Inflated the expansion chamber today, ended up just okay. I think I will try a slightly different pattern shape and make another one. I will give the next one a bit more pressure, the waterblaster didn't even break a sweat. I cut the ends off and hammered out some of the buckled parts on a round stake. Some stretch marks where I annealed the steel I cut a bit of metal from the 'corners' and rewelded it. Side view, could have done a with a bit more pressure but it was slightly scary seeing it stretching so much! looks alright cleaned up. Fits on the plane too!