guide to painting new h2o based paint?
Discussion
hi folks
i couldn't get a hold of cellulose recently, all seems to be water based.
can someone please give me some quick guidelines as to how to use?
it's to paint a bumper. so, as per usual, prime (2 coats?) and then 2000 grit wet sand.
then spray 2-3 coats of metallic water based paint, 50/50 paint to water?
now, wet sand 2000 grit?
then 2 coats of clear?
cheers
steven
i couldn't get a hold of cellulose recently, all seems to be water based.
can someone please give me some quick guidelines as to how to use?
it's to paint a bumper. so, as per usual, prime (2 coats?) and then 2000 grit wet sand.
then spray 2-3 coats of metallic water based paint, 50/50 paint to water?
now, wet sand 2000 grit?
then 2 coats of clear?
cheers
steven
Steven,
Waterborne paint systems vary. What you need as a first reference is the technical data sheet for the paint system you're going to use. If your paint supplier can't give you one (shop elsewhere!) then the manufacturer's website probably can.
We can't recommend a single process that will work with all paint systems. In fact there isn't even one simple rule that always works with an individual paint system - some waterborne systems are thinned down varying amounts by the painter, and the coverage, gun setup and correct grit paper to use when preparing the surface for paint vary depending on how much it's been thinned down.
Which manufacturer's paint were you planning to buy?
Tol
ETA - I'd be very surprised if your paint system expected you to sand the final metallic coats. First of all, you'd destroy the proper lay-down of the flakes. And second, this paint is water soluble. Wet sanding it once it's on the panel would have a similar effect to rubbing down cellulose paint with abrasives dripping in thinners - the surface is going to dissolve into a horrible mess.
Waterborne paint systems vary. What you need as a first reference is the technical data sheet for the paint system you're going to use. If your paint supplier can't give you one (shop elsewhere!) then the manufacturer's website probably can.
We can't recommend a single process that will work with all paint systems. In fact there isn't even one simple rule that always works with an individual paint system - some waterborne systems are thinned down varying amounts by the painter, and the coverage, gun setup and correct grit paper to use when preparing the surface for paint vary depending on how much it's been thinned down.
Which manufacturer's paint were you planning to buy?
Tol
ETA - I'd be very surprised if your paint system expected you to sand the final metallic coats. First of all, you'd destroy the proper lay-down of the flakes. And second, this paint is water soluble. Wet sanding it once it's on the panel would have a similar effect to rubbing down cellulose paint with abrasives dripping in thinners - the surface is going to dissolve into a horrible mess.
Edited by Anatol on Friday 20th June 06:47
Its water borne paint, not water soluble paint. It it were, all our cars would wash back to the metal when it rained. Cleaning your car with a bucket and sponge would ruin it.
I don't know how long you'd have to wait for the paint to cure, but you would be able to wet sand it after a time.
I don't know how long you'd have to wait for the paint to cure, but you would be able to wet sand it after a time.
smart51 said:
Its water borne paint, not water soluble paint. It it were, all our cars would wash back to the metal when it rained. Cleaning your car with a bucket and sponge would ruin it.
Sorry, that's simply wrong. The paint (pigment, particulates, any binder or resins) is 'borne' in water in that water is the solvent that carries it. Some waterborne paints contain activators that make them more or less resistant to future dissolving in water once they've flashed off, but that's a side point.The finish on the car doesn't dissolve when sponged wet because the paint layer on modern C-o-B paint finishes is under a clear lacquer, which isn't water soluble, generally because it's a crosslinked 2k polymer product.
Tol
Indeedy! We're using a PPG base tinter set, but with 6 proprietary additives - although it means the paint has a shelf life once mixed (rarely an issue with the amounts you mix for SMART repair) the big big plus is that the flashing-off process activates the paint (cross-links it) so it's resistant to water. Big plus when working out of doors...
Tol
Tol
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