I'm in the process of attempting to repair some interiaor door panels with have cracks and broken bits in the screw flange area.

An initial attempt to "glue" the pieces back together with an epoxy theoretically for use with "slippery" plastics such as ABS has failed.

Instead, I'm now using a "Plastic Welder" (scored at Harbor Freight) and initial results look very good. Trouble is, I thought the panels were ABS, but the ABS filler rod I have melts at a much higher temp than the door panels and seems incompatible. What are these panels made of and what works best as a filler material? Are there other methods to effect this repair that work better?

Thx

Astrobuf

Polypropylene got any old junk panels to use as filler?

Polypropylene (PP) is a VERY common material (milk jugs are made from it), you should be able to buy rods of it. BTW, ABS is not really a "slippery" material at all, but PP certainly is.

Scott,

Polypropylene is not the same as Polyethelyne. HDPE and LDPE are high and low density polyethylene. I'm not sure if they'd be compatible with polypropylene. PP is a chain of 3 carbon monomers, PE is a chain of 2 carbon monomers.

All the above technical info is about what I remember form HS Chemistry of 30 years ago! It may not matter if they are different? Have you done this kind of repair on these panels? Is there a better way to do this?

Astrobuf

Scott is the resident Mad Scientist when dealing with plastic...





And Bugs, can't forget about bugs.........

Actually he's right, I was having a brain fart when I wrote that. Sorry for the confusion, I fixed the first post.

For the record I have never had a material test done on Cuda/Challenger door panels so It's a bit of a guess as to what the exact blend of materials they are composed of. They are more than likely Polypropylene, but they could also be Polyethylene, they have similar physical properties but niether is even remotely similar to ABS.

*I have welded PP with PE rod and vice versa, either works fine.

Scott,

Thanks for the confirmation that I can use a PP rod on PE. I'm a Mech Engineer in my spare time, and work for a large specialty materials company surrounded by Chem Engr's. My buddies know everything about these materials when run through an extruder, but nothing about fixing them on a car!

My calibrated fingers think the panels are PP. PE, especially LDPE is much softer and sliperier than the panels. I vaguely recall there is a test one can run, burning a small sample of the material, the smoke generated is different between PE and PP, I just don't recall how. I'll let you know what I figure out.

Meanwhile, I bought a scrap panel on Ebag to have some matching stock to work with!

Astrobuf

Yes you can do a burn test to determine the basic plastic family, but it's not going to nail down specific blends (and most of the THOUSANDS of materials out there are blends) PE and PP are bit difficult to distinguish in a home brewed burn test, a plastics lab spectragraph test can nail it down but that requires.... Well, a lab



Feel like playing around with it here's a site that can help you:

Burn Test

*And yes, I agree, door panels are most likely PP