6 replies to this topic

[min ritz ryan]

Hi all. I need to do a lot of welding to my car then planning to sand down and primer up.

 

I was thinking of using a weld through zinc primer on and around the welds, then a red oxide or grey primer on the rest of the body to prepare for a respray.

 

Are these the correct primers to use and which should I choose, red oxide or grey primer? baring in mind the body will be silver and roof black, eventually

 

Any guidance would be great, thank you

[sonikk4]

The zinc rich primer is fine for the welded areas. Then you will need an etch primer on all the bare metal areas.

Then you may need to use a filler primer on any affected areas then the colour of your primer will be dictated by the top coat. Red primer from Halfords etc is not red oxide just red primer. I would think with the car being Silver a grey primer is what you will need.

[Daz1968]

Bare metal if not being top coated for a while is best painted in epoxy primer, you can fill over this then use high build primer. Areas being welded you can get a weld through primer but only use it where you need to weld as inside of panels can be painted with epoxy before fitting.

[tiger99]

Yes, but I would also suggest using etch berfore the epoxy, on the areas not to be covered by the weld-through, unless it has been grit-blasted, which will give better adhesion than etch and allow a zinc based primer to be used under the epoxy. But definitely use epoxy as part of the process, it is fairly impervious without a top coat, unlike other primers, which are porous. As Daz1968 says, paint as far as the epoxy, on all areas which will not be welded, before fitting, as weld-through primer will not attack anything else, but if you prime the weld areas first, then try to use etch, the etch will remove the weld-through where they meet, and may well damage even epoxy.

[rally515]

Can i just ask what is the conclusion for this then on a full re-spray from bare metal ?

 

1) All welded areas and in-between seams coated in Zinc rich/weld through primer,

2) Rest of shell in etch primer after rub down and tack cloth (1 light coat follwoed by 3 covering coats)

3) Seam sealer applied were needed after a resto

4) Epoxy or high uild primer in required areas ?

5) And finally the numorous layers of final top coat

 

Always something that baffled me is paint prep so pplease someone list an order like above of whats needed haha

 

Cheers,

Cliff

[Daz1968]

Think if you use epoxy an etch primer isn't required as it bonds to bare metal.
I went for 1k etch primer one light coat on bare metal areas followed by 3 coats of 2k high build and now about to apply 3 coats of 2k direct gloss,
The underside was painted with zinc rich primer and stonechip, then seam sealed where required, now awaiting a couple of coats of 2k direct gloss. If bare metalling whole car then paint it in epoxy and fill etc over this, just omit the etch primer.
Etch primer only needs 1light coat as it just gives a key to bare metal

Edited by Daz1968, 30 September 2013 - 07:34 PM.

[rally515]

Ahh great, so i'l not be needing much etch then, been thinking about what to do and in what order for a while now haha