Homebrew PCBs

Leon Crowther wrote:
> 
> Although I have not tried it myself, It was suggested to me that for 
> best results a layer of uniform thickness is essential. 
> So to accomplish this place the PCB flat and with two strips strips 
> of brass shim place them on the board along two opposite edges and 
> then spray the board. Now with a glass tube or suitable rod gently 
> roll this along the board with its ends bearing on the shim. This 
> should roll an even thickness of resist equal to the thickness of the 
> shim. 
> Note - I have not tried this, so there may be unforseen problems, I 
> realise the glass would pick up some of the resist behind it, so 
> maybe more than one rollover is necessary. Anyway it may be worth a 
> try, unless someone warns against it from experience.
> 
> What are you spraying the board with, the Electrolube product or is 
> there another product available?
> Electrolube also sell a developer for their product, a bit expensive 
> but it may be something special. 
> Does anyone know if their developer is necessary or will anything 
> else do?

11g/Lt of sodium hydroxide is ideal for developing prp. It is important
that the pcb is free of oil before coating with prp.

> --- In Homebrew_PCBs@yahoogroups.com, "crankorgan" <john@k...> wrote:
> 
>>1.Clean board
>>2.Shake can before each use.(What I did not do the first few times)
>>
>>(in the dark with safe light)
>>3.Tilt board upright on 45 degree angle
>>4.Spray from right to left working your way to the bottom
>>5.Blot off excess that runs to the bottom of board
>>6.Lay board flat to dry. (I used an old hair drier to
>>dry the board.)
>>
>>I found I need more exposure time than the instructions in order
>>to get a good trace.