Homebrew PCBs

David Griffith wrote:
>  
> 
> 
> Where can I find a decent etch tank setup in the US that I won't have to
> spend a fortune on? I'd like to get one of these:
> http://www.computro nics.com. au/kinsten/ et/ 
> <http://www.computronics.com.au/kinsten/et/> but the shipping is going 
> to be
> a killer. Cereal boxes just don't do it for me.
> 

I'm afraid the hobby PCB market is too small to make etching tanks 
widely available and at low cost. You best to make it. If you are not 
far from a plastics supplier, then order some appropriate sized acrylic 
sheets (I recommend 4 to 6mm thick, 3mm is too week in my experience) 
and buy some solvent glue. Unless you have proper equipment you won't 
cut smooth enough edges for solvent gluing. Glue on some side stands (as 
shown above link). Buy a cheap aquarium 200W heater if your want to use 
persulfate. Keep the tank width under 30mm so the bubbles are forced to 
flow vertically. A wide tank is more difficult to get uniform bubbles. 
Most aquarium heaters are under 30m diameter, but check before you 
build. A bubbler is 1mm holes spaced at 20mm in PVC pipe running the 
*whole* length of the tank. Jam a block of rubber between this tube and 
tank wall or lay down a couple of stones to stop the tube from floating. 
Use largest air pump you want to pay for. Use plastic coated wire for 
PCB hanger. Let the PCB hang freely in the tank and provided you have 
sufficient air volume the board should randomly move about aiding etch 
uniformity. Keep at least 70mm of tank height above the liquid level.

Adam