Archive of the former Yahoo!Groups mailing list: Homebrew PCBs

----- Original Message -----
From: "Leon Heller" <leon355@...>
To: <Homebrew_PCBs@yahoogroups.com>
Sent: Wednesday, January 06, 2010 2:35 PM
Subject: Re: [Homebrew_PCBs] Dry film tenting problem & pattern plating


> ----- Original Message -----
> From: "Volkan" <v_sahin@...>
> To: <Homebrew_PCBs@yahoogroups.com>
> Sent: Wednesday, January 06, 2010 8:04 AM
> Subject: [Homebrew_PCBs] Dry film tenting problem & pattern plating
>
>
>> Hi,
>> I'm facing dry film tenting problems. It couldn't protect THP holes and
>> tents start to break during developing. I did some googling and saw that
>> this problem is known and according to Dupont technical articles, it is
>> recommended to increase exposure duration to avoid tent break. I tried it
>> and I saw great improvement.
>> Another recommendation was, to reduce roller pressure to avoid hole
>> sharp
>> edge cutting of the film. It is stated that pressure in the holes
>> decreases after lamination and it sucks film (film is liquid during
>> lamination) to the holes and because of that, sharp hole edges cut the
>> film. This cut decreases film strength. Another advise was to decrease
>> the
>> lamination temperature. I also tested both, they helped but didn't solve
>> the problem completely.
>>
>> My second try was to use pattern plating method. I tried electroplated
>> tin
>> as a resist and ammonium persulfate as an etcher, it didn't act as an
>> etch resist and etched away with copper.
>>
>> Any ideas/suggestions or does anyone faced similar tenting problems?
>> Which etcher can be used for tin or nickel etch resist? Is there any
>> practical formula for homebrewers?
>> I'll appreciate a lot on any guidance.
>> Thanks,
>
> There aren't many of us homebrew PCB makers here. Try the Homebrew PCB
> Yahoo
> group. Someone there has probably done something similar.

Sorry about that, I thought I was on the Pulsonix forum for some reason.
It's probably senile dementia setting in.

Leon