I have had to repair several cracked plastic body parts recently, and have found the following repair procedure to work very well:

1) Drill stop crack ends depended on nature of crack and difficulty in glue placement. If you stop drill you will need to fill the hole for best result.

2) Tolulene-base glue (model aircraft glue) is used to soften/reconnect the crack line. Work glue into crack by shifting the parts. Clamp if possible to bring crack line surfaces as close together as possible.

3) Let glue dry completely, 2-4 hours in warm temps.

4) Reinforce back side of crack line w/ ripstop nylon strips (old umbrella is my source of nylon ripstop) throughly soaked in tolulene glue and laid over the crack line. Use knife or spatula to work all bubbles out of nylon strips. The nylon is resistant to the solvent in the glue.

5) Let repaired part dry overnight, if possible before 1st use.

Result is a strong, reinforced repair seam that will barely show the crack line on the front side.

I adapted this from a description I read of a plastic bumper crack repair using epoxy glue. I've found the tolulene glue is better at fusing the crack seams than epoxy.

Any holes or missing parts can be filled w/ a 2-part epoxy repair material such as J&B weld, my favorite. Smooth and paint if necessary.

Anyone else got any tips for plastics repair?

Regards

 

ABS plastic will bond well with the same glue that is used to bond sprinkler pipe. It's cheap and it holds very well. John

 

Ditto the above. Most plastic parts are marked witha recycle symbol that tells what type of plastic it is. For ABS parts I use ABS plastic pipe adhesive. For PVC I use PVC pipe cement. For other plastics if I can't find the "proper" cement to match the recycle mark I use the std plastic welder type glue. For metal to plastics I use epoxy or JB Weld which is a "filled" epoxy. Clean surfaces are important. Surface prep either with a solvent or mechanical (sandpaper) method is very important.

Most of the plastic parts in cars are either ABS or a filled plastic with epoxy or polyester binder. The filled plastic will usually appear grainy inside or will have threads or fibers in it. Epoxy works well on these types of filled plastics unless you hit one that is a filled polyethylene (like plastic milk jugs) that nothing sticks to...

 

Outstanding help. Please keep it up.

 

Reasonably priced, high quality commercial plastic welders with easy to replace parts.
These units are a sort of a cross between a soldering iron and a hot-melt glue gun, and work well. One job often pays for the welder because of the plastic body parts you don't have to buy.
They also work beautifully on motorcycle plastics, including those on ATVs and motocrossers.

http://www.laramyplasticwelders.com/tipspage.html