Return-Path: Received: from mail.cruzio.com ([208.226.92.37]) by truman.olsusa.com (Post.Office MTA v3.5.1 release 219 ID# 0-52269U2500L250S0V35) with ESMTP id com for ; Wed, 27 Oct 1999 04:02:45 -0400 Received: from testelectronics.mail (sa-207-251-8-29.cruzio.com [207.251.8.29]) by mail.cruzio.com with SMTP id BAA29109 for ; Wed, 27 Oct 1999 01:06:57 -0700 (PDT) Received: from main [192.168.16.1] by testelectronics.mail [192.168.16.1] with SMTP (MDaemon.v2.5.rB.b2.32-R) for ; Wed, 27 Oct 99 01:07:14 -0700 Received: by localhost with Microsoft MAPI; Wed, 27 Oct 1999 01:07:13 -0700 Message-ID: <01BF2017.9A830E40.ed@testelectronics.com> From: Ed Armstrong Reply-To: "ed@testelectronics.com" To: "'lancair.list@olsusa.com'" Subject: Plexiglass and solvents Date: Wed, 27 Oct 1999 01:07:12 -0700 Organization: Test Electronics X-Mailing-List: lancair.list@olsusa.com Mime-Version: 1.0 <<<<<<<<<<<<<<<<--->>>>>>>>>>>>>>>> << Lancair Builders' Mail List >> <<<<<<<<<<<<<<<<--->>>>>>>>>>>>>>>> >> Just in case any of you have used solvents with Plexiglass, and your Plexiglass has started crazing (little cracks forming at the cut edges and spreading out). You can stop it by flame polishing the edges with a propane torch. You can actually make the cracks disappear permanently if they have not gotten too deep. This probably anneals the edges of the part like Jim Cameron was saying. The idea of flame polishing is to melt the surface with the hottest (blue) part of the flame for a short time so that it flows but does not burn or boil. Hold the torch at the edge and move it along the edge at a rate of about 3 inches per second. Try some experimental pieces first to get the hang of it. I hate Plexiglass and never use it any more. Everything cracks up Plexiglass. Isopropyl alcohol will crack it up overnight. Cool Mist machining coolant will crack it up in about a week. I have used gasoline once to remove spilled paint, and it seemed to be OK, but I kept it away from the edges. Windex and Simple Green might work, but I would watch it carefully and stand by with the torch. Lately I have only been using polycarbonate commonly referred to as Lexan in my shop, it is much more chemically durable. I was hoping our windows were not Plexiglass. Regards, Ed Armstrong Watsonville CA. >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> LML website: http://www.olsusa.com/Users/Mkaye/maillist.html