Homebrew PCBs

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 ?