't do much for the remainder.  Xylene helped a little, but
there's still residue.

Time to email the manufacturer, I suppose.

Syd H. Levine:

Yes, come to think of it, I have heard that Tektronix did that sort of thing
when they did refurbs on oscilloscopes. I think they did some of that at
the facility in Orange County, California.

Roland F. Harriston

DJ Delorie <dj@...> writes:
> Time to email the manufacturer, I suppose.

Kester's knowledgebase suggests alcohol also, but notes that it's
"slow".

----- Original Message ----- 

From: "DJ Delorie" <dj@...>
To: <Homebrew_PCBs@yahoogroups.com>
Sent: Monday, November 27, 2006 4:37 PM
Subject: Re: [Homebrew_PCBs] mini-project done, and cleaning no-clean flux


>
> "Leon Heller" <leon.heller@...> writes:
>> I forgot to mention that it might contain oil of wintergreen, which will
>> leave an oily residue. Pure IPA is best, and is easy to obtain from
>> electronic suppliers.
>
> Ok, the two alcohols I have are both 70% alcohol, with nothing else
> but water.  They got off most but not all of the residue.  The water
> pic didn't do much for the remainder.  Xylene helped a little, but
> there's still residue.

The IPA I use is 99.7% pure. It's made by Electrolube.

Leon

I can always find 90% isopropyl alcohol at my local Walgreens drug 
emporium or
at the  Safeway supermarket. I'm quite sure that this material is widely 
available.
A 16oz  bottle  is worth about a  dollar.
The stuff is water clear with no additives. I also see on the shelves a
"Rubbing Alcohol" that is tinted green and  it contains some other
ingredients, perhaps wintergreen or some such.

I've been using  90% isopropyl for many years as a general purpose
cleaner.

It is relatively safe, although flammable, and the fumes are
not too nasty.

Roland F. Harriston











DJ Delorie wrote:

>
>
> "Leon Heller" <leon.heller@... 
> <mailto:leon.heller%40bulldoghome.com>> writes:
> > I forgot to mention that it might contain oil of wintergreen, which 
> will
> > leave an oily residue. Pure IPA is best, and is easy to obtain from
> > electronic suppliers.
>
> Ok, the two alcohols I have are both 70% alcohol, with nothing else
> but water. They got off most but not all of the residue. The water
> pic didn't do much for the remainder. Xylene helped a little, but
> there's still residue.
>
> Time to email the manufacturer, I suppose.
>
>

--- In Homebrew_PCBs@yahoogroups.com, DJ Delorie <dj@...> wrote:
> 
> Ok, the two alcohols I have are both 70% alcohol, with nothing else
> but water.  They got off most but not all of the residue.  The water
> pic didn't do much for the remainder.  Xylene helped a little, but
> there's still residue.
> 
> Time to email the manufacturer, I suppose.
>
I use a 2:1 mixture of absolute ethyl alcohol and acetone.  The 
acetone is probably not necessary and does evaporate over time, but 
the removal speed is excellent.  Just dip it, wipe with a towel or 
toothbrush, and the the flux is gone.  The acetone also attacks 
certain plastics, but not the epoxy used for ICs or PCBs.  I used 
absolute ethyl alcohol because it was readily available to me.  
Denatured alcohol would probably work just as well, as would 100% IPA 
(isopropyl alcohol), as has been already suggested.  But, the latter 
is hard to find locally.  That is probably because it is not as good 
an antiseptic as 50% or 70% IPA, which is the usual consumer use for 
it.  Come to think of it, E95 might work too, but I haven't tried it.

I think keeping water out of the solvent is probably important, 
unless the flux is water soluble or you use heat and a detergent. John

"Leon Heller" <leon.heller@...> writes:
> The IPA I use is 99.7% pure. It's made by Electrolube.

Hmmm... I'll have to check all the containers I've got, one of them
might be useful.  I've got some denatured alcohol, but I'm not sure
what the additives would do to the board.

On 27/11/06, Roland Harriston <rolohar@...> wrote:
>
>
>
>
>
>
> I can always find 90% isopropyl alcohol at my local Walgreens drug
>  emporium

Thought that was a posh London store then I saw you put

>  at the  Safeway supermarket

So yes I may be on a winner we have safeway in the UK

>  A 16oz  bottle  is worth about a  dollar.

Ahh, they must be a safeway company in the US


>  It is relatively safe, although flammable, and the fumes are
>  not too nasty.

And not generally sold in the UK, especially since vinyl records have
been replaced by cd's

Its _really_ hard to buy anything in the UK thats not a food product,
even strong toilet cleaners are becoming rare! (they dont want us
making bombs etc)





Lez

"Leon Heller" <leon.heller@...> writes:
> The old 541 scopes were dunked in a large vat of hot detergent.

My dad used to have a 5 gal bucket of something called "electrical
cleaner" which was specifically designed to be safe for cleaning
electrical stuff.  I have no idea what was in it, though.

I get 91% for cheap at either target or WalMart and it owrks for most
general purpose applications. No good for things like video heads and
other sensitive applications though.

I used to always get 99% at the local Snyders Drug store for still a
reasonable price (few bucks for a pint). I haven't checked recently
(still have quite a lot on hand) but I think they still sell it. If
it's not on the shelf, ask at the pharmacy counter. I'm sure they can
order it and Snyders has always been easy to work with.




--- In Homebrew_PCBs@yahoogroups.com, DJ Delorie <dj@...> wrote:
>
> 
> "Leon Heller" <leon.heller@...> writes:
> > I forgot to mention that it might contain oil of wintergreen,
which will 

> > leave an oily residue. Pure IPA is best, and is easy to obtain from 
> > electronic suppliers.
> 
> Ok, the two alcohols I have are both 70% alcohol, with nothing else
> but water.  They got off most but not all of the residue.  The water
> pic didn't do much for the remainder.  Xylene helped a little, but
> there's still residue.
> 
> Time to email the manufacturer, I suppose.
>

On Mon, 27 Nov 2006 20:10:53 +0100, Bert <bertd.geo@...> wrote:

> I get 91% for cheap at either target or WalMart and it owrks for most
> general purpose applications. No good for things like video heads and
> other sensitive applications though.
> I used to always get 99% at the local Snyders Drug store for still a
> reasonable price (few bucks for a pint). I haven't checked recently
> (still have quite a lot on hand) but I think they still sell it. If
> it's not on the shelf, ask at the pharmacy counter. I'm sure they can
> order it and Snyders has always been easy to work with.


I was wondering, can one accurately measure the purity of IPA or ethanol  
by measuring the density?
Like measuring volume and weight, or using a hydrometer?
I recently found a 0-100% ethanol hydrometer, but i'm wondering if the  
measurement would tell me much, what if the other ingredients are not  
water? What if they have a density other than 1kg/l, then the measurement  
would not tell me the purity?

ST

Stefan Trethan:

I just rechecked the new bottle of iso that I recently purchased from 
Safeway supermarket,
and it is 99% iso alcohol,  not 90% as I might have stated previously.

Honestly,  I don't think that for the purpose of cleaning off home-made 
printed circuit boards,
the character and integrity of the iso alcohol that one uses is of any 
great significance insofar
as purity is concerned. If one is doing work for NASA or some Hi-Rel 
defense system, then
doing the analysis might be important. And even in those cases the 
vendor of the material would
most likely supply you with those types of quality data.

Better to spend that time making good, clean PC layouts
for your projects.

Besides who has all that lab equipment, and who wants to work to the 
degree of cleanliness
required to make the measurements meaningful??

This stuff is supposed to be fun!

Just my opinion.

Roland F. Harriston
**************

> On Mon, 27 Nov 2006 20:10:53 +0100, Bert <bertd.geo@...> wrote:
>
>   
>> I get 91% for cheap at either target or WalMart and it owrks for most
>> general purpose applications. No good for things like video heads and
>> other sensitive applications though.
>> I used to always get 99% at the local Snyders Drug store for still a
>> reasonable price (few bucks for a pint). I haven't checked recently
>> (still have quite a lot on hand) but I think they still sell it. If
>> it's not on the shelf, ask at the pharmacy counter. I'm sure they can
>> order it and Snyders has always been easy to work with.
>>     
>
>
> I was wondering, can one accurately measure the purity of IPA or ethanol  
> by measuring the density?
> Like measuring volume and weight, or using a hydrometer?
> I recently found a 0-100% ethanol hydrometer, but i'm wondering if the  
> measurement would tell me much, what if the other ingredients are not  
> water? What if they have a density other than 1kg/l, then the measurement  
> would not tell me the purity?
>
>   




> ST
>
>
> Be sure to visit the group home and check for new Links, Files, and Photos:
> http://groups.yahoo.com/group/Homebrew_PCBs
>
> If Files or Photos are running short of space, post them here:
> http://groups.yahoo.com/group/Homebrew_PCBs_Archives/ 
> Yahoo! Groups Links
>
>
>
>
>

On Mon, 27 Nov 2006 21:53:30 +0100, Roland Harriston <rolohar@...>  
wrote:

> Stefan Trethan:
> I just rechecked the new bottle of iso that I recently purchased from
> Safeway supermarket,
> and it is 99% iso alcohol,  not 90% as I might have stated previously.
> Honestly,  I don't think that for the purpose of cleaning off home-made
> printed circuit boards,
> the character and integrity of the iso alcohol that one uses is of any
> great significance insofar
> as purity is concerned. If one is doing work for NASA or some Hi-Rel
> defense system, then
> doing the analysis might be important. And even in those cases the
> vendor of the material would
> most likely supply you with those types of quality data.
> Better to spend that time making good, clean PC layouts
> for your projects.
> Besides who has all that lab equipment, and who wants to work to the
> degree of cleanliness
> required to make the measurements meaningful??
> This stuff is supposed to be fun!
> Just my opinion.
> Roland F. Harriston


Well, that doesn't change my curious nature ;-)

The only reason i have not yet used the hydrometer is because i don't have  
a suitable container to float it in. The thing is precise and quite high  
(about what you'd call a foot). A foot high of alcohol is quite a lot so i  
need a narrow container.

But one day i'll find the right glass for it, and then i'll need to know  
what the measurement actually means (if it is likely the contaminants are  
water or not).


ST

Roland Harriston <rolohar@...> writes:
> Honestly, I don't think that for the purpose of cleaning off
> home-made printed circuit boards, the character and integrity of the
> iso alcohol that one uses is of any great significance insofar as
> purity is concerned.

Unless, as one person noted, "water just makes the flux sticky".  If
so, you'd want to have the least amount of water in the alcohol so as
to avoid that.

> > Leon wrote:
> > The old 541 scopes were dunked in a large vat of hot detergent.

> Mr DJ Delorie wrote:
> 
> My dad used to have a 5 gal bucket of something called "electrical
> cleaner" which was specifically designed to be safe for cleaning
> electrical stuff.  I have no idea what was in it, though.
>

A bucket full of CFCs.

Ah I can hear the ozone dying as we speak :D

Stefan

Yes you can, as long as we're talking a simple binary mixture of IPA and
H2O. After that is gets complicated real quick....

Density of IPA (also known as 2-Propanol) is 0.7855 g/ml @ 20C
Density of H2O is, of course, 1 g/ml

If you can measure the volume and the weight of the mixture, you can
calculate the density of the mixture

From this you can get the ratios of the components

Let me know if you need more info on how to arrive at the ratios

Randy

> -----Original Message-----
> From: Homebrew_PCBs@yahoogroups.com
> [mailto:Homebrew_PCBs@yahoogroups.com]On Behalf Of Stefan Trethan
> Sent: Monday, November 27, 2006 2:33 PM
> To: Homebrew_PCBs@yahoogroups.com
> Subject: Re: [Homebrew_PCBs] Re: mini-project done, and cleaning
> no-clean flux
>
>
> I was wondering, can one accurately measure the purity of IPA or ethanol
> by measuring the density?
> Like measuring volume and weight, or using a hydrometer?
> I recently found a 0-100% ethanol hydrometer, but i'm wondering if the
> measurement would tell me much, what if the other ingredients are not
> water? What if they have a density other than 1kg/l, then the
> measurement
> would not tell me the purity?
>
> ST

On Tue, 28 Nov 2006 00:35:27 +0100, Randy Ledyard  
<rll_groups@...> wrote:

> Stefan
> Yes you can, as long as we're talking a simple binary mixture of IPA and
> H2O. After that is gets complicated real quick....
> Density of IPA (also known as 2-Propanol) is 0.7855 g/ml @ 20C
> Density of H2O is, of course, 1 g/ml
> If you can measure the volume and the weight of the mixture, you can
> calculate the density of the mixture
> From this you can get the ratios of the components
> Let me know if you need more info on how to arrive at the ratios
> Randy


Thank you, I understand that.
What i was asking is if there are likely contaminants far off the density  
of water.
I have no means (and no intention) to analyze it exactly, but there is no  
point in going through with the hydrometer measurement if the result is  
meaningless.

I've weighed a bottle of IPA a while ago, using an identical bottle filled  
with water to the same level to determine the volume. But this process was  
not very accurate. Now that i found the ethanol hydrometer, i could use  
that (observing the tiny correction factor between IPA and ethanol).


ST

The common stuff is only about 70%, but you can get the 91% at Wal-Mart and elsewhere for a few cents more.  The balance of the mix is of course water.  I have never been impressed with IPA as an electronics cleaning material (the expensive anhydrous stuff sucks also)..  Ethanol is a much better cleaner.  The denatured stuff stinks, but it just has a little methanol added to make the whinos go blind.  If you want really good Ethanol, go to the liquor store and buy Everclear (PGA).  We have been using it as flux cleaner here ever since they outlawed our 1,1,1.  One caution:  ethanol will attack some of the nastier plastics like styrene; it does not bother typical PCB material at all.

http://www.logwell.com/editorials/1-1-1.html

Syd

  ----- Original Message ----- 
  From: Roland Harriston 
  To: Homebrew_PCBs@yahoogroups.com 
  Sent: Monday, November 27, 2006 1:02 PM
  Subject: Re: [Homebrew_PCBs] Isopropyl Alcohol 90%


  I can always find 90% isopropyl alcohol at my local Walgreens drug 
  emporium or
  at the Safeway supermarket. I'm quite sure that this material is widely 
  available.
  A 16oz bottle is worth about a dollar.
  The stuff is water clear with no additives. I also see on the shelves a
  "Rubbing Alcohol" that is tinted green and it contains some other
  ingredients, perhaps wintergreen or some such.

  I've been using 90% isopropyl for many years as a general purpose
  cleaner.

  It is relatively safe, although flammable, and the fumes are
  not too nasty.

  Roland F. Harriston

  DJ Delorie wrote:
  >
  >
  > "Leon Heller" <leon.heller@... 
  > <mailto:leon.heller%40bulldoghome.com>> writes:
  > > I forgot to mention that it might contain oil of wintergreen, which 
  > will
  > > leave an oily residue. Pure IPA is best, and is easy to obtain from
  > > electronic suppliers.
  >
  > Ok, the two alcohols I have are both 70% alcohol, with nothing else
  > but water. They got off most but not all of the residue. The water
  > pic didn't do much for the remainder. Xylene helped a little, but
  > there's still residue.
  >
  > Time to email the manufacturer, I suppose.
  >
  > 



   

[Non-text portions of this message have been removed]

Prolly 1,1,1.  I bet that fella was single handedly responsible for environmental catastrophe.

  ----- Original Message ----- 
  From: Andrew 
  To: Homebrew_PCBs@yahoogroups.com 
  Sent: Monday, November 27, 2006 5:09 PM
  Subject: [Homebrew_PCBs] Re: Dish Washer PC Board Cleaning


  > > Leon wrote:
  > > The old 541 scopes were dunked in a large vat of hot detergent.

  > Mr DJ Delorie wrote:
  > 
  > My dad used to have a 5 gal bucket of something called "electrical
  > cleaner" which was specifically designed to be safe for cleaning
  > electrical stuff. I have no idea what was in it, though.
  >

  A bucket full of CFCs.

  Ah I can hear the ozone dying as we speak :D



   

[Non-text portions of this message have been removed]

On 28/11/06, AnaLog Services, Inc. <wireline@...> wrote:
>
>
>
>
>
>
> The common stuff is only about 70%, but you can get the 91% at Wal-Mart and

wrong side of the pond m8y.

Our 'wal-mart' is www.asda.co.uk

We dont 'sell' chemicals over here.

IPA is like at a chemists only, and they ask questions, and mine does
not sell it anymore, except in 25ml tubs for about $4 (£2)

I bet someone will post and prove me wrong, but if its not used for
cleaning your car, or for granny to bake with, its not on sale over
here.

We do have 'specialist' chemical supply companys with big metal drums
often seen exploding in movies, but they would want to know why I need
so much, and could I afford it, then they would want to know how I was
going to store/use it.

When I wanted to paint my car, I went to buy 10ltrs of paint, and was
refused it as I was going to paint it without the required ventilation
equipment....(I did get some at another supplier)

Even our drain cleaners are nearly getting safe enough to drink.......

Lez

On Tue, 28 Nov 2006 01:32:54 +0100, AnaLog Services, Inc.  
<wireline@...> wrote:

>  One caution:  ethanol will attack some of the nastier plastics like  
> styrene; it does not bother typical PCB material at all.


I've yet to observe ethanol attack styrene, but maybe the additives are  
different in some places for denatured. I use mine on all plastics with no  
hesitation.

I agree with you that IPA seems to have less cleaning action, and it  
stinks like a doctors office. Denatured ethanol OTOH tastes _really_ bad,  
no i don't try to drink it but if you blow out a tubular part a tiny  
amount of residue tastes very bad on your lips. Same with antifreeze, and  
intentional in both cases.

ST

Ethanol will most definitely attack polystyrene and its cousins.  If you 
have not noticed it, it is because you have not been handling true 
polystyrene.  It does not attack most other plastics.  My paper towel 
dispensers in the shop are polystyrene, and if my fingers are wet with 
ethanol, they will stick to the darn things and leave fingerprint marks.

----- Original Message ----- 

From: "Stefan Trethan" <stefan_trethan@...>
To: <Homebrew_PCBs@yahoogroups.com>
Sent: Monday, November 27, 2006 7:54 PM
Subject: Re: [Homebrew_PCBs] Isopropyl Alcohol 90%


> On Tue, 28 Nov 2006 01:32:54 +0100, AnaLog Services, Inc.
> <wireline@...> wrote:
>
>>  One caution:  ethanol will attack some of the nastier plastics like
>> styrene; it does not bother typical PCB material at all.
>
>
> I've yet to observe ethanol attack styrene, but maybe the additives are
> different in some places for denatured. I use mine on all plastics with no
> hesitation.
>
> I agree with you that IPA seems to have less cleaning action, and it
> stinks like a doctors office. Denatured ethanol OTOH tastes _really_ bad,
> no i don't try to drink it but if you blow out a tubular part a tiny
> amount of residue tastes very bad on your lips. Same with antifreeze, and
> intentional in both cases.
>
> ST
>
>
> Be sure to visit the group home and check for new Links, Files, and 
> Photos:
> http://groups.yahoo.com/group/Homebrew_PCBs
>
> If Files or Photos are running short of space, post them here:
> http://groups.yahoo.com/group/Homebrew_PCBs_Archives/
> Yahoo! Groups Links
>
>
>
>

----- Original Message ----- 

From: "Lez" <lez.briddon@...>
To: <Homebrew_PCBs@yahoogroups.com>
Sent: Tuesday, November 28, 2006 12:49 AM
Subject: Re: [Homebrew_PCBs] Isopropyl Alcohol 90%


On 28/11/06, AnaLog Services, Inc. <wireline@...> wrote:
>
>
>
>
>
>
> The common stuff is only about 70%, but you can get the 91% at Wal-Mart 
> and

wrong side of the pond m8y.

Our 'wal-mart' is www.asda.co.uk

We dont 'sell' chemicals over here.

IPA is like at a chemists only, and they ask questions, and mine does
not sell it anymore, except in 25ml tubs for about $4 (\ufffd2)


The 99% stuff is available from RS, Farnell and Rapid Electronics in 1l 
cans.

Leon

On Tue, 28 Nov 2006 06:43:34 +0100, Syd H. Levine  
<wireline@...> wrote:

> Ethanol will most definitely attack polystyrene and its cousins.  If you
> have not noticed it, it is because you have not been handling true
> polystyrene.  It does not attack most other plastics.  My paper towel
> dispensers in the shop are polystyrene, and if my fingers are wet with
> ethanol, they will stick to the darn things and leave fingerprint marks.


I'll try again then!

Did you use pure ethanol or a denatured variety?

ST

On Tue, 28 Nov 2006 06:43:34 +0100, Syd H. Levine
<wireline@...> wrote:

> Ethanol will most definitely attack polystyrene and its cousins.  If you
> have not noticed it, it is because you have not been handling true
> polystyrene.  It does not attack most other plastics.  My paper towel
> dispensers in the shop are polystyrene, and if my fingers are wet with
> ethanol, they will stick to the darn things and leave fingerprint marks.

I just tried, with a solid polystyrene cup (marked), expanded polystyrene  
foam (marked), and ABS.
None of these plastics shows any reaction whatsoever, when exposed for  
like a minute or so. I have rubbed the ethanol around with my finger and  
there was no stickyness, nor was there any surface disturbance after  
drying.

So you are either mistaken (solvent not ethanol or towel holder not PS),  
or your ethanol is denatured with something agressive. I was told they  
used to denature it with petrol in some places.

I'm sorry, but it's just not happening. I have used different brands of  
denatured ethanol here for at least 10 years, regularly on ABS and PS with  
no adverse effects. Some of my parts boxes are styrene plastic, and i  
remove obsolete markings all the time with ethanol.


ST

Either is aggressive against polystyrene.  For instance, those white foam 
expanded polystyrene cups cannot survive PGA (as if anybody could stand to 
drink it straight).

I have gotten away from the denatured stuff due to the stink.  I buy bottles 
of PGA (Everclear) and use it for flux cleaning.  I pay the outrageously 
high tax on it that way, but I use so little, it is much easier to do that 
than to buy it from a chemical supplier.

Syd


----- Original Message ----- 

From: "Stefan Trethan" <stefan_trethan@...>
To: <Homebrew_PCBs@yahoogroups.com>
Sent: Tuesday, November 28, 2006 4:58 AM
Subject: Re: [Homebrew_PCBs] Isopropyl Alcohol 90%


> On Tue, 28 Nov 2006 06:43:34 +0100, Syd H. Levine
> <wireline@...> wrote:
>
>> Ethanol will most definitely attack polystyrene and its cousins.  If you
>> have not noticed it, it is because you have not been handling true
>> polystyrene.  It does not attack most other plastics.  My paper towel
>> dispensers in the shop are polystyrene, and if my fingers are wet with
>> ethanol, they will stick to the darn things and leave fingerprint marks.
>
>
> I'll try again then!
>
> Did you use pure ethanol or a denatured variety?
>
> ST
>
>
> Be sure to visit the group home and check for new Links, Files, and 
> Photos:
> http://groups.yahoo.com/group/Homebrew_PCBs
>
> If Files or Photos are running short of space, post them here:
> http://groups.yahoo.com/group/Homebrew_PCBs_Archives/
> Yahoo! Groups Links
>
>
>
>

On Tue, 28 Nov 2006 13:06:09 +0100, AnaLog Services, Inc.  
<wireline@...> wrote:

> Either is aggressive against polystyrene.  For instance, those white foam
> expanded polystyrene cups cannot survive PGA (as if anybody could stand  
> to
> drink it straight).
> I have gotten away from the denatured stuff due to the stink.  I buy  
> bottles
> of PGA (Everclear) and use it for flux cleaning.  I pay the outrageously
> high tax on it that way, but I use so little, it is much easier to do  
> that
> than to buy it from a chemical supplier.
> Syd


Then you must have different polystyrene than we have. Ethanol does  
nothing to mine.

ST

Most peculiar.  I originally noticed this with denatured alcohol.  The 
denaturing agent is usually methanol.  I *THINK* I have seen the same effect 
with PGA ethanol, but now I am questioning my sanity.  I will do some 
experimenting down in the lab later today.

I did come across a mention of 0.37% solubility of polystyrene cup material 
in PGA, but not much else with a web search.

----- Original Message ----- 

From: "Stefan Trethan" <stefan_trethan@...>
To: <Homebrew_PCBs@yahoogroups.com>
Sent: Tuesday, November 28, 2006 5:15 AM
Subject: Re: [Homebrew_PCBs] Isopropyl Alcohol 90%


> On Tue, 28 Nov 2006 06:43:34 +0100, Syd H. Levine
> <wireline@...> wrote:
>
>> Ethanol will most definitely attack polystyrene and its cousins.  If you
>> have not noticed it, it is because you have not been handling true
>> polystyrene.  It does not attack most other plastics.  My paper towel
>> dispensers in the shop are polystyrene, and if my fingers are wet with
>> ethanol, they will stick to the darn things and leave fingerprint marks.
>
> I just tried, with a solid polystyrene cup (marked), expanded polystyrene
> foam (marked), and ABS.
> None of these plastics shows any reaction whatsoever, when exposed for
> like a minute or so. I have rubbed the ethanol around with my finger and
> there was no stickyness, nor was there any surface disturbance after
> drying.
>
> So you are either mistaken (solvent not ethanol or towel holder not PS),
> or your ethanol is denatured with something agressive. I was told they
> used to denature it with petrol in some places.
>
> I'm sorry, but it's just not happening. I have used different brands of
> denatured ethanol here for at least 10 years, regularly on ABS and PS with
> no adverse effects. Some of my parts boxes are styrene plastic, and i
> remove obsolete markings all the time with ethanol.
>
>
> ST
>
>
> Be sure to visit the group home and check for new Links, Files, and 
> Photos:
> http://groups.yahoo.com/group/Homebrew_PCBs
>
> If Files or Photos are running short of space, post them here:
> http://groups.yahoo.com/group/Homebrew_PCBs_Archives/
> Yahoo! Groups Links
>
>
>
>

On Tue, 28 Nov 2006 13:44:32 +0100, AnaLog Services, Inc.  
<wireline@...> wrote:

> Most peculiar.  I originally noticed this with denatured alcohol.  The
> denaturing agent is usually methanol.  I *THINK* I have seen the same  
> effect
> with PGA ethanol, but now I am questioning my sanity.  I will do some
> experimenting down in the lab later today.
> I did come across a mention of 0.37% solubility of polystyrene cup  
> material
> in PGA, but not much else with a web search.


Polystyrene foam cups are virtually non-existent here. I can't remember  
ever seeing one in my life.
Coffee machines use polystyrene cups, but not foam, they are vacuum formed  
sheet with a rolled edge, or some cardboard polyethylene composite  
material.

But still, expanded or extruded polystyrene should be the same all around  
the world, since it is shipped as packing material everywhere. My ethanol  
did not do anything to that, or vacuum-formed sheet polystyrene cups.  
Acetone or laquer thinners will eat all that though.

ST

Stefan Trethan wrote:
> On Tue, 28 Nov 2006 13:44:32 +0100, AnaLog Services, Inc.  
> <wireline@...> wrote:
> 
>> Most peculiar.  I originally noticed this with denatured alcohol.  The
>> denaturing agent is usually methanol.  I *THINK* I have seen the same  
>> effect
>> with PGA ethanol, but now I am questioning my sanity.  I will do some
>> experimenting down in the lab later today.
>> I did come across a mention of 0.37% solubility of polystyrene cup  
>> material
>> in PGA, but not much else with a web search.
> 
> 
> Polystyrene foam cups are virtually non-existent here. I can't remember  
> ever seeing one in my life.
> Coffee machines use polystyrene cups, but not foam, they are vacuum formed  
> sheet with a rolled edge, or some cardboard polyethylene composite  
> material.
> 
> But still, expanded or extruded polystyrene should be the same all around  
> the world, since it is shipped as packing material everywhere. My ethanol  
> did not do anything to that, or vacuum-formed sheet polystyrene cups.  
> Acetone or laquer thinners will eat all that though.
> 
> ST
> 

I would suggest you may both be right. I was curious about this so I 
popped down to the garage and tried some polystyrene foam in both IPA 
and denatured ethanol. Neither had any noticeable effect upon the 
polystyrene foam. This is perfectly reasonable. Imagine a world where it 
was not possible to go to those classy parties where you get to drink 
beer and wine from polystyrene cups for fear that they dissolve in your 
hands.

On the other hand, the monomer styrene is soluble in ethanol apparently. 
  see http://www.oehha.ca.gov/air/acute_rels/pdf/100425A.pdf
but should not be present in any quantity in polystyrene. I really don't 
know how much might be there. The styrene monomer is toxic. Table 6 in 
this paper: 
http://www.mindfully.org/Plastic/Polystyrene/Polystyrene-Foods-Styrene-Monomer.htm
indicates that even then, the amount of styrene you would get out is 
tiny and that the polystyrene cup is not destroyed in the test.

If Everclear - which claims to be a non-toxic ethanol product - really 
can dissolve polystyrene I would be worried either about the quality of 
the polystyrene or exactly what can be present in small proportions in 
Everclear that can wreak such havoc with polystyrene.

Pete Harrison

--- In Homebrew_PCBs@yahoogroups.com, "Stefan Trethan"
<stefan_trethan@...> wrote:
>
> On Tue, 28 Nov 2006 01:32:54 +0100, AnaLog Services, Inc.  
> <wireline@...> wrote:
> 
> >  One caution:  ethanol will attack some of the nastier plastics like  
> > styrene; it does not bother typical PCB material at all.
> 
> 
> I've yet to observe ethanol attack styrene, but maybe the additives
are  
> different in some places for denatured. I use mine on all plastics
with no  
> hesitation.

Denatured alcohol has methyl alcohol added, and denatured -does-
attack styrene, albiet very slowly. Most VCR front panels are/were
made of styrene. IPA wipes crayon off of it very well, denatured works
even better but you'll end up with bits of fluff from your rag welded
into the top layer of plastic.

Now things are made of different kinds of plastic, usually painted.

Steve Greenfield

On Wed, 29 Nov 2006 01:14:48 +0100, Peter Harrison  
<peter.harrison@...> wrote:

> I would suggest you may both be right. I was curious about this so I
> popped down to the garage and tried some polystyrene foam in both IPA
> and denatured ethanol. Neither had any noticeable effect upon the
> polystyrene foam. This is perfectly reasonable. Imagine a world where it
> was not possible to go to those classy parties where you get to drink
> beer and wine from polystyrene cups for fear that they dissolve in your
> hands.


How could both be right? Either is is attacked significantly or it isn't.
I can't see no effect of ethanol on styrene and i'm tired of hearing those  
claims without any proof.

ST

On Wed, 29 Nov 2006 02:11:40 +0100, Steve <alienrelics@...> wrote:

> Denatured alcohol has methyl alcohol added, and denatured -does-
> attack styrene, albiet very slowly. Most VCR front panels are/were
> made of styrene. IPA wipes crayon off of it very well, denatured works
> even better but you'll end up with bits of fluff from your rag welded
> into the top layer of plastic.
> Now things are made of different kinds of plastic, usually painted.
> Steve Greenfield


I think our denatured here just has no methanol then.

I find most electronics plasticwork is still ABS.

ST

On Wed, 29 Nov 2006 02:30:23 +0100, Stefan Trethan <stefan_trethan@...>  
wrote:

>
> I think our denatured here just has no methanol then.


confirmed, german MSDS list 1% MEK (and or other ketones and maybe tiny  
amounts of other denaturing agents) and english MSDS 5% methanol.

While MEK will solve some plastics the lower concentration and/or it's  
difference to methanol in agressiveness seems to explain the discrepancy  
in observations.

I'm satisfied that's the reason, maybe it's why IPA is so widely used in  
the US while here denatured ethanol replaces it in almost all capacities.  
If denatured alcohol solved plastics it would have fallen out of favour  
quickly.

Good night.

ST

Steve:

Is it the methanol additive doing that?  My experience is that it will actually smear clear polystyrene windows like you describe (and stick the fuzz particles to it).  I was pretty sure pure ethanol was doing it too, but now I am questioning that. 

  ----- Original Message ----- 
  From: Steve 
  To: Homebrew_PCBs@yahoogroups.com 
  Sent: Tuesday, November 28, 2006 8:11 PM
  Subject: [Homebrew_PCBs] Re: Isopropyl Alcohol 90%


  --- In Homebrew_PCBs@yahoogroups.com, "Stefan Trethan"
  <stefan_trethan@...> wrote:
  >
  > On Tue, 28 Nov 2006 01:32:54 +0100, AnaLog Services, Inc. 
  > <wireline@...> wrote:
  > 
  > > One caution: ethanol will attack some of the nastier plastics like 
  > > styrene; it does not bother typical PCB material at all.
  > 
  > 
  > I've yet to observe ethanol attack styrene, but maybe the additives
  are 
  > different in some places for denatured. I use mine on all plastics
  with no 
  > hesitation.

  Denatured alcohol has methyl alcohol added, and denatured -does-
  attack styrene, albiet very slowly. Most VCR front panels are/were
  made of styrene. IPA wipes crayon off of it very well, denatured works
  even better but you'll end up with bits of fluff from your rag welded
  into the top layer of plastic.

  Now things are made of different kinds of plastic, usually painted.

  Steve Greenfield



   

[Non-text portions of this message have been removed]

I found a good chemical compatibility table indicating ABS (a common styrene 
based plastic used in electronics) is severely attacked by Methanol, but 
only very slightly attacked by Ethanol.  Methanol is the common denaturing 
agent in the US and this probably explains my experience with denatured 
alcohol attacking styrene based plastics.

I have not had a chance to test some PGA (Everclear) on ABS, but I am now 
assuming I was merely extrapolating my experience with the denatured 
ethanol.  I must have never actually tried the PGA, but simply assumed it 
acted the same way as the denatured stuff.  This also makes me wonder if 
Methanol might actually make a good flux cleaner since I have had a nagging 
suspicion that the denatured alcohol actually works a bit better as a flux 
cleaner than the PGA.  But not really sure about that observation.

As to the denaturing agent being Methyl Ethyl Ketone (MEK) in Europe, that 
is rather interesting.  MEK is VERY aggressive against ABS and PVC.  It 
would be hard to believe that Ethanol denatured with MEK would not be as bad 
as Ethanol denatured with Methanol with respect to attacking ABS.

Syd H. Levine
AnaLog Services, Inc.
Phone:  (270) 276-5671
Telefax:  (270) 276-5588
E-mail:  analog@...
Web URL:  www.logwell.com

----- Original Message ----- 

From: "Stefan Trethan" <stefan_trethan@...>
To: <Homebrew_PCBs@yahoogroups.com>
Sent: Tuesday, November 28, 2006 8:17 PM
Subject: Re: [Homebrew_PCBs] Isopropyl Alcohol 90%


> On Wed, 29 Nov 2006 01:14:48 +0100, Peter Harrison
> <peter.harrison@...> wrote:
>
>> I would suggest you may both be right. I was curious about this so I
>> popped down to the garage and tried some polystyrene foam in both IPA
>> and denatured ethanol. Neither had any noticeable effect upon the
>> polystyrene foam. This is perfectly reasonable. Imagine a world where it
>> was not possible to go to those classy parties where you get to drink
>> beer and wine from polystyrene cups for fear that they dissolve in your
>> hands.
>
>
> How could both be right? Either is is attacked significantly or it isn't.
> I can't see no effect of ethanol on styrene and i'm tired of hearing those
> claims without any proof.
>
> ST
>
>
> Be sure to visit the group home and check for new Links, Files, and 
> Photos:
> http://groups.yahoo.com/group/Homebrew_PCBs
>
> If Files or Photos are running short of space, post them here:
> http://groups.yahoo.com/group/Homebrew_PCBs_Archives/
> Yahoo! Groups Links
>
>
>
>

On Wed, 29 Nov 2006 10:17:30 +0100, Syd H. Levine  
<wireline@...> wrote:

>
> As to the denaturing agent being Methyl Ethyl Ketone (MEK) in Europe,  
> that
> is rather interesting.  MEK is VERY aggressive against ABS and PVC.  It
> would be hard to believe that Ethanol denatured with MEK would not be as  
> bad
> as Ethanol denatured with Methanol with respect to attacking ABS.


I can not be sure if it is is my denatured ethanol, since i do not have a  
MSDS for the brand i currently use. But all MSDS i've downloaded listed  
MEK, and i used several brands over the years, so it is highly likely some  
if not all contained MEK.

I have used it on ABS countless times, and never observed any trouble like  
surface damage in any way.
Maybe the low percentage renders MEK harmless.

ST

As a rule, mixing solvents is fairly predicable.  There are exceptions, so 
maybe MEK does not act as aggressively as Methanol as a small percentage of 
the mix with Ethanol.

Note that MEK is often the principal agent in ABS and PVC pipe cleaners, and 
maybe in the solvent cements themselves.  MEK is nasty stuff.

----- Original Message ----- 

From: "Stefan Trethan" <stefan_trethan@...>
To: <Homebrew_PCBs@yahoogroups.com>
Sent: Wednesday, November 29, 2006 4:50 AM
Subject: Re: [Homebrew_PCBs] Isopropyl Alcohol 90%


> On Wed, 29 Nov 2006 10:17:30 +0100, Syd H. Levine
> <wireline@...> wrote:
>
>>
>> As to the denaturing agent being Methyl Ethyl Ketone (MEK) in Europe,
>> that
>> is rather interesting.  MEK is VERY aggressive against ABS and PVC.  It
>> would be hard to believe that Ethanol denatured with MEK would not be as
>> bad
>> as Ethanol denatured with Methanol with respect to attacking ABS.
>
>
> I can not be sure if it is is my denatured ethanol, since i do not have a
> MSDS for the brand i currently use. But all MSDS i've downloaded listed
> MEK, and i used several brands over the years, so it is highly likely some
> if not all contained MEK.
>
> I have used it on ABS countless times, and never observed any trouble like
> surface damage in any way.
> Maybe the low percentage renders MEK harmless.
>
> ST
>
>
> Be sure to visit the group home and check for new Links, Files, and 
> Photos:
> http://groups.yahoo.com/group/Homebrew_PCBs
>
> If Files or Photos are running short of space, post them here:
> http://groups.yahoo.com/group/Homebrew_PCBs_Archives/
> Yahoo! Groups Links
>
>
>
>

--- In Homebrew_PCBs@yahoogroups.com, "Syd H. Levine" <wireline@...>
wrote:
>
> I found a good chemical compatibility table indicating ABS (a common
styrene 
> based plastic used in electronics) is severely attacked by Methanol,
but 
> only very slightly attacked by Ethanol.  Methanol is the common
denaturing 
> agent in the US and this probably explains my experience with denatured 
> alcohol attacking styrene based plastics.

There are a BUNCH of different denaturing agents used for ethanol
in the US.  The authoratative list is here:

http://www.access.gpo.gov/nara/cfr/waisidx_06/27cfr21_06.html

Some of those things are pretty nasty, even nastier than methanol
or MEK!

> I have not had a chance to test some PGA (Everclear) on ABS, but I
am now 
> assuming I was merely extrapolating my experience with the denatured 
> ethanol.  I must have never actually tried the PGA, but simply
assumed it 
> acted the same way as the denatured stuff.  This also makes me
wonder if 
> Methanol might actually make a good flux cleaner since I have had a
nagging 
> suspicion that the denatured alcohol actually works a bit better as
a flux 
> cleaner than the PGA.  But not really sure about that observation.
> 
> As to the denaturing agent being Methyl Ethyl Ketone (MEK) in
Europe, that 
> is rather interesting.  MEK is VERY aggressive against ABS and PVC.  It 
> would be hard to believe that Ethanol denatured with MEK would not
be as bad 
> as Ethanol denatured with Methanol with respect to attacking ABS.
> 
> Syd H. Levine
> AnaLog Services, Inc.
> Phone:  (270) 276-5671
> Telefax:  (270) 276-5588
> E-mail:  analog@...
> Web URL:  www.logwell.com

Dave

From what others are saying, I suspect that it's either the methanol,
or there are some other additives to denature it that mildly eat into
some plastics.

Steve Greenfield

--- In Homebrew_PCBs@yahoogroups.com, "Syd H. Levine" <wireline@...>
wrote:
>
> Steve:
> 
> Is it the methanol additive doing that?  My experience is that it
will actually smear clear polystyrene windows like you describe (and
stick the fuzz particles to it).  I was pretty sure pure ethanol was
doing it too, but now I am questioning that. 
>

Yes, that does appear to be the case.  I just tested PGA on some ABS, and there is no detectable degradation.  The denatured material I have causes marked damage to susceptible plastics.

The denaturing agent is NOT Methanol alone I now see from the federal regulation which states the formulas for Completely Denatured Alcohol.  If it comes from Lowes, Wal-Mart, a paint store, etc., it can only be one of the CDA formulas.  And that means it will have some gasoline or kerosene in it, and possibly a number of other nasty ingredients.  Looking at the formulas for CDA is a real eye-opener!  I will never use the denatured product again for flux cleaning.

This has been an educational experience.  Thank you for making me re-examine something I thought I understood.

Syd H. Levine
AnaLog Services, Inc.
Phone:  270-276-5671
Telefax:  270-276-5588
E-mail:  analog@...
URL:  www.logwell.com

  ----- Original Message ----- 
  From: Steve 
  To: Homebrew_PCBs@yahoogroups.com 
  Sent: Wednesday, November 29, 2006 1:30 PM
  Subject: [Homebrew_PCBs] Re: Isopropyl Alcohol 90%


  From what others are saying, I suspect that it's either the methanol,
  or there are some other additives to denature it that mildly eat into
  some plastics.

  Steve Greenfield

  --- In Homebrew_PCBs@yahoogroups.com, "Syd H. Levine" <wireline@...>
  wrote:
  >
  > Steve:
  > 
  > Is it the methanol additive doing that? My experience is that it
  will actually smear clear polystyrene windows like you describe (and
  stick the fuzz particles to it). I was pretty sure pure ethanol was
  doing it too, but now I am questioning that. 
  > 



   

[Non-text portions of this message have been removed]

--- "Syd H. Levine" <wireline@...> wrote:
> ...  My paper towel 
> dispensers in the shop are polystyrene, and if my fingers are wet with 
> ethanol, they will stick to the darn things and leave fingerprint marks.

usually they are ABS...
styropor (or whatever brand) is 'pure' foamed styrene. is this attacked?


 
____________________________________________________________________________________
Cheap talk?
Check out Yahoo! Messenger's low PC-to-Phone call rates.
http://voice.yahoo.com

It is now clear that PGA (Everclear) ethyl alcohol (ethanol) only very mildly attacks polystyrene.  It does not noticeably attack ABS, but is listed as very mildly aggressive.  My PGA test on my paper towel dispenser showed no noticeable effect.  My confusion stemmed from what is in denatured ethyl alcohol.  It is denatured with a variety of crap, some of which will attack ABS.

  ----- Original Message ----- 
  From: Herbert E. Plett 
  To: Homebrew_PCBs@yahoogroups.com 
  Sent: Wednesday, November 29, 2006 10:53 PM
  Subject: Re: [Homebrew_PCBs] Isopropyl Alcohol 90%



  --- "Syd H. Levine" <wireline@...> wrote:
  > ... My paper towel 
  > dispensers in the shop are polystyrene, and if my fingers are wet with 
  > ethanol, they will stick to the darn things and leave fingerprint marks.

  usually they are ABS...
  styropor (or whatever brand) is 'pure' foamed styrene. is this attacked?

  __________________________________________________________
  Cheap talk?
  Check out Yahoo! Messenger's low PC-to-Phone call rates.
  http://voice.yahoo.com


   

[Non-text portions of this message have been removed]

On Thu, 30 Nov 2006 04:53:22 +0100, Herbert E. Plett <cachureos@...>  
wrote:

>
> styropor (or whatever brand) is 'pure' foamed styrene. is this attacked?


No, not when applying a small puddle in a depression and rubbing it  
around. No softening, no stickyness, nothing, with my (european) denatured  
alcohol. Vacuum formed polystyrene cups (white, solid no foam, for dairy  
products) also show no reaction either. I believe they are also plain  
polystyrene.

Seems a bit silly to me to denature it with something that dramatically  
reduces it's applications. May be why IPA is used in the US instead.

ST

Many thanks to Stefan for making me examine an incorrect belief I have long 
held about Ethanol.  I have revised my pages on Ethanol as a cleaner, and 
added a page on the formulas used here in the US.  It would be interesting 
to know the actual formula for the denatured alcohol that Stefan is using. 
Clearly the stuff sold as denatured alcohol here in the US is nasty stuff, 
and it will definitely attack ABS.  True PGA is next to harmless on ABS.

http://www.logwell.com/tech/servtips/cleaning.html
http://www.logwell.com/tech/servtips/CDA_formulas.html

Syd H. Levine
AnaLog Services, Inc.
Phone:  (270) 276-5671
Telefax:  (270) 276-5588
E-mail:  analog@...
Web URL:  www.logwell.com

----- Original Message ----- 

From: "Stefan Trethan" <stefan_trethan@...>
To: <Homebrew_PCBs@yahoogroups.com>
Sent: Thursday, November 30, 2006 9:15 AM
Subject: Re: [Homebrew_PCBs] Isopropyl Alcohol 90%


> On Thu, 30 Nov 2006 04:53:22 +0100, Herbert E. Plett <cachureos@...>
> wrote:
>
>>
>> styropor (or whatever brand) is 'pure' foamed styrene. is this attacked?
>
>
> No, not when applying a small puddle in a depression and rubbing it
> around. No softening, no stickyness, nothing, with my (european) denatured
> alcohol. Vacuum formed polystyrene cups (white, solid no foam, for dairy
> products) also show no reaction either. I believe they are also plain
> polystyrene.
>
> Seems a bit silly to me to denature it with something that dramatically
> reduces it's applications. May be why IPA is used in the US instead.
>
> ST
>
>
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>
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>
>
>

On Fri, 01 Dec 2006 17:52:30 +0100, AnaLog Services, Inc.  
<wireline@...> wrote:

> Many thanks to Stefan for making me examine an incorrect belief I have  
> long
> held about Ethanol.  I have revised my pages on Ethanol as a cleaner, and
> added a page on the formulas used here in the US.  It would be  
> interesting
> to know the actual formula for the denatured alcohol that Stefan is  
> using.
> Clearly the stuff sold as denatured alcohol here in the US is nasty  
> stuff,
> and it will definitely attack ABS.  True PGA is next to harmless on ABS.
> http://www.logwell.com/tech/servtips/cleaning.html
> http://www.logwell.com/tech/servtips/CDA_formulas.html
> Syd H. Levine
> AnaLog Services, Inc.
> Phone:  (270) 276-5671
> Telefax:  (270) 276-5588
> E-mail:  analog@...
> Web URL:  www.logwell.com


I'm also glad the mystery is solved, i was starting to believe some people  
must have been drinking the ethanol when it attacked their plastics, but  
you guys are not crazy after all, it is just your suppliers mixing nasty  
stuff in there rendering it useless.

I will pester the chemicals shop people until they surrender either the  
name of the supplier or the denaturing agent, i promise. But i will have  
to wait until i need to make a purchase, to aid in loosening their tongue.  
They dispense all chemicals in the shop from larger tanks so i do not know  
what manufacturer it comes from. It may even be different from the usual  
stuff that you get in DIY stores.
I have used denatured ethanol in a tin can from a paint manufacturer  
before, and it was the same on plastic. But i can't find a MSDS for that  
brand.

ST