Homebrew PCBs

Leon wrote:
> I get excellent results with manual agitation - rocking the container. Some 
> years ago the ARRL Handbook had a simple PCB etching system using a 
> eccentric powered by a small electric motor to provide the rocking motion, 
> with a heat lamp for keeping the etchant hot.
> 

I'd have to agree. Periodic rocking produces about the best results next 
to full blown spray etching. The only drawback is it can be fairly 
labour intensive. You need hot solution to minimise time. The rocking 
method also has least amount of equipment and cost. Nothing more than a 
plastic lunch box filed with an inch of ferric chloride, heated in a 
microwave oven.

I think what would help is building some kind of special purpose holder 
so the PCB is elevated about 10mm above the container bottom.
One method I used was get some 6mm or 10mm acrylic plastic sheet (not 
PVC) and cut three squares 30 x 30mm.  A jigsaw or hacksaw cut is made 
down the middle of each piece about half way. This creates a slot for 
pushing in a PCB. To get the slot a tight fit over the PCB, you heat the 
plastic with a hot air gun until it goes soft. Quickly force in some PCB 
material into the slot and clamp it in a vice so the slot conforms to 
the correct width as it cools down. Now you have three push-on style PCB 
spacers that will keep a double sided board elevated.

I don't think there is an ultimate etching method, but it seems vertical 
bubble tank and manual rocking/brushing are the two most popular.

Adam