MTFCA Forum

I recently primed and sanded a coil box lid in preparation for a new coat of black paint. Seconds after the black paint hit the primer it started to react with a cracking and spidering of the paint. I stopped immediately to reduce the amount I now have to sand of. I typically have good results with rattle can paint on small parts but this is also not the first time I have encountered this problem. My question is does anybody know what causes this and how to avoid it in the future? Both the primer and paint were Rust-Oleum products but I believe I have had the same problem with other brands in the past.
Thanks,
Chris

I have found that when the instructions say to wait 2 days before recoat, a week is a lot safer (regardless of brand). The heavier the prime coat, the longer it takes to cure.

I use a lot of Rustoleum paint products. They are not nearly as good as they were before government morons forced them to meet senseless demands (any demand that reduces pollutants by 50 percent per volume, but requires three times as much volume to accomplish a task IS senseless!!). Many of their products today are the best value that can be bought in spray can paint.
However. I also bought a can just like the one you show, the "High Performance Enamel". Written by me in big bold felt pen on the can is "LOUSY WRINKLES". I will use it up on things that do not show. I suspect it might be better protection than their other paints. And I don't know what sort of thinners they are using in it. But it does not give a good finish.

I use ALOT of Rustoleum for stuff in my shop and if I can't hit the primer with a top coat within an hour I wait a few days. Same goes for coats of paint over paint... I get wrinkles if I wait too long (over an hour or so) or not long enough (less than a few days). Throw in humidity and temperature and the party is just getting started.

That's strange. I've not had that kind of reaction. I just did some pieces for a friend's Pontiac Firebird. Bead blasted, cleaned with denatured alcohol, show them with the gray primer (Rustoleum), wiped them down after drying with more denatured alcohol and then used the black. They came out show-car perfect. I also used some of their semi-gloss on a few other pieces and had the same result. I'll be using a lot of the semi-gloss as we are restoring another MG this year. I'll be in the garage later and will be testing a few pieces to see if I can duplicate that reaction. Is your primer red oxide or the gray?
Terry

I have had good luck with the Rust-oleum High Performance Enamel. You have to closely follow the instructions on the can. If it says wait 10 minutes to recoat, watch the time and spray in 10 minutes. If it says wait a few minutes, I usually wait about five. If you can’t recoat in the specified time, you will have to wait at least seven days. If you don’t, it will wrinkle. Temperature matters, too. I usually don’t use primer under it, but if I do, I use the High Performance Primer. I wouldn’t try mixing different products even if they are the same brand.

A lot has to do with primer-less paints in they use an aggressive solvent of natural organic base. This “junk” is a nightmare. If you require using a spray can, try using a good quality such as Dupli-color etching primer first with very light coats. Let cure for about 2-4 hours and then overcoat with their gloss black or what ever color.

Try staying away from big box paints that state, “no primer needed, or for all surfaces” big red flag to a paint guy. Just like one size fits all.

Ever seen a real fat girl in a bikini? Where’s the bikini?

Sorry if I left a cranium impression!

All the Best,

Hank

Hi Chris. One of the two, primer or top coat, contains something like xylene or toluene, etc which will react with enamel paints. We used to get this interaction if you sprayed Lacquer on an enamel primer. One of the reasons they say to wait for a full dry cycle. I try to stick with the same brand of rattle can paint and primer. I have had good results with ACE Hardware rattle can paints for those misc small parts. So let it dry good, sand it down and use the same brand of primer as the top coat and you should be good. If your not sure, do at test on a piece of scrap metal.

Thanks to everyone with for the input. It sounds like the types of primer and paint along with letting them cure seem to be the keys points. I'll make some changes and give it another go.

Hank,

You are a baaaaad boy! Now I will see that image in my mind every time I see a rattle can.

As mentioned, follow the directions. I believe they specify recoat within 1 hour (I dont wait that long---maybe 1/2 that), or you have to wait 48 hours. If you try to deviate from this, you are gambling and may have a finish that reacts and wrinkles. Sometimes I have gotten lucky, sometimes not. So I just try and get it all painted at one time, usually waiting 15-30 minutes between coats, then let it dry overnight.