1k Clear Coat Test
August 17, 2023 9:24 AM   Subscribe

Will 1k clear coat work on my car? Isocyanites in 2k clear coat make me not want to use it. What can I expect? Details and further questions inside.

I'd like to paint the hood of my car. There are a few rust spots that need to be dealt with. If everything otherwise is done well (I properly sand the paint, remove all the rust, prime and paint according to material specifications), can I expect a 1k clear coat to last?

It has been difficult to find details about the difference between 1k and 2k clear regarding the 1k's durability and longevity. Marketing materials say 2k is better (harder, longer lasting), but how much better?

I don't have a fully equipped paint booth, so 2k isn't an option because of its harmful health effects. Is this a project worth doing?

Any knowledge you have about the issue is helpful. Thanks.
posted by mr_bovis to Home & Garden (3 answers total) 1 user marked this as a favorite
Best answer: The actual difference between 1k and 2k is that 1k paints are air-dry and 2k use a catalyst to 'set' the paint through a chemical reaction. This means that, for a 1k paint, it can be re-dissolved by anything that has the properties of a solvent, including things like oil and fuel. This is because it relies on the evaporation of solvents in the paint to make it harden. Because a 2k paint doesn't rely on evaporation of solvents to dry, it's much more resistant to damage just because the chemical make-up of the paint means that it won't be dissolved by common solvents.

If you want to use a 1k clear coat, you also need to use a 1k base coat, because a 2k clear coat may dissolve the 1k base coat and vice-versa. So, whichever way you go, you need to use the same system for both base and clear.

As far as longevity goes, 2k is better simply because the catalytic reaction that dries it makes it harder than can be achieved using air-dry paint. So, it will last longer and be more resistant to solvents and to UV just because it's harder for it to be broken down by these things. Which one you use depends on how long you want the paint to last. If you plan to keep the car for 10 years, find a way to make 2k work for you, although it's likely the paint on the rest of the car won't last that long, so it may not be worth the effort and cost.

Any paint you apply with a spray gun presents health risks just because so much of it ends up in the air due to atomisation. Yes, 2k paints are worse because the chemicals they're made from are more harmful, but don't kid yourself that 1k paints are safe to spray without proper protection. You don't need a 'proper' spray booth to spray 2k any more than you need one for 1k and you can make something that will work well enough with plastic sheeting and timber. Either way, you need a decent mask that will protect you from breathing in the paint fog.

Honestly, unless you're very experienced with a spray gun, you aren't going to get a perfect finish, but you should be able to get a 'good enough' finish with the help of some College of Youtube study. Unless you are experienced already though, I would go for the 1k finish and save yourself some money. It might only last 5 years instead of 10, but does that really matter?

The best way to preserve paint is to keep it protected by a coat of wax like Carnubia wax, because this maintains a layer between the sun and everything else that attacks paint and the paint itself. I would use 1k and keep the car polished.
posted by dg at 3:51 PM on August 17, 2023 [2 favorites]

Response by poster: @dg: Thanks, this is all really helpful information. I appreciate the detail.
posted by mr_bovis at 9:04 AM on August 18, 2023

have a look at dipyourcar.com. they have a clearcoat, but also their youtube might be habdy for showing you workspacs prep etc.

they have a lot of DIY resources, great customer service, excellent facebook group.
posted by wowenthusiast at 11:21 PM on August 18, 2023

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