4 replies to this topic

[DS2011]

I have read that you need some sort of sealant to help prevent rust. I came across some zinc primer which says it helps prevent rust would this work as as sealant? It also says I can spray it over existing primer.....so could I do the body repairs first (body filler, filler primer) then apply the zinc primer as a final coat?

Also what grit should I sand the final coat with?

Thanks.

[sonikk4]

Zinc rich primer is normally used for welding, so for instance you are welding two flanges together, these need to be bare metal for welding to take place so obviously no paint of any kind will let rust start.

By using Zinc rich primer this is normally weldable, i use it all the time so a coating of this on the flanges then plug welded affords some extra protection to the joint.

Sealant is a different product altogether, this is normally found in tubes for using with a sealant gun or in tins. The tinned variety you can normally brush on and the tube variety you can leave a nice bead of sealant along seams / joins etc.

Look for products like Tiger seal etc.

Yes you can use Zinc primer over normal primer but it won't give you any more protection. If you have a bare metal area then you should give it a light dusting of Etch primer then filler primer if required then a final coat of normal primer if required.

If you need to apply body filler then you need to apply this to bare metal, but key it first with some coarse wet and dry. Sand flat using either a DA sander or by hand then apply a coat or two of filler primer. Use some 400 to 600 grit wet and dry to flat this back. You can now apply a guide coat of something like black paint. Apply enough to dust over the area, let it dry then using a flat block and again 400 or 600 wet and dry sand over the area. By removing the guide coat will let you see if there are any low areas that need any more filler or a bit more filler primer.

Once you are happy you can then use some fine scotch bright to ensure the area you need to paint is keyed for the paint to adhere. If not use some 600 to 800 wet and dry.

[1964Woody]

Sonikk4: Just to clear up confusion (mine) do you etch prime and then zinc prime the flanges or straight zinc primer over bare metal? Thanks.

[sonikk4]

Sonikk4: Just to clear up confusion (mine) do you etch prime and then zinc prime the flanges or straight zinc primer over bare metal? Thanks.

If you are joining two flanges together ie the A panel to wing flange i normally strip off all of the E coat that you get on new panels then use Zinc rich weldable primer prior to plug welding the two flanges together.

Once i have ground down the plug welds i then dust over with etch primer (on bare metal only) before filler primer or normal primer.

Etch is always used on bare metal to act as a key as like it says is uses a slightly acidic mixture to bond to the bare metal.

[Mini Mad Drakeley]

i think he may have meant zinc phosphate primer that you can paint on?

like this stuff?

ive got a tin of a different make and il be using it underneath for more rust protection and it will hopefully work ok