# Is primer waterproof?



## sunnydude959 (Jan 3, 2014)

I was machine polishing, trying to get rid of a relatively deep scratch, and I very foolishly ended up going too far, down to the primer on my driver side A-pillar (very embarrassed about this, I still don't quite know how this happened so quickly, but that's another discussion... what's done is done now!).
Whilst I wait for the coronavirus lockdown to end so I can go and take it to a bodyshop to get it resprayed, I'm concerned about the waterproof-ness of the current situation.



1) As there is still primer there, is it still water-proof against rain and puddles etc.?* I do not want any rust whatsoever to develop* (my main concern right now)

2) Is there any weatherproof protective tape available that I can apply to the damaged area for now, that won't damage the paint when removed?

Thanks


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## wayne451 (Aug 15, 2016)

No, primer is permeable. 

Ok, mine was in cellulose, which you can no longer buy but 20+ years ago when my mini roof was in primer it blossomed and had to be rubbed back down.


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## James_R (Jun 28, 2007)

Well its knackered now anyway, I'd get some lacquer and spray over it.
Or a really durable wax.

Your bodyshop/repair man will have to prep this again anyway and at least you've protected it from the elements til then.


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## sunnydude959 (Jan 3, 2014)

James_R said:


> Well its knackered now anyway, I'd get some lacquer and spray over it.
> Or a really durable wax.
> 
> Your bodyshop/repair man will have to prep this again anyway and at least you've protected it from the elements til then.


Thanks for the replies guys.

I'm not comfortable with spraying (knowing my luck it'll overspray onto the other panels)... I was thinking, if I get a small piece of car wrap and stick it in that area, would that do the trick to keep the water out? Or is applying car wrap material more complex than that?


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## Demented (Nov 3, 2014)

I thought car manufacturers use an epoxy primer now and have done for at least 20 years. If so, epoxy primer is non-porous when cured and not permeable.

I believe the latest waterborne paint still requires an epoxy type sealant applied to combat corrosion.

Traditional solvent primers are permeable; to aid adhesion of the base or top coat and like wayne451 has already said, if not painted, will absorb moisture from the atmosphere and eventually blister and corrode from within.


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## mikechesterman (May 25, 2013)

Primer is porous.

Cars wouldn't normally be epoxy-primed from factory. They usually get an e-coat, followed by a regular primer.

In restoration, an epoxy may be used over bare metal before regular primer and in some cases may be used as a final seal over the top of regular primer prior to wet-flatting on concours-level jobs as it is waterproof and allows for wet-flatting, or it's usually cheaper to use a ready-mixed cheap gloss white or gloss black commercial paint at this stage and wet-flat that prior to topcoat.


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## ianrobbo1 (Feb 13, 2007)

As long as you mask up the other panels you don't want spray over give it a go with a can of spray paint, and a dash of laquer, as your paying to have it professionally repaired later it won't matter that the painter has to do what little more work it'll take to get your efforts off.


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## DLGWRX02 (Apr 6, 2010)

I would just put some vinyl wrap over it for now (just like putting a sticker over it) , it’s easy to remove and you won’t get spray every where.


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## sunnydude959 (Jan 3, 2014)

I've decided to just leave it in the garage for now.

Thanks for the replies guys, appreciate it


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## SamD (Oct 24, 2015)

Just put some clear tape over the area.


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