Homebrew PCBs

Hi

  MG Chemicals now sells a "Negative Photoresist Film" (product #416-
DFR5) that I believe may be Riston.

  I have tried it several times now with mediocre results.  The 
traces turn out good when they turn out.  The problem I'm getting is 
actually getting the film to stick to the board uniformly before 
exposure.

  Someone suggested using water between the board and the film to 
allow rolling of any bubbles out from underneath with your thumb 
after positioning, then drying it in an oven at about 200 degrees for 
10 min to get it to stick.

  They were right, it worked great...until I tried to dry it.  Small 
mutations formed, sometimes in the form of lines, sometimes what look 
like small blobs.  They aren't bubbles per se, but somehow there are 
areas of the film that appear to stick to the board at a deeper level 
than the surrounding film, or maybe they are melting and deforming.

  The manufacturer recommends using a laminator to apply the film, 
which I tried initially, but it appears to have the same problem.  My 
laminator is adjustable heat, and I've tried from hi to low with 
similar results.  I haven't as yet put the board between any 
protective sheets when laminating like you might to laminate paper 
items...I'm going to try that next (the manufacturer never 
specifically said to do it).

  Here are their instructions: 

  http://www.mgchemicals.com/techsupport/416dfr_inst.html

  I clean the board ahead of time with steel wool, alcohol and 
acetone.  I am using clean gloves throughout.

  Can anyone help me with any tricks to get this stuff to adhere 
uniformly?

  Thank you so much in advance!


-Josh

Josh,

Water makes the resist adhere quite well w/o bubbles, but it causes 
two problems for me; ther first is the one you described, and the 
second is the tendency for the resist to 'lump' instead of melt when 
developed, leaving ragged edges.

I have a laminator, and it works well for the thinner board material, 
but you do have to place the board into a carrier for this to work 
properly.

On thicker board material, where I cannot use a laminator, this is my 
method for applying it sucessfully:

This product is a 3-layer laminate, consisting of a photo-sensitive 
polymer layer between two protective layers of clear plastic film.  
It can be used without process equipment or exotic chemicals, and 
develops easily in a slightly caustic soda solution.

 Here is my own procedure for applying this resist:

         I.      Cut your board to size, clean and dry the copper 
surface

·        Whatever your finished board size will be, make it about 
1/4" larger all the way around. This will allow you to do a final 
trim later to remove any ragged edges or other defects after etching. 
These defects tend to appear right at the edges of the board.

·        Wearing latex gloves is helpful; you must clean any oils, 
corrosion or other defect from the copper. One way to do this is to 
use a scouring powder (like Kleen-King) and water. Very fine steel 
wool is also OK. If the copper surface is already in good shape, 
clean with soap and water only and dry.



     II.     Prepare the laminate and apply it to the the board

·        Cut a piece of the laminate stock into a sheet about 1/2 
inch larger than your board all the way around.

·        Lay the laminate flat on a cool surface, and with the point 
of a needle or Xacto knife, pick away at a corner until the 
protective layer begins to separate.

Note: You will be able to separate the first protective layer only on 
one side of the laminate, the other will not peel away until the 
laminate is heated and cooled later on in the process.

.        Heat a 3/8" thick aluminum plate to 125f. Lay the board on 
it, and when it comes to temp, apply the resist 1/4" at a time, 
moving your finger side-to-side to apply it evenly, while continuing 
to peel back the protective layer as you go. Trim off the excess 
material.

·        Warm the board slowly using a hot plate and that piece of 
3/8" aluminum plate. Move the temp up from room temp to 150f (max) 
over 15 minutes, allowing the resist to cure to the board; Allow to 
cool gradually. Test for proper curing by peeling back the outer 
protective layer at the edges; if it comes away clean, it's OK; if 
the resist comes with it, it's not cured yet. Do not remove the outer 
layer entirely, just test the edges.

.	I find that one layer of this material is not enough 
protection (I got a lot of pin-hole penetration through the resist), 
so I always add a second layer of resist, this time at room 
temperature. Peel away the protective layer over the first layer a 
bit at a time, and apply the second layer a bit at a time, peeling 
it's first layer as you go. Cure the board again as in the previous 
step.


III.      Expose

·        Using a negative image of your artwork, expose the board 
with the proper light. I use a glass picture frame to hold the 
artwork and board together, and expose it in direct sunlight for 
about 15 seconds. Store in a cool, dark place for 15 minutes to allow 
the polymers to set.

IV.      Develop and etch your board

·        I use Arm & Hammer washing soda (not baking soda), 1/2 
TEAspoon (TSP) per 8 oz of water.

·        Peel away the other protective layer remaining over the 
photo resist, and pour developer over the board until the done, then 
rinse immediately. The resist should slowly melt away. If it comes 
off in clumps, strands or gobs, the resist did not cure properly.

·        Now you can etch your PC board

·        Resist can be stripped with Acetone, or if you don't like 
Acetone, you can use a more concentrated developer solution (2 
Tablespoons per 6 oz of water). Allowing either to sit on the resist 
for a few minutes will cause the resist to bubble up and lift away 
from the copper.

·        Don't forget the final water rinse.

·        Trim the board to size (this is where the ragged edges 
disappear).

Hope this helps.../ Jim


--- In Homebrew_PCBs@yahoogroups.com, "joshdewinter" 
<joshdewinter@...> wrote:
>
> Hi
> 
>   MG Chemicals now sells a "Negative Photoresist Film" (product 
#416-
> DFR5) that I believe may be Riston.
> 
>   I have tried it several times now with mediocre results.  The 
> traces turn out good when they turn out.  The problem I'm getting 
is 
> actually getting the film to stick to the board uniformly before 
> exposure.
> 
>   Someone suggested using water between the board and the film to 
> allow rolling of any bubbles out from underneath with your thumb 
> after positioning, then drying it in an oven at about 200 degrees 
for 
> 10 min to get it to stick.
> 
>   They were right, it worked great...until I tried to dry it.  
Small 
> mutations formed, sometimes in the form of lines, sometimes what 
look 
> like small blobs.  They aren't bubbles per se, but somehow there 
are 
> areas of the film that appear to stick to the board at a deeper 
level 
> than the surrounding film, or maybe they are melting and deforming.
> 
>   The manufacturer recommends using a laminator to apply the film, 
> which I tried initially, but it appears to have the same problem.  
My 

> laminator is adjustable heat, and I've tried from hi to low with 
> similar results.  I haven't as yet put the board between any 
> protective sheets when laminating like you might to laminate paper 
> items...I'm going to try that next (the manufacturer never 
> specifically said to do it).
> 
>   Here are their instructions: 
> 
>   http://www.mgchemicals.com/techsupport/416dfr_inst.html
> 
>   I clean the board ahead of time with steel wool, alcohol and 
> acetone.  I am using clean gloves throughout.
> 
>   Can anyone help me with any tricks to get this stuff to adhere 
> uniformly?
> 
>   Thank you so much in advance!
> 
> 
> -Josh
>

Josh,

I don't know your particular film as I'm using a different product 
(Ordyl Alpha 900). However, the one I use is also pickey. I posted some 
pics to the forum a while ago showing how I feed the laminator to avoid 
bubbles. From what it sounds however I have the impression that the 
particular laminator you are using is just too hot even in it's lowest 
setting. The other thing is the applied pressure during lamination. My 
solution was to try several different laminators and I ended up using 
one where I was able to adjust the pressure of the rolls with screws 
(had to loosen them quite a bit) and one that also works with pretty low 
temperature setting. It took quite some experimentation to find the 
propper setting but overall, off the shelf laminators apply too much 
pressure and usually also are too hot.

HTH

Markus

joshdewinter schrieb:

>
> Hi
>
> MG Chemicals now sells a "Negative Photoresist Film" (product #416-
> DFR5) that I believe may be Riston.
>
> I have tried it several times now with mediocre results. The
> traces turn out good when they turn out. The problem I'm getting is
> actually getting the film to stick to the board uniformly before
> exposure.
>
> Someone suggested using water between the board and the film to
> allow rolling of any bubbles out from underneath with your thumb
> after positioning, then drying it in an oven at about 200 degrees for
> 10 min to get it to stick.
>
> They were right, it worked great...until I tried to dry it. Small
> mutations formed, sometimes in the form of lines, sometimes what look
> like small blobs. They aren't bubbles per se, but somehow there are
> areas of the film that appear to stick to the board at a deeper level
> than the surrounding film, or maybe they are melting and deforming.
>
> The manufacturer recommends using a laminator to apply the film,
> which I tried initially, but it appears to have the same problem. My
> laminator is adjustable heat, and I've tried from hi to low with
> similar results. I haven't as yet put the board between any
> protective sheets when laminating like you might to laminate paper
> items...I'm going to try that next (the manufacturer never
> specifically said to do it).
>
> Here are their instructions:
>
> http://www.mgchemicals.com/techsupport/416dfr_inst.html 
> <http://www.mgchemicals.com/techsupport/416dfr_inst.html>
>
> I clean the board ahead of time with steel wool, alcohol and
> acetone. I am using clean gloves throughout.
>
> Can anyone help me with any tricks to get this stuff to adhere
> uniformly?
>
> Thank you so much in advance!
>
> -Josh
>
>

Hi Jim

Thanks very much for the in-depth tutorial.  I didn't know you could 
put one layer of resist over another like that.

When you mention heathing with the aluminum plate, you must mean 
between the burner and the board itself, not on top of the board, 
right?  (I thought you had to use pressure to press on the film, but 
from your explanation, it sounds like you can get away without it).

The pressure you use when actually touching the film must not be 
that great?

Also, I don't have very dependable sun here where I live.  I use a 
regular UV lamp, which seems to work best for me after about 20 
minutes, even though the manufacturer says 10-12.  I've heard bug 
lights can offer better exposure times too, but I have yet to try.
 

Thanks for the help!

-Josh


--- In Homebrew_PCBs@yahoogroups.com, "Jim Klitzing" <wb6myc@...> 
wrote:
>
> Josh,
> 
> Water makes the resist adhere quite well w/o bubbles, but it 
causes 
> two problems for me; ther first is the one you described, and the 
> second is the tendency for the resist to 'lump' instead of melt 
when 
> developed, leaving ragged edges.
> 
> I have a laminator, and it works well for the thinner board 
material, 
> but you do have to place the board into a carrier for this to work 
> properly.
> 
> On thicker board material, where I cannot use a laminator, this is 
my 
> method for applying it sucessfully:
> 
> This product is a 3-layer laminate, consisting of a photo-
sensitive 
> polymer layer between two protective layers of clear plastic 
film.  
> It can be used without process equipment or exotic chemicals, and 
> develops easily in a slightly caustic soda solution.
> 
>  Here is my own procedure for applying this resist:
> 
>          I.      Cut your board to size, clean and dry the copper 
> surface
> 
> ·        Whatever your finished board size will be, make it about 
> 1/4" larger all the way around. This will allow you to do a final 
> trim later to remove any ragged edges or other defects after 
etching. 
> These defects tend to appear right at the edges of the board.
> 
> ·        Wearing latex gloves is helpful; you must clean any oils, 
> corrosion or other defect from the copper. One way to do this is 
to 
> use a scouring powder (like Kleen-King) and water. Very fine steel 
> wool is also OK. If the copper surface is already in good shape, 
> clean with soap and water only and dry.
> 
> 
> 
>      II.     Prepare the laminate and apply it to the the board
> 
> ·        Cut a piece of the laminate stock into a sheet about 1/2 
> inch larger than your board all the way around.
> 
> ·        Lay the laminate flat on a cool surface, and with the 
point 
> of a needle or Xacto knife, pick away at a corner until the 
> protective layer begins to separate.
> 
> Note: You will be able to separate the first protective layer only 
on 
> one side of the laminate, the other will not peel away until the 
> laminate is heated and cooled later on in the process.
> 
> .        Heat a 3/8" thick aluminum plate to 125f. Lay the board 
on 
> it, and when it comes to temp, apply the resist 1/4" at a time, 
> moving your finger side-to-side to apply it evenly, while 
continuing 
> to peel back the protective layer as you go. Trim off the excess 
> material.
> 
> ·        Warm the board slowly using a hot plate and that piece of 
> 3/8" aluminum plate. Move the temp up from room temp to 150f (max) 
> over 15 minutes, allowing the resist to cure to the board; Allow 
to 
> cool gradually. Test for proper curing by peeling back the outer 
> protective layer at the edges; if it comes away clean, it's OK; if 
> the resist comes with it, it's not cured yet. Do not remove the 
outer 
> layer entirely, just test the edges.
> 
> .	I find that one layer of this material is not enough 
> protection (I got a lot of pin-hole penetration through the 
resist), 
> so I always add a second layer of resist, this time at room 
> temperature. Peel away the protective layer over the first layer a 
> bit at a time, and apply the second layer a bit at a time, peeling 
> it's first layer as you go. Cure the board again as in the 
previous 
> step.
> 
> 
> III.      Expose
> 
> ·        Using a negative image of your artwork, expose the board 
> with the proper light. I use a glass picture frame to hold the 
> artwork and board together, and expose it in direct sunlight for 
> about 15 seconds. Store in a cool, dark place for 15 minutes to 
allow 
> the polymers to set.
> 
> IV.      Develop and etch your board
> 
> ·        I use Arm & Hammer washing soda (not baking soda), 1/2 
> TEAspoon (TSP) per 8 oz of water.
> 
> ·        Peel away the other protective layer remaining over the 
> photo resist, and pour developer over the board until the done, 
then 
> rinse immediately. The resist should slowly melt away. If it comes 
> off in clumps, strands or gobs, the resist did not cure properly.
> 
> ·        Now you can etch your PC board
> 
> ·        Resist can be stripped with Acetone, or if you don't like 
> Acetone, you can use a more concentrated developer solution (2 
> Tablespoons per 6 oz of water). Allowing either to sit on the 
resist 
> for a few minutes will cause the resist to bubble up and lift away 
> from the copper.
> 
> ·        Don't forget the final water rinse.
> 
> ·        Trim the board to size (this is where the ragged edges 
> disappear).
> 
> Hope this helps.../ Jim
> 
> 
> --- In Homebrew_PCBs@yahoogroups.com, "joshdewinter" 
> <joshdewinter@> wrote:
> >
> > Hi
> > 
> >   MG Chemicals now sells a "Negative Photoresist Film" (product 
> #416-
> > DFR5) that I believe may be Riston.
> > 
> >   I have tried it several times now with mediocre results.  The 
> > traces turn out good when they turn out.  The problem I'm 
getting 
> is 
> > actually getting the film to stick to the board uniformly before 
> > exposure.
> > 
> >   Someone suggested using water between the board and the film 
to 
> > allow rolling of any bubbles out from underneath with your thumb 
> > after positioning, then drying it in an oven at about 200 
degrees 
> for 
> > 10 min to get it to stick.
> > 
> >   They were right, it worked great...until I tried to dry it.  
> Small 
> > mutations formed, sometimes in the form of lines, sometimes what 
> look 
> > like small blobs.  They aren't bubbles per se, but somehow there 
> are 
> > areas of the film that appear to stick to the board at a deeper 
> level 
> > than the surrounding film, or maybe they are melting and 
deforming.
> > 
> >   The manufacturer recommends using a laminator to apply the 
film, 
> > which I tried initially, but it appears to have the same 
problem.  
> My 
> > laminator is adjustable heat, and I've tried from hi to low with 
> > similar results.  I haven't as yet put the board between any 
> > protective sheets when laminating like you might to laminate 
paper 

> > items...I'm going to try that next (the manufacturer never 
> > specifically said to do it).
> > 
> >   Here are their instructions: 
> > 
> >   http://www.mgchemicals.com/techsupport/416dfr_inst.html
> > 
> >   I clean the board ahead of time with steel wool, alcohol and 
> > acetone.  I am using clean gloves throughout.
> > 
> >   Can anyone help me with any tricks to get this stuff to adhere 
> > uniformly?
> > 
> >   Thank you so much in advance!
> > 
> > 
> > -Josh
> >
>

Josh,

I feel your pain!  I too am working with this stuff, I am on my second roll now.  Some boards 
turn out perfect, others, not so good.

I have not found a reliable method of applying the film without bubbles.  I am using a 
laminator with two heat settings, same results on both settings.  I have not yet tried running 
the board through the laminator BEFORE it heats up though.  I suspect this may help in 
getting the bubbles out before the bonding occurs.

If I don't get this worked out soon, I am going to abandon the film and just buy pre-coated 
boards.  In the end, it is probably going to be cheaper provided you get better and more 
consistent results.

Sorry I couldn't be of more help.

Chris

On Tue, Nov 25, 2008 at 7:28 AM, lcdpublishing <lcdpublishing@...>wrote:

>   Josh,
>
> I feel your pain! I too am working with this stuff, I am on my second roll
> now. Some boards
> turn out perfect, others, not so good.
>
> I have not found a reliable method of applying the film without bubbles. I
> am using a
> laminator with two heat settings, same results on both settings. I have not
> yet tried running
> the board through the laminator BEFORE it heats up though. I suspect this
> may help in
> getting the bubbles out before the bonding occurs.
>

Wetting the board and then letting the resist "wick" onto the board,
applying light pressure with a roller or a credit card to move the excess
water to the leading edge is very important to avoid too much water in
places or bubbles. Make sure you leave a quarter-inch or more of overhang
when applying the resist.  You want a fair amount of water on the board so
it sucks the resist onto the board and makes bubbles impossible (or easily
eliminated since there's a thin layer of water between the board and the
resist).  Too little water makes the resist instantly stick to the board
which is bad since it can trap bubbles and doesn't allow movement to
properly center the resist.  Once you've applied and centered the resist use
increasing pressure to force out the excess water.  I have a laminator with
an (added) off/on switch for the heat which works perfectly to apply
uniform, strong pressure to squeeze out the excess water.  I first trim the
resist with scissors so it has very little overhang, run it through the
laminator a couple times, and then let the laminator heat up to around
150-180F for the final run through.  Let the board sit for an hour or so
afterwards to help the water become completely absorbed or it won't be very
sensitive to UV.

Hope this helps-
Larry


>
>
> If I don't get this worked out soon, I am going to abandon the film and
> just buy pre-coated
> boards. In the end, it is probably going to be cheaper provided you get
> better and more
> consistent results.
>
> Sorry I couldn't be of more help.
>
> Chris
>
> 
>


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

"lcdpublishing" <lcdpublishing@...> writes:
> I have not found a reliable method of applying the film without bubbles.

I've had good luck with water and a heat gun, based on Adam's technique:

Wash the board and leave it wet.

Remove the first backing off the film and rinse the film too.  Place
it on some overhead transparency, exposed side still exposed, for
manageability.

Re-rinse board and film.  Pick up the transparency (which picks up the
film too), flex it a bit so the film bulges out, and apply the film to
the board.  Most of the water/air gets out at this point.

While the transparency is still on top of the film, use a credit card
or other squeegie to squeeze out as much water as you can.  Hold the
transparency still with the other hand; this protects the film against
damage.

Peel off the transparency.  Note: do not yet peel off the film's
second backing layer.

Heat the film with the heat gun while continuing to gently squeegie
out the remaining water (if any).  I heat until it's just a bit too
hot to hold in my bare hand, and the film is dry, and that seems to be
just right.

Too much heat and it bubbles and wrinkles.

Hi Markus and all

I tried and tried tonight to make this work.  I even tried the dual 
layer of Riston technique, but I just can't seem to ever get it on 
the board without some kind of imperfection that screws up the 
traces in that area.

Markus, can you tell us what brand and model your laminator is?  I 
think you (and others who said so) are probably right on the money 
in that my laminator just doesn't have enough room between the 
rollers.  It's got a temp adjust, which is nice, but I hear a "chunk 
chunk chunk" sound, which sounds like gears slipping, probably 
because there just isn't enough clearance in there.


I also noticed very fine squares on the pcb copper layer itself that 
were causing some of the lines in the film.  A friend noted that 
these are the fiberglass underlayer's telegraphing through from 
beneath.  I got an electric sander, and used 250 then 500 grit paper 
to smooth them out.


I found that I could use a hair dryer to pre-heat the film once 
applied, and push on it with my fingers in rubber gloves and get it 
to bond a little better.  It wasn't hot enough to cure it, but if I 
then placed it on a clothes iron for about 5 seconds on the low 
setting - just enough to heat but not make it boil - that would cure 
it.


Still trying....frustrated...but trying.


-Josh



--- In Homebrew_PCBs@yahoogroups.com, Markus Zingg <homebrew-
pcb@...> wrote:
>
> Josh,
> 
> I don't know your particular film as I'm using a different product 
> (Ordyl Alpha 900). However, the one I use is also pickey. I posted 
some 
> pics to the forum a while ago showing how I feed the laminator to 
avoid 
> bubbles. From what it sounds however I have the impression that 
the 
> particular laminator you are using is just too hot even in it's 
lowest 
> setting. The other thing is the applied pressure during 
lamination. My 
> solution was to try several different laminators and I ended up 
using 
> one where I was able to adjust the pressure of the rolls with 
screws 
> (had to loosen them quite a bit) and one that also works with 
pretty low 
> temperature setting. It took quite some experimentation to find 
the 
> propper setting but overall, off the shelf laminators apply too 
much 
> pressure and usually also are too hot.
> 
> HTH
> 
> Markus
> 
> joshdewinter schrieb:
> >
> > Hi
> >
> > MG Chemicals now sells a "Negative Photoresist Film" (product 
#416-
> > DFR5) that I believe may be Riston.
> >
> > I have tried it several times now with mediocre results. The
> > traces turn out good when they turn out. The problem I'm getting 
is
> > actually getting the film to stick to the board uniformly before
> > exposure.
> >
> > Someone suggested using water between the board and the film to
> > allow rolling of any bubbles out from underneath with your thumb
> > after positioning, then drying it in an oven at about 200 
degrees for
> > 10 min to get it to stick.
> >
> > They were right, it worked great...until I tried to dry it. Small
> > mutations formed, sometimes in the form of lines, sometimes what 
look
> > like small blobs. They aren't bubbles per se, but somehow there 
are
> > areas of the film that appear to stick to the board at a deeper 
level
> > than the surrounding film, or maybe they are melting and 
deforming.
> >
> > The manufacturer recommends using a laminator to apply the film,
> > which I tried initially, but it appears to have the same 
problem. My
> > laminator is adjustable heat, and I've tried from hi to low with
> > similar results. I haven't as yet put the board between any
> > protective sheets when laminating like you might to laminate 
paper

> > items...I'm going to try that next (the manufacturer never
> > specifically said to do it).
> >
> > Here are their instructions:
> >
> > http://www.mgchemicals.com/techsupport/416dfr_inst.html 
> > <http://www.mgchemicals.com/techsupport/416dfr_inst.html>
> >
> > I clean the board ahead of time with steel wool, alcohol and
> > acetone. I am using clean gloves throughout.
> >
> > Can anyone help me with any tricks to get this stuff to adhere
> > uniformly?
> >
> > Thank you so much in advance!
> >
> > -Josh
> >
> >
>

Josh,

It's a GMP Mr. PHOTO-230TC. However, this particular one is already some 
years old, and I have no idea wether it's still available and if it was 
ever available in the area where you live. The all important factor is 
that the pressure of the rolls itself can be ENVENLY adjusted. Usually 
this is the case through the mounting screws of the rolls which usually 
press a feather per screw which in turn applies the pressure to the 
rolls. The other thing is that you usually have to open the case of the 
laminator in order to make the entry/exit free for the 1.5mm PCB 
material. As mentioned in my previous post, laminate does not need very 
high temperature so the other important factor is that the laminator is 
able to heat the rolls EVENLY to the propper, relatively low 
temperature. I never measured it on mine, but it's only a tad above the 
the lowest setting it is having. The other laminator I used bevore this 
one also gave not as consistent results and I thus changed it. The MR. 
PHOTO I'm using is also having compareably thick rolls, maybe another 
factor.... The problem with this kind of equipement is that since it's 
mass market, you never can be sure to buy the same model again after 
even a relatively short amount of time. I'm too scared from the moment 
in time where mine may will stop to work some hopefully very distant day 
in the future.

What I can say though is that with this laminator I do not have to apply 
the film "wet" as Adam and others aparently do it and that I do not end 
up with boubles etc. On the other hand theres is also nothing to correct 
once the laminate is applied. It either works, or it's a failure with no 
other option to correct it than stripping it off and reapply fresh 
laminate. However, with the Mr. PHOTO thingy, I only have very rare 
cases where it does not work (say once out of 50 or better).

The smallest trace width I can regularly do is 4mils with this setup. 
This of course also requieres that the other steps (exposure and 
etching) are optimized. IMHO the type of laminate also dictates the 
minimum resolution you can achive. This is a function of the thikness of 
the laminate itself if I'm not mistaken and the behaviour during 
exposure etc. etc.

HTH

Markus

joshdewinter schrieb:

>
> Hi Markus and all
>
> I tried and tried tonight to make this work. I even tried the dual
> layer of Riston technique, but I just can't seem to ever get it on
> the board without some kind of imperfection that screws up the
> traces in that area.
>
> Markus, can you tell us what brand and model your laminator is? I
> think you (and others who said so) are probably right on the money
> in that my laminator just doesn't have enough room between the
> rollers. It's got a temp adjust, which is nice, but I hear a "chunk
> chunk chunk" sound, which sounds like gears slipping, probably
> because there just isn't enough clearance in there.
>
> I also noticed very fine squares on the pcb copper layer itself that
> were causing some of the lines in the film. A friend noted that
> these are the fiberglass underlayer's telegraphing through from
> beneath. I got an electric sander, and used 250 then 500 grit paper
> to smooth them out.
>
> I found that I could use a hair dryer to pre-heat the film once
> applied, and push on it with my fingers in rubber gloves and get it
> to bond a little better. It wasn't hot enough to cure it, but if I
> then placed it on a clothes iron for about 5 seconds on the low
> setting - just enough to heat but not make it boil - that would cure
> it.
>
> Still trying....frustrated...but trying.
>
> -Josh
>
> --- In Homebrew_PCBs@yahoogroups.com 
> <mailto:Homebrew_PCBs%40yahoogroups.com>, Markus Zingg <homebrew-
> pcb@...> wrote:
> >
> > Josh,
> >
> > I don't know your particular film as I'm using a different product
> > (Ordyl Alpha 900). However, the one I use is also pickey. I posted
> some
> > pics to the forum a while ago showing how I feed the laminator to
> avoid
> > bubbles. From what it sounds however I have the impression that
> the
> > particular laminator you are using is just too hot even in it's
> lowest
> > setting. The other thing is the applied pressure during
> lamination. My
> > solution was to try several different laminators and I ended up
> using
> > one where I was able to adjust the pressure of the rolls with
> screws
> > (had to loosen them quite a bit) and one that also works with
> pretty low
> > temperature setting. It took quite some experimentation to find
> the
> > propper setting but overall, off the shelf laminators apply too
> much
> > pressure and usually also are too hot.
> >
> > HTH
> >
> > Markus
> >
> > joshdewinter schrieb:
> > >
> > > Hi
> > >
> > > MG Chemicals now sells a "Negative Photoresist Film" (product
> #416-
> > > DFR5) that I believe may be Riston.
> > >
> > > I have tried it several times now with mediocre results. The
> > > traces turn out good when they turn out. The problem I'm getting
> is
> > > actually getting the film to stick to the board uniformly before
> > > exposure.
> > >
> > > Someone suggested using water between the board and the film to
> > > allow rolling of any bubbles out from underneath with your thumb
> > > after positioning, then drying it in an oven at about 200
> degrees for
> > > 10 min to get it to stick.
> > >
> > > They were right, it worked great...until I tried to dry it. Small
> > > mutations formed, sometimes in the form of lines, sometimes what
> look
> > > like small blobs. They aren't bubbles per se, but somehow there
> are
> > > areas of the film that appear to stick to the board at a deeper
> level
> > > than the surrounding film, or maybe they are melting and
> deforming.
> > >
> > > The manufacturer recommends using a laminator to apply the film,
> > > which I tried initially, but it appears to have the same
> problem. My
> > > laminator is adjustable heat, and I've tried from hi to low with
> > > similar results. I haven't as yet put the board between any
> > > protective sheets when laminating like you might to laminate
> paper
> > > items...I'm going to try that next (the manufacturer never
> > > specifically said to do it).
> > >
> > > Here are their instructions:
> > >
> > > http://www.mgchemicals.com/techsupport/416dfr_inst.html 
> <http://www.mgchemicals.com/techsupport/416dfr_inst.html>
> > > <http://www.mgchemicals.com/techsupport/416dfr_inst.html 
> <http://www.mgchemicals.com/techsupport/416dfr_inst.html>>
> > >
> > > I clean the board ahead of time with steel wool, alcohol and
> > > acetone. I am using clean gloves throughout.
> > >
> > > Can anyone help me with any tricks to get this stuff to adhere
> > > uniformly?
> > >
> > > Thank you so much in advance!
> > >
> > > -Josh
> > >
> > >
> >
>
>

Do laminators have hard rollers? I worked for Rank-Xerox many years ago and 
the Xerox 3600 and 7200 photocopiers used a heated teflon-coated soft roller 
for fusing the image. Something like that should work a lot better. It was 
heated by a central quartz halogen tube.

Leon
--
Leon Heller
Amateur radio call-sign  G1HSM
Yaesu FT-817ND transceiver
Suzuki SV1000S motorcycle
leon355@...
http://www.geocities.com/leon_heller

No, the rolls are "soft". Atleast all rolls from the laminators I had a 
chance to look at. I don't know what particular material the rolls are 
made off, but they feel like "rubber" or something like this. Obviousely 
they can take the heat though. I just noticed that most laminators seem 
to have smaller diameter rolls and the one I'm having most sucess with 
is useing a bigger diameter (more in the range of 35 to 40mm as oposed 
to ~30mm).

Markus

leon Heller schrieb:

>
> Do laminators have hard rollers? I worked for Rank-Xerox many years 
> ago and
> the Xerox 3600 and 7200 photocopiers used a heated teflon-coated soft 
> roller
> for fusing the image. Something like that should work a lot better. It 
> was
> heated by a central quartz halogen tube.
>
> Leon
> --
> Leon Heller
> Amateur radio call-sign G1HSM
> Yaesu FT-817ND transceiver
> Suzuki SV1000S motorcycle
> leon355@... <mailto:leon355%40btinternet.com>
> http://www.geocities.com/leon_heller 
> <http://www.geocities.com/leon_heller>
>
>

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

From: "Markus Zingg" <homebrew-pcb@...>
To: <Homebrew_PCBs@yahoogroups.com>
Sent: Thursday, November 27, 2008 5:24 PM
Subject: Re: [Homebrew_PCBs] Re: Help needed with Riston film


> No, the rolls are "soft". Atleast all rolls from the laminators I had a
> chance to look at. I don't know what particular material the rolls are
> made off, but they feel like "rubber" or something like this. Obviousely
> they can take the heat though. I just noticed that most laminators seem
> to have smaller diameter rolls and the one I'm having most sucess with
> is useing a bigger diameter (more in the range of 35 to 40mm as oposed
> to ~30mm).

Thanks, Markus.

The Xerox rollers must have been about 80 mm diameter, and should work even 
better. I suppose something like that is used in the laminators used by PCB 
manufacturers.

Now I think of it, Xerox used two rollers - the heated one was coated in 
Teflon and was hard, and the lower roller was soft. A film of silicone oil 
was applied to the heated roller.

Leon