Homebrew PCBs

On 16/03/2010 19:03, Philip Pemberton wrote:
> Hi guys,
>     Just a quick note -- it appears the developing chemistry in the Seno
> SN110 roll-on developer is too weak to successfully develop Fotoboard2
> (which is currently sold by Rapid as their "RVFM Photo-Etch PCB"). I've
> just wasted two Eurocard blanks trying to figure out what was going on,
> only to find that the boards developed FAR quicker in a higher-strength
> metasilicate developer.
>
>     Whatever the developer in the SN110 roll-on is, it isn't
> metasilicate. It does work fine on the CIF photo boards (e.g. Farnell
> P/N 126-7748; in fact, it's a really fast-working developer on those). I
> haven't tried it on the Farnell-sourced boards I have (P/N 320-4959)
> though I suspect the results will be similar. From what I can gather,
> these are the MicroTrak boards that Mega sell -- light blue lightproof
> sticker with a white paper label on top of that which covers almost the
> whole 160x100 board. Country of origin is Germany, recommended developer
> is CPD5 (320-4996).
>
>     Also, the Farnell metasilicate developer (320-4996, made by Mega and
> sold by them as CPD5) is FAR too strong at 1:1 strength for these
> boards. The bottle says 1ltr developer to 4ltr water (1+4 mix, or 1/5th
> dev to 4/5ths water). Mixing at this ratio caused the "stringy peeling"
> effect noted in the Rapid datasheet; it seems half or a quarter of this
> concentration may be more appropriate.
>
>     Three and a half hours wasted...
>
>     Does anyone know of any other "incompatibilities" like this?
>

I use sodium hydroxide solution to develop Fotoboard 2 (12 gm/litre).

Leon
-- 
Leon Heller
G1HSM