Repairing plastic parts on your bike

Here are some pictures that LRCXed posted about how he has used Plastifix on some side covers:

http://s325.photobucket.com/albums/k378/LRCXed/Plastic%20repair/

Here is a post that gopher posted on side cover tab repair (photos now missing thanks to Photobucket):

There seem to be many good ways to repair broken side cover posts. This method uses plasticene and plaster of paris to make a 2 piece mold to cast a replica.

The knob and its shoulder is the part needed. A plasticene base was made roughly parallel with the flat shoulder.

A flat piece of plasticene placed over the mid line of the knob and stuck to the base. The indents are for registering each mold piece to each other.

The wall for one side of the mold in place. Watered down dish soap was brushed onto the plastic parts so the plaster of paris wouldn't stick.

Filled with plaster

The mid-line wall pulled back, a little rough but it'll work. The indents had air bubbles trapped in them but it will still do the job.

The other side wall stuck on and filled after the plastic and the hardened plaster on the first side was well lubed with the dish soap.

Plasticene pulled off and the halves seperated. The side covers are not damaged but do need a clean-up.

I also made a mold of the other bigger post just in case. The trimmed mold halves fit beautifully together but need a few days to dry out and harden before the epoxy and fiberglass cloth posts are cast. More then.

Lots of 15 minute jobs. 6 or 7 strips of fiberglass cloth were folded at their centres, dipped in epoxy and poked down into the mold with a small paintbrush.

The cured cast was hard enough to remove from the mold in a couple of hours. The softer construction grade plaster was worn out after four casts.

The knob and shoulder was trimmed and shaped with a file and sandpaper.

The knob was fine tuned with 320 gr. sandpaper so when lightly lubricated it snapped into place with no in/out slop.

The side cover is held in the proper place in the front by the two remaining posts. At the rear, a thin rubber block held with masking tape temporarily position it out from the frame(top) and paper shims and masking tape centre the covers' notch around the chrome rail.

A 6mm(1/4") square spacer was hacksawed out of some cured epoxy left over from the bottom of a mix cup. A small needle-nosed vise-grip was used to hold it while the ends were trimmed with a file to approximate length and angle. Couldn't think a of a good way to clamp it in place while the 5 minute epoxy hardened so I held them (did both sidecovers) myself. Yes DavidfromW, there was another 10 minutes.

The recreated knob and shoulder is positioned correctly relative to the front two posts, it is the right distance out from the cover, the oblong head is aligned with the oblong grommet hole and the shoulder in the same plane as the grommet face. Back in a few days with the final installment.

Epoxy mixed to a putty consistency with lightweight 'microballoons'

Excess carved off. The shoulder and post was changed to round instead of the original square to make the cloth application easier.

Sanded with 120gr. Faired part sanded easily, epoxy was hard.

4 strips of fiberglass cloth were epoxied overlapping the sidecover at the bottom and edge of the shoulder at the knob.

Sanded to 320gr.

Leftover 1998 GMC Astro 'red maple' rattlecan is surprisingly close. Finished.

Thanks for the tutorial, Gopher.