Paint crazy cracking as you spray it on

[badger]

Ok hunting for a little advise from all you pro painters out there.
Few mates and i went in and bought a MK wagon as a play truck http://www.outerlimits4x4.com/viewtopic.php?t=104755. It had a bit of rust so we decided to cut it all out and give the car a respray.
We sanded it all back properly, whiped it down with surface prep. and went to spray it. The paint is just plain old acrylic mixed 1:2 paint to thinners.
Almost immediatly it crazy cracked and you can just scratch it backoff.
I then tryed spraying some acrylic etch primer i had laying around and same thing.

Any suggestions why its doing this and what we have to do to stop it?.
The car has had a few resprays in the past and im guessing one of them wasnt with car paint or was from cheap rattle cans.

Hopeing we dont have to bare metal it
so any help would be appreciated

[NutterGQ]

Etch primer is for bare metal give that a miss, normal acrylic primer is cheap at round $30-40 for 4 litres so its worth doing anyway. Rub the car back with 320 wet and hit it with acrylic primer, high fill is the way to go. This shouldnt crack.

What your seeing is alligatoring, it can be caused by a few things heavy coat, different type of base (if you haven't primered your most likely cause), applying the second coat before the first is dry and many many more.

[ssfabricator]

its not crackin cos you are paintin acrylic over enamel is it ?????

[Pauwolf]

I would say I has been painted with enamel in the past, you cannot put ANY acrylic paint over enamel.

there are 2 things you can do
1. Spray it with enamel
2. Spray on isolator, it is not acrylic based it uses metho to thin it, then spray acrylic primer, then top coat

either way there is no easy way out. Bare metaling the car wont help if the enamel was painted over bare metal it gets into the pores of the steel. Isolator is your best bet

Paul

[Mick.]

I would say I has been painted with enamel in the past, you cannot put ANY acrylic paint over enamel.

there are 2 things you can do
1. Spray it with enamel
2. Spray on isolator, it is not acrylic based it uses metho to thin it, then spray acrylic primer, then top coat


Paul

I agree with this.

You can bare metal it and repaint it and this would be the proper way to fix this problem. This is what I would do.

Cheers Mick.

[chops]

looks like it's back to bare metal for us

[KiwiBacon]

2. Spray on isolator, it is not acrylic based it uses metho to thin it, then spray acrylic primer, then top coat

Who makes isolator? What brands and names is it sold under?

[Mick.]

2. Spray on isolator, it is not acrylic based it uses metho to thin it, then spray acrylic primer, then top coat

Who makes isolator? What brands and names is it sold under?

Just go to any automotive paint shop and ask for Enamel Isolator.

There are heaps of different brands but there not usually well known automotive paint manafacturers because it's not a recomended practice to use this product.

I personly haven't used Enamel isolator and never will. It only masked problems it doesn't fix them. It also makes touch ups in the future 10 times harder.

Cheers Mick.

[badger]

not quiet the advise i was hopeing for. lots of hard work n more time b4 we can go out n break it:P

but i guess better to do it right from the start.

[KiwiBacon]

Just go to any automotive paint shop and ask for Enamel Isolator.

There are heaps of different brands but there not usually well known automotive paint manafacturers because it's not a recomended practice to use this product.

I personly haven't used Enamel isolator and never will. It only masked problems it doesn't fix them. It also makes touch ups in the future 10 times harder.

Cheers Mick.

Excellent.
I got a bonnet stripped and repainted by a mate a few years back. The paint has lifted in spots all over. The problem fits completely with acrylic painted over steel which was previously enamelled.

Question now is what's the best thing to do?
Work owns a paint-shop completely with glass blasting and spray-galv. Will glass blasting remove all traces of enamel?

[Mick.]

Just go to any automotive paint shop and ask for Enamel Isolator.

There are heaps of different brands but there not usually well known automotive paint manafacturers because it's not a recomended practice to use this product.

I personly haven't used Enamel isolator and never will. It only masked problems it doesn't fix them. It also makes touch ups in the future 10 times harder.

Cheers Mick.

Excellent.
I got a bonnet stripped and repainted by a mate a few years back. The paint has lifted in spots all over. The problem fits completely with acrylic painted over steel which was previously enamelled.

Question now is what's the best thing to do?
Work owns a paint-shop completely with glass blasting and spray-galv. Will glass blasting remove all traces of enamel?

I'd just use chemical paint stripper mate. Provided it's paint striped properly all the way back to bare metal with no primer showing you won't have any problems at all.

I'm not a fan of blasting and car bodies or body panels for a number of reasons.

1. Blast grit get in places you cant get out and usually only comes out when putting your last coat of colour or clear on.

2. It can easily warp and dent panels, sometimes it's not enough to see untill you put the gloss paint over the top.

3. This is rare but can happen. If you are getting your panels basted most sand blasters recycle there grit over and over which means if they have sandblasted a dirty greasy engine just before they sand blast your parts it can enbed contamination into the metal. Like I said it doesn't happen very often but can happen.

Cheers Mick.

[Mick.]

not quiet the advise i was hopeing for. lots of hard work n more time b4 we can go out n break it:P

but i guess better to do it right from the start.

It is a prick of a job to do but well worth it in the long run.

The advantage of it being enamel is it will come off very quickly if you use a chemical paint stripper. Just make sure you mask off all the areas you don't want stripped and don't get any on your skin because it hurts like hell.

Cheers Mick.

[badger]

im pretty sure this car wasnt ever painted with 2pac or the like.
we have found evidence of atleast 3 different paint jobs on the cab itself and going by the condition of the last one and the body work done with it (all oxidised and covered in white powder) id assume it was a cheap rattle can job.
it was painted less than 2 years ago according to the last owner

[RUFF]

im pretty sure this car wasnt ever painted with 2pac or the like.
we have found evidence of atleast 3 different paint jobs on the cab itself and going by the condition of the last one and the body work done with it (all oxidised and covered in white powder) id assume it was a cheap rattle can job.
it was painted less than 2 years ago according to the last owner

All Oxidised and white powder is almost defianatly Enamal. Big mistake a lot of people make is they get told something was painted in 2 Pac and just assume that 2 Pac is not enamal. There is 2 pac Enamal.

[badger]

why do people use enamel then?
is it a cheaper option or something? because for a 2 year old job it sure looks forked
i am a bit of a novice at paint types and obviosly only knew of acrylic and 2pac.

[chimpboy]

For this particular job... what about painting it in enamel again?

It is carp but it might be your easy way out if it's just a play truck.

[chook05]

paint it in 2pak, to easy

[badger]

i was thinking that. but we have already bought paint. and also if its going to look that sh1t in the future id prefer to do it right.

[Mick.]

why do people use enamel then?
is it a cheaper option or something? because for a 2 year old job it sure looks forked
i am a bit of a novice at paint types and obviosly only knew of acrylic and 2pac.

The reason people use enamel is because it's cheaper then 2pack and has gloss off the gun which acrylic doesn't.

It can also be easier to get hold of because you don't need a hardener which means more shops sell it, you also don't have to worry about correct mixing ratios etc.

Without trying to confuse the situation I will try and explain.

Enamel paint and 2 pack are both technically 2pack if used correctly.

Enamel can be used with a hardener and should be (usually only 5% though) which then makes it a 2pack. (2pack is short for two component meaning you need paint and hardener for it to cure) If the enamel is used with a hardener you can just rub it down and prep it like you would if you where painting over 2 pack

Enamel can also be used without a hardener which is what causes all the problems at a later date like your having. The hardener makes it go hard, helps protect against the wheather and makes touch ups so much easier.

2 pack is actually called Acrylic Urethane which is used on all cars in the smash repair industy these days which needs a hardener to go off or the moment you try and wash your car the sponge will get stuck.

Hope this helps and doesn't confuse you more.

Cheers Mick.

[KiwiBacon]

I'd just use chemical paint stripper mate. Provided it's paint striped properly all the way back to bare metal with no primer showing you won't have any problems at all.

I'm not a fan of blasting and car bodies or body panels for a number of reasons.

1. Blast grit get in places you cant get out and usually only comes out when putting your last coat of colour or clear on.

2. It can easily warp and dent panels, sometimes it's not enough to see untill you put the gloss paint over the top.

3. This is rare but can happen. If you are getting your panels basted most sand blasters recycle there grit over and over which means if they have sandblasted a dirty greasy engine just before they sand blast your parts it can enbed contamination into the metal. Like I said it doesn't happen very often but can happen.

Cheers Mick.

Thanks for the advice.
The blast shop at work crushes and cleans it's own glass grit, it's only used once.

[badger]

well the paint stripping is going absolutly sh1thouse.
used almost 4 litres ($60) and done bonnet and 2 pannels. god only knows how many coats of paint are on this car.
any other tips for paint stripping?

we have no gone to stripping as much as we can then wire brush wheeling the panel. wich is slow but not wasting expensive stripper

[Mick.]

I'd just use chemical paint stripper mate. Provided it's paint striped properly all the way back to bare metal with no primer showing you won't have any problems at all.

I'm not a fan of blasting and car bodies or body panels for a number of reasons.

1. Blast grit get in places you cant get out and usually only comes out when putting your last coat of colour or clear on.

2. It can easily warp and dent panels, sometimes it's not enough to see untill you put the gloss paint over the top.

3. This is rare but can happen. If you are getting your panels basted most sand blasters recycle there grit over and over which means if they have sandblasted a dirty greasy engine just before they sand blast your parts it can enbed contamination into the metal. Like I said it doesn't happen very often but can happen.

Cheers Mick.

Thanks for the advice.
The blast shop at work crushes and cleans it's own glass grit, it's only used once.

No worries mate.

Just make sure you get all that grit out from underneather the bonnet properly before you paint it and it should be right.

Cheers Mick.