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Acrylic topcoat over 2-pak primer?
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Author:  captainwaldopepper [ Sun Feb 04, 2018 4:37 pm ]
Post subject:  Acrylic topcoat over 2-pak primer?
I've always used etch primer, then acrylic filler/primer and then acrylic topcoat (same brand-Protec for all) and this has worked well for me for home-based spray jobs (rather than professional booth-based ones).
I'm starting a new project and I know 2-pak primer is easy to use and a better coating over bare metal but i was thinking of using acrylic over the top so it has that classic look rather than a shiny 2-pak look (and, even though it is not ideal i can spray it at home without a professional booth).
Has anyone done this and does it work long term or are there incompatibility issues with the 2 paint systems?
If it is possible, do i need an acrylic undercoat over the 2-pak primer or can the acrylic be sprayed straight on top of the 2-pak primer?
Do you need to use the same brand of 2-pak primer and acrylic topcoat?
PS-yes i know 2-pak primer should ideally be sprayed in a booth with an air fed respirator and has the same hazards as 2-pak topcoat
Cheers
Dave
Author:  Ian_B [ Sun Feb 04, 2018 6:57 pm ]
Post subject:  Re: Acrylic topcoat over 2-pak primer?
Yes and yes Ive done it and the two pack primers leave the acrylic rubbish for dead .Rub the two pack primer with 400 wet is what I did for a key for the acrylic topcoat to stick to.
You will have superior filling levelling and its not based on solvents totally like the crap acrylic spray putty.
Rub the primer in two steps guide coating each One to level with coarser grit then finer pre top coats
I would never use acrylic primers and putties again :D
A group effort one in the works now A stubborn man wants his Holden Acrylic It will be lol On top anyway
Get a good mask very seriously.
Author:  Goldbrocade_62 [ Sun Feb 04, 2018 7:25 pm ]
Post subject:  Re: Acrylic topcoat over 2-pak primer?
Ian_B wrote:
Yes and yes Ive done it and the two pack primers leave the acrylic rubbish for dead .Rub the two pack primer with 400 wet is what I did for a key for the acrylic topcoat to stick to.
You will have superior filling levelling and its not based on solvents totally like the crap acrylic spray putty.
Rub the primer in two steps guide coating each One to level with coarser grit then finer pre top coats
I would never use acrylic primers and putties again :D
A group effort one in the works now A stubborn man wants his Holden Acrylic It will be lol On top anywa
Get a good mask very seriously.

Sounds like you like to give it a good rub
Author:  Ian_B [ Sun Feb 04, 2018 7:53 pm ]
Post subject:  Re: Acrylic topcoat over 2-pak primer?
Yes but not dry Rob :P
Author:  drmini in aust [ Sun Feb 04, 2018 8:03 pm ]
Post subject:  Re: Acrylic topcoat over 2-pak primer?
I have used it when I first repainted my car in jet red acrylic 25+ years ago.
Don't leave it for months before rubbing it, it gets harder.
Author:  Ian_B [ Sun Feb 04, 2018 8:15 pm ]
Post subject:  Re: Acrylic topcoat over 2-pak primer?
Yes Doc and the acrylic thinners dont bite into the primer fillers like old days .
Author:  captainwaldopepper [ Sun Feb 04, 2018 9:36 pm ]
Post subject:  Re: Acrylic topcoat over 2-pak primer?
Thanks for the replies gents-2-pak primer it is then!!
Cheers
Dave
Author:  p7676 [ Mon Feb 05, 2018 4:16 pm ]
Post subject:  Re: Acrylic topcoat over 2-pak primer?
Worth considering, 2 pack epoxy primer is made to spray 2 pack paint over the top. You get different shrinkage rates between 2 pack and acrylic Always stick with the same brand all the way through the paint process. Check with your paint supplier before you paint acrylic. Just send them an email, better to be safe than sorry. Lets know the result .
Author:  Ian_B [ Mon Feb 05, 2018 6:27 pm ]
Post subject:  Re: Acrylic topcoat over 2-pak primer?
Well worth considering is that when you do out of the of the ordinary you are on your own.If something goes wrong you are on your own .I accepted this and if something went wrong it was on my shoulders entirely
Author:  p7676 [ Mon Feb 05, 2018 7:11 pm ]
Post subject:  Re: Acrylic topcoat over 2-pak primer?
sometimes good advise can save you a lot of heartache. I have recently fitted a new guard on a mini ,I think even the heritage come from China ,not are they hard to fit you have to file out the hole for the headlight using a square file. Also the round holes are in a different position each side. If you don't elongate the large round holes the position of the headlights will be different 5mm.Work you should not have to do, then you need to punch up the top curve at the front using a curved brickies bolster. Otherwise the bonnet sticks up too high. You even have to make some templates to check the work is the correct shape.
Wo is me never had this problem with old American cars except Mustangs.
Author:  Ian_B [ Mon Feb 05, 2018 8:10 pm ]
Post subject:  Re: Acrylic topcoat over 2-pak primer?
Ive seen a MDF Tv unit prepped in epoxy and finished in acrylic black rubbed and buffed.But that never sees UV .
My dads WB ute was done bare metal high fill then acrylic Dad wasnt gunna blow up if it went wrong but it didnt.
If you want warranty pay the bucks with a good shop.If you want to play around be prepared to learn.I will do another acrylic over 2k primer soon and the bloke wont blow up if something goes wrong =no bucks involved.Hard under is better than soft under.
I fix electronics since school I guarantee my work .Ive done night tafe Im not a tradesman at paint panel and I wont do it to make money but its good to be able to do some stuff for yourself .You may surprise yourself .Hope this helps someone
Author:  captainwaldopepper [ Mon Feb 05, 2018 9:55 pm ]
Post subject:  Re: Acrylic topcoat over 2-pak primer?
So far I've painted 3 minis and a Moke in acrylic only and all turned out OK.
As I understand it, 2-pak is a hard coating and acrylic is soft.
My van originally had 2-pak topcoat painted over acrylic and the entire paint job was cracked when i bought it.
The reason this happened is that the softer acrylic underneath the 2-pak moves and so cracks the harder topcoat.
I have painted acrylic over KBS Rustguard, a hard isocyanate-based polyurethane coating on a couple of my cars and have had no problems yet (been 5 years now).
I'll keep you all posted when i start painting the new project (still stripping the car down at the moment)!!
Cheers
Dave
Author:  low n blown [ Wed Feb 07, 2018 2:43 pm ]
Post subject:  Re: Acrylic topcoat over 2-pak primer?
p7676 wrote:
Worth considering, 2 pack epoxy primer is made to spray 2 pack paint over the top. You get different shrinkage rates between 2 pack and acrylic Always stick with the same brand all the way through the paint process. Check with your paint supplier before you paint acrylic. Just send them an email, better to be safe than sorry. Lets know the result .


I always paint in acrylic as it gives the right finish and have won many many prizes for show cars including best paint at a hotrod and custom car show. I once tried acrylic over 2k primer and it did not hold properly. I questioned PPG and they said the same thing, that the 2k remains flexible like rubber but the acrylic will pull away from the 2k eventually. Also acrylic will "melt" into the acrylic primer giving a tighter bond. It will not dissolve some of the 2k primer, so it actually sits on top.
Author:  captainwaldopepper [ Wed Feb 07, 2018 4:54 pm ]
Post subject:  Re: Acrylic topcoat over 2-pak primer?
I have my doubts now after speaking to a painter-if you stick to the same type (acrylic or 2K) and the same brand he reckons no problems.
I'm sure others may have different experiences (like me when painting acrylic over KBS rust seal albeit with an acrylic undercoat applied first!!).
I've always used the Protec etch, Protech acrylic primer and Protech acrylic topcoat and have had no issues so far.
I guess it will be either acrylic or 2K all the way at the moment as a mixed and matched job may end in tears (most likely mine!!)
Thanks for the advice gents.
Author:  Ian_B [ Wed Feb 07, 2018 8:00 pm ]
Post subject:  Re: Acrylic topcoat over 2-pak primer?
Yes we were taught this and success is far more guaranteed .Painting 2K is different technique to acrylic so I get a mate that can.
My jobs done unorthidox didnt matter much Good choice the way you have decided
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