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Greetings SMMO's, ;)' I couldn't let Emile and Greg Cottrell have all the fun. So to get my feet wet with blow molding acrylic domes, I worked up a small fixture and made my first acrylic dome. It's just 7.25" OD and made from a .093" thick piece of Optix by Plaskolike acrylic sheet. I had a extra piece of this acrylic, of which I usually cut up into sandblasting hood lenses. I was shooting for a 135 degree dome, but I didn't have the right amout of heat soaked up into the acrylic to be able to make it blow that far, so I ended up with about a 125 degree dome. I just used my oven to heat the whole assembly. I don't currently have a computer controlled oven, or a proper way to check the oven temperature, so I set the oven to the middle of the thermoforming temperature speced for this brand of acrylic and it worked out. I used clay to seal the acrylic to the bottom layer of plywood. But next time I would like to use a rubber sheet and craft faced plywood or metal. http://www.frappr.com/?a=viewphoto&id=2384531&pid=9407839 I had some moister in the plywood I used that I should of cooked out before I attached the acrylic. Next time I'll do a shrink cycle on the acrylic before I try to form it so I don't get any bubbles in the finished product. As it turned out, I only got a couple of small bubbles. But for a first attemp I'm very happy with it and I learned a fair bit. Does anyone need a bow dome for there RC sub. ;)' Regards,
Brent Hartwig |