thermoplastic repair question

How does one perform crack repair?

this is actually for a car bumper cover with a small crack; I’m thinking I can repair it from the backside. I just want to keep the crack from spreading. Any tips?

Drill round holes at the termini,
fill, sand, prep and paint.

I have heard good things about this stuff:

I have not used it myself. I actually heard about it being used to repair polyethylene boats. Ironically, it is said to work well on bumpers as well.

Here is an instructional pdf file:

awesome! thank you
Sounds like the ticket. Thank you so much. There is an Advance Auto down the road from me and I need to get this fixed before driving halfway across the country.

Thanks again!

Any reason not to use G-flex if one has
it already? If bumpers are ABS, I know that G-flex sticks “like glue.”

I would reinforce from behind is the cracked area will be under significant stress. What caused it to crack, a collision, or just the bumper bouncing on its mounts?

May well not be ABS

– Last Updated: Dec-19-11 12:02 PM EST –

A lot of automotive bumpers are made of so-called TPO (thermoplastic poly ofefin) which is often a blend of the polyolefins polyethylene and polypropylene. There are also mold release agents added to the plastic which makes adhesive bonding problematical.

G-Flex will adhere to polypropylene if the surface can be thoroughly cleaned and flame treated but it is tricky. Not even G-Flex will adhere to polypropylene.

More info here:

I hit a big chunk of ice that fell off a semi mudflap! The crack is very clean as of now, but I’m worried about it spreading.

3 M…

Video How-to