[brandonA.]

Hi guys I am in the process of welding in some steel into the old scout II I will be putting in new floorboards soon. My question is the steel I get locally has *I believe galvanized coating* on it and it is very hard to get off. The only way to remove it is to use a grinder disc.

-I will be painting these and in the past paint doesn't want to stick to galvanized coatings. It may for awhile but eventually peels off.

-Now I can't see myself grinding off this coating on both sides of an entire floor board.

-How does one properly remove galvanized coating or paint on it?????



Thanks....

[Underground]

First off, welding galvanized puts off HIGHLY toxic fumes! Second, use etch primer or epoxy primer. Third,you need to either find a new source of sheet metal or talk to the manager of where you get your metal, and have them order NON-galvanized.

[Runnin'OnEmpty]

Like UG says, use an etch (or wash) primer on it before topcoating.
Don't use epoxy primer over the etch, use a 2k primer and then
paint it. Epoxy tends to lift when sprayed over etch.



The galvanized metal will be much more rust resistant than normal
steel, because of the zinc coating. I'd keep using it, but that's a
life-saving tip about fumes......they're deadly.

[Underground]

Originally Posted by Underground

use etch primer or epoxy primer.

I didn't recommend shooting epoxy OVER etch. Is there a problem of shooting epoxy over galvanized? I have never done it because I don't use galvanized for repairs. I would use the epoxy before I would etch, for the simple fact of it being a superior primer.

[302 Z28]

No etch for me either, only epoxy on bare clean metal.

Vince

[Old Fool]

Sand and degrease as normal, coat with SPI epoxy.

[brandonA.]

Thanks for all the replies and reminding me how toxic it is to weld on. I always grind off the area where I weld so I don't think that is a problem but removing it off an entire panel is a major pain.

*So to clarify
1. You only have to sand over the galvanized metal and paint
with an epoxy primer? In other words epoxy primer will bite
into the galvanizing ?


2. Secondly I usually use a metal cleaner degreaser on bare metal
but I never have on the galvanized metal. So will the cleaner
get into the galvanizing and cause the paint to lift or bubble?
Do you guys use a metal cleaner over galvanized coating?


Thanks guys!!!!!!!!!!!!!

[Underground]

Originally Posted by brandonA.

Thanks for all the replies and reminding me how toxic it is to weld on. I always grind off the area where I weld so I don't think that is a problem but removing it off an entire panel is a major pain.

That is just as dangerous. Grinding makes the particles airborne. And you should ALWAYS clean the metal before you spray any paint/primer.

[Runnin'OnEmpty]

Originally Posted by Underground

I didn't recommend shooting epoxy OVER etch. Is there a problem of shooting epoxy over galvanized? I have never done it because I don't use galvanized for repairs. I would use the epoxy before I would etch, for the simple fact of it being a superior primer.

Underground, I wasn't being critical of your epoxy suggestion, just
reminding Brandon in case he wasn't aware of this.

The problem with galvanized is that the zinc coating when in contact with
oxygen forms zinc oxide, which makes the applied paint lift. As good as
epoxy is, it'll happen to it also. The best way to prepare galvanized is to
clean it thoroughly with tri-sodium phosphate, then spray with an etching
primer (which contains zinc phosphate). Then you can apply the topcoat.

[302 Z28]

So just how does galvanized metal come in contact with oxygen if it's been coated with an epoxy primer?

Vince

[DanielC]

Zinc is a very reactive metal. It oxidizes almost immediately upon contact with air.

[Old Fool]

Originally Posted by brandonA.

Thanks for all the replies and reminding me how toxic it is to weld on. I always grind off the area where I weld so I don't think that is a problem but removing it off an entire panel is a major pain.

*So to clarify
1. You only have to sand over the galvanized metal and paint
with an epoxy primer? In other words epoxy primer will bite
into the galvanizing ?


2. Secondly I usually use a metal cleaner degreaser on bare metal
but I never have on the galvanized metal. So will the cleaner
get into the galvanizing and cause the paint to lift or bubble?
Do you guys use a metal cleaner over galvanized coating?


Thanks guys!!!!!!!!!!!!!

Just give Barry a call and get the answer direct from the manufacturer of the best epoxy primer on the planet. 404-307-9740, after you talk to Barry go ahead and order the SPI epoxy.

[DanielC]

I would suggest you get the tech sheets for the products you are going to use.
For example, PPG DX 1791/DX 1792 says it can be applied over properly cleaned and sanded galvanized Galvanized metal.