Paint cracking?

[psycoreefer]

I just picked up a parts bike over the weekend, its got a cool painjob on the tank and covers but the paint is all cracked - like you'd see cracks in mud when it drys.

Anyone ever seen cracks like that? Are they likely to be all the way down to the metal/primer or maybe only in the clear topcoat?

I'm hoping that it will be most likely a top coat flaw and I can wet sand through the cracked clear coat and just re-spray a clear coat on it.

[DiverRay]

You can try and sand the clearcoat, but it may go all the way down. When I was trying to repaint my tank, it kept doing that to me! I think it's caused from NOT letting the paint cure before putting on the next layer. This last time I painted the bike, I had a week between the base and clear coat, and it still looks good after a year.

[WMarshy]

Does it look like this?



Mine is weird, almost thought it was some crazy factory texture because it was so uniform but after I looked closer I could see that the "texture" didnt go around to the bottom of the tank, and the bottom is blue like me side covers and not black looking like the top of the tank. I havent tried to do any repainting yet but, if I do Im stripping and starting from new, at this point the OEM paint is not worth trying to save.

[psycoreefer]

yeah, it looks a lot like that, but mine is clearly and aftermarket paint job.

[fredintoon]

Does it look like this? - - - Mine is weird, almost thought it was some crazy factory texture - - -

Hi Wade,
I kinda like that textured look. But the only way to get rid of it is, as you say, take the tank down to bare metal and start over.
And Ray, I did my tank and side panels with each coat applied as soon as the previous one wasn't tacky and that ain't crazed either. Runs and orange peel, yes; but no crazing.
I'd guess that either waiting a week or so to clearcoat or doing it right away would be OK; it's doing it in between that can trigger the crazing?

[WMarshy]

yeah, it looks a lot like that, but mine is clearly and aftermarket paint job.

Maybe they had paint like mine and decided to try and paint over it without removing it down to bare metal? Im no painter but, for the life of me I dont know how one could get that type of texture... Look at the tank down by the petcock and if its smooth then I would say its likely that they just were lazy and didnt remove all the old paint and decided to paint over it... maybe they like it and tried to excentuate it?

[cywelchjr]

My understanding from my bodyshop days in high school (and I understand it really hasn't changed) is that you have two choices when painting. You either have to paint each coat while the previous is still fresh enough to get a chemical bond with the previous layer (next coat melts into the previous a little), meaning it's only flashed but not really dried completely yet, or you have to wait for it to cure and do a sanding job and it's a mechanical bond between the layers (the first is the best, but can indeed be harder to do well, but is more durable if done right), but if you wait a little too long, or use incompatible paints in the first method, it will not work and will crack or crinkle up (the crinkling if controlled is sometimes desired though).

Here's the rub though, at least with Lacquer type finishes. If you go more than a few hours between coats, you have to wait long enough for a cure, or it's gonna crinkle or crack. It's a tight window there. Two parts are different I'm told, and those are based on how much hardener you put in. And now they have water based paints that are supposed to be as shiny and durable as the older stuff. I'll bet their expensive though, but I understand they use the same guns, the just need more air flow to help dry your paint work cause the carrier (water, duh) doesn't flash as fast. Apparently PPG introduced the product somewhat recently (in the last year or so I guess?). The stuff I've seen them do with it looked really good, but of course I can't say for the durability as of yet, and with not having checked I don't know what the stuff costs. But at least in Cantafordya with the enviromental laws, I understand it's a LOT less likely to bring the gestapo down on you when painting your car at home, since there are no organic solvents involved in the process only water, so I guess you just don't get to water you lawn if you paint your car?