Homebrew PCBs

synchronousmosfet@... pravi:
> Guys, thanks very much, I appreciate the feedback.
>
> I can definitely see some mistakes I've been making with the transfer method...it really surprised me to find out from several of you that 8 passes are sometimes needed, it honestly didn't occur to me that additional passes would make any difference.
>
> I have to make a fundamental decision...whether to try yet again to make the toner transfer method work....I mean, I DO have all the stuff, the special paper, the green film, the laminator, etc., etc., ...and just get CRAZY about cleaning boards, using solvent, doing a zillion passes, etc., and WORKING on the process until I finally get it to work RIGHT....
>
> ....or to go straight to the photoresist method. I realized in writing this I accidentally lied...I had forgotten that even though I did buy an exposure setup and photoresist boards, etc., I never tried using that method...because the cost of those photoresist boards seemed too high to me.
>
> So....go crazy on the toner transfer method until I get it RIGHT, or go with photoresist and accept the higher cost of the boards....
>
> Any consensus on this?
>
> Very Best, Charlie
>
>   
Photo VS Toner Transfer?

That's the question...

Do not use TT for lines under 8 mils. (I do my routing with at least 12 
mils and go thinner just where need to be - SMD chips with 0.5mm raster)
TT is NOT PRECISE. I can get TQFP44 package on board with TT. But I 
can't get 10cm long connector to fit into holes. The paper and printout 
is just skewed and not precise enougth for that job. The image is very 
hard to align(near imposible) with CNC drill.

So if you careful plan board and isn't big the TT is way to go. If you 
have big board or big component with many pads then don't use TT.
You must find where limit is. The 20cm x 30cm board and just ordinary 
chips (CD40xx, 74HC... DIP PACKAGE) is plausible. Same board with ONE 
connector run in one side is NOT.

And TT is cheap. You can transfer image and check if component's fit. If 
not You can scale image and try again. Just use one piece of 'other' 
unetched pcb and scrub all the toner from the working one. Don't use 
chemical.

I do not use photo. If board is double sided or I can't do it with TT 
then I send that to the PCB house to manufacture it.

Slavko.