Tom, I would like to know if what you have is positive resist or negative?
I like the positive to work with in the home because of the pcb
programs and
Ink jet printers. ( I use 2 prints stacked to get it black enough)
I used KPR resist for a number of years for all my hobbies, Ham Radio
and R/C Airplanes.
I sprayed some and dip some and found the best for me was an old 78 rpm
record player
and I just used an eye dropper to put some on the board in the center
with it spinning
this gave me the best results with it.
regards
Robert Blumer
Billings MT
twb8899 wrote:
> --- In Homebrew_PCBs@yahoogroups.com, "jcarlosmor" <jcarlosmor@...> wrote:
>
>> Hi to everybody. I would like to start this thread to know/share
>> different experiencies about dry-film processing (home-made lamination,
>> imaging, developing, etc.)
>> Right now I am planning to build a laminator, uv-exposure unit,
>> developing tanks, etc. (all of them DIY of course). After almost 15
>> years using all other methods of PCB fabrication, including silk-
>> screening for whole big quantities of PCBs, I am tired of doing that
>> kind of stuff again and I am planning to use the dry-film method (the
>> only one that I should learned many years ago).
>> What about the ThinkTink supplies (resist and soldermask)?
>>
>>
>
>
>
> I may be able to help with dry film if anyone is interested. I ran a
> commercial multilayer board shop for over twenty five years. Dry film
> was the only resist we ever used. The earliest dry films were
> processed with solvents and bad news to work with. We got into the
> business right as solvent based films were being phased out.
>
> We started out with semi-aqueous dry film which required a small
> amount of butyl carbitol solvent to be added to the water based
> developer. Butyl carbitol is a water soluble solvent and it helps to
> remove the adhesion promoters left on the copper surface. When the
> total aqueous films came on the market the solvents were no longer
> needed. Now days all dry films are processed with weak sodium
> carbonate (soda ash) solutions.
>
> I use a DuPont HRL-24 laminator to apply the dry film. Developing is
> done in a batch type spray tank similar to a spray etcher. After
> etching the dry film is stripped in a weak sodium hydroxide(lye) solution.
>
> When Kepro shut down their facility I purchased most of the larger
> equipment they had for my own use. This included their CNC drilling
> equipment and the entire silk screening department. Jim Keil who owned
> Kepro is a personal friend of mine and he said I should offer the
> photo resist coated materials for the small shops and hobby guy's that
> use it. Thought about doing that many times but I don't know if there
> is enough interest these days. Kepro couldn't do it any longer but
> then again they had a large operation and the overhead that comes with
> it.
>
> Using photoplotted or camera shot films and dry film photo resist will
> produce the finest quality printed wiring with a minimal reject rate.
> The boards I use for my products are not very large and working alone
> I can produce as many as one hundred pieces in an afternoon using
> these methods with almost a 100% yield everytime.
>
> If there was enough interest I would offer these materials for sale.
> Any comments or suggestions on this topic would be appreciated.
>
> Tom
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