Homebrew PCBs

On Thu, 22 Jan 2004 03:47:41 -0000, Ben H. Lanmon <bhleavi@...> 
wrote:

>  > i think with the proper tubes (4 at 7") you should have 30s.
>
> Well I tried the Blacklite tubes that I ended up with because as I
> remember M.G. Chemicials had said that they could be used but that
> the none filtered or non blue tubes where recommended.
>
> I have never exposed a board for 30 seconds.  As I said it is about
> 5 - 6 seconds what I found that worked and have been for years.  I
> used a mechical timer switch to set the time.  The longest I have
> exposed is maybe 10 sec. I dropped down to the 5-6 secs just
> expermenting to see how short of time that I could do.
>
> I took a picture of one of my boards the other evening, I will see
> about posting it in the files area. It was exposed for 5-6 sec.
> developer is the M.G. Chemicals  which is Sodium Hydroxide.  I etch
> in Ferric Chloride 5 gal. homemade bubble tank.
>
> Ben
>

maybe the MG resist is just different from the one i used with 30 
seconds...
most likely...

Everybody has to try it out, with his boards and light source.
Anything else seems to lead not very far..

ST