Electronics > Projects, Designs, and Technical Stuff

applying dry film without water??

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coppercone2:
After about 20 attempts to laminate a PCB, I discovered that the water method is basically the only thing that works.

under 20x zoom I basically see that there are tons of microscopic air bubbles that form if I actually try to use it dry. I think a big bubble gets squashed into molten gel and it makes little bubbles.


Pushing water out of the thing seems to work alot better (putting a soaked one in the laminator)


Has anyone honestly managed a good PCB that stands up to microscope inspection by applying dry film to it dry?

I dunno if there is some mechanical trick I am missing, but it seems totally impossible to lay this shit down without air under neath it that turns into micro bubbles.


It seems to work OK to wet apply 1 side, roll it on with laminator, then do the other side.


Its like air gets sucked under neath as its being laid down. I dunno how the fuck it gets in there because it does not make any sense conceptually. as slow and steady as I can manage I still got air.


Its not that the wet does not work, its just that its fucking baffling as to why it won't apply dry .

i mean its like feels like its sweeping air under a rug while your trying the lay the rug down. like some fucker with a broom is sweeping sand in your direction you are your unrolling a carpet.


I feel like all this shit would need to be gauge block flat and aligned to work properly. the foil aint gonna do that.

I don't think it can actually push out much air if its dry. it just mashes it into the gel and makes micro bubbles to hide the air. i don't think its even deforming like you would think it deform  like a bed with a bowling ball. i think its like deforming more in 1 direction and making some kinda cross shape that sucks air into the edge or something.


does tension fix these fucking problems? is it because they got a giant ass roll of it thats being pulled on and they end up wasting 10 inches of copper before it gets like properly extended to make actual like good contact ? like they end up cutting a 10 foot pcb to 9 feet because the foil is fucked up where it starts before it stretches out or something?

Terry Bites:
It only works with a laser printer.
Make sure the board is really clean.
Use fine steel wool and rinse with IPA, MEK or Acetone.
Wipe with kitchen towel. Do not touch with fingers again.
Moderate your language.

Watch Herr Carlson:

antenna:
I do it dry, but I don't inspect mine with a microscope.  I do get bubbles, but usually no more than 10 small ones on a 3"x4" board.  All of the ones I can see with a magnifying glass I poke with a sharp needle before heating with the hair dryer and pressing the film so the air bubbles can escape directly through the film backing.  After the carbonate wash to remove the unexposed film, I touch up any bubbled spots that didn't stick using a small metal fingernail paint applicator and fingernail paint before etching.  After etching, I wipe off the nail paint with acetone so the KOH wash gets all the film that the paint may have covered.

coppercone2:
alright I meant the PCB material I know the printer can do it OK

the gel film you put it on terry, it will make you nuts if you try to use it dry


basically when I apply it wet, that is, I get a sink filled with water with a plug, throw the PCB in there, peel a corner of the film, take it under water and open it in such a way that its opened all bubbles go up. Make sure you don't flip it, but you can feel its tacky even under water


then you align the top with the board and gently drag it out at a 45 degree angle. then you can use scissors when wet to trim it exactly around the PCB


then you dunk it in water again and make sure its applied after cutting. It should be 100% adhered. it makes a vacuum when you pull it out

then I noticed with the thin blue film its ready to stuff into lamina tor with the green thick solder resist film the water might veal a wrinkle because its too thick for the water vacuum to work. so you might need to massage it a bit with a drinking glass or something


anyway once you roll it through lamina tor around 8 times it seems to push out the water and be glued on. If you notice a wrinkle in the lamina tor after first pass through, you can still peel it off if yo run it at 100c and put new film on (don't drain the sink till your done).



for double sided, do 1 side, then go back to sink and apply to other side. it stays (including protective film) if you redunk it). you don't need to apply it on both sides wet at the same time.


also it seems to skid in the laminator so you need to maintain pressure on the back of board


I am getting 0 bubbles with this method. make sure u wipe away excess water by padding with a task wipe so make sure the minimum of water goes into your laminator. having a manual laminator to do the first push water out pass by hand would make the process safer.


for the blue film it hardly matters I think, I use tap water. for those doing HV boards with DIY solder resist, you might wanna get a tub of distilled water to keep the interface cleaner (the film seems to be tough as hell but it can't hurt to use cleaner water for a permanent coating)



I scrub my stainless sink down good, then apply citric acid spray to passivate it, rinse again after 1/2 an hour, rinse it good. then its a good stainless steel tank to use for this process. If you have a old beat up stainless sink you can restore it. I mean or you can use a plastic tub but I get mad irritated when I have to put water in a tupperware, the sink is like official. And scrub it down with soap and soft towel when you finish to get any PCB-crap out of there that might have diffused from the gel


and for the sink, let it settle for 10 minutes to get out any bubbles in the water, squeegee the surface of the sink from bubbles under water that might rise up under the dry film

coppercone2:

--- Quote from: antenna on June 17, 2024, 05:48:13 pm ---I do it dry, but I don't inspect mine with a microscope.  I do get bubbles, but usually no more than 10 small ones on a 3"x4" board.  All of the ones I can see with a magnifying glass I poke with a sharp needle before heating with the hair dryer and pressing the film so the air bubbles can escape directly through the film backing.  After the carbonate wash to remove the unexposed film, I touch up any bubbled spots that didn't stick using a small metal fingernail paint applicator and fingernail paint before etching.  After etching, I wipe off the nail paint with acetone so the KOH wash gets all the film that the paint may have covered.

--- End quote ---

the water method gets 0 bubbles its amazing. its not as nice as MG chemicals for me yet, but I think thats because there is some gunk stuck on my roller, I need to take the laminator apart


the biggest issue for keeping them clean is to trim the PCB very precisely when the foil is applied, or leave extra copper around the edge.


I trim it after applying because I noticed every time I use the 'tape trick", it distorts the film a little bit under where the tape was. so I cut that off after its applied to the PCB



The other problem with running it dry is that sometimes it will stick to the material under the PCB (work surface) more then the PCB and then you get a tension line when you try to apply it with air under neath. glass is a bad choice for dry work. Maybe if you had a big teflon sheet. but i think its worth working wet



and for practice use oven cleaner to dissolve it off the PCB. you spray it on and 10 min later its all dissolved. then rinse it with a strainer

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