<html><head><meta http-equiv="content-type" content="text/html; charset=utf-8"></head><body dir="auto"><div></div><div>Hank,</div><div>Spelling mistake. Pressure is going to be HUGE.</div><div>Alan</div><div><br>On 22/04/2019, at 8:28 AM, Alan <<a href="mailto:alanlindsayjames@yahoo.com">alanlindsayjames@yahoo.com</a>> wrote:<br><br></div><blockquote type="cite"><div><meta http-equiv="content-type" content="text/html; charset=utf-8"><div></div><div>Hank,</div><div>I had a go at forming an acrylic ring out of a straight piece of 1" thick</div><div>cast acrylic, using a modified kitchen oven.</div><div>At forming temperature the acrylic was like the hardness of eraser rubber.</div><div>Maybe there is technical literature on what shore hardness it actually is at</div><div>forming temperature. Anyway if you are forming a 5" block the pressure</div><div>Required is going to be used.</div><div>When I had a 1" thick dome blown for me they had to stop & get thicker</div><div>Clamping rings made.</div><div>Emile or Greg may like to comment on this as they have had a lot more experience.</div><div>You will need a temperature controller for a kiln, & program it for your requirements.</div><div>It will be a few days in the oven I would imagine.</div><div>If you machine it, can you get away with not heat treating it afterward?</div><div>I would imagine the stress would only be superficial.</div><div>Alan</div><div><br></div><div><br>On 22/04/2019, at 2:11 AM, hank pronk via Personal_Submersibles <<a href="mailto:personal_submersibles@psubs.org">personal_submersibles@psubs.org</a>> wrote:<br><br></div><blockquote type="cite"><div><div class="yahoo-style-wrap" style="font-family:Helvetica Neue, Helvetica, Arial, sans-serif;font-size:13px;"><div>Hi All,</div><div>I am looking for the actual PVHO rules for Acrylic forming. I can find all the references to the rules but not the rules. I am planning to make a 5 inch thick 60 degree Hemispherical segment either from forming or from machining out of a thick slab. I prefer to form it because I will need an oven to heat treat it after anyways, but I don't want to form it without the rules.</div><div>Hank</div></div></div></blockquote><blockquote type="cite"><div><span>_______________________________________________</span><br><span>Personal_Submersibles mailing list</span><br><span><a href="mailto:Personal_Submersibles@psubs.org">Personal_Submersibles@psubs.org</a></span><br><span><a href="http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles">http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles</a></span><br></div></blockquote></div></blockquote></body></html>