primer/ undercoat prior to top coat?

[Dazco]

I'll be doing some bodywork on Jambo in the next few weeks , mainly the dreaded seem rash. Once all cleaned out and vactaned I'll need to paint to keep protected as she is kept outside in all weathers. I know grey primer tends to absorb moisture so isnt the best option. What's the best choice that will protect the treated areas until I can re roller it all ?
Thanks

[Jawin89]

I would go for an epoxy primer if it is being stored outside. It will provide protection and can be bought in rattle cans now. It's not cheap though and the cans have to be used within a few hours once activated. I no expert on this but it is what I would use.

[Jonnyb416]

Red Oxide. Worked wonders for me for years!

[Dazco]

And theres no problem with red oxide absorbing moisture? If not that will be ideal as i have plenty

[Jonnyb416]

And theres no problem with red oxide absorbing moisture? If not that will be ideal as i have plenty

I'm not exactly sure on that, however, on some repairs I did 4 plus years ago it has done well. Probably won't be ideal if you are want a perfect paint finish afterwards but it's fine on my eyes.

The bloke that did a lot of my welding around 4 years ago was looking at my van recently. Not sure what he uses but he watched me use Vactan and red oxide immediately after the work he'd done. A lot of repairs sat in red oxide for many years until I painted it last year with Rustoleum. He was very impressed with how it has lasted!

[boatbuilder]

Another vote for epoxy primer here...

[Dazco]

How long does the epoxy primer need to cure before it can be sanded back? Been looking at it and think it may be the best thing to use .
Daz

[boatbuilder]

A day or so depending on temperature. You don't need to sand it back at all if you're over coating it within a certain period of time, up to a week with some epoxies.

[Dazco]

Thanks boatbuilder

[what2do]

I too have been wondering about sanding back epoxy primer and the time required post application. I'm not confident of it being 100% perfect, hence, the necessity of flatting it where required.