Homebrew PCBs

Helo all.

I just had a few random thoughts about toner transfer and I wondered if 
anyone has tried them.  I am using an iron with a good level of success 
as the boards I am using are quite small.  However, I read that many 
people prefer the laminator to supply heat and pressure.  

So I was letting my mind wander with heat and pressure and the thought 
about sandwich presses (obviously you would need a flat plate) and 
shirt iron presses (I am not sure of the proper name but the things 
that iron a whole shirt in one pull of the handle)?  The disadvantage 
would be the size, but both would require no modification unlike some 
laminators.

Has anyone tried either of these two?

Mike

MIke,

That isn't a bad idea at all - I have not tried it myself, but while 
ironing some boards this weekend, I was thinking of something very 
similar.  

The presure is important in this process - and it must be even 
presure which means there has to be something between the heat 
source and the PCB to deal with any high spots so you get even 
transfer. CUrrently I use a heavy duty paper towel for 
this "padding".

Heat is another key element - I have been have good luck at 360 
Degrees F for my paper.  So the press would need to create the 
proper amount of heat - evenly across it's platten.

When using the Iron, it is very easy to mess up in a couple of 
areas....

1) Not getting a transfer where the steam holes are in the iron - I 
usually press 10 seconds, move the iron, press another 10 second to 
make sure I avoid the steam hole problem

2) No sideways movement when pressing.  This is a problem when the 
transfer paper slides sideways during the pressing and smears the 
toner.  Pushing straight down with a good amount of force is harder 
than it seems.

3) Having to press several times because the iron is not big enough.

So, while pressing this weekend, I was thinking of the same thing, a 
T-Shirt press for Iron on transfers.  I expect that they are 
expensive though.  Making one mechanically should not be all that 
difficult.  The heating element is the big problem - you need even 
heat across the whole surface and I have no idea how to make a 
heating element :-(

So, in my opinion, you don't have a crazy idea!

Chris







--- In Homebrew_PCBs@yahoogroups.com, "mikegw20" <mikegw20@h...> 
wrote:
>
> Helo all.
> 
> I just had a few random thoughts about toner transfer and I 
wondered if 
> anyone has tried them.  I am using an iron with a good level of 
success 
> as the boards I am using are quite small.  However, I read that 
many 
> people prefer the laminator to supply heat and pressure.  
> 
> So I was letting my mind wander with heat and pressure and the 
thought 
> about sandwich presses (obviously you would need a flat plate) and 
> shirt iron presses (I am not sure of the proper name but the 
things 
> that iron a whole shirt in one pull of the handle)?  The 
disadvantage 
> would be the size, but both would require no modification unlike 
some 

> laminators.
> 
> Has anyone tried either of these two?
> 
> Mike
>

to me, pid controlled laminator is an unbeatable solution.

  ----- Original Message ----- 
  From: mikegw20 
  To: Homebrew_PCBs@yahoogroups.com 
  Sent: Monday, October 17, 2005 8:01 AM
  Subject: [Homebrew_PCBs] Ideas (stupid??) for toner transfer


  Helo all.

  I just had a few random thoughts about toner transfer and I wondered if 
  anyone has tried them.  I am using an iron with a good level of success 
  as the boards I am using are quite small.  However, I read that many 
  people prefer the laminator to supply heat and pressure.  

  So I was letting my mind wander with heat and pressure and the thought 
  about sandwich presses (obviously you would need a flat plate) and 
  shirt iron presses (I am not sure of the proper name but the things 
  that iron a whole shirt in one pull of the handle)?  The disadvantage 
  would be the size, but both would require no modification unlike some 
  laminators.

  Has anyone tried either of these two?

  Mike





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

On my copious "to do" list.

I have a Tshirt press and I bought a used HP 6L, and a couple of
laminators, and I found this little sandwich press (very flat) quite
some time ago. Someone here was going to send me a few sheets of their
favorite paper but I guess he forgot, so I need to pick up something
to try.

For pressing dye sub onto tiles, they make a thin sheet of silicone
rubber to place between the press and the tile. The press is very
flat, it is the tiles that are uneven. It does make pressing take
quite a bit longer. I suspect it would not be that necessary with a PCB.

My "to do" list is about a mile long, though...

Also, unless you already have a Tshirt press, it's a spendy way to do
toner transfer. "Cheap" Tshirt presses don't have a temp control and
cost about $250 and are a bit bulky compared to a laminator.

I've heard of people bolting a sheet of aluminum onto an old iron to
get rid of the steam hole problem.

Steve Greenfield


--- In Homebrew_PCBs@yahoogroups.com, "mikegw20" <mikegw20@h...> wrote:

>
> Helo all.
> 
> I just had a few random thoughts about toner transfer and I wondered if 
> anyone has tried them.  I am using an iron with a good level of success 
> as the boards I am using are quite small.  However, I read that many 
> people prefer the laminator to supply heat and pressure.  
> 
> So I was letting my mind wander with heat and pressure and the thought 
> about sandwich presses (obviously you would need a flat plate) and 
> shirt iron presses (I am not sure of the proper name but the things 
> that iron a whole shirt in one pull of the handle)?  The disadvantage 
> would be the size, but both would require no modification unlike some 
> laminators.
> 
> Has anyone tried either of these two?
> 
> Mike
>

Quoting lcdpublishing <lcdpublishing@...>:

> The heating element is the big problem - you need even
> heat across the whole surface and I have no idea how to make a
> heating element :-(

I have an approximately 5 by 7 inch stainless cooler block from
an old electrophoresis cell.  I was thinking it could be fed
steam from a coffee maker element instead of water to make a heat
block.

Unfortunately I also have too much on my plate to play with it.
(And I have a couple laminators already.)

If anyone wants to do the work I'd be happy to mail it to them.
-Dan Barlow

----------------------------------------------------------------
This message was sent using IMP, the Internet Messaging Program.

--- In Homebrew_PCBs@yahoogroups.com, dbarlow@b... wrote:
>
> Quoting lcdpublishing <lcdpublishing@y...>:
> 
> > The heating element is the big problem - you need even
> > heat across the whole surface and I have no idea how to make a
> > heating element :-(
> 
> I have an approximately 5 by 7 inch stainless cooler block from
> an old electrophoresis cell.  I was thinking it could be fed
> steam from a coffee maker element instead of water to make a heat
> block.

It would have to be live steam, so it'd take more than a coffee maker
element.

BTW, noncontact pyrometers are about $40 to $50 at Sears. Online I've
seen them as cheap as $25. I use one to check my Tshirt press. Very
handy. Make sure you get one that goes up to about 600F.

Steve Greenfield

dbarlow@... wrote:

> electrophoresis

???

>>So I was letting my mind wander with heat and pressure and the thought 
>>about sandwich presses (obviously you would need a flat plate) and 
>>shirt iron presses (I am not sure of the proper name but the things 
>>    
>>
  A good electric griddle/grill might do very well here, along with a 
jack and some hardware.  Think of an old screw type printing press..  
Might be an excellent idea, especially since the grill could do double 
duty for reflowing SMT boards.

Alan

>
>  >>So I was letting my mind wander with heat and pressure and the thought
>  >>about sandwich presses (obviously you would need a flat plate) and
>  >>shirt iron presses (I am not sure of the proper name but the things
>  >>
>  >>
>    A good electric griddle/grill might do very well here, along with a
>  jack and some hardware.  Think of an old screw type printing press..
>  Might be an excellent idea, especially since the grill could do double
>  duty for reflowing SMT boards.
>
>  Alan


Tom Goottee (spelling?) did something like this a while back (check the
archives).  Not a simple as it sounds, he had a few hassles getting even
pressure over the board.  I think he got it sorted out eventually.

http://www.sparkfun.com found SMT on a hot plate worked better than their
reflow oven.

Tony

On Tue, 18 Oct 2005 06:12:43 +0200, Alan King <alan@...> wrote:

>
>   A good electric griddle/grill might do very well here, along with a
> jack and some hardware.  Think of an old screw type printing press..
> Might be an excellent idea, especially since the grill could do double
> duty for reflowing SMT boards.
> Alan


you will probably run into more trouble (uneven pressure and heat) than  
you get advantage over a laminator/fuser.

The thing is, pressure, as in force per area, depends, well, like on area.  
In a fuser/laminator you only have a "line" thus 1-dimensional  
relationship between boardsize and pressure.  In a press you have that  
squared, which could be another problem.

ST

--- In Homebrew_PCBs@yahoogroups.com, "Stefan Trethan"
<stefan_trethan@g...> wrote:
...
> The thing is, pressure, as in force per area, depends, well, like on
area.  
> In a fuser/laminator you only have a "line" thus 1-dimensional  
> relationship between boardsize and pressure.  In a press you have that  
> squared, which could be another problem.

Very good point. I doubt an electric griddle could stand up to much
pressure, too.

Steve Greenfield

Steve wrote:

>--- In Homebrew_PCBs@yahoogroups.com, "Stefan Trethan"
><stefan_trethan@g...> wrote:
>...
>  
>
>>The thing is, pressure, as in force per area, depends, well, like on
>>    
>>
>area.  
>  
>
>>In a fuser/laminator you only have a "line" thus 1-dimensional  
>>relationship between boardsize and pressure.  In a press you have that  
>>squared, which could be another problem.
>>    
>>
>
>Very good point. I doubt an electric griddle could stand up to much
>pressure, too.
>
>Steve Greenfield
>
>
>  
>

  A ton or two may be closer than you'd think off hand, remember the 
rollers flatten out a bit and create a contact patch.  Not sure extreme 
pressure is really important, with correct heat the toner should flow 
without that much pressure.  Reinforcing a plate is easy enough, and 
actually had thought of using a levered hand roller like in the manual 
tile cutter I used last week.  But probably too much work to keep the 
board and print aligned that way..  Just worth investigating a bit, 
since the griddle is useful on it's own for SMT reflow anyway.  If it 
can be made to work it'd be great, if not there is no real loss either..

Alan

Hmm, this is a good point so it bears checking on.  I currently use 
a clothes iron and press it by hand and use about 5 inches square of 
the sole plate at any one time.  I weigh about 225 pounds these days 
and am pushing down on the iron with a fair amount of force - lets 
say half my weight 112 pounds - which I am sure is more than I am 
pushing down.

5 x 5 = 25 sqaure inches of surface area
112 / 25 = 4.48 pounds per square inch

This has worked very good for me so far (although I suspect I have 
beginners luck).  So, a 12" x 12" board would require

12 x 12 = 144 square inches x 4.48 pounds per square inch = 645 
pounds of presure on that plate for a large circuit board.  This 
would be pretty hard to achieve without some form of mechanical 
advantage (unless I keep putting on weight since I quit smoking!)

Chris






--- In Homebrew_PCBs@yahoogroups.com, Alan King <alan@n...> wrote:
>
> Steve wrote:
> 
> >--- In Homebrew_PCBs@yahoogroups.com, "Stefan Trethan"
> ><stefan_trethan@g...> wrote:
> >...
> >  
> >
> >>The thing is, pressure, as in force per area, depends, well, 
like on
> >>    
> >>
> >area.  
> >  
> >
> >>In a fuser/laminator you only have a "line" thus 1-dimensional  
> >>relationship between boardsize and pressure.  In a press you 
have that  
> >>squared, which could be another problem.
> >>    
> >>
> >
> >Very good point. I doubt an electric griddle could stand up to 
much
> >pressure, too.
> >
> >Steve Greenfield
> >
> >
> >  
> >
> 
>   A ton or two may be closer than you'd think off hand, remember 
the 
> rollers flatten out a bit and create a contact patch.  Not sure 
extreme 
> pressure is really important, with correct heat the toner should 
flow 
> without that much pressure.  Reinforcing a plate is easy enough, 
and 
> actually had thought of using a levered hand roller like in the 
manual 
> tile cutter I used last week.  But probably too much work to keep 
the 
> board and print aligned that way..  Just worth investigating a 
bit, 
> since the griddle is useful on it's own for SMT reflow anyway.  If 
it 
> can be made to work it'd be great, if not there is no real loss 
either..

> 
> Alan
>

On Thu, 20 Oct 2005 21:58:52 +0200, lcdpublishing  
<lcdpublishing@...> wrote:

> Hmm, this is a good point so it bears checking on.  I currently use
> a clothes iron and press it by hand and use about 5 inches square of
> the sole plate at any one time.  I weigh about 225 pounds these days
> and am pushing down on the iron with a fair amount of force - lets
> say half my weight 112 pounds - which I am sure is more than I am
> pushing down.
> 5 x 5 = 25 sqaure inches of surface area
> 112 / 25 = 4.48 pounds per square inch
> This has worked very good for me so far (although I suspect I have
> beginners luck).  So, a 12" x 12" board would require
> 12 x 12 = 144 square inches x 4.48 pounds per square inch = 645
> pounds of presure on that plate for a large circuit board.  This
> would be pretty hard to achieve without some form of mechanical
> advantage (unless I keep putting on weight since I quit smoking!)
> Chris


My worry was not so much about the magnitude of pressure in general, but  
how to adjust if from board size to board size.
With the fuser i can choose to let the wide or the narrow side run  
through, thus i can keep the "length" in the fuser similar with all the  
different boards i make. I have not found variations of a factor 2 or even  
3 a problem. The rubber roller is doing a pretty good job at keeping  
things in contact.


If a press should work, i think it must have a rubber plate below the  
board, a rigid material both sides will probably cause trouble. Also, i  
would be afraid of temperature patterns, they can be quite extreme with  
heating elements that are concentrated in one area. A pressure gauge could  
be made easily, just take the bathroom scale and put it between the press  
plate and the screw/lever you use to tighten it.

At this point, i'm just not seeing the advantages.
But you know - never listen to the nay sayers. Look at the arguments why  
it mightn't work, fix them, and do it.

ST

I agree completely about the two primary points - 

1) Rubber or some other material that gives to compensate for board 
thickness variations

2) un-even heat from the element - this would be the biggest problem 
to correct I believe.  The only thing that comes to mind is to have 
a thick metal plate on the heating element side of the press.  Then, 
to use it, turn it on and let it get good and hot prior to use.  
Even then, I still think there is going to be some problems with 
some areas being hotter than others.  

My brother in-law is a garage sale junkie.  I will describe to him 
what I am looking for and he will find one for a couple of bucks 
somewhere - that's worth a try :-) 

Chris





--- In Homebrew_PCBs@yahoogroups.com, "Stefan Trethan" 
<stefan_trethan@g...> wrote:
>
> On Thu, 20 Oct 2005 21:58:52 +0200, lcdpublishing  
> <lcdpublishing@y...> wrote:
> 
> > Hmm, this is a good point so it bears checking on.  I currently 
use
> > a clothes iron and press it by hand and use about 5 inches 
square of
> > the sole plate at any one time.  I weigh about 225 pounds these 
days
> > and am pushing down on the iron with a fair amount of force - 
lets
> > say half my weight 112 pounds - which I am sure is more than I am
> > pushing down.
> > 5 x 5 = 25 sqaure inches of surface area
> > 112 / 25 = 4.48 pounds per square inch
> > This has worked very good for me so far (although I suspect I 
have
> > beginners luck).  So, a 12" x 12" board would require
> > 12 x 12 = 144 square inches x 4.48 pounds per square inch = 645
> > pounds of presure on that plate for a large circuit board.  This
> > would be pretty hard to achieve without some form of mechanical
> > advantage (unless I keep putting on weight since I quit smoking!)
> > Chris
> 
> 
> My worry was not so much about the magnitude of pressure in 
general, but  
> how to adjust if from board size to board size.
> With the fuser i can choose to let the wide or the narrow side 
run  
> through, thus i can keep the "length" in the fuser similar with 
all the  
> different boards i make. I have not found variations of a factor 2 
or even  
> 3 a problem. The rubber roller is doing a pretty good job at 
keeping  
> things in contact.
> 
> 
> If a press should work, i think it must have a rubber plate below 
the  
> board, a rigid material both sides will probably cause trouble. 
Also, i  
> would be afraid of temperature patterns, they can be quite extreme 
with  
> heating elements that are concentrated in one area. A pressure 
gauge could  
> be made easily, just take the bathroom scale and put it between 
the press  
> plate and the screw/lever you use to tighten it.
> 
> At this point, i'm just not seeing the advantages.
> But you know - never listen to the nay sayers. Look at the 
arguments why  

> it mightn't work, fix them, and do it.
> 
> ST
>

An easier way is to warm up the copper first with a hair dryer, before 
putting  the the paper with the toner on it , and then use the iron.


Regards

Tony VK2IC

lcdpublishing wrote:

>I agree completely about the two primary points - 
>
>1) Rubber or some other material that gives to compensate for board 
>thickness variations
>
>2) un-even heat from the element - this would be the biggest problem 
>to correct I believe.  The only thing that comes to mind is to have 
>a thick metal plate on the heating element side of the press.  Then, 
>to use it, turn it on and let it get good and hot prior to use.  
>Even then, I still think there is going to be some problems with 
>some areas being hotter than others.  
>
>My brother in-law is a garage sale junkie.  I will describe to him 
>what I am looking for and he will find one for a couple of bucks 
>somewhere - that's worth a try :-) 
>
>Chris
>
>
>
>
>
>--- In Homebrew_PCBs@yahoogroups.com, "Stefan Trethan" 
><stefan_trethan@g...> wrote:
>  
>
>>On Thu, 20 Oct 2005 21:58:52 +0200, lcdpublishing  
>><lcdpublishing@y...> wrote:
>>
>>    
>>
>>>Hmm, this is a good point so it bears checking on.  I currently 
>>>      
>>>
>use
>  
>
>>>a clothes iron and press it by hand and use about 5 inches 
>>>      
>>>
>square of
>  
>
>>>the sole plate at any one time.  I weigh about 225 pounds these 
>>>      
>>>
>days
>  
>
>>>and am pushing down on the iron with a fair amount of force - 
>>>      
>>>
>lets
>  
>
>>>say half my weight 112 pounds - which I am sure is more than I am
>>>pushing down.
>>>5 x 5 = 25 sqaure inches of surface area
>>>112 / 25 = 4.48 pounds per square inch
>>>This has worked very good for me so far (although I suspect I 
>>>      
>>>
>have
>  
>
>>>beginners luck).  So, a 12" x 12" board would require
>>>12 x 12 = 144 square inches x 4.48 pounds per square inch = 645
>>>pounds of presure on that plate for a large circuit board.  This
>>>would be pretty hard to achieve without some form of mechanical
>>>advantage (unless I keep putting on weight since I quit smoking!)
>>>Chris
>>>      
>>>
>>My worry was not so much about the magnitude of pressure in 
>>    
>>
>general, but  
>  
>
>>how to adjust if from board size to board size.
>>With the fuser i can choose to let the wide or the narrow side 
>>    
>>
>run  
>  
>
>>through, thus i can keep the "length" in the fuser similar with 
>>    
>>
>all the  
>  
>
>>different boards i make. I have not found variations of a factor 2 
>>    
>>
>or even  
>  
>
>>3 a problem. The rubber roller is doing a pretty good job at 
>>    
>>
>keeping  
>  
>
>>things in contact.
>>
>>
>>If a press should work, i think it must have a rubber plate below 
>>    
>>
>the  
>  
>
>>board, a rigid material both sides will probably cause trouble. 
>>    
>>
>Also, i  
>  
>
>>would be afraid of temperature patterns, they can be quite extreme 
>>    
>>
>with  
>  
>
>>heating elements that are concentrated in one area. A pressure 
>>    
>>
>gauge could  
>  
>
>>be made easily, just take the bathroom scale and put it between 
>>    
>>
>the press  
>  
>
>>plate and the screw/lever you use to tighten it.
>>
>>At this point, i'm just not seeing the advantages.
>>But you know - never listen to the nay sayers. Look at the 
>>    
>>
>arguments why  
>  
>
>>it mightn't work, fix them, and do it.
>>
>>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
>
>
>
> 
>
>
>
>
>  
>


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

Nicely put, Stefan!  Mike

You know Stefan, I had zero problems since I started using a 
laminator. It works predictably every time and when I tried ironing 
TT, it was a nightmare for me. With presses I had never any luck.

I saw an interesting solution somewhere on the net: a guy placed an 
iron upside down and placed the PC on top of it. Then he loaded heavy 
weights on top of it. Apparently that process allowed him successful a 
TT. Mike

On Thu, 20 Oct 2005 22:51:20 +0200, lcdpublishing  
<lcdpublishing@...> wrote:

> 1) Rubber or some other material that gives to compensate for board
> thickness variations

Yes, some silicone rubber maybe. I guess one could take RTV silicone and  
spread it evenly.
Or a baking sheet, maybe several if not thick enough.

> 2) un-even heat from the element - this would be the biggest problem
> to correct I believe.  The only thing that comes to mind is to have
> a thick metal plate on the heating element side of the press.  Then,
> to use it, turn it on and let it get good and hot prior to use.
> Even then, I still think there is going to be some problems with
> some areas being hotter than others.

Well, a thick copper or aluminum plate would certainly help. There are  
also heating foils to stick on a plate which should heat fairly evenly  
(probably colder at the edges). Someone here tried one of those some time  
back, and a ingenious pressing force mecanism consisting of a lever and a  
bucket with weights i think. I do not know what came of it, the machine  
was finished (i've seen a picture), but i don't know about the results and  
it was probably pre-HD crash so i can't find it.
I know for fact that the heat in things like electric contact toasters or  
waffle irons is not even.
Also, i inspected a clothes press and deemed it not even worthy of trying.  
The guys using a skillet for SMD reflow also mention a heat pattern where  
the element is.
I guess avoiding it by even heating as far as possible is better than  
fighting it. But hey, maybe it isn't even a problem...


> My brother in-law is a garage sale junkie.  I will describe to him
> what I am looking for and he will find one for a couple of bucks
> somewhere - that's worth a try
> Chris

Sure is.
I'm just frightened it brings back some of the problems i had with the  
clothes iron, so i'll stick with my fuser for now.

ST

--- In Homebrew_PCBs@yahoogroups.com, "lcdpublishing"
<lcdpublishing@y...> wrote:
>
> I agree completely about the two primary points - 
> 
> 1) Rubber or some other material that gives to compensate for board 
> thickness variations

A Tshirt press has exactly this. They use a silicone rubber foam. And
it is possible to buy sheets of it if you are making your own press.

> 2) un-even heat from the element - this would be the biggest problem 
> to correct I believe.  The only thing that comes to mind is to have 
> a thick metal plate on the heating element side of the press.  Then, 
> to use it, turn it on and let it get good and hot prior to use.  
> Even then, I still think there is going to be some problems with 
> some areas being hotter than others.  

Growing up, Sunday morning breakfast was usually cooked on an electric
griddle with a simple 3/4 circle of heating element on the bottom. You
could clearly see on the bottom of pancakes where it was hotter.

However, my commercial Tshirt press, to my great surprise, had
essentially the same pattern for the element. Yet it holds very good
temp across the whole thing.

The differences:

1. Bottom of the griddle is open to the air, the top of the Tshirt
press platen is well insulated with fiberglass under a thin metal top.

2. A water filled pancake has a fairly high heat capacity.

3. The griddle is very thin, whereas the Tshirt press platen is very
thick.

BTW, common practice in the past was to paint/anodize them black on
the theory of increased heat transfer, when in fact that only helps it
-radiate- heat. Now many heat presses are anodized natural aluminum,
or painted white.

Keep in mind this prevents a pyrometer from getting an accurate temp
reading. However, it makes it -much- more comfortable to work in front
of it! I picked up some white porcelain 1200F engine paint to repaint
my Tshirt press.

Steve Greenfield

On Sun, 23 Oct 2005 22:19:06 +0200, Steve <alienrelics@...> wrote:

>
> BTW, common practice in the past was to paint/anodize them black on
> the theory of increased heat transfer, when in fact that only helps it
> -radiate- heat. Now many heat presses are anodized natural aluminum,
> or painted white.


Right, many are black, all sorts of grills too.
Never noticed how silly that is.


ST