I have a couple of cracks and one small piece broken off an interior rear side panel in my '69 convertible and am looking for experiences and opinions on how to repair without actually making the damage worse. Several years ago, I had a good result on a similar project hiring an experienced plastic welder but I have had no luck finding a shop or an individual with that skill where I now live. Any experience out there using an off-the-shelf epoxy adhesive (or similar) that would work for a "DIY' fix? I'm getting closer and closer to sending it off to a qualified plastic welder but kinda nervous about shipping damage. Would appreciate ideas.....

what type of plastic are the panels made of, and are you doing a crack repair that is adding a type of support behind the crack that won't be seen once installed, or repairing the crack on the front side that will require a texture match to the panel surface ?

Would a fiberglass repair on the back side work? Will that stick to the plastic? My 68 Dart rear panels are a hard rigid plastic like an E-body console. I assume a 69 B is the same?

It has to be something similar...probably the same but I don't know what type of plastic that is which is one of the reasons I'm so hesitant with DIY fix. The plastic welding I had done a few years ago was all done on the back side as you guys have already mentioned. Hadn't considered the fiberglass idea.

I's probably ABS. If you wipe a little acetone on the back of the panel and you get plastic on the rag that will confirm if it's a butyl type of plastic. If it is you can use regular ABS cement or even acetone and a reinforcing strip of ABS plastic on the back side.

Thanks....will check this next week when I'm back in town and have access to the part.

Eastwood sells the plastic welding kit with the wire inserts... Hot stapler I think. My body and paint guy did a 71 Cuda lower grill for me a few years ago. I bought a flawless piece from a Delaware dealer. It arrived with a broken piece and a major crack. After a brief negotiation about the price paid, my guy said he could fix it. I couldn't find the fix afterwards.

If you do a search Scott Smith used some spare extra material melted it and used it to patch and or weld ABS.
Sadly he left do to having to Opt-Out same as I had to do to post this
Gets old

How structurally strong does the repair have to be? In case this is useful:
I had a '67 side panel with a hairline crack from the lower edge near it's mounting bracket, extending up about 4inches. One of those situations where the crack would disappear if I just pushed the sides together. I'd say it was Medium structural. Anyway, I used Super Glue - cyanoacrylate. I applied the liquid to the back, and let the glue weep into the hairline crack, and it set up nice. Not visible from the front. But you gotta be careful if it oozes to the front surface, because wiping it will leave a streak.

Let us know what type of plastic you find, I swear mine has fibers embedded in it, but it's def not traditional epoxy resin fiberglass. I think Mopar put fibers it the plastic to control shrinking and cracks.
- Art

This…….

Loctite makes an adhesive that i have found works extremely well on most plastics. Way stranger that anything else I've used. A friend recommended it to me so i tried it. So far, I'm really impressed

Look up places that sell or fabricate using acrylic (plexiglass). They will have Methylene Chloride which is what is used to fuse acrylic, polycarb and ABS. Commonly sold as "Weld-on". Done properly the joint is stronger than the base plastic. The advantage of using this product is that it does not haze or leave the white residue like crazy glue does. The stuff is as thin as water so you can apply it from the back side and it will creep into the finest crack. Any excess evaporates - its a chemical, not an adhesive. You'll need to buy the applicator bottle and needles as well. Once the cracks are fix you could reinforce the area with some scrap abs (pulled from a wreck in a wrecking yard).