Homebrew PCBs

Hi,

say, must i get titanium grade 2 (or 1) for CuCl resistance or is Grade 5  
(Ti-6AL-4V) allright? It has 6% Aluminum and 4% Vanadium? in it, will that  
be a corrosion problem?

thanks

ST

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

From: "Stefan Trethan" <stefan_trethan@...>
To: <homebrew_pcbs@yahoogroups.com>
Sent: Saturday, March 12, 2005 12:05 PM
Subject: [Homebrew_PCBs] titanium grades


>
>
> Hi,
>
> say, must i get titanium grade 2 (or 1) for CuCl resistance or is Grade 5
> (Ti-6AL-4V) allright? It has 6% Aluminum and 4% Vanadium? in it, will that
> be a corrosion problem?

It'll dissolve the Al content, I would think. The Vanadium should be OK.

Leon

On Sat, 12 Mar 2005 13:00:28 -0000, Leon Heller  
<leon.heller@...> wrote:

>
> It'll dissolve the Al content, I would think. The Vanadium should be OK.
> Leon


So no good?
I don't think missing 6% of the shaft would be acceptable (as the shaft  
should stay smooth for good bearing action).

Do you guys think it will be ok to have a 6 to 10mm titanium shaft (I'll  
polish it) running in teflon at that rpm?
Higher tube diameter means same pressure with lower RPM, right? I'd have  
some sewage tubes (50 or 60mm) which i could use.
Matching the motor is not a problem (might use a pulley and belt if i find  
something suitable to have the motor in a box at the side or direct  
drive/straight with hose as coupler).

I haven't worked with titanium or teflon before so i will see.. wonder if  
teflon can be drilled with standard tools...
What bending strength has titanium? aluminum-like?

I'm hoping to balance the rotor like a aircraft prop, but it will not  
reflect the weight when wet so it must still be good precision work. Oh  
well, the proof of concept worked ok with no care...

wondering if i must make some sort of "sump" in the etcher, to provide  
enough depth for the tube to suck in etchant (it makes a vortex that  
drives it out), i don't want to have more than 2 liters or so in the  
etcher.

The mechanical setup seems not too difficult (just a reliability issue)  
seeing the bucket approach works, the hard part will be the  
nozzles/uniformity so i must select a tubing where i have/get enough and  
figure out a way to attach endcaps with little fuss.

I don't like the idea of commercial nozzles, as it seem expensive, and too  
big for the device. Also, it isn't sure nozzles meant for static  
application will create a fan pattern when rotating.

I decided to go for a single sraying tube and only one sided application  
for now. It will be hard enough this way, and i hope i don't regret that  
limitation later. Oh well, the first version is never perfect anyway...

ST

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

From: "Stefan Trethan" <stefan_trethan@...>
To: <Homebrew_PCBs@yahoogroups.com>
Sent: Saturday, March 12, 2005 1:40 PM
Subject: Re: [Homebrew_PCBs] titanium grades


>
> On Sat, 12 Mar 2005 13:00:28 -0000, Leon Heller
> <leon.heller@...> wrote:
>
>>
>> It'll dissolve the Al content, I would think. The Vanadium should be OK.
>> Leon
>
>
> So no good?
> I don't think missing 6% of the shaft would be acceptable (as the shaft
> should stay smooth for good bearing action).
>
> Do you guys think it will be ok to have a 6 to 10mm titanium shaft (I'll
> polish it) running in teflon at that rpm?
> Higher tube diameter means same pressure with lower RPM, right? I'd have
> some sewage tubes (50 or 60mm) which i could use.
> Matching the motor is not a problem (might use a pulley and belt if i find
> something suitable to have the motor in a box at the side or direct
> drive/straight with hose as coupler).
>
> I haven't worked with titanium or teflon before so i will see.. wonder if
> teflon can be drilled with standard tools...
> What bending strength has titanium? aluminum-like?

Titanium is *very* stiff, more like steel than Al. It's difficult to 
machine. Why not use a plastic shaft, something like Delrin should be OK?


Leon
--
Leon Heller, G1HSM
http://www.geocities.com/leon_heller

On Sat, 12 Mar 2005 13:57:27 -0000, Leon Heller  
<leon.heller@...> wrote:

>
> Titanium is *very* stiff, more like steel than Al. It's difficult to
> machine. Why not use a plastic shaft, something like Delrin should be OK?
> Leon
> --
> Leon Heller, G1HSM
> http://www.geocities.com/leon_heller


Oh well, that would need a larger diameter.
I guess it would be ok if i go with the bigger diameter pipe.

But then, i don't need to machine it at all (maybe saw to length and  
polish as well as smooth the bottom end that rides in the bearing, so i  
might as well use titanium if i get it surplus.


Which diameter would a delrin shaft need to be if we say the tube is 50mm  
dia and 20cm long? the shaft is supportint the tube via the two endplates.  
How would i make the bearing with a delrin shaft? Does it run well in ptfe?


I also would have a carbon fiber tube from model building with 8mm dia for  
a shaft that could easily take the load, but i don't know how i would make  
the bearing if i use that. It is carbon fiber in some resin, probably  
epoxy, wall thickness is about a mm.

ST

>
>Which diameter would a delrin shaft need to be if we say the tube is 50mm
>dia and 20cm long? the shaft is supportint the tube via the two endplates.
>How would i make the bearing with a delrin shaft? Does it run well in ptfe?

You may be aware of this, but some plastics, like nylon, absorb water 
nicely, and swell.

On Sat, 12 Mar 2005 10:24:58 -0500, Dave VanHorn <dvanhorn@...>  
wrote:

>
> You may be aware of this, but some plastics, like nylon, absorb water
> nicely, and swell.


Yes, i was aware of nylon, i know PE ans PP and PVC are ok with water, and  
i expect PTFE to be ok.

Do you know about delrin (isn't it similar to nylon??)

thanks

ST

At 10:34 AM 3/12/2005, Stefan Trethan wrote:

>On Sat, 12 Mar 2005 10:24:58 -0500, Dave VanHorn <dvanhorn@...>
>wrote:
>
> >
> > You may be aware of this, but some plastics, like nylon, absorb water
> > nicely, and swell.
>
>
>Yes, i was aware of nylon, i know PE ans PP and PVC are ok with water, and
>i expect PTFE to be ok.
>
>Do you know about delrin (isn't it similar to nylon??)

AFAIK, delrin is ok..  We had an embarrassing incident with a bearing that 
was nylon vs delrin, because the engineer in charge insisted on using the 
materials with the lowest possible coefficient of friction.  The prototype 
worked fine in wisconsin in the winter, but failed miserably at a demo. The 
bearing locked up so tight you couldn't turn it with pliers.

Did I mention that the demo was in Cancun?

On Sat, 12 Mar 2005 10:54:32 -0500, Dave VanHorn <dvanhorn@...>  
wrote:

>
> AFAIK, delrin is ok..  We had an embarrassing incident with a bearing  
> that
> was nylon vs delrin, because the engineer in charge insisted on using the
> materials with the lowest possible coefficient of friction.  The  
> prototype
> worked fine in wisconsin in the winter, but failed miserably at a demo.  
> The
> bearing locked up so tight you couldn't turn it with pliers.
> Did I mention that the demo was in Cancun?


ok thanks.

ST

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

From: "Stefan Trethan" <stefan_trethan@...>
To: <Homebrew_PCBs@yahoogroups.com>
Sent: Saturday, March 12, 2005 3:03 PM
Subject: Re: [Homebrew_PCBs] titanium grades


>
> On Sat, 12 Mar 2005 13:57:27 -0000, Leon Heller
> <leon.heller@...> wrote:
>
>>
>> Titanium is *very* stiff, more like steel than Al. It's difficult to
>> machine. Why not use a plastic shaft, something like Delrin should be OK?
>> Leon
>> --
>> Leon Heller, G1HSM
>> http://www.geocities.com/leon_heller
>
>
> Oh well, that would need a larger diameter.
> I guess it would be ok if i go with the bigger diameter pipe.
>
> But then, i don't need to machine it at all (maybe saw to length and
> polish as well as smooth the bottom end that rides in the bearing, so i
> might as well use titanium if i get it surplus.
>
>
> Which diameter would a delrin shaft need to be if we say the tube is 50mm
> dia and 20cm long? the shaft is supportint the tube via the two endplates.
> How would i make the bearing with a delrin shaft? Does it run well in 
> ptfe?

I just checked Delrin's properties, it's no good in acid or alkaline 
solutions:

http://www.upchurch.com/TechInfo/matDelrin.asp

It's a pity, as it's otherwise a very good material.

>
>
> I also would have a carbon fiber tube from model building with 8mm dia for
> a shaft that could easily take the load, but i don't know how i would make
> the bearing if i use that. It is carbon fiber in some resin, probably
> epoxy, wall thickness is about a mm.

Carbon fibre uses a similar epoxy resin to fibre-glass.

Leon

On Sat, 12 Mar 2005 16:33:07 -0000, Leon Heller  
<leon.heller@...> wrote:

>
> I just checked Delrin's properties, it's no good in acid or alkaline
> solutions:
> http://www.upchurch.com/TechInfo/matDelrin.asp
> It's a pity, as it's otherwise a very good material.
>

Thanks a lot.
I especially like that:
" It is best to use Delrin with neutral pH aqueous solutions or organic  
solutions for guaranteed best performance."
As if i could choose the liquid to suit their plastic, silly people...

>>
>>
>> I also would have a carbon fiber tube from model building with 8mm dia  
>> for
>> a shaft that could easily take the load, but i don't know how i would  
>> make
>> the bearing if i use that. It is carbon fiber in some resin, probably
>> epoxy, wall thickness is about a mm.

> Carbon fibre uses a similar epoxy resin to fibre-glass.
> Leon

Seems so.
But i have not the slightest idea how i could make bearings for the carbon  
fiber tube...

ST

Leon Heller wrote:
> 
> It's a pity, as it's otherwise a very good material.

http://www.machinist-materials.com/comparison_table_for_plastics.htm

Try this table, it has many parameters for many types of plastic.  They 
also sell this stuff, but I've never ordered from them.  I was looking 
at this the other day because a guy in #electronics on irc.freenode.net 
(shameless plug for my channel:) was going on about Delrin and how great 
it was.

At 11:45 AM 3/12/2005, Stefan Trethan wrote:

>On Sat, 12 Mar 2005 16:33:07 -0000, Leon Heller
><leon.heller@...> wrote:
>
> >
> > I just checked Delrin's properties, it's no good in acid or alkaline
> > solutions:
> > http://www.upchurch.com/TechInfo/matDelrin.asp
> > It's a pity, as it's otherwise a very good material.
> >
>
>Thanks a lot.
>I especially like that:
>" It is best to use Delrin with neutral pH aqueous solutions or organic
>solutions for guaranteed best performance."
>As if i could choose the liquid to suit their plastic, silly people...

Hmmm...
I seem to remember, that when we put equipment in at Dole Pineapple, Delrin 
and stainless steel were the only two materials we could use.  That stuff 
is VERY acid, and has nasty enzymes.

On another note,

while looking for the ptfe and stuff i've come across a ebay supplier in  
Austria that sells various transparent plastic plates at very reasonable  
prices (say around 10eur for the whole tank).

Initially i planned to make the sprayer bottom/walls out of glass as is my  
current etcher, but for that price i think i would prefer plastic,  
especially as there's now fast rotating parts and i don't want breakage.


He offers:

PMMA
S A N  (Styrol-Acrylnitril)
Polycarbonat / Lexan

PMMA and Lexan should be fine with HCl, i couldn't find anything about SAN.

So, what's best, what should i buy?

I must do some machining to the top plate (a 50mm or so hole with a hole  
cutter, a long slot for the PCB holder, 3 holes for motor and mounting).
My previous experience with unknown clear material and machining was very  
bad, it shattered when driling and cutting wasn't nice. I received some  
tips in the meanwhile (like using a steep-angled drill) and i have a lexan  
datasheet that gives suggestions on how to machine it.

It would be great if someone has experience with that stuff and can give  
me suggestions what to select.

My plan is to make the tank triangular, but with rectangular base and top  
still. one "free" corner of the top plate could be used to mount the motor  
pointing up, under the plate, and with a pulley/belt on top of the machine  
to drive the sprayer).


Also, which of the materials is best for gluing/welding? i'd have a heat  
gun for welding but have never done that. I was satisfied with the  
silicone-glued glass tank and i would use the same method if there isn't  
something much better.

Thanks

ST

--- In Homebrew_PCBs@yahoogroups.com, Jason Giglio <jgiglio@n...> wrote:

> http://www.machinist-materials.com/comparison_table_for_plastics.htm
> 
> Try this table, it has many parameters for many types of plastic.  

Excellent. I added it to the links, remember you can add to Links, too.

Also this link Stefan uploaded:

Cole-Parmer Chemical Compatibility
Lists loads of materials and chemicals and shows if they are compatible
http://www.coleparmer.com/techinfo/ChemComp.asp

You can select the plastic and/or chemicals and/or ratings. I just put
in Copper Chloride and chose Resistance A-Excellent and got a nice
simple list of things with excellent resistance to Copper Chloride.
Including ceramic magnets, which I did not know. Anyone know what
materials those cheap submergeable water fountain pumps are made out of?

Steve Greenfield

On Mon, 14 Mar 2005 17:22:49 -0000, Steve <alienrelics@...> wrote:

>
> You can select the plastic and/or chemicals and/or ratings. I just put
> in Copper Chloride and chose Resistance A-Excellent and got a nice
> simple list of things with excellent resistance to Copper Chloride.
> Including ceramic magnets, which I did not know. Anyone know what
> materials those cheap submergeable water fountain pumps are made out of?
> Steve Greenfield


That's interesting.

The only "metal" object exposed to water in Eheim aquarium/fountain pumps  
is the magnet, they have a ceramic shaft.

But then, the pressure from those pumps is minimal.

Bad thing cole-parmer has N/A for lexan/polycarbonate (no data), But  
Hydrochloric acid is "good" so i hope i'm ok.
I suggest always check for HCl too if you check for CuCl as it isn't sure  
it's included...

Steve, do you know about lexan machining/gluing? Should i ask at  
propmasters?


ST

--- In Homebrew_PCBs@yahoogroups.com, "Stefan Trethan"
<stefan_trethan@g...> wrote:
> On Mon, 14 Mar 2005 17:22:49 -0000, Steve <alienrelics@y...> wrote:
> 
> >
> > You can select the plastic and/or chemicals and/or ratings. I just put
> > in Copper Chloride and chose Resistance A-Excellent and got a nice
> > simple list of things with excellent resistance to Copper Chloride.
> > Including ceramic magnets, which I did not know. Anyone know what
> > materials those cheap submergeable water fountain pumps are made
out of?
> > Steve Greenfield
> 
> 
> That's interesting.
> 
> The only "metal" object exposed to water in Eheim aquarium/fountain
pumps  
> is the magnet, they have a ceramic shaft.

Depends on brand as all that I've taken apart had what looked like
stainless steel or chromed shafts. I've been picking up old ones at
thrift stores, have only taken a couple of them apart.

> But then, the pressure from those pumps is minimal.

I wasn't thinking for a spray nozzle, but rather just to keep the acid
moving. For low backpressure, they have a pretty darn high flowrate.

> Bad thing cole-parmer has N/A for lexan/polycarbonate (no data), But  
> Hydrochloric acid is "good" so i hope i'm ok.
> I suggest always check for HCl too if you check for CuCl as it isn't
sure  
> it's included...

This is true and occured to me after sending that message.

> Steve, do you know about lexan machining/gluing? Should i ask at  
> propmasters?

Ask on Propmasters.

Steve Greenfield

Steve wrote:

  Anyone know what
> materials those cheap submergeable water fountain pumps are made out of?
> 
> Steve Greenfield
> 
> 
Not sure about the materials, but Harbor Freight often has 
their smallest (~150 GPH) on sale for $7.00 or so.  Might be 
worth a try!

Norm


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Stefan Trethan wrote:

> But then, the pressure from those pumps is minimal.
> 

I know nothing about this thread except, I have a pond pump with ceramic 
shaft magnet, the magnet is in a plastic jacket btw, it is a 12mm 
diameter magnet, about 22mm fan on the end, and produces a column of 
water 10mm in diameter at about 1.5 meters.

was on sale at local fish pond place at 30ukp/60$

surely thats more than enough flow for an etchant?

On Tue, 15 Mar 2005 10:32:03 +0000, Lez <lez.briddon@...> wrote:

>
> I know nothing about this thread except, I have a pond pump with ceramic
> shaft magnet, the magnet is in a plastic jacket btw, it is a 12mm
> diameter magnet, about 22mm fan on the end, and produces a column of
> water 10mm in diameter at about 1.5 meters.
> was on sale at local fish pond place at 30ukp/60$
> surely thats more than enough flow for an etchant?


1.5meters is 0.15bar, while 1bar is more or less the lower, lower limit of  
reasonable spray etching pressure.
(and the 1.5 meters is usually at almost zero volume)

We were not talking about only pumping, we need pressure for spraying.

But thanks anyway, your pump shows there are etchant-compatible pumps out  
there, just not suited for spraying.

ST

Actually, I -was- only talking about pumping the etchant around, not
spraying it. I'm thinking of something just to get the etchant moving.

Steve Greenfield

--- In Homebrew_PCBs@yahoogroups.com, "Stefan Trethan"
<stefan_trethan@g...> wrote:
...
> We were not talking about only pumping, we need pressure for spraying.
> 
> But thanks anyway, your pump shows there are etchant-compatible
pumps out  
> there, just not suited for spraying.

On Tue, 15 Mar 2005 21:22:30 -0000, Steve <alienrelics@...> wrote:

>
> Actually, I -was- only talking about pumping the etchant around, not
> spraying it. I'm thinking of something just to get the etchant moving.
> Steve Greenfield


oh, then i mixed the threads up, sorry.

As said, the eheim aquarium pump is the same, ceramic shaft, no metals.
we have a second report of such a pump now so they seem common....

I guess in a big shop you can go and take the pumps apart, the one i have  
has sort of a bajonett mechanism.

ST

--- In Homebrew_PCBs@yahoogroups.com, "Stefan Trethan"
<stefan_trethan@g...> wrote:
> On Tue, 15 Mar 2005 21:22:30 -0000, Steve <alienrelics@y...> wrote:
> 
> >
> > Actually, I -was- only talking about pumping the etchant around, not
> > spraying it. I'm thinking of something just to get the etchant moving.
> > Steve Greenfield
> 
> 
> oh, then i mixed the threads up, sorry.

No, my fault for not changing the subject line.

> As said, the eheim aquarium pump is the same, ceramic shaft, no metals.
> we have a second report of such a pump now so they seem common....
> 
> I guess in a big shop you can go and take the pumps apart, the one i
have  
> has sort of a bajonett mechanism.

At least some of mine have metal shafts, I guess I'll be taking all of
them apart now.

Steve Greenfield