Repairing Plastic Body Panels

Most street motorcycle plastic bodywork is made with either Styrene or ABS plastic. Here's a method for repairing these bodywork panels that's effective and inexpensive.

I've repaired any number of motorcycle side covers and fairings over the years. Up until now my stand by material was JB Weld. Even though I knew that it didn't adhere to any plastics very well.
Today there are many plastic repair epoxies that actually do adhere to a wide range of plastics. My first comment is that: Most of them smell like nerve poison, Seconded quickly by my stumbling on their unit costs. You know that they're exotic chemicals because you're Paying for Exotic Chemicals!!!
I don't pretend to be a chemical engineer and I've never worked in a body shop, but recently I did have a momentary flash of understanding that may make your plastic repair experience less expensive and significantly easier.
For purposes of this discussion, since I'm not an enjuneer, I'd like to divide motorcycle plastics into three crude categories.
1) Black plastic, usually ABS.
2) Chromed plastic, usually a sputtered metallic coating on what I loosely refer to as styrene plastic.
3) Polyethylene plastics, usually used on dirt bikes and personal water craft because they are very flexible and float.


Black or ABS plastic:
Currently I'm repairing a chopped down fairing for my 85 1300. It has several large stress fractures that I think are caused by vibration and flexure. I could see that the PO had applied some sort epoxy filler in futile attempt to reinforce the cracks. His effort failed when the epoxy filler split at the same locations, probably because it was much stiffer than the plastic. I used a wood chisel to split most of the thicker sections of his epoxy off of the plastic and cleaned the area with alcohol. In the past at this point I had usually resorted to fiberglass fabric and JB Weld, which probably would have sufficed this time except that this effort was going to consume way more JB Weld than I had ever used before. I knew that whatever I tried would have to incorporate some sort of fiber reinforcement. I also knew that the plastic was ABS. It took a while but I finally realized that there was no reason why I couldn't use fiberglass fabric for the reinforcement and black ABS pipe cement for the adhesive/resin. It worked great! It's the perfect combination. Cheap, Fast and Durable! And the results look like they grew that way with no sanding. Probably a good idea to use gloves as ABS cement is toxic and is not easily removed from your hands. You can also use the "universal" cement as long as it says ABS on the can.

Here's the crack before I went after it.





Here it is with the fabric bedded into the glue.



And with a topping coat worked into the fabric.




Here's the inside surface.






The glue cured up smooth and hard in about an hour.

Chromed plastic, styrenes as far as I need to know. I've repaired styrene plastic with a similar technique. Here is a styrene side cover from my 1300 Voyager that had the lower post broken off. In this first picture I've scraped off the chrome covering to expose the cream colored plastic, which I believe is styrene. I cleaned the whole area with denatured alcohol and then used plastic model cement to glue the post back in place.




Of course model cement alone would never be strong enough so I used fiberglass fabric to reinforce the base connection. Here's a picture of the fabric laid into a wet layer of model cement. There are actually two layers of fiberglass fabric. The model cement anchors the fiberglass soundly to the base plastic.



Here's the post after I've trimmed up the glass fabric and applied another coat of model cement.



That brings us to the polyethylene's, the floating plastics, these are really unimportant as they have never been used on KZ's.
Thanks

Bill

New here, this is my 5th post. I have repaired a lot of ABS motorcycle body parts with exactly what you have used, ABS drain pipe cement, and fiberglass cloth, works excellent, stays forever, low cost. I had one of the side panels for my RZ500 crack from vibration, did the ABS and cloth fix, no problems in the last 2o years with it.

Great minds know to Keep It Simple!
Regards
Bill

When the Ducati 996 firts came out my dog knocked it off the side stand(Japanese Akita 50KG) no one knew in perth how to fix the crack
so i sanded the paint off and considered the process of welding alloy/steel
i cut a strip off the fairing underneath the engine where the 2 sides overlap and used that as a filler rod and a soldering iron as the heat!
it worked perfectly
i then sanded the part repaired and painted never had a problem
i had to do a repair for my brother on his bike, not knowing what type of plastic it was and unable to slip a piece off some where to use as filler i simply used a soldering iron to melt the weld in small areas of the crack and blend the 2 sides together
it worked perfectly and have done this on everything from motorbike fairings to car bumpers and my kids toys
just clean up job after and if a little hollow use knifing compound to flush off then paint, you are better to leave any build up on the surface of the side you cant see as it gives the repair strenght
i have just finished joining the middle panel and bottom panel of my 996s together by doing this(so i dont have all the cap screws that look ugly)
i then ran a coat of plain weave fiber glass with epoxy enamel to hide the joint
1 you can see the soldering Iron heat punch marks heat up and slowly push right through both sides mix this area around and push it back flush on the outside
2 this is a pic of the whole area done
3 this is the outside section of fairing after plastic infusion! , you can see my strip of fiber glassing (Epoxy resin and plain weave matting)
Bill what is JB weld?
i back up what Bill says as Epoxy will stick like crap to virtually any blanket (as the saying goes,(BE VERY CAREFULL WHAT HARDENER YOU USE)
their are different speed hardners depending on the temperatures you are working in IE summer winter
but some of the hardners available here are EXTREMELY CARCINOGENIC
Dion

I've been using ABS cement and fiberglass cloth to repair ABS motorcycle parts for just over 42 years, now. I just reattached a mounting plug on the left side cover of my 1983 Honda GL650 twin. About 3 years ago, I repaired the rear mounting area of rhe right side cover of my 1985 RZ500 V4 using the same method. I've fixed bunches of bike parts with ABS cement and fiberglass cloth.

I've also used the ABS cement to fill voids in some side covers, sanding works like Bondo repairs, but stronger.

I haven't found any PVC parts to repair so far, but I think it'd work the same way with PVC cement and fiberglass cloth.

JB Weld (Justice Brothers Weld) is a two part epoxy filler and adhesive, virtually the same as compounds used in the marine repair venues, like Dov-It, Marine-Tex, etc. NONE of these work well with ABS plastics.

usakz1300 wrote: JB Weld (Justice Brothers Weld) is a two part epoxy filler and adhesive, virtually the same as compounds used in the marine repair venues, like Dov-It, Marine-Tex, etc. NONE of these work well with ABS plastics.

JB Weld make more than one type of epoxy and they make one specifically for plastics: PlasticWeld Epoxy Putty