Hey guys, I once did a short course at Tafe and they told us that you cant spray 2-pak over acrylic because acrylic never fully hardens and in a hot day the acrylic will move around under the 2-pak and crack it? which all seemed to make sense...
But my mate started doing a spray painting apprenticeship a few months ago and he said they do do it occasionally and when he asked they said its not the best thing to do but its... ok... he also said if you put a layer of putty between it helps as well...
so yea now im confused can your or cant you?
Spraying 2-pak over Acrylic?
Started by
_Viper_
, Apr 16 2009 08:31 PM
13 replies to this topic
#2
_darrenmark1_
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Posted 16 April 2009 - 08:37 PM
I would say no, i think you can spray acrylic over 2 pac primer, but not 2 pac over acrylic.
#3
_LH SLR 3300_
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Posted 16 April 2009 - 10:56 PM
As long as the acrylic paint to be painted over is in good condition with no cracking etc I recommend a PPG product called Scansealer. It's basicly an adhesion promoter & sealer in one. When I use it I give the panel I want to paint a light scuff with P800 or P1000, prepsol & apply the scansealer. Let it tack off then spray the 2K over it. It comes out clear so there are no colour issues & it can be used over new panels, blocked primer etc. Really good for doing the undersides of second hand bonnets etc with hard to sand areas as it will adhere to almost anything. It's a 2K product & it has to mixed with a hardener at 4:1
#4
_gtr161s_
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Posted 18 April 2009 - 08:45 PM
Back in the 80's there was a product called "isolator", like the name suggests it could go over any old paint in good condition then prep n paint as normal in acylic, acran or enamel
#5
71xu1
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Posted 18 April 2009 - 09:32 PM
Back in the 80's there was a product called "isolator", like the name suggests it could go over any old paint in good condition then prep n paint as normal in acylic, acran or enamel
Isolators purpose is to isolate incompatible paint acrylic over spraying enamel so the thinners can,t attack the enamel and cause the underlying enamel to wrinkle. I was always taught that you can put soft over hard and not hard over soft which makes sense. If a layer of paint is moving underneath it has to eventually crack the inflexible top.
Hope this helps
Cheers Dave
#6
_booral1_
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Posted 18 April 2009 - 09:36 PM
Sorry to steal your thread Viper but can you use 2 pak under coat with acrylic paint on top?
I'm worried big time about shrinkage.Seen so many acrylic paint jobs with shrinkage through the paint.
If 2k sets so hard and you use 2k undercoat and paint the the colour and top coats in acrylic to get the acrylic affect.
Would that be a better result then using acrylic undercoat?
I'm worried big time about shrinkage.Seen so many acrylic paint jobs with shrinkage through the paint.
If 2k sets so hard and you use 2k undercoat and paint the the colour and top coats in acrylic to get the acrylic affect.
Would that be a better result then using acrylic undercoat?
#7
_LH SLR 3300_
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Posted 18 April 2009 - 09:47 PM
Yes that is true, Scansealer is, for lack of a better word, elastic so it will move with the softer acrylic paint without causing the 2K enamel to crack or peel off. 2K still has a degree of elasticity, otherwise it wouldn't be suitable for painting over plastic bumpers etc.
#8
_LH SLR 3300_
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Posted 18 April 2009 - 10:09 PM
Sorry to steal your thread Viper but can you use 2 pak under coat with acrylic paint on top?
I'm worried big time about shrinkage.Seen so many acrylic paint jobs with shrinkage through the paint.
If 2k sets so hard and you use 2k undercoat and paint the the colour and top coats in acrylic to get the acrylic affect.
Would that be a better result then using acrylic undercoat?
I've painted acrylic over 2K primer with great results, but then if the preperation isn't up to scratch, & or the 2K primer isn't applied correctly you will still get shrinkback. 2K primers are excellent for filling minor scratches etc but I still finish off any body filler in P120 & feather all edges right back using P240 & P320. I also let each coat of primer tack off well & truely between coats. Try to avoid applying heavy coats coats too. I also leave the primer to cure for at least a few days or more before blocking & painting. I don't use acrylic primers at all & never use them under 2K as I've found the paint will delaminate over time, especially if it gets stonechips or scratches. Hope this helps
#9
_Bomber Watson_
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Posted 19 April 2009 - 11:28 AM
Yes you can spray 2k over Acrylic, with four main considerations.
No 2k topcoat i know of will adhere to acrylic no matter how it is prepped, so you must coat the whole car in 2k primer first.
Not all 2k primers are suitable over Acrylic. Check this first.
Most acrylics would have had a silicone based polish used on them. This is a big enemy. Before doing any sanding operation always thoroughly prepwash a panel. This is a good rule of thumb no matter what the circumstance.
And lastly if the paint is old enough. More than about five years should show no problems at all. Acrylic keeps shirinking for about a year or so, so definitely no chance over a fresh job.
Cheers.
No 2k topcoat i know of will adhere to acrylic no matter how it is prepped, so you must coat the whole car in 2k primer first.
Not all 2k primers are suitable over Acrylic. Check this first.
Most acrylics would have had a silicone based polish used on them. This is a big enemy. Before doing any sanding operation always thoroughly prepwash a panel. This is a good rule of thumb no matter what the circumstance.
And lastly if the paint is old enough. More than about five years should show no problems at all. Acrylic keeps shirinking for about a year or so, so definitely no chance over a fresh job.
Cheers.
#10
_booral1_
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Posted 20 April 2009 - 05:12 PM
Cheers thanksYes you can spray 2k over Acrylic, with four main considerations.
No 2k topcoat i know of will adhere to acrylic no matter how it is prepped, so you must coat the whole car in 2k primer first.
Not all 2k primers are suitable over Acrylic. Check this first.
Most acrylics would have had a silicone based polish used on them. This is a big enemy. Before doing any sanding operation always thoroughly prepwash a panel. This is a good rule of thumb no matter what the circumstance.
And lastly if the paint is old enough. More than about five years should show no problems at all. Acrylic keeps shirinking for about a year or so, so definitely no chance over a fresh job.
Cheers.
So what if your starting from bare metal?would that be easyer prep.
What 2k primers would suit ?or because I'm starting from bare metal would i just be better to use acrylic primers.
cheers
#11
brocks72xu1
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Posted 20 April 2009 - 08:29 PM
get yourself some dupont expoxy primer that elimanates etch priming and you can do your repairs over the top it aswell ,you wont get any sink backs at all
#12
_Bomber Watson_
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Posted 23 April 2009 - 06:52 PM
Why the hell would you use an acrylic primer???
Use 2k primers. If your back to bare metal then go all 2k.
Havnt tried that stuff ^, just make sure whatever you get is non corrosive and you will be set.
Cheers.
Use 2k primers. If your back to bare metal then go all 2k.
Havnt tried that stuff ^, just make sure whatever you get is non corrosive and you will be set.
Cheers.
#13
brocks72xu1
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Posted 23 April 2009 - 09:12 PM
hi bomber
dupont epoxy primer is a two pack product that you can apply straight over bare metal and do all your niki repairs on top of it, then you apply two to three coats over again to seal your repairs,its a really good product and dries like concrete ,i have used over my xu1 and have had no problems at all not even a sink back that you would get using hi fill and it cost around $230.00 dollars for a kit
dupont epoxy primer is a two pack product that you can apply straight over bare metal and do all your niki repairs on top of it, then you apply two to three coats over again to seal your repairs,its a really good product and dries like concrete ,i have used over my xu1 and have had no problems at all not even a sink back that you would get using hi fill and it cost around $230.00 dollars for a kit
Edited by brocks72xu1, 23 April 2009 - 09:13 PM.
#14
_bronzehatch_
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Posted 24 April 2009 - 08:54 AM
Standox have a 1k full primer to use on bare metal witch can be painted over wet on wet (primer or topcoat)or sanded, thinned differently (with either 2k 0r basecoat thinner, i find this product great for wet on wet jobs of good clean steel like roll cages chassis etc
shane
shane
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