Niels Blaauw <niels.blaauw_at_wanadoo.nl> wrote: Closing holes is not that difficult, but the result will never be as strong as the original. Too true, especially as most polyethylene that isn't actually a copolymer with other units will absorb quite a bit of water. To fix a hole: Put a support under the hole, with a piece of wood, metal, wet towels or whatever. Metal (steel) works really well, as resolidified PE will not stick to it, and it doesn't suck off too much heat, weakening the bond. Heat up a strip of plastic till it is melting/burning/vaporizing/dripping. Really hot. While keeping this strip hot, heat up the edge of the hole, so that too is melting. You want it almost burning-hot. Use your knife or a piece of scrap metal to scrape off any soot or carbon- that is guaranteed to weaken the bond and be immensely water pervious. I generally try to hold my breath at this point! Word of caution: molten PE has a really high thermal capacity. A pinhead-size drop will give you a heat blister the size of a dime. You may not be able to wear gloves without sacrificing dexterity, but do wear a sturdy apron! Obviously, it is also a bad idea to wear synthetic-material clothing at this point. the finishing touch. Holes up to 8 millimeters can be closed quite nice in this way. It does take practice! 8mm is a really good size threshold; above that you'll really want to use a solid patch or dutchman (term of art-sorry Niels!) slightly bigger than the hole. It is useful to clean the surfaces first (sandpaper, 0000 steel wool, and acetone are what I use, in that order). Finding a strip of plastic to make the repairs can be difficult. Various fun melty-goo plastics can be had from ski-repair outfitters like www.tognar.com The copolymers they offer are quite a bit more rubbery and flexible than PE, useful if you need more adhesive power. They take quite a bit more heat than straight PE, and it is good to have a gas torch with a brass anvil to actually make the weld. The delamination repair epoxy they offer is really, really fun. Not as solid as West System or PC7, but nicely flexible. It works on carbon fiber bikes, too, hee. --------------------------------- Do you Yahoo!? The New Yahoo! Search - Faster. Easier. Bingo. *************************************************************************** PaddleWise Paddling Mailing List - Any opinions or suggestions expressed here are solely those of the writer(s). You must assume the entire responsibility for reliance upon them. All postings copyright the author. Submissions: PaddleWise_at_PaddleWise.net Subscriptions: PaddleWise-request_at_PaddleWise.net Website: http://www.paddlewise.net/ ***************************************************************************Received on Thu Apr 17 2003 - 13:26:42 PDT
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