Paint: Some questions about primer

[StudeMann]

Is 2k epoxy primer the only waterproof primer?

If so, can it be applied over top of other self-etching primers or primer-surfacers? I have read postings on other sites that 2k primer is not compatible with self-etching primers.

I ask these questions because I am nearing completion on blocking all the panels but I can't afford to have the top coats done until next year.

I would like to get a waterproof primer applied so I don't need to worry about moist air or a little rain. I learned the hard way that primer-surfacer is NOT waterproof when I stored my fenders out of the rain but in the moist air.

Thanks.

Jim

[(S)]

Follow the manufacturers directions. Talk to the paint guys where you get paint is also recomended.

[swvalcon]

Get you car sanded and ready to paint. Then put down at least two good coats of epoxy primer and you should be good for about 6 months to a year. Spi is a good brand name of epoxy to use. Look up their web site or call Berry at 706-781- 2220

[SN-60]

Yes, lacquer-type primers will definitely absorb water.

[52 Ragtop]

NO primers are waterproof! IF you need to put the vehicle outside in primer, mix in some clear with the primer, that will help, but still not 100% waterproof.

Jim

[StudeMann]

Thanks, folks,

I realize that there are so many variables involved I need to talk the local autmotive paint experts about the specifics of what I am looking for.

Cheers,

Jim

[wdills]

2K epoxy will not hold up well outside. UV light will cause it to break down over time. Unfortunately I am not sure how long it will last before the UV starts affecting it. Your local supplier should be able to tell you how hong it will last. Putting it under a tarp to keep the sun off the primer should help protect the epoxy.

Normally the epoxy goes down over bare metal, then a high build primer goes over the epoxy and you do your blocking on the high build. Since your post says you are almost done blocking, I assume you did an etching primer with high build over that. It is common to use thinned down epoxy as a sealer right before spraying the top coat. If you spray the epoxy and leave it for a year, you will have to sand it before you can spray your topcoat. Cured epoxy is not easy to sand, so be prepared for a tuff prep job when you get ready for your top coat next year. If you are going to do your own prep, then it is just a matter of time and work. If a paint shop is going to do the final sanding prior to paint, they may want to charge you extra when they realize they are sanding epoxy.

SEM came out with a 2K high build epoxy primer a few years ago. It was advertised as easy sanding. I made the mistake of using it once, thinking I was saving myself time and money. It sprayed fairly rough like a 2K high build, but it sanded like regular epoxy. I didn't think I would ever get that stuff sanded flat enough to spray a top coat on it.

Hope this helps.
Wayne

[swvalcon]

Thats why i recomended SPI epoxy. It sands the next day real nice, has a uv protector in it so you can use it on frame with no top coat and matches factory frame and inner wheel wells very close. Comes in black. Price is not that bad about $70-80 for two sprayable qts. And if you need any information Berry is always there for his customers. I've called him on a Sat afternoon and he picks up his phone.

[R1 3137]

2x for SPI epoxy primer which IS water proof as evidenced by its use as a boat paint.
Not the same UV protection in each color though, I believe the White has very little in it but the Black should be good for several years on its own and more it topped with a UV clear coat.

And even cured it sands great once you bust the skin off

[wdills]

I have used regular gray SPI and agree that it is a really good epoxy. I didn't know that the black color could stand up to UV. That is great info to find out.

I must say that after my experience sanding SEM epoxy, I have never sanded another epoxy. I always spray my high build within the re-coat window of the epoxy.

Thanks for posting about the UV protection in black primer.

[swvalcon]

Spi sands just like a regular 2-k filler primer when dry. Berry says a lot of his corvette guys use nothing for primer but his epoxy. They fill with it sand and paint.

[StudeMann]

2K epoxy will not hold up well outside. UV light will cause it to break down over time. Unfortunately I am not sure how long it will last before the UV starts affecting it. Your local supplier should be able to tell you how hong it will last. Putting it under a tarp to keep the sun off the primer should help protect the epoxy.

Normally the epoxy goes down over bare metal, then a high build primer goes over the epoxy and you do your blocking on the high build. Since your post says you are almost done blocking, I assume you did an etching primer with high build over that. It is common to use thinned down epoxy as a sealer right before spraying the top coat. If you spray the epoxy and leave it for a year, you will have to sand it before you can spray your topcoat. Cured epoxy is not easy to sand, so be prepared for a tuff prep job when you get ready for your top coat next year. If you are going to do your own prep, then it is just a matter of time and work. If a paint shop is going to do the final sanding prior to paint, they may want to charge you extra when they realize they are sanding epoxy.

Wayne, you are correct that I have been blocking high build primer over etching primer. I ask about a waterprrof primer because I am somewhat eager to be able to drive the car sometimes before I will be able to afford the top coat. The car is garaged so there isn't a UV concern, just a general concern that I won't ruin all my hard work if the car is exposed to a little moisture.

Jim

[swvalcon]

StudeMann. I wouldn't be conserned about the water proofing of a good epoxy primer. Just prep your car as you where going to paint it put down at least two good coats of a good grade of epoxy and I think you would be ok for 6 months to a year. Then when ready to paint wash real good with wax & grease remover, sand good with 400 wet, reseal with a coat of epoxy and put down your color coat. AS a side note 2-k over etching primer is kind of 80's tech. Most restoration shops are now doing the epoxy under 2-k myself included. Some are using nothing but epoxy and using very little 2-k primer at all. That is on a nice straight car needing very little filling and block sanding.

[StudeMann]

Yes, I now know 2k over etching primer is old tech. 2 years ago I got a retired body man to do my initial rust repair and he applied the primers. I didn't know anything better existed. I hadn't even heard of high-build primer at that time. If I had it to do over again I would start with the epoxy primer.