El_Duderino
Promoted Users
Why does epoxy need adhesion promoter to adhere to plastic?
Epoxy on plastic
- Thread starter El_Duderino
- Start date
On plastics like TPO, TEO, PP and PE adhesion promoters are a must for proper adhesion with most products.
Now off the record and I'm only speaking of SPI epoxy over proper prepped TPO etc just straight epoxy seems to come in with about the mid 70% adhesion with out using adpro.
AM I recommending you do this? NO! However we have a number of production shops or shops that do insurance work that have been doing this for years but they prep like the bumper should be.
Now off the record and I'm only speaking of SPI epoxy over proper prepped TPO etc just straight epoxy seems to come in with about the mid 70% adhesion with out using adpro.
AM I recommending you do this? NO! However we have a number of production shops or shops that do insurance work that have been doing this for years but they prep like the bumper should be.
Could you expand a bit on the right way to prep said bumpers?
Is it basically what's outlined in the tech manual, use 700-1, scuffing paste, etc?
jlcustomz
evil painter
Yes, wherever a factory bumper has it's original paint, you treat it like any painted surface. you don't want ad pro where not needed.
If raw plastic, then it needs some sanding to help give a little mechanical bond, wiping before & after with alcohol based cleaner, NEVER solvent based.
I did a little torture test last year seeing if I could bond a layer of raw fiberglass matt to a sanded (approx. 220 grit) teo bumper with epoxy to add additional layers of custom fiberglass work to. Left matt hanging off as a handle to pull from. it gave a fair amount of fight before everything pulling away from the soft oily plastic with no ad pro. So it would definitely stick under normal conditions without ad pro, though I'd still use it for any quality work.
If raw plastic, then it needs some sanding to help give a little mechanical bond, wiping before & after with alcohol based cleaner, NEVER solvent based.
I did a little torture test last year seeing if I could bond a layer of raw fiberglass matt to a sanded (approx. 220 grit) teo bumper with epoxy to add additional layers of custom fiberglass work to. Left matt hanging off as a handle to pull from. it gave a fair amount of fight before everything pulling away from the soft oily plastic with no ad pro. So it would definitely stick under normal conditions without ad pro, though I'd still use it for any quality work.
We are talking bumpers . New raw bumper yes proper prep and adhesion promoter . Aftermarket bumper cover they come primerd and clean them suff and paint. Altho I know of 2 direct repair shops who will strip the primer off the aftermarket covers and treat them like a new raw cover. I use epoxy most of the time as a sealer before base color.
jcclark
Oldtimer
Yes, some do that.
And the reason is that some aftermarket primed bumpers have a real problem painting over.
I don't know what it is but some of these bumpers will wrinkle the base very quickly on the first
couple of coats. I've had this problem several times.
A lot of shops have started stripping them first.