Paint compatibility

[harryj]

Has anyone sprayed a new coat of acrylic over existing enamel ?
Technically, was there a compatibility problem ??

[d@rk51d3]

Enamel over acrylic is fine, but acrylic won't go over enamel without pre spraying a barrier. The acrylic thinners will eat the enamel like paint stripper.

[harryj]

What kind of 'barrier', do you mean a primer ?

[d@rk51d3]

A bit like a primer, but specially formulated to stop the 2 paint types fighting each other.

Not sure what it's called, sorry. I'll text my painter B.I.L to find out.

[d@rk51d3]

Ok, here's his reply:

"With enamel you need to sand it flat so that there is no sheen level. Then the transition coat can be an arylic PSU primer sealer undercoat very strong, make sure surface is wiped clean before, then put your finish acrylic coat over top."

Hope it makes sense. ;)

[harryj]

OK on all that, thanks for your help. :)

[geodon]

I had this problem on my bulkhead.

Parts of it had been resprayed in some wierd rattle can enamel & the acrylic primer just blistered like crazy!

I fixed it by stripping as much as much I could.

Funnily enough, I found that a phosphoric acid rust killer was a damn goods surface preparation on the bits I could not strip.