What is causing this
 

Hi , painting the mudguard on my bike and the last time it was painted the paint cracked after it was lacquered , so took a palm sander to a bit of it yesterday and primered with high build primer , went back to it today and its gone like this , any help much appreciated

The same thing happened to me when I painted my bike's fuel tank:
https://s26.postimg.org/m1202xm1x/IMG_1277.jpg
Help With Troubleshooting Paint Problems

Thanks for that , it looks like sanding blisters for me then , only the front mudguard , tank , both side fairings to go!!!

Looks like a paint reaction caused by a mix of the wrong type of paint.


Flat it smooth then a good coat of stopper before you prime and all will be well.

It could also be shrinkage of the paint due to too cold of a temperature either during or after painting.. primer filler is alot thicker remember...

... I agree with paint reaction too - but I have defo had it due to temperature..

Not temperature , garage is heated , plus painted during the day , about 15 degrees outside , originally painted and after about 2 weeks was lacquered and the paint looked like it was cracked about a week after that , I then sanded the mudguard back and primed and this was the result , I'm leaning towards the lacquer causing it ,
Thanks for all the info so far

We have seen similar when we use water based paints (The Law for most things now) and 2K lacquer. The lacquer seems to react to the paint...

Are you using Water based paints or 2K paints? (Bikes are still ok for 2K iirc)

The original black was halfords rattle can and not sure about the lacquer as this was done by someone else , and the primer is also halfords rattle can ,
The person who did the lacquer hasn't got a professional set up(own garage)so not sure on what he would of used and can't check with him as he has moved on

You can get 2K lacquer in spray can form from http://www.specialistpaints.com/coll...at-kustom-canz

The fan from those "Kans" are awesome for a can :) and they deliver direct to your door... They also have a good range of colours for the base coat too.

My partner runs an Airbrush company and has access to various paints and bodyshops if we can be of any assistance :)

Thanks for that , I am planning on stripping and rebuilding the bike between now and about march/April , would it be possible to airbrush the Honda wings logo on the tank , my only concern being Honda have been known to prosecute people for using the Honda logo , but then they would have to know who did the work:D
If it is poss I could leave the tank with you for a month or so , so there wouldn't be any rush.