The Latest in Waterborne Technology for the Aerospace Industry
We accept Visa We accept Mastercard

Eko Poly over Zinc chromate on aluminum

Posted: Wednesday, March 13, 2013 5:44 PM Quote
I have a few parts that have already been primed with Zinc Chromate. Can I just
paint with the Eko Poly over the zinc chromate...or should i use EKO prime over
the zinc chromate first....basiclly will the EKO Poly finish lift the zinc chromte primer?
I just dont want to restrip those parts if I can help it and would like to just paint
with the Eko poly on top of the zinc chromate, if possible? as the parts are ready for
a finish coat.
Posted: Thursday, March 14, 2013 6:36 PM Quote
Zinc Chromate is the one primer you should not put waterborne paints over. Other rattle can primers seem to work just fine. Or if concerned then prime or RE-prime all parts with EkoPrime or EkoPoxy before painting with EkoPoly Premium or EkoCrylic paint


Jason
Posted: Wednesday, March 27, 2013 5:46 AM Quote
Jason,

Why should we not use waterborne paint over zinc chromate? What will happen?

I zinc chromate primed my leading edge skins before glueing the fabric on with Ekobond & then apply the Ekofill over that. No doubt some of the ekobond will have come into contact with the zinc chromate primed LE skins when I brushed in the first coats.

Thanks,
Don H
Auster J4 VH-CRR
Posted: Saturday, March 30, 2013 11:04 AM Quote
When Doug and Dan Stewart bought the company from Aircraft Finishing Systems they were told not to do it but no body seems to know exactly why. I asked our chemist and he didn't have an exact answer for why you shouldn't do it. He did say the current version of our EkoPoly Premium or EkoCrylic should not have any adverse effect but that it has never been tested or subjected to accelerated weathering tests.

I can tell you that if the surface of the aluminum has not been properly prepped before it was sprayed with ZC primer you can have adhesion issues of the primer to the aluminum which will effect the overall performance of the coating system.


Jason
Posted: Saturday, March 30, 2013 6:14 PM Quote
Thank you Jason,

I'll remember this for future reference.

However as I was reading you reply I realised I'd made a mistake in my post. I didn't use Zinc Chromate primer on the LE skins and can't think why I'd have thought I did. I don't even have any Zinc Chromate. It was your note about surface prep on the aluminum that clued me in ;-)

What I used on the LE skins was a self etch primer.

Don