hey. I know this has been addressed but I am too lazy to search. I have a plastic crack and wanted to know the best product to use. I assume that i sand the back and use plastic epoxy with a patch to hold everything. But what epoxy?

 

epoxy by itself will not hold up, it'll crack in the same spot either that day, that week, or that month.

I found the best method is to use fiber glass with a very thick gel resin, and some body filler. I went ahead and sanded the back with 80 grit, took a strip of fiberglass cloth and dipped it into the resin, applied and waited around 5 minutes to apply another. I did 3 pieces total.

Note you must put the fiberglass around the crack too, I did not my first run and a small crack appeared very close to the edge where I did not apply any fiberglass. I used the resin to fill in the crack on the other side as well.

I used a UPOL Raptor Liner and painted the entire bumper. Looked great! Very strong.

 

I use this drywall tape and black epoxy. Repaired a ton of cracks and saved the front bumper on my 2004 with this method.

https://www.homedepot.com/p/Saint-Go...66-U/202723942

Take the bumper off, masking tape the cracked area on the front of the bumper, and put this tape and epoxy down on the backside.

 

I just cut off the cracked parts, the bumper looks better although a little bit different.

 

I just repaired 2 cracks on a front bumper and was very impressed with a plastic welding kit from ebay for about $36. Worked very well and feels like it is still strong.

 

Drill a hole at the end of the crack so it doesnt continue.

Sand the crack and if you can, V it out to get more adhesive in there.

My media of choice is JB Weld. I apply it on both sides and also drill holes on both sides of the crack to add support.

I sand the epoxy off to make everything flush and then paint with a decent plastic paint.

If you degrease the plastic it will stick forever. Fiberglas will unstick eventually especially if it gets wet alot.

I've rebuilt all kinds of things with JB Weld, for an added tip, get some Reynolds Aluminum foil and you can even make rough moulds to form your repair.

 

ABS cement should work best, since the bumper is made out of ABS (correct me, if I am wrong). You can apply thin layers of ABS sheet (cheap on ebay) as patches and use ABS cement as filler, and of course as glue. ABS cement is nothing else than dissolved ABS plastics in acetone, so you can make your own ABS cement yourself. The process is actually welding, since the acetone dissolves the ABS parts at the surface to create the bond. ABS can be sanded easily and painted as well. I did some small projects with ABS, maybe I should try that on the bumper (I just wonder why I didn't get that idea earlier) and save almost $1,000 for a new bumper.

Thanks shanechevelle, great idea how to stop those cracks!

 

Now I am faced with the same problem when I need to rebuild the bumper. I am planning to buy a suitable plastic welder so that I have this equipment now and for the future.

 

I hate to say this but -- I've repaired other car's bumpers, more flexible. On D2's, I spent tons of time once trying to redo a front bumper on a 2003. Lasted a month. I'd just get a new one.

These D2 bumpers - front and rear - get very brittle as they age, unsure why but it's different than most cars with flexible "urethane" bumpers.