I been looking for a forum to post this question and this seems like the best place.

I am doing my bike fairings and gas tank using Rustoleum 2x paint. The clear is the same brand and type. Most of the fairings look great but the gas tank and the very front headlight fairing will not stop cracking no matter what I do...

The side fairings I just did a coat of base every 5, 7 minutes for about 3 coats, waited 15 mins and did 3 coats of clear 5, 7 minutes apart, they turned out great and no cracking and very smooth.

This actually worked for the gas tank but noticed I had a run after I dried for a while. I figured id wet sand it and touch it up the next day and all heck broke loose... it started crackling bad.... So I sanded the whole tank way down and tried it again. It didnt work,

So I sanded it down again... This time I went slower, allowing 10 minute between base coats, the base went on fine. Waited 30 minutes and started the clear, 2 coats 10mins in between and everything looks great. After waiting another 10 mins I go look at the clear and the base underneath is starting to crackle in alot of spots....

Ive tried 5 minutes between coats all the way up to 15 mins between. Tried very light coats for first 3 coats and then a nice smooth wet one. Nothing seems to work. Weird thing is when I first painted it it was perfect except that run ruined everything. I should have put a sticker over it.

The front Fairing is the same way, it just crackles all over and cant get it to work either.

I am not sure what the temp was when I painted the side fairings that turned out great, I think like 70f. Anytime I painted the front of gas tank tho its been about 50f.

Anyways that is a long post, does anyone have any advice?

you should call Rustoleum and ask them. a lot of times if you wait to long between dry times the coats before have a chance to dry to much then the next coat is applied and it tries to lift the under coats. its a sensitive state ,to dry but not dry enough. are you spraying over an old substrate?
Jay D.

Jay's on the right track for timing between coats but this isn't quite that.

Many paints have what is known as a 'withholding' period. This is between a day and a couple of weeks and during this time rework is not possible because, while apparently dry, the paint is not fully cured and therefore sensitive to the thinners in any subsequent paint applied over it. Sanding just exacerbates the problem because it exposes a greater surface area.

Temperatures during and after initial application can have an effect on the duration.

The issue is one of the reasons why we only use high quality automotive paints in my shop. These tend not to suffer from the issue or the withholding period is short, allowing reworks when necessary.

Details should be in the Technical Data Sheet for the product you used. Alternately, as suggested, contact the manufacturer.

Any tips? I stripped/sanded that tank back down. All the 2x rustoleum paint is now off it. I had to use some paint stripper because the paint was so thick doing it 4 times to just sand it off. Stripper didnt seem to affect the factory paint at all.
It is to late to have a body shop paint it, plus they wanted $1000....

I am going to wet sand it for a while with 400 grit and get it ready to be painted again. Will I have to do something special to make sure all that paint stripper if off?

I will be waiting till Saturday its supposed to get up to 68 degrees here in NY.

Wash well with detergent and warm water and rinse thoroughly and dry. There should be no residual paint stripper and at this point you can sand and repaint because there will be none of your previous paint left to react with the new.

Okay, first, this is right off the technical data sheet....

DRY & RECOAT
Dry and recoat times are based on 70ºF and 50% relative
humidity. Allow more time at cooler temperatures. Dries to
touch in 20 minutes, to handle in 1 hour, and is fully dry in
24 hours. Apply a second coat or clear coat within 1 hour or
after 48 hours. Apply clear in 2-3 light coats a few minutes
apart.

Second, that stuff is $3.88 a can. You got your money's worth. There's a reason they wanted a $1000 at the shop for a good pro job. Why not try and go inbetween? How about going to a local paint jobber and getting some good base/color canned up in aerosol. As small as these parts are see if they carry the Spraymax 2k primers and clear coats. Yes, you are still going to have a couple of hundred bucks in the project but it will be DIY and you can get near pro results. I don't care what the internet or boob tube shows you about stuff that costs $3.88 a can. It's not going to look good and it sure isn't going to last....

^^^^ ^^^^ with spray can enamels its very important to watch that SENSITIVE TIME PERIOD and it can be way off. second coating un catalyzed enamels is a crap shoot it may work and it may not.
Jay D.

Just wanted to chime in with a similar experience I went through today. I also used a Rustoleum product - aluminum primer followed by a sand/fill primer. I then used paint from AutomotiveTouchup (I think urethane based). I followed the instructions about timing and prep and also experienced the crackling as soon as the paint went on the primer.

I was doing this because the paint began to crackle a year after application on the same surface. Not sure of the cause.