Etch primer

[vic008]

Have done a bit of epoxy fairing on alloy mast. Does etch primer go over the top of epoxy ok, prior to painting.

 

[Rigger Mortice]

Probably but, as you haven't said what brands you have used, it's anyone's guess. The data sheets should tell you.

 

[VicS]

Etch primer is surely for metal surfaces. Id have thought unsuitable for use over epoxy .

Consult the manufacturers literature.

 

[charles_reed]

Adding to VicS's comment - etch primer is only specified on unpainted metal surfaces - however epoxy is not as UV-resistant as polyester and you might want to paint over it.
I've found 2-pot polyester very satisfactory (12 years in the Med)

 

[KellysEye]

Etching primer goes on bare metal to prepare the aluminium surface for painting, if you don't etch then the paint won't hold properly. It pointless to use etching primer over a painted surface.

 

[Rigger Mortice]

I assumed that OP is painting his mast, has repaired some dings with filler, and wants to check that when he applies the etch primer to the aluminium, it will be Ok if he also applies (sprays?) it to the filler.
He seems to have gone into hiding though.............

 

[fishermantwo]

Replacing sills on my race car. Smoothed out with body filler and when faired I sprayed with etch primer over the exposed metal and filler. Most etch primers seem to be single pot epoxy these days and can be over coated with just about anything. I paint over epoxy all the time. It has to be covered in either clear coat or paint to protect it from UV rays.

 

[lpdsn]

He seems to have gone into hiding though.............

If he's in NZ as he claims, he's probably just gone to bed for the night.

 

[vic008]

I assumed that OP is painting his mast, has repaired some dings with filler, and wants to check that when he applies the etch primer to the aluminium, it will be Ok if he also applies (sprays?) it to the filler.
He seems to have gone into hiding though.............

Thats the one, exactly. Was thinking the etch primer may react with the epoxy?

 

[Rigger Mortice]

Thats the one, exactly. Was thinking the etch primer may react with the epoxy?

We're back to square one. Without knowing what products you are using it's anyone's guess. If the data sheets don't answer the question the best thing to do is to test some out on a spare bit of alloy.....you'll know soon enough if it isn't going to work.

FWIW etch primer is only primer with a little acid (phosphoric IIRC?) added.