[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index][TeamRC17] Plastic welding instructions in case people need them
Morning all,
I found this gem in one of the Usenet groups that I read, and thought it may
be of some use to some of you. (Particularly Benn, if he's looking for new
fairings...)
Viking
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Cracked plastic fairings are actually quite easy to repair by plastic
welding, and well within the scope of a 'first timer'. Get yourself a
pencil type soldering iron, some exacto knives, enough bits of busted
fairing to make a whole (eg two halves damaged on opposite sides, or all
the pieces of one fairing) some ABS welding rod, a foot or so of stainless
steel window screen and proceed as follows;
Use exacto knife or similar instrument to match odd fairing bits. If you
are working with the pieces of one fairing, 'vee' each crack you are going
to weld so that you have a 60 degree included angle vee groove. The vee
should be on the side you will weld, which should be the back, unless this
is impossible.
When you are ready to weld stick the bits together with duct tape on the
opposite side you are welding. All you want to do is apply enough tape to
keep everything from moving around while you weld. Using your soldering
iron make tacks spaced about 1" to further hold everything in place. Stick
the soldering in the groove, let it melt the sides of the groove, and feed
in a small amount of filler rod. Same process as gas welding. Your
objective is to soften the plastic to point where a bit of pressure causes
it all to mush together. When it is all tacked up, start filling between
tacks. Move around, do an inch at the top, the bottom and the middle,
don't be heating the same place constantly. You are trying to get the same
kind of bead you would get if you were welding steel with welding
equipment.
When you have a bead in place, cut stainless steel screen about 1" wide and
1" longer than the seam you are welding. Put the screen on top of the
weld, so you have about 1/2" on all sides. Apply heat to the screen so
that it melts the plastic below and gently push down so the plastic is
forced through the screen. Smooth it all down with soldering iron and
filler rod if necessary. Hide all of the screen or at least bury it in
plastic. The resulting reinforced weld will be stronger than the original
piece if you do it right.
Remove duct tape, check for full penetration, rasp down the high spots,
fill the low spots with bondo, sand, prime and paint.
Work in a well ventilated area, do not allow soldering iron to get so hot
that it smokes more than just a little bit, and do not inhale the fumes, or
you will die. Contrary to what you might think the plastic does not stick
to the hot soldering iron. It will stick to a cold one tho, so if the
plastic sticking, let the soldering iron get hotter.
Most bike wreckers will have plenty of busted fairings, and they generally
will let you have them for not much money. Practice on a scrap piece, it
really is easy. You can find more information on the internet, most of it
pertains to auto body. Guess what most cage bumpers are made of these
days? Don't get sucked into buying expensive plastic welders tho, chances
are they won't work any better than a 10 dollar home depot soldering iron
(at least one $400 professional auto body kit is exactly that). Auto body
supply stores are also a good source for ABS welding rod. Most MC plastic
is ABS, but if it ain't you will need to find out what type of plastic it
is. This is not easy. In a pinch you can cut your own welding rod from
scrap.
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--
ObRandomCynicalComment:
C is like a huge V8 engine, attached directly to wheels with no
gearing, no brake and must be steered by hand. Perl is a car with an
autopilot designed by insane aliens.
-- Jeff Smith
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