roel_cnc wrote:
> --- In Homebrew_PCBs@yahoogroups.com, Adam Seychell
> <adam_seychell@y...> wrote:
>
>>
>>roel_cnc wrote:
>>
>>>i already use dry film - spray etch and cnc drilling and works
>
> for
>
>>>several years now .
>>>
>>
>>How do you apply the dry film ?
>
> not with (boiling)water - it wolnd be a dry film anymore :)
> I used in the past a aloy plate aprox. 30 mm thick and build a heater
> from a washing machine:) in, and a thermo unit from an oven to
> control temp.(+/-100 C.)
> clean the board putt the film on and lay it on the heated element-
> instant roll with a soft one over it pressing hard off cause.
> i still use this for the soldermask dry film part
>
> the resist (new way) i use this moment parts from an big copier
> silicon roll with heater inside - works awesome.
>
> remember there are 2 sorts off film the resist and soldermask ive got
> from both 2 rolls 25 meters eatch as samples :)
>
>
>
>
> the spray etcher i build has on both sides a ring off pvc pipe (used
> as air-pressure tube in factory's) with nozzles from a carwash unit.
> just washing your car sometimes with the right wrench :) wil do.
> same unit for development but cheaper pump
>
> the pump is the most expensive part off all got some docs somewere
> around - and dont forget a real pump use atleast 1 to 1,5hp motor
>
Roel,
What type of etching solution do you use ? I assume
everything is plastic, including the nozzles. A 1,5hp pump
definitely is a good size. I was thinking of using more like
1/4 hp centrifuge pump. to give 1,5 bar at 20 liters/minute.
That should be enough for a single sided spray etch with
sweeping spray nozzles. Does the spray oscillate in any way
or is both the PCB and the spray stay still during the
entire etching time ?
I do not have any solder mask material yet. Does the
soldermask you own work by photo imaging ? If so then does
it also develop in 1% sodium carbonate ?