[FRANKBULLITT]

I am repairing a pp plastic bumper and the evercoat poly-flex filler says to flame treat the pp plastic before to promote adhesion.Never did this before.Whats it mean and how do you do it.I always just put on spray adesion promoter . Is it better to flame treat?

[crashtech]

I've never done it. What we have done here is use adhesion promoter, then epoxy primer. Polyflex can then be applied on top of the epoxy primer.

More typically we will use a dedicated semi-rigid repair material that is designed for use with conventional adhesion promoters.

I think flame treating is stupid.

[FRANKBULLITT]

I contacted evercoat this afternoon an talked to their tech person.They stated flame treating is done by heating up the damaged area before applying the filler.This is done to remove the impurity of the substurate i.e. PP
and promote bonding which cant be done to PP with spray adhesion promoter.So to do this the stated use a light flame from a propane torch or butane lighter over the area.I tried it on a test bumper.1 the old way with adhesion promoter.2 flame treating on the other. Let them both dry for several hours.Then tried to bend and peel back.The test results show they were right.The flame treated piece wouldnt come loose.The chemical treated piece peeled back. Conclusion for repairs on EFDM TPO PP and other promblem plastics best to flame treat.I have implemented this procedure in the shop now, to insure better repairs.I quess you never stop learning with these high tech plastics, which are around us everyday now.

[crashtech]

So your test shows adhesion promoters don't work with polyflex, which was already known. I want to reiterate that I did not nor would I recommend this be done.

I wonder if flame treating also produces satisfactory results with epoxy based fillers made for semi-rigid plastic. There might be a material savings to be realized there.

[deadbodyman]

I was wondering about that process Frank ,Thanks for the heads up..