Not to sure if this is in the right section but i'm painting a set of alloy wheels and when I primed one of the them the primer has bubbled and cracked, why would this be happening and what can I do to stop it? I have already done 2 wheels and they have turned out ok.

 

The paint has reacted, normally due to silcone or oil based products been used on the wheels, wait till the paint hardens then ull have to rub it right back down again.

 

Do you mean rub the whole wheel back to metal or just the bits that hace reacted?

 

Where the paint has reacted.

 

Wd40 and Brillo pad?

 

Could be a number of things get a pic up if your going straight on alloy uou should etch prime first , you should panel wipe before to take off any oil /dirt, put the primer on light coats if you put it on heavy it can't dry fully and can crack , you will need clean primer off thinners or rub it off and start from scratch .

 

If they have been painted before can be this bubbling up when new paint eats in can be a cunt to sort you have to rub it right back and go on with nice light coats

 

As said can be a number of things, paint reacting with pervious paint or not cleaned off properly before priming or too heavy a coat. Did u use 2k or aerosol by the way?!

Either way will have to be rubbed back or it will keep coming back on you!!