Coating galvinized parts

[Electrathon]

Everything I have heard says not to coat over galvanization. When doing engine heat shields that are galvanized I have been blasting all the zinc off, a slow process at best. If I just do a good sandblast is that enough, or do I really need to remove all the zinc?

[Noob2PC]

Originally Posted by Electrathon

Everything I have heard says not to coat over galvanization. When doing engine heat shields that are galvanized I have been blasting all the zinc off, a slow process at best. If I just do a good sandblast is that enough, or do I really need to remove all the zinc?

Are you talking out the Fiero Heat shields if so look in the album as I have done 3 sets of air tubes and upper shields, along with the V6 cross over shields. I just blasted them.

[Electrathon]

Originally Posted by Noob2PC

Are you talking out the Fiero Heat shields if so look in the album as I have done 3 sets of air tubes and upper shields, along with the V6 cross over shields. I just blasted them.

Yes. I know that I can do that and they will coat with an inferior bond. I guess I am just asking how far down the scale this is compared to a proper strip of the zinc. Possibly an answer in percentage or something. Is there 50% less adhesion, 80% less?

The air tubes are very easy, they are aluminum. This is the various galvanized heat shields that are slowing me down.

[mcaswell]

An easy way to remove zinc plate is to immerse the part in a 10% solution of muriatic acid. The zinc will go black when it is dissolved. Then a light bead blast will remove the oxide.
You should rinse in fresh water to remove the acid prior to blasting.

[Noob2PC]

Which heat shield Elect? I had no issues with durability with the ones I did. also shot me an email with your Phone # to nelvar42 @ hotmail.com

[Electrathon]

Just looked at the ones you have posted in the album, I am doing the same ones. Yours look very good, but if you went over the zinc you will not have good long term durability. As I understand it, zinc is about like coating over painted or rusted metal. It may sort of stick, but nothing by comparison with the extreme durability we expect from powder coat.

Caswell: Thank you! That is exactly what I was looking for.

[Noob2PC]

Originally Posted by Electrathon

Just looked at the ones you have posted in the album, I am doing the same ones. Yours look very good, but if you went over the zinc you will not have good long term durability.
Caswell: Thank you! That is exactly what I was looking for.

Well I cleaned with degreaser, stripped with a wire wheel and then sandblasted them so I think i got the factory coating off.