Hot dip galvanizing with Zintec

[Frosted]

Hi

Has anyone used Zintec and then galvanized the metal. The galvanizer wants me to remove all the paint from the metal. I'm not sure if I need to remove the zinc from the repair panels made with Zintec.

Thanks!

 

[roofman]

Hi

Has anyone used Zintec and then galvanized the metal. The galvanizer wants me to remove all the paint from the metal. I'm not sure if I need to remove the zinc from the repair panels made with Zintec.

Thanks!

you must remove the paint or the galvo with come out with black hard blobs..the zintec should be no problem

 

[TurtleDude]

The reason they want the paint removed is as follows:

The galvanising process is Pickle in Hydroclauric Acid for several hours (minimum) to clean off rust and oils.

Next the metal is submerged in a flux tank with magic powders and salts in (woooo)

Then the steel is dried in a heated pit called a 'dryer' funnily enough.

Next, the exciting bit: it's dipped into the 440-460 degree Celsius molten zinc, where a metallurgic reaction bonds the zinc to the steel, even forming a 'crust' of hybrid material between the steel and the pure zinc, which is harder than the steel itself (woooo#2)!

Ok, so if you don't clean, flux and dry the steel, the last bit don't happen dawg, no siree!

A friendly Galvanizer may agree a higher 'per tonne' rate and offer to burn off the paint. This is basically skipping to the last step without pickling or fluxing (or drying).

Then when the paint's burnt off, it goes back to square one, and hey presto - it'll galvanize!

The extra charge covers the time you're occupying the crane and bath for a non productive activity.

If it's just a few bits and bobs, they just hang 'em on the end of a boom and stick 'em through with some production work.

Negotiate with the nice men at the (I presume) Joseph Ash.

 

[Frosted]

I had it all paint shot blasted before I started repairing it. I used normal mild steel sheet, but the tricky A-post bits are made with Zintec sheet by the YRM which as I understand is just electro coated zinc. Should I wire brush the zinc coating off before fitting or just leave it on?

Thanks

 

[Gareth J]

the tricky A-post bits are made with Zintec sheet

How thick is this sheet? "A-post" sounds a bit automotive... It'll warp beyond recognition if it's thin sheet. 2mm will dip ok but any larger flat areas will still be prone to buckling.

If the zinc coating is just zinc, it should be OK. The galv place I've used don't mind dipping things that have bits that are galvanised attached.

 

[Frosted]

Its a LandRover Defender bulkhead, I am prepared for some buckling of the panels but its worth it to stop it rusting again!

I have used 1.2mm and 2mm for my repairs but the original areas are 1mm:-)

 

[TurtleDude]

How thick is this sheet? "A-post" sounds a bit automotive... It'll warp beyond recognition if it's thin sheet. 2mm will dip ok but any larger flat areas will still be prone to buckling.

If the zinc coating is just zinc, it should be OK. The galv place I've used don't mind dipping things that have bits that are galvanised attached.

Because the acid pickle will remove that easily. As long as it's just 'bits' here and there. Otherwise it counts as 'acid stripping' which knackers the acid and is usually a cost option extra.

Paint won't come off in the pickle so needs to be burnt off. Zinc coatings will disappear in the pickle.

 

[TurtleDude]

Its a LandRover Defender bulkhead, I am prepared for some buckling of the panels but its worth it to stop it rusting again!

I have used 1.2mm and 2mm for my repairs but the original areas are 1mm:-)

May turn into a steel Pringle, depends how vigilant the charge hand is on the pot.

You could always consider a zinc rich spray since it's such a small area.