Look for the sem plastic bumper repair... good autobody supply places will carry it. Then you can use a screen looking fiberglass sheet. Don;t ask me what its actually called. But I repair plastic buspers with this method. You sand the back of the crack area, put down the epoxy bumper repair, the screen sctuff, then more of the epoxy. It dries and is as stronger of stronger than original. You just have to keep the cracked area pushed toght together. Best thing to do is use superglue in the crack before you use the epoxy and such. This will hold it til the epxoy is applied. If your painting it, the paint should fill in the hairline from the crack.
