flow forming hammer and process

Several weeks ago I decided to build a flow forming set-up for my advanced DCRL course. We're doing metal shaping and I thought this would be a good way for them to cut simple mdf or pvc dies to shape metal with. I purchased a 4X rivet gun and then machined the little delrin hammer tool you see above. It worked great and I was able to form these two pieces within a few minutes. The texture from my CNC die was even transferred. I think a urethane hammer tool would assist with not creating as many small dents, but these bumps are nothing for the air planisher to take care of. The 4X rivet gun has tremendous trigger control. If you're looking to get deep form in a small amount of time on a small scale object, then this is the way to go. I was working with 3003 aluminum; I might also mention that I didn't anneal the AL as I was too excited to try it out. The final depth was achieved without any annealing. This is totally not what I should do, but I just was too anxious to give it a shot.