RE: PCB Etching (Was : Phono Faceplate - Photos)

["Keith Doxey" <keith.doxey@xxxxxxx>]

Hi Ian,

Etching Instructions posted separately.

> -----Original Message-----
> From: Ian [mailto:I.Bird@xxxxxxx]
>
> How did your etching and circuit building go as below

2 of my boards etched OK. I cocked up the exposure times for 2 of them so
they went in the bin. Drilling the boards went reasonably well apart from
snapping one of my Tungsten Carbide drill bit :-(

Fitting components and testing tomorrow night......

YES MARK....I know thats slower than I told you but things dont always
happen like they should :-(

> I still
> haven't got the etching fluid out but I will this weekend (in the
> garage). I
> have enough for one pint so only one weekends worth.
>

You can save the etchant in a plastic container. I went to the local photo
lab and got a couple of their old developer bottles. WASH THEM THOROUGHLY.

You cant save the developer but its only a teaspoonfull of sodium hydroxide
and that is dirt cheap.

> A quick question. I have lots of clear transparencies from my college
days
> and plan to print on these using a laser. You are talking about opaque
> film - are you referring to ink jet tranparencies which are
> coated? I assume
> this is not ideal if thats what you mean. If not, why opaque drafting
film
> and where do you get it? Will ordinary transparencies do?
>

Clear transparencies are OK but the image always looks more solid on opaque
film. You can get it from any office supply place. Opaque is better because
it diffuses the UV so that you get even distribution all over the board.

> Do you print the component outlines and numbers like R1, C1 etc. on
the
> 'top' side or work from a printout. How can these be printed?

The Pro boards have a green solder mask printed on them on both sides and
then a silk screen overlay on the top to show component placement. That
isnt
easy to do at home !!!

Someone mentioned that a Laser print can be ironed and the toner will stick
to the board. Print the image reversed and give it a try!
You will have to align it properly. Thats probably easiest after drilling
so
you can put a couple of pins through to aid alignment.
If it works then great....if not...nothing lost.

If it fails then just work from a printout. Print it at 200% so you can
read
the legend ;-)

Hope that helps

Keith



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