I've had my Power pro 256 about a year now. When I first got it I tried to weld some aluminum but had a lot of trouble controlling the arc. Over time it just got worse and worse until this month when I couldn't even get the arc to start unless I scratch started it. I decided to open up the unit last night and look at the spark gap electrodes. One of them was twisted like a pretzel. I used a needle nose pliers and straightened them out and set the gap to 0.03" with a feeler gauge. I haven't had a chance to try it out again but here is my question. Do other people find that their spark gaps get misaligned over time? Or once you set them they stay set? My machine has been on a cart in my garage and hasn't moved more than four feet since I've bought it. I looked at Miller's spark gap and they look like something the military would have spec'd out. So I have started to design my own spark gap. I am going to mount it remote from the high frequency board on a piece of polycarbonate. Two aluminum blocks will each hold a piece of 4mm tungsten rod. The gap will be set just like the Miller set up by sliding the rods in the clamps and locking them down. I will round off all corners of the clamp to reduce ionization losses and use good quality high voltage wire to connect the unit to the board. Any thoughts? I think it will make this machine almost bulletproof.