Painting with 2pak (HELP NEEDED)

[small talk]

Gday guys, the situation is my car has been painted over with enamel (im pretty sure) and i want to respray it in 2pak, so do i have to sand back all the enamel before i can apply the 2pak, or can i rough it up and spray it in primer then in 2pak, (providing that the enamel is sealed under the primer)???

If this is completely wrong let me know as im just picking up what i can, also if this wont work how can i quickly and easily remove the enamel?? have heard of sand blasting it but mixing the garnet with water so keep the panel cool and stop warping.

Please help me out, i wanna get alot of this work done between now and the weekend.

thanks if you can help.

Brock.

[6.5 rangie]

I'm sure you can paint 2pak straight over enamel, i did mine and its fine, no primer needed.

[small talk]

Hmmm thats not what ive heard, ive been told that the 2pak n enamel react with eachother. can anyone confirm this??

Brock.

[ISUZUROVER]

Hmmm thats not what ive heard, ive been told that the 2pak n enamel react with eachother. can anyone confirm this??

Brock.

Acrylic over enamel will react (looks like a relief map of a mountain range). Never tried 2pak over enamel.

[guzzla]

the thinners in the 2pak have a good chance of eating the enamel while drying. if it doesnt craze it will bubble in parts.

i strongly suggest you do a test sample

[bru21]

i know for a fact it will not work. might get away with it here and there but there will be enough reacted areas to make you cry

even sealing it with a primer is not enough. enamel is thermoplastic and softens with thinners etc. 2k has a slow drying time and will give the enamel plenty of time to react. also even if it is successful never mix paints eg acrylic under or over 2k as in the long term it will crack due to different coefficients of expansion, should be ok for a few years though

[Moose45]

Dont no if its any help but on many occasions ive put 2 pack clear
over the top of ordinary quick dry enamel, and that works a treat.
they are smaller items than a car, but principal is the same.

[small talk]

The orriginal sierra paint (green) has been painted over so if i sand it back to that (removing the enamel) then spray it in primer, then 2 pak. would this be the way to go??

Brock.

[Moose45]

Im no guru painter, but have done a few cars in the past, I would say do all ur repairs lightly rub whole car back (no need to go back to original paint) then use primer/filler.
That then isolates paintwork underneath, then do ur top coat.
Thats worked 4 me in the past, hope it helps you out a little.

[andrew e]

Ive stuffed around with enamal and 2 pack a bit and it is best to use 2 pack a primer between them if you want a high quality finish. If it was an off road car that i would be crashing into rocks etc i wouldnt bother about the primer, just rough it up with say 6-800 and go straight over it with 2 pack.

To be on the safe side do as guzzla said and do a test sample and leave it for an hour to see if it reacts.

i know 2 pack doesnt like plastic stuff without a primer between the plastic paint and the final coat, i did a motorbike fairing once and it was a nightmare, i had to strip it all off and start again. SEVERAL TIMES!

If you put 2 pack clear over enamal colour it looks nice, but it chips easily and you cant touch it up, so you have to rub back the clear from the entire pannel and start again.

Also dont let the EPA catch you painting 2pack in your garage, as the fumes are bad for mother nature and you can be fined. You are meant to catch and filter the fumes.

Also wear a mask when doing 2 pack as its not nice coughing up blue snot

Ps i'm not a painter by trade, only a backyarder. Automotive paint shops are normally happy to help out with advice too.

Andrew.

[mico]

The biggest prob with using 2K over enamel is the fact that enamel will move with temperture changes and the 2k won't this "may" result in any number of problems from the paint becoming crazed to de-lamination both of which can only be repaired by stripping it back to a solid/suitable surface (ie. metal, original 2k...)

But you may be lucky and have no problems, personally i wouldn't risk it, may as well do it properly if your gunna do it at all!!

[sudso]

There is an auto product called Barcoat that I used years ago for incompatible paintovers.
Its just like a sealer or barrier coat between the 2 paints.
Just rub the old back with 600 wet n dry or so, apply the Barcoat and then your primer but dont sand the Barcoat before you put the primer on.
From memory the primer has to go on the Barcoat within a certain time of the Barcoat being applied.

I painted over enamels and 2pak with standard acrylic lacquer using Barcoat and never had any reactions or even no "shifting" after years of application although the cars were ready for another paint job by then anyway

cheers