Homebrew PCBs

Hi,

I was wondering if anyone has considered or tried using a heat press
for the toner transfer method. They are usually used for transferring
images onto t-shirts.

At 10:44 am ((PDT)) Mon Jun 18, 2007, erantapaa wrote:
>I was wondering if anyone has considered or tried using a heat press
>for the toner transfer method.

I wonder if anyone ever looks into the archives
before expressing their curiosity ;-)

>They are usually used for transferring
>images onto t-shirts.

Oh, sorry, was that meant to be a "good idea"(TM).

How does your typical T-shirt press compare with
a smoothing iron or a laminator for pressure?
(That's units of 'force per area' not just force.)

And how important does pressure seem to be
using a smoothing iron, where it is completely
under the operator's control, though not
necessarily very closely controlled?

(And for the laminators, the force is so high it
is difficult to get the board in - and it is concentrated
along a line, so the resulting pressure is quite high.)

How does a press compare with a medium-quality
business laminator for price?

So, unless you already have a T-shirt press
or you are thinking of setting up a T-shirt
business alongside PCB production,
it is basically a non-starter.


Regards, LenW
-- 
   Content of a follow-up post should exceed quoted content. (rfc1855)

> Hi,
> 
> I was wondering if anyone has considered or tried using a 
> heat press for the toner transfer method. They are usually 
> used for transferring images onto t-shirts.


There was a thread about it a while back (A year? More?).

Track down Tom Gootee's page, I think it was him who tried it.  Might be
some results there.

Apparently it's a bit hard to apply enough pressure.  Clamping causes
distortion, so you get pressure in one spot but not another, etc.  Dumping
weights on top didn't seem to help either.

Tony

Tony Smith wrote:
>> Hi,
>>
>> I was wondering if anyone has considered or tried using a 
>> heat press for the toner transfer method. They are usually 
>> used for transferring images onto t-shirts.
>>     
>
>
> There was a thread about it a while back (A year? More?).
>
> Track down Tom Gootee's page, I think it was him who tried it.  Might be
> some results there.
>
> Apparently it's a bit hard to apply enough pressure.  Clamping causes
> distortion, so you get pressure in one spot but not another, etc.  Dumping
> weights on top didn't seem to help either.
>
> Tony
>
>   
I use a heat press of sorts ... I make small PCB's  no larger than 3x4 
inches ... I have a 4x6x1 inch piece of steel ... I took a piece of 
aluminum oxide abrasive paper (8x10 inch) laid it flat on the top of my 
table saw and dragged the steel plate back and forth across the abrasive 
paper until it was flat and shiny (I actually made a motor driven 
fixture to do the dragging in a random fashion for me ... it took 
several days and several sheets of abrasive) ... I use a hot plate to 
heat the steel plate until it is the temp I want (usually 350 to 400 
degrees F) using a thermocouple attached to the steel plate to measure 
the temp ... I have ready a flat wooden surface that has the blank 
PCB/laser image/plane paper  ready to receive the hot steel plate ... I 
place the steel plate on the top cover paper and clamp the steel plate 
with about 300 pounds of pressure (about 25 pounds per square inch) 
using a wide mouth vice grip pliers (this is moderate pressure ... you 
can easily get 400 to 500 pounds of pressure) ... I leave it clamped for 
about 1 minute then off to the water soak ... I get good resolution and 
consistent results ... the flat surface insures an even distribution of 
pressure ... the thick steel plate holds the heat and won't distort 
under the moderate pressures and temps  used ...
Jim KI6MZ

>
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>

> > There was a thread about it a while back (A year? More?).
> >
> > Track down Tom Gootee's page, I think it was him who tried 
> it.  Might 
> > be some results there.
> >
> > Apparently it's a bit hard to apply enough pressure.  
> Clamping causes 
> > distortion, so you get pressure in one spot but not another, etc.  
> > Dumping weights on top didn't seem to help either.
> >
> > Tony
> >
> >   
> I use a heat press of sorts ... I make small PCB's  no larger 
> than 3x4 inches ... I have a 4x6x1 inch piece of steel ... I 
> took a piece of aluminum oxide abrasive paper (8x10 inch) 
> laid it flat on the top of my table saw and dragged the steel 
> plate back and forth across the abrasive paper until it was 
> flat and shiny (I actually made a motor driven fixture to do 
> the dragging in a random fashion for me ... it took several 
> days and several sheets of abrasive) ... I use a hot plate to 
> heat the steel plate until it is the temp I want (usually 350 
> to 400 degrees F) using a thermocouple attached to the steel 
> plate to measure the temp ... I have ready a flat wooden 
> surface that has the blank PCB/laser image/plane paper  ready 
> to receive the hot steel plate ... I place the steel plate on 
> the top cover paper and clamp the steel plate with about 300 
> pounds of pressure (about 25 pounds per square inch) using a 
> wide mouth vice grip pliers (this is moderate pressure ... 
> you can easily get 400 to 500 pounds of pressure) ... I leave 
> it clamped for about 1 minute then off to the water soak ... 
> I get good resolution and consistent results ... the flat 
> surface insures an even distribution of pressure ... the 
> thick steel plate holds the heat and won't distort under the 
> moderate pressures and temps  used ...
> Jim KI6MZ


Sounds like you've got too much time on your hands, you need a hobby  :)

I can't remember what the original thread was about, but it was something
like a clothes press.  I guess a lot of people start eyeing the sandwich
maker in their kitchen as well...

That chunk of steel you have won't bend easily, one problem solved.  How
long does it take to heat up?  Obvious for making a batch it'll be faster
than a laminator, but for one-offs?

So for double sided you just flip the board over afterwards?

(BTW, gluing the sandpaper to a sheet of glass works well for lapping stuff,
in case you don't have a cast iron table saw handy.  Glass is very flat.)

Tony

Tony Smith wrote:
>>> There was a thread about it a while back (A year? More?).
>>>
>>> Track down Tom Gootee's page, I think it was him who tried 
>>>       
>> it.  Might 
>>     
>>> be some results there.
>>>
>>> Apparently it's a bit hard to apply enough pressure.  
>>>       
>> Clamping causes 
>>     
>>> distortion, so you get pressure in one spot but not another, etc.  
>>> Dumping weights on top didn't seem to help either.
>>>
>>> Tony
>>>
>>>   
>>>       
>> I use a heat press of sorts ... I make small PCB's  no larger 
>> than 3x4 inches ... I have a 4x6x1 inch piece of steel ... I 
>> took a piece of aluminum oxide abrasive paper (8x10 inch) 
>> laid it flat on the top of my table saw and dragged the steel 
>> plate back and forth across the abrasive paper until it was 
>> flat and shiny (I actually made a motor driven fixture to do 
>> the dragging in a random fashion for me ... it took several 
>> days and several sheets of abrasive) ... I use a hot plate to 
>> heat the steel plate until it is the temp I want (usually 350 
>> to 400 degrees F) using a thermocouple attached to the steel 
>> plate to measure the temp ... I have ready a flat wooden 
>> surface that has the blank PCB/laser image/plane paper  ready 
>> to receive the hot steel plate ... I place the steel plate on 
>> the top cover paper and clamp the steel plate with about 300 
>> pounds of pressure (about 25 pounds per square inch) using a 
>> wide mouth vice grip pliers (this is moderate pressure ... 
>> you can easily get 400 to 500 pounds of pressure) ... I leave 
>> it clamped for about 1 minute then off to the water soak ... 
>> I get good resolution and consistent results ... the flat 
>> surface insures an even distribution of pressure ... the 
>> thick steel plate holds the heat and won't distort under the 
>> moderate pressures and temps  used ...
>> Jim KI6MZ
>>     
>
>
> Sounds like you've got too much time on your hands, you need a hobby  :)
>   
If you are going to do a process several times, you will always spend 
LESS total time if you take the time up front to build the proper tools 
... the steel I used was a mill "cut-off" so it had some ripples in it 
... if the steel had been cut when the steel was cool, the lapping would 
be done in 30 to 90 minutes
> I can't remember what the original thread was about, but it was something
> like a clothes press.  I guess a lot of people start eyeing the sandwich
> maker in their kitchen as well...
>
> That chunk of steel you have won't bend easily, one problem solved.  How
> long does it take to heat up?  Obvious for making a batch it'll be faster
> than a laminator, but for one-offs?
>   
It takes about 10 minutes from room temp the first use ... I always 
allow the temp to over-shoot by about 20 degrees then set the steel 
block on a narrow strip of wood ... when the temp comes back down to the 
target   i use it ... the thermocouple is on the top of the steel so 
there is a temp gradient across the steel
> So for double sided you just flip the board over afterwards?
>   
I do one side at a time ... I spray paint side 2 .. image transfer and 
etch side 1 ... then spray paint side 1 ... image transfer and etch side 
2 ... I do drill alignment holes for registration

> (BTW, gluing the sandpaper to a sheet of glass works well for lapping stuff,
> in case you don't have a cast iron table saw handy.  Glass is very flat.)
>   
> Tony
>
>
>
> Be sure to visit the group home and check for new Links, Files, and Photos:
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>
>
>
>
>

On 6/21/07, Jim Hutchinson <jhutch17@...> wrote:
> If you are going to do a process several times, you will always spend
> LESS total time if you take the time up front to build the proper tools
> ... the steel I used was a mill "cut-off" so it had some ripples in it
> ... if the steel had been cut when the steel was cool, the lapping would
> be done in 30 to 90 minutes

> It takes about 10 minutes from room temp the first use ... I always
> allow the temp to over-shoot by about 20 degrees then set the steel
> block on a narrow strip of wood ... when the temp comes back down to the
> target   i use it ... the thermocouple is on the top of the steel so
> there is a temp gradient across the steel
> > So for double sided you just flip the board over afterwards?
> >
> I do one side at a time ... I spray paint side 2 .. image transfer and
> etch side 1 ... then spray paint side 1 ... image transfer and etch side
> 2 ... I do drill alignment holes for registration

Aluminum might be a better choice it conducts heat much better.
I find it amazing that you actually built a motor for the lapping and
let it run for several days ;-)

ST

> > LESS total time if you take the time up front to build the proper 
> > tools ... the steel I used was a mill "cut-off" so it had 
> some ripples 
> > in it ... if the steel had been cut when the steel was cool, the 
> > lapping would be done in 30 to 90 minutes
> 
> > It takes about 10 minutes from room temp the first use ... I always 
> > allow the temp to over-shoot by about 20 degrees then set the steel 
> > block on a narrow strip of wood ... when the temp comes 
> back down to the
> > target   i use it ... the thermocouple is on the top of the steel so
> > there is a temp gradient across the steel
> > > So for double sided you just flip the board over afterwards?
> > >
> > I do one side at a time ... I spray paint side 2 .. image 
> transfer and 
> > etch side 1 ... then spray paint side 1 ... image transfer and etch 
> > side
> > 2 ... I do drill alignment holes for registration
> 
> Aluminum might be a better choice it conducts heat much better.
> I find it amazing that you actually built a motor for the 
> lapping and let it run for several days ;-)
> 
> ST


I built a similar rig to grind glass for a telescope mirror.  Doing it by
hand gets a bit boring after a while...

Aluminium would distort more (more flexible than steel), so you'd need to
make the plate smaller (small boards), or used a thick piece of metal, which
might take away the fast heating.

Still, the answer is now "Yes you can, got a big lump of steel handy?".

Good idea for small scale production.  I tend to do one-offs every so often,
so I'll stick with the printer fuser laminator.

Tony

Stefan Trethan wrote:
> On 6/21/07, Jim Hutchinson <jhutch17@...> wrote:
>   
>> If you are going to do a process several times, you will always spend
>> LESS total time if you take the time up front to build the proper tools
>> ... the steel I used was a mill "cut-off" so it had some ripples in it
>> ... if the steel had been cut when the steel was cool, the lapping would
>> be done in 30 to 90 minutes
>>     
>
>   
>> It takes about 10 minutes from room temp the first use ... I always
>> allow the temp to over-shoot by about 20 degrees then set the steel
>> block on a narrow strip of wood ... when the temp comes back down to the
>> target   i use it ... the thermocouple is on the top of the steel so
>> there is a temp gradient across the steel
>>     
>>> So for double sided you just flip the board over afterwards?
>>>
>>>       
>> I do one side at a time ... I spray paint side 2 .. image transfer and
>> etch side 1 ... then spray paint side 1 ... image transfer and etch side
>> 2 ... I do drill alignment holes for registration
>>     
>
> Aluminum might be a better choice it conducts heat much better.
> I find it amazing that you actually built a motor for the lapping and
> let it run for several days ;-)
>
> ST
>   
Hello ST ... I didn't build a motor ... I used an existing motor 
attached to a simple wooden frame ... The motor already had a 10 inch 
pulley ... the motor was a DC gear head motor so I could vary the speed 
... it took all of 30 minutes to build the fixture ... along with some 
"C" clamps and wood screws ... when I tried to lap by hand, It became 
clear that it was going to take more than an hour or so ... it was in 
the summertime and my garage is hot 100+ degrees ... so I made the 
fixture , turned it on and come in to the cool house and had a glass of 
iced tea ... ... the man at the metal shop gave me the 4x6x1 hunk metal 
... I later bought a larger 6x10 inch piece of steel for just a few 
dollars ... it was smoother and lapped in a couple of hours ... I rarely 
make more than two of anything and heating the steel clamping it down on 
the transfer stack is faster than a laminator or ironing and most 
important of all, I have control of all the important parameters and few 
limitations ...
I didn't use Aluminum because I thought strength (or resistance to 
distortion) was more important and the steel was free ...
Jim KI6MZ

>
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>
>
>
>
>
>

Guys

I have been facing a problem in getting 15x10 sq.cm
single side boards etched under 5 mins. I use
commercial grade FeCl3 and heat up the water to
boiling point. Then add it in a plastic tray having
FeCl3 and after mixing thoroughly, drop the boards.

I keep enough solution in the tray to just have the
board below the surface at an uniform 4mm.

But I have to heating mechanism due to which the
solution cools down after 2 mins. I also constantly,
manually rock the tray a little to remove "dust"
formed on the boards.

Currently this is taking me more than 20 mins for the
etching to complete !

I think I am wasting too much time behind an
ineffective/inefficient etching process - the
equipments I am using ssem to be far from optimal..

Any tips on ultrafast (sub 10 mins) etching ?

KamalS



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

From: "Kamal Shankar" <kbshankar2000@...>
To: <Homebrew_PCBs@yahoogroups.com>
Sent: Monday, June 25, 2007 6:32 PM
Subject: [Homebrew_PCBs] Etching Tips and Tricks


> Guys
>
> I have been facing a problem in getting 15x10 sq.cm
> single side boards etched under 5 mins. I use
> commercial grade FeCl3 and heat up the water to
> boiling point. Then add it in a plastic tray having
> FeCl3 and after mixing thoroughly, drop the boards.
>
> I keep enough solution in the tray to just have the
> board below the surface at an uniform 4mm.
>
> But I have to heating mechanism due to which the
> solution cools down after 2 mins. I also constantly,
> manually rock the tray a little to remove "dust"
> formed on the boards.
>
> Currently this is taking me more than 20 mins for the
> etching to complete !
>
> I think I am wasting too much time behind an
> ineffective/inefficient etching process - the
> equipments I am using ssem to be far from optimal..
>
> Any tips on ultrafast (sub 10 mins) etching ?

I use a similar technique (the etchant is deeper, though), and my boards 
take less than 10 minutes to etch. Have you got the right concentration for 
the FeCl3?

Leon

I pre-heat the etchant (in it's bottle) in a few inches of hot water;
it doesn't have to be *that* hot.  However, I don't just soak the
board in etchant, I use a sponge to wipe the etchant across the board.
I did a 3"x3" board today (er, 1 or 2 oz) in just a few minutes.  The
mechanical action of the sponge really speeds up the process, but you
need more than just toner - the sponge trick is a Pulsar trick that
works with their green TRF, which seals and protects the toner.

The problem with unagitated FeCl is that the sludge left is thick and 
inhibits further reaction.  It's the reason why the spray method works well.

It's my opinion that the sludge from FeCl is worse than several of the 
alternatives.  I've come to use Amonium PerChlorate in a tank with a 
submersible aquarium pump to keep things stirred up.

The trouble with using an air pump for agitation is that it tends to 
create some aerosols that you might not want to mess with.  I lost the 
head off of every nail in a storage shed that way :)

DJ Delorie wrote:

> I pre-heat the etchant (in it's bottle) in a few inches of hot water;
> it doesn't have to be *that* hot.  However, I don't just soak the
> board in etchant, I use a sponge to wipe the etchant across the board.
> I did a 3"x3" board today (er, 1 or 2 oz) in just a few minutes.  The
> mechanical action of the sponge really speeds up the process, but you
> need more than just toner - the sponge trick is a Pulsar trick that
> works with their green TRF, which seals and protects the toner.
>
>
> 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
>
>
>
>

> I use a similar technique (the etchant is deeper,
> though), and my boards 
> take less than 10 minutes to etch. Have you got the
> right concentration for 
> the FeCl3?

A question I have been dreading - right concentration
!

As I mentioned.. I am using a commercial grade, and by
that I think the retailer meant it has as much FeCl3
as everything else...

Is that a wrong thought ?

But I still mix about a table spoon in 250ml of hot
water.

Also.. does the depth of the etchant matter ?

KamalS


 
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> few minutes.  The
> mechanical action of the sponge really speeds up the
> process, but you
> need more than just toner - the sponge trick is a
> Pulsar trick that
> works with their green TRF, which seals and protects
> the toner.

I think this would be too risky for us TT types who
use the Flyers for transfer and often have to
"correct" bad traces by a Sharpie ?


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Kamal Shankar <kbshankar2000@...> writes:
> I think this would be too risky for us TT types who use the Flyers
> for transfer and often have to "correct" bad traces by a Sharpie ?

Well, it's worth a try anyway, but even with the special Pulsar paper,
Pulsar strongly recommends adding the TRF to seal the toner.

http://www.pulsarprofx.com/PCB/a_Pages/5_Support/5b_Tips_Tricks/Tips_Tricks.html#Anchor-49575

Have you tried the pulsar paper?  Or, you can buy just the green TRF
from digikey for $9 for an 8"x15' roll.

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

From: "Kamal Shankar" <kbshankar2000@...>
To: <Homebrew_PCBs@yahoogroups.com>
Sent: Tuesday, June 26, 2007 2:28 AM
Subject: Re: [Homebrew_PCBs] Etching Tips and Tricks


>> I use a similar technique (the etchant is deeper,
>> though), and my boards 
>> take less than 10 minutes to etch. Have you got the
>> right concentration for 
>> the FeCl3?
> 
> A question I have been dreading - right concentration
> !
> 
> As I mentioned.. I am using a commercial grade, and by
> that I think the retailer meant it has as much FeCl3
> as everything else...
> 
> Is that a wrong thought ?
> 
> But I still mix about a table spoon in 250ml of hot
> water.

That is nowhere near concentrated enough!

> 
> Also.. does the depth of the etchant matter ?

Not really, I just like to have plenty of it.

Leon

> > But I still mix about a table spoon in 250ml of
> hot
> > water.
> 
> That is nowhere near concentrated enough!

Oh no !

What IS the right proportion?

Do you use lab grade or commercial grade?

> > Also.. does the depth of the etchant matter ?
> 
> Not really, I just like to have plenty of it.

How do you deal with excess etchant?

Have you ever tried anything else other than FeCl3?

KamalS


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

From: "Kamal Shankar" <kbshankar2000@...>
To: <Homebrew_PCBs@yahoogroups.com>
Sent: Tuesday, June 26, 2007 5:49 PM
Subject: Re: [Homebrew_PCBs] Etching Tips and Tricks


>> > But I still mix about a table spoon in 250ml of
>> hot
>> > water.
>>
>> That is nowhere near concentrated enough!
>
> Oh no !
>
> What IS the right proportion?

Something like 500g/litre.

>
> Do you use lab grade or commercial grade?

I just buy the stuff from Mega Electronics, or one of their distributors.

>
>> > Also.. does the depth of the etchant matter ?
>>
>> Not really, I just like to have plenty of it.
>
> How do you deal with excess etchant?

Pour it down the lavatory.

>
> Have you ever tried anything else other than FeCl3?

I used ammonium persulphate many years ago, it doesn't last long once it's 
made up as a solution.

Leon

I discovered about 15 years ago a technique which has worked 
flawlessly for me and etches in about 5 min.:  Float the board, 
copperside down, on the etchant.  The surface tension of the FeCL3 
easily supports the board.  As the copper disolves into the FeCL3 
the Fe, which is heavier, drops to the bottom of the container.  
This leaves fresh etchant on the surface of the board all the time.  
Best of all, NO AGITATION is required!  On FR4, you can see the 
progress just fine through the board.  Heating (luke warm) the FeCL3 
first does help, but we all know that.  Just drop the board on to 
the etchant, walk away for 5 minutes, and the board is done.  Give 
it a try next time.

Jim 

--- In Homebrew_PCBs@yahoogroups.com, Kamal Shankar 
<kbshankar2000@...> wrote:
>
> Guys
> 
> I have been facing a problem in getting 15x10 sq.cm
> single side boards etched under 5 mins. I use
> commercial grade FeCl3 and heat up the water to
> boiling point. Then add it in a plastic tray having
> FeCl3 and after mixing thoroughly, drop the boards.
> 
> I keep enough solution in the tray to just have the
> board below the surface at an uniform 4mm.
> 
> But I have to heating mechanism due to which the
> solution cools down after 2 mins. I also constantly,
> manually rock the tray a little to remove "dust"
> formed on the boards.
> 
> Currently this is taking me more than 20 mins for the
> etching to complete !
> 
> I think I am wasting too much time behind an
> ineffective/inefficient etching process - the
> equipments I am using ssem to be far from optimal..
> 
> Any tips on ultrafast (sub 10 mins) etching ?
> 
> KamalS
> 
> 
> 
>        
> 
_____________________________________________________________________
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>

> I discovered about 15 years ago a technique which
> has worked 
> flawlessly for me and etches in about 5 min.:  Float
> the board, 
> copperside down, on the etchant.  The surface
> tension of the FeCL3 
> easily supports the board.  As the copper disolves
> into the FeCL3 
> the Fe, which is heavier, drops to the bottom of the
> container.  

Anyone else had this brainwave ?

Sounds nice ! So why do others use agitators ?

Anyone ?

> progress just fine through the board.  Heating (luke
> warm) the FeCL3 
> first does help, but we all know that.  Just drop
> the board on to 
> the etchant, walk away for 5 minutes, and the board
> is done.  Give 
> it a try next time.

How much FeCl3 you mix up with the water ?

Do you keep it heated ?

KamalS


       
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Just don't put it in, walk away, forget about it, and go to bed. That's 
the quick way to get the toner floating on the etchant. :)
Kamal Shankar wrote:

> > I discovered about 15 years ago a technique which
> > has worked
> > flawlessly for me and etches in about 5 min.: Float
> > the board,
> > copperside down, on the etchant. The surface
> > tension of the FeCL3
> > easily supports the board. As the copper disolves
> > into the FeCL3
> > the Fe, which is heavier, drops to the bottom of the
> > container.
>
> Anyone else had this brainwave ?
>
> Sounds nice ! So why do others use agitators ?
>
> Anyone ?
>

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

From: "Chris Hart" <kc8ufv@...>
To: <Homebrew_PCBs@yahoogroups.com>
Sent: Wednesday, July 25, 2007 2:21 AM
Subject: Re: [Homebrew_PCBs] Re: Etching Tips and Tricks


> Just don't put it in, walk away, forget about it, and go to bed. That's
> the quick way to get the toner floating on the etchant. :)
> Kamal Shankar wrote:
>
>> > I discovered about 15 years ago a technique which
>> > has worked
>> > flawlessly for me and etches in about 5 min.: Float
>> > the board,
>> > copperside down, on the etchant. The surface
>> > tension of the FeCL3
>> > easily supports the board. As the copper disolves
>> > into the FeCL3
>> > the Fe, which is heavier, drops to the bottom of the
>> > container.
>>
>> Anyone else had this brainwave ?
>>
>> Sounds nice ! So why do others use agitators ?

It's difficult to see when it is fully etched. The technique has actually 
been around for 30 years or so!

Leon

> > Sounds nice ! So why do others use agitators ?
> >
> > Anyone ?
> >
>

They might want to etch two sides?

ST