Plastic strengthening question

[Sleeka]

Couldn't find any prior posts except the video of repairing the plastic parcel. I have a couple of plastic pieces (including those a pillar triangle pieces) that have cracked at the seams but have not come apart. If I could reinforce them from the backside they should be fine. What can be used to beef them up? Fiberglass? Strips of ABS? Epoxy? Not sure what would work best on this brittle plastic.

[Jamie N]

As long as the plastic is not too thin I often use the soldering iron to heat weld cracked or broken stuff, use a bit of similar type plastic to melt onto the split for extra strength.

[Sleeka]

So that works to fix the crack itself but this stuff seems brittle so would like to add something so it doesn't crack again. Especially as time goes on these parts will become impossible to replace.

Do we know what this plastic material is? Or is it different piece by piece?

Thanks

[dapinky]

I think that if it were me, I'd just scuff the rear of the panel and then brush some fibreglass resin onto it, with a small piece of matting across the cracked bit.

[lotusflasherman]

So that works to fix the crack itself but this stuff seems brittle so would like to add something so it doesn't crack again. Especially as time goes on these parts will become impossible to replace.

Do we know what this plastic material is? Or is it different piece by piece?

Thanks

Variety of plastics used - the thin brittle bits are usually ABS so solvent cement for plastic plumbing (ABS, PVC-U & MuPVC) is ideal. Clean it up with the related Degreasing Cleaner and if a shiny surface goes matt you'll know it's the solvent and will work. The plastic of old Loyalty Cards (smooth) or Credit Cards (bit stronger with embossed letters) are usually a useful source of reinforcing sheets or strips, but test with Cleaner first ...

[Saltire]

- I've used both fibreglass mat (as suggested by dapinky) for the tops of the B-pillars underneath the caps, and also a scrap piece of ABS fixed with plumbing pipe adhesive in another location. Both working fine some months later. Make sure you clean and rough up the surfaces well to achieve a good bond.