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primer cracking

10583 Views 13 Replies 5 Participants Last post by  demon340v
Before winter, I was doing some bodywork on my Duster - filler primer and block sanding. Each morning, part of the primer from the day before had cracked and I would have to redo it. Its been sitting in the shop since the cold weather hit, and I looked closely today and there were little cracks everywhere. Does anybody have some suggestions? I would appreciate it. -Evan
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what brand of primer you using? i have never had that happen to me. I buy more of teh pricey stuff Rustoleum's primer it's real good
Well, its just from the local O'reilly's - its called autobody master or something like that. I've used a little over a gallon. Its filler primer.
is it just laquer primer? most people try to steer away from that stuff. it has a tendency to shrink and crack. you might have been spraying it too thick.
You've applied(Sprayed it too thick). Your reduction ratio or either your application created a too thick layer. Also if you've applied that in or on a High humidity day that also can play a role by trapping invisible moisture. As paint shrinks, the water vapor prevents the srinkage (Because you can not compress a liquid), cracks the layer.

Having been a Dupont Distr in the past and such, that would be two of many possible reasons that happened.
[]{} sounds like you sprayed it on too thick
that could definitely be it - too thick. I tried to make it thin, but I have the tendency to put on just a little more and a little more. also, i didn't know about the humidity thing. I live in Arkansas, and we have plenty of moisture in our air! I know the primer was not the best. Can anybody recommend a good primer to use?
I live in Arkansas as well, we used Nason 2k on a buddies car and it worked great its made by dupont. but is there lower cost line of paints.
ive been using the evercoat uro-fill. urethane based high build primer, it seems to work well, not that expensive either.
Where can I get good primer like these?
Check your yellow pages for a company named "Automotive Finishes" or see if their home page has a shop in your area. Oriliey also sells Dupont. Nason is made by Dupont but is lower scale as far a color goes.

I would sand off the majority of the primer you used and use a 2k Ureathane primer such as a Nason product or the Evercoat Eurofill2k. IN Eather case, be sure to shoot a test panel. I have always reduced my primers another 10 to 15% to gain better drying and flow thickness.

ALWAYS REMEMBER--your top coats are a direct result of your primer coat.

The secret with nason is use it in your Base coat saving yourself some paint cost and use a high quality Clear like High Glaumor Clear. It will be as nice as using a high Dollar Base with a medium $$ clear. With any of this unless you you use Spies or BASF that your base coat is a "closed coat" meaning you have XXX hours to apply the Clear before you lose adheasion properties and having to skuff up the base coat. (Metallics dont skuff well after closed window)

I'd think with the problems you have with the primer now, your just asking for problems if ya dont sand it off and start over.

I'm not trying to suggest you've done wrong, something isnt right. just be thankful you hadnt gotten color and clear on it yet.
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where are you from, maybe some one knows of a auto body supply in your area. denerally there stuff costs a little more to the public, then going to the auto parts store, but you are getting muche better quality, i tend to buy anythin g i need at the local supply shop, even if the prices are kind of high, at leasty they know what they are talking about and can give me advice.
Thanks, Guys, I appreciate the advice. I will definitely sand off what I have put on, and when it warms up, I will check into supply shops and get some better primer. thanks again, -Evan
i use Rustoleum's primer works great! lol
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