Why the new paint crazes and splits?

[adamukcorrado 0]

Can anyone tell me why i have been doing wrong- whenever i have painted any bits of trim (rear number plate panel for example) I take great care in rubbing down, cleaning, priming, undercoat, topcoat, then lacquer. Always looks fantastic when finished, but then within a month it starts to craze and crack.

 

What am i doing wrong? I check the primer/undercoat/topcoat are all compatible - (both on the cans and with local shop), i ensure the surfaces are correctly cleaned, painted at correct temperature etc etc. i have only tried aerosol spray cans but have tried different brands.

 

Any advice would be much apprieciated before i attempt my grill spoiler again!

 

cheers.

 

Adam

[davidwort 0]

I have the same problem, stevo29 was a body shop guy, I'll pm him.

[steveo29 0]

pics would help

 

too much paint in a short can cause cracking , or is it over a less than perfect repair?

 

for now id suggest you sand back to metal/plastic and start again with light coats, let the primer sit a couple of days or more before painting, could also be a miss match between the primer and top coats

 

im happy to advise on msn if you need more help

[adamukcorrado 0]

It has done it both from starting from bare plastic and from sound old paint,

The cracking starts after few weeks and continues getting worse over a period of months.

 

I suspect too much paint in a short time may be the problem then, although i always wait the recommended time between coats but i may be applying it too heavily.

 

Car's covered at the moment, but when i take the grill spoiler off to repaint it i will post some pics,

 

Thanks for your help

[coolrado 0]

are you using a dedicated plastic primer?

[adamukcorrado 0]

Maybe not, thats something else to check when i have another go, cheers,

[andy 0]

Plastic primer has to be the most important thing when spraying plastic bits. I've done mirrors before and learnt that normal primer just wont cut it.

[steveo29 0]

while its true that you need plastic primer on bare plastic...not using it wouldnt cause it to crack and craze, it would just flake off easily when hit/jet washed

 

might be worth grabbing another brand of paint..im thinking its not liking each other ...but all the dodgy stuff needs sanding right off

[davidwort 0]

I've had the same problem on bare metal with Acrylic spray can primers and just a can of halfords top coat, can't see it's a paint and primer issue as the cans have both been from halfords on occasion.

It does seem fine when I've just sprayed some top coat over some existing top coat on the car though, so perhaps it's a problem of thick cheap primer applied??? Was going to try an etching primer next time.

[steveo29 0]

the upol etch primer they sell is pretty decent

[Jim Bowen 1]

i sprayed loads of stuff with rattle cans and never had a problem, on my last car i did the mirrors (plastic) and complete tailgate (metal) and it all lasted for 3yrs

 

that was just using all halfords stuff

 

are you cleaning everything with white spirits?

 

how are you letting it dry etc

[davidwort 0]

doesn't white spirit leave an oil film, I've tried nothing (just wiping with clean cloth after sanding) and meths, it's like the top coat shrinks sometimes, and it takes weeks if not a few months to go like it.

[steveo29 0]

idealy get a tin of panel wipe for cleaning up...or do a final wipe over with some isophroprly ( god knows how you spell it ) alcohol

[adamukcorrado 0]

Out of interest what kind of approximate cost is a full respray these days? Not back to metal or anything, just to fix a couple of chips, scratches, small panel repair, and sort out the dodgey job someone has done it the past!, I realise the car will never be worth a vast amount and so not looking to spend £000's! (considering i have already spend probably 3-4 times more than i could ever get back! :cuckoo: )

[steveo29 0]

decent jobs are really £2000 upwards

[davidwort 0]

I had a 2nd hand wing and tailgate prepped and painted for 250 quid, top job from a local chap who's sadly retiring now, would have liked him to do the rest of the car, generally it works out at around 200 quid a panel for the work my dad's garage get done for them, obviously this would be cheaper per panel the more work is done on one car.