Homebrew PCBs

On 19/03/12 22:10, John Anhalt wrote:
> For my aerator, I use an aquarium pump and plastic tubes from the pet
> store.  I would not recommend the stone variety.

Funny you should say that.... you just described the aeration setup in
my etch tank :)

I've got one of those foam bubbler hoses glued to the bottom of the tank
with five-minute epoxy, then a hose running up one side to an aquarium
air pump.

I've also got the option of using a VisiTherm heater to warm the
etchant, but I need to fix the holder -- the rubber pads have started to
degrade and no longer stick to the plastic tank wall. In any case, it's
only a 50W heater and takes ages to bring the tank up to a reasonable
temperature.

> I agree with you on the photoresist.  Occasionally, a seller of small
> quantities will appear on ebay.  I haven't tried it yet, but have
> wanted to ever since first reading about it several years ago.  I am
> afraid the manufacturer for my pre-sensitized boards (Injectorall,
> available from DigiKey) is about to close shop.

Thankfully I don't think Mega are going that way -- they seem to have
been around for many years, and actually make two different precoated
boards --
  - Fotoboard2 -- a roller-coated positive-acting board (Leon seems to
like this one, I haven't tried it.. yet). Rapid sell this quite cheaply.
  - Microtrak -- dip-coated, positive acting. Apparently produced by
Instagraphic Products, then later by Mega themselves. Allegedly better
for fine-pitch work, bugger all price difference vs. Fotoboard (IIRC
Fotoboard is about 5p cheaper). I've had problems with one or two edges
of this stuff being uncoated, up to 1/3rd of an inch from the edge...

Well, I've got 10x Fotoboard2 blanks on order.. who knows, maybe they'll
work better than Microtrak?

Thanks,
-- 
Phil.
ygroups@...
http://www.philpem.me.uk/