>> Hi,
>>
>> Microwave? Heh heh that's kewl. I'll have to try that.
>>
>> 8 minutes is very reasonable.
>>
>> However, I reliably etch 6 mil traces in about 45 seconds, in a cup of hot acid using a sponge.
>>
>> We each have our own schemas, I tip my hat..
Come to think of it, I'd like to share a bit more of my process.
I don't do laser and ironing (although I have LaserJet 2100 to print on drafting paper, or for traces under 10mil I give the job to a local shop with a phototypesetter on film)
I always do UV. Works very well for double-sided boards.
I cut the PCB material with an extra centimeter around the perimeter. UV work tends to be super precise, but quality decreases around the edges. In that extra centimeter, I place three vias/holes, two of them 1mm, one 2.5mm. With these, I can achieve excellent alignment between top and bottom masks.
I tie a piece of wire in the 2.5mm hole. I use it to slosh the board around in the developer; then, cold water wash, then etching in a 50C FeCl3, tupperware container, again moving the board around by that wire. Then a good wash again.
I then score the PCB along the 'real' dimensions, preparing that 1cm extra for removal. I drill, remove the lacquer with acetone, and maybe add a chemical tinning step (only if warranted)
Next, I make 'vias' with pieces of 0.7mm wire in 0.8mm via holes. The extra perimeter stuff still helps at this point, to hold the board in a vise.
Then, a was with soap, good drying, and I just snap the perimeter pieces off, sand the edges, and coat with flux pen.
Then it's on to component soldering, or perhaps keeping it in storage for a couple of weeks until I find the time for soldering and debugging :)
Two key lessons from the above:
∗ If doing UV masking, leave extra perimeter space. The masking there is always mediocre compared to what's in the center.
∗ A wire is probably the best way to agitate your PCB in chemicals, short of a full-blown specialized FeCl tank with heating and bubbling.