Single-Stage Paint Good Idea for Old Truck?

[Pevehouse]

I'm not painting this huge truck myself. I have nowhere to do it and no skills. I want to know what to ask for. I was thinking single-stage would save me money and also make the truck easier to fix in the future.

I have been reading up some more, and as is so often the case, environmentalism, not value for the consumer, is the reason carmakers abandoned a product that worked. Two-stage paints give off fewer VOC's during application. On the down side, which is pretty severe, repeat exposure to isocyanates in two-stage paint can cause permanent allergies to develop, resulting in incurable asthma. So the trees and bunnies benefit, but if you become sensitive to isocyanates, you have a very unpleasant health problem that will never go away. And it has killed a bunch of people.

And isocyanate allergies can be triggered by SKIN exposure, so a respirator won't protect you. And you can't predict when the allergy will develop. Could be the 5th time you paint, or the 50th.

Isocyanates are also used in Great Stuff foam, which I have been exposed to a lot.

I don't know if all two-stage urethane paints contain this stuff or not.

Chances are your gonna have a hard time finding anyone or any shop that does over all paint jobs and an even harder time finding one that will use single stage

 

[Chips O'Toole]

Base coat clear coat systems are the way to go actually. If you use a good product and the prep is done correctly then it will last a very very long time and keep its shine

In Florida, for dark colors, that's 7-8 years unless you park in a garage. That's not very good for $8000 or whatever.

 

[Aaron_W]

Not sure how much it helps, but my Dad has a 1952 GMC pickup with original paint. It has been parked outdoors since at least the late 80s when he got it. The paint has been dull and chalky most of the time he has had it, but when we have occassionally thrown a coat of wax on it, it brought back a decent shine to the paint.

I'm sure 1950s paint has all kinds of bad stuff long since outlawed even in the least restrictive places. It does match your recollections of paint lasting a long time in the "good old days".

 

[derf]

Skip the paint.....get it wrapped.

 

[Nesse1]

The paint used in auto plants is totally different from what repair shops use. You can't compare "paint failures" from one OEM to another, since the type of paint varies widely. And you surely can't compare OEM paint to aftermarket. Totally different.

Some OEM's use thermo-set paints, many transported via a waterborne carrier to reduce VOC release. It's not unusual for the paint cure to go up into the 400F range. I think of these as almost like water carried powder coat. Other OEM's use a solvent based paint, or maybe a waterborn paint, that's not thermoset. It just depends on the plant and local environmental rules.

In the auto repair industry, you can buy a variety of different paints, but most are urethane based catalyzed two part paint. There used to be a lot of (cheaper) acrylic enamel paints in the marketplace, but I'm not sure about today. Most paints are base coat and clear coat, and that's just fine. Just be sure it's high grade urethane catalyzed paint. And use a two pack epoxy primer, for direct to metal sealing. Build primer come in either catalyzed versions or non. Two part is best, but more expensive.

When I painted my motorcycle frame and various parts, I bought some Dupont Nason fleet urethane black paint. This is catalyzed, but one stage, meaning no clear coat. I'm no pro, but I've painted several projects like motorcycles, bicycles, and similar, and let me tell you, that Nason was the best spraying stuff I've ever used. If you can somehow find some of that stuff, get it!

P1010483 by nessism, on Flickr

 

[Red96]

Regarding automotive paints:
Clearcoat delamination is mainly caused by UV exposure. UV will chemically destroy the bond between the basecoat and sealer, or the bond between the basecoat and the clear, or both. Darker colors usually fail between clear and color coat. Lighter colors, especially silver & white tend to fail at the sealer layer, below the color coat. The expansion/contraction cycle theory is baloney.

Single-stage paint means it is color only, no clear coat. May or may not be catalyzed. Available in both flavors.
Two-stage paint systems have a color coat under a clear coat. Almost universally, both stages are catalyzed if the color coat is solvent based. Basecoat (color) might be solvent based or waterborne. Clear will always be a solvent based product.

'1K' (Single part) paints mean non-catalyzed. They harden due to evaporation of the carrier solvents, and underperform as a form of corrosion protection in comparison to an epoxy type coating. They bond poorly to bare metals.
'2K' paints means they are catalyzed. They harden due to a chemical reaction. Isocyanates will be involved. Once you're sensitized to isocyanates, you're forever susceptible to potentially severe reactions to very small exposures. Essentially you're done in the industry at that point.

You can not 'sand off' the clear and reapply over the original base coat. Both must be reapplied after proper preparation of the substrate. Clear cannot bond to cured base coat. There is a window of time to apply the clear after the basecoat to form a proper crosslinked bond between the two.

Longevity of the finish will depend upon (1)correct prep & application, (2)the quality of the paint used and (3)the exposure to sun the vehicle receives afterwards. Delamination is a big thing in the sunny states, not so much here in rain-land. (Though it was here too back in the 70's & 80's when the OEM's were not putting sufficient UV blockers in the clear. Pretty much every white or silver car here became a peeler eventually too)

You can spend $1200+ on paint materials that will perform well for 10-15 years with proper preparation and application, or you can spend $300-400 on your paint and have a toad in 18 mo. Bargain paint is a false economy.

The suggestion of a wrap might be worthy of consideration, depending upon your personal requirements.

 

[deakin]

In Florida, for dark colors, that's 7-8 years unless you park in a garage. That's not very good for $8000 or whatever.

in my past life i have painted many large vehicles - almost all high metallics and quite a number in silver - in florida - and over 20 years later they are still good
i used ppg dbc and (at that time) 2020 clear. dp40 or dp50 as an initial primer and then as a seal coat. follow the directions exactly

 

[Pevehouse]

The paint used in auto plants is totally different from what repair shops use. You can't compare "paint failures" from one OEM to another and blame the "clear coat" system. And you surely can't compare OEM paint to aftermarket, and try to blame "clear coat" again.

Some OEM's use thermo-set paints, many transported via a waterborne carrier to reduce VOC release. It's not unusual for the paint cure to go up into the 400F range. I think of these as almost like water carried powder coat. Other OEM's use a solvent based paint, or maybe a waterborn paint, that's not thermoset. It just depends on the plant and local environmental rules.

In the auto repair industry, you can buy a variety of different paints, but most are urethane based two part. Most paints are base coat and clear coat, and that's just fine. Just be sure it's high grade urethane catalyzed paint. Use a two pack epoxy primer, for direct to metal sealing too.

When I painted my motorcycle frame and various parts, I bought some Dupont Nason fleet urethane black paint. This is catalyzed, but one pack, meaning no clear coat. I'm no pro, but I've painted several projects like motorcycles, bicycles, and similar, and let me tell you, that Nason was the best spraying stuff I've ever used. If you can somehow find some of that stuff, get it!

P1010483 by nessism, on Flickr

Mason is good stuff as is PPG. We spray scales chroma now but used to use PPG both are pretty similar except for the price. PPG had just gotten high as giraffe ***** so we stopped and switched to axalta

 

[Pevehouse]

Regarding automotive paints:
Clearcoat delamination is mainly caused by UV exposure. UV will chemically destroy the bond between the basecoat and sealer, or the bond between the basecoat and the clear, or both. Darker colors usually fail between clear and color coat. Lighter colors, especially silver & white tend to fail at the sealer layer, below the color coat. The expansion/contraction cycle theory is baloney.

Single-stage paint means it is color only, no clear coat. May or may not be catalyzed. Available in both flavors.
Two-stage paint systems have a color coat under a clear coat. Almost universally, both stages are catalyzed if the color coat is solvent based. Basecoat (color) might be solvent based or waterborne. Clear will always be a solvent based product.

'1K' (Single part) paints mean non-catalyzed. They harden due to evaporation of the carrier solvents, and underperform as a form of corrosion protection in comparison to an epoxy type coating. They bond poorly to bare metals.
'2K' paints means they are catalyzed. They harden due to a chemical reaction. Isocyanates will be involved. Once you're sensitized to isocyanates, you're forever susceptible to potentially severe reactions to very small exposures. Essentially you're done in the industry at that point.

You can not 'sand off' the clear and reapply over the original base coat. Both must be reapplied after proper preparation of the substrate. Clear cannot bond to cured base coat. There is a window of time to apply the clear after the basecoat to form a proper crosslinked bond between the two.

Longevity of the finish will depend upon (1)correct prep & application, (2)the quality of the paint used and (3)the exposure to sun the vehicle receives afterwards. Delamination is a big thing in the sunny states, not so much here in rain-land. (Though it was here too back in the 70's & 80's when the OEM's were not putting sufficient UV blockers in the clear. Pretty much every white or silver car here became a peeler eventually too)

You can spend $1200+ on paint materials that will perform well for 10-15 years with proper preparation and application, or you can spend $300-400 on your paint and have a toad in 18 mo. Bargain paint is a false economy.

The suggestion of a wrap might be worthy of consideration, depending upon your personal requirements.

Spoken like a true painter

 

[Rich Berg]

HI there is no reason you need to go with "base coat clear coat" that is done to improve the final appearance of the product (they cover a multitude of sins). the new finishes are the way to go, avoid colors like silver and reds. the longest lasting is black's and greens. most shops can spray single step epoxy type finishes quite well now.
Rich