Paint Drying Time?

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Vitamin K
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Paint Drying Time?

Post by Vitamin K » Tue Jan 14, 2014 1:51 pm

You guys who run workshops, how do you handle painting of the cars?

My typical paint routine involves at least two coats of primer (sanding after each) and two coats of base color. Colors need a few days between coats to dry, with wet sanding between.

Obviously, you can't do this at a workshop, where you have a window of a few hours.

I could possibly see one shot of primer, quickie dry (maybe with a blow dryer) and then a coat of color. I don't have high hopes for the results, though.

Please share your workshop paint experiences/strategies. :mrgreen:



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Re: Paint Drying Time?

Post by BallBoy » Tue Jan 14, 2014 5:14 pm

In workshops that I have coordinated painting the car is not offered. Each racer is given the opportunity to leave the workshop with a rough-cut car body that is weighted within about 0.2 ounces of the allowable weight as well as polished axles and wheels. I send little pieces of sandpaper (80, 100, 150, and 220 grit in 1x2" pieces) home with the scout for finish sanding. Painting or otherwise decorating the car is something that is within the realm of almost all parents to provide guidance and oversee.



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Darin McGrew
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Re: Paint Drying Time?

Post by Darin McGrew » Tue Jan 14, 2014 5:33 pm

At our workshops, we provide spray primer and an assortment of spray paint. We also provide paint booths made from large cardboard boxes, with cheap plastic turntables and "trigger" style handles that snap onto the rattle cans. And we have a supply of paper cups to use as stands, and a supply of nitrile gloves to simplify everyone's cleanup.

We encourage everyone to apply multiple light coats rather than one heavy coat, Most of the spray paints specify that you should recoat within 1 hour or 2 hours, or you should recoat after 48 hours or 72 hours. It is perfectly possible to apply multiple light coats during a single hour at a workshop. And sufficiently motivated teams can apply additional coats at home, or can apply additional coats at a later workshop.

But we don't push more advanced techniques (e.g., allowing the top coat to dry for several days, then wet sanding before applying another coat). We don't discourage them either, but it's up to more ambitious teams to take the initiative.



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Re: Paint Drying Time?

Post by TXDerbyDad » Tue Jan 14, 2014 10:02 pm

What about with something like Testors lacquer which has a 20 min drying time.



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Re: Paint Drying Time?

Post by Speedster » Wed Jan 15, 2014 8:11 am

We don't offer painting at our workshops. Unless you are really into refinishing and going for a super smooth, high gloss finish, spray painting is not necessary. In fact, it's dangerous. A little boy with a dust mask isn't being protected. Many people think if the over spray is stopped they're fine. The truth is it's the fumes that kill you. If you can smell it you're not being protected. I think the scouts, especially the younger ones, want to pick out their favorite color and put it on with a brush. Walmart has bottles of paint that are very inexpensive and are water based. Painting his car with a brush might be the most exciting and enjoyable part of building his car.



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Re: Paint Drying Time?

Post by TXDerbyDad » Thu Jan 16, 2014 4:55 pm

Speedster wrote:We don't offer painting at our workshops. Unless you are really into refinishing and going for a super smooth, high gloss finish, spray painting is not necessary. In fact, it's dangerous. A little boy with a dust mask isn't being protected. Many people think if the over spray is stopped they're fine. The truth is it's the fumes that kill you. If you can smell it you're not being protected. I think the scouts, especially the younger ones, want to pick out their favorite color and put it on with a brush. Walmart has bottles of paint that are very inexpensive and are water based. Painting his car with a brush might be the most exciting and enjoyable part of building his car.
I believe you're talking about the water-based acrylic craft paints. They do work well, and even come in metallic colors. We used them our first year of Derby car making and loved them.

And you're correct. An N95 dust mask doesn't stop VOCs (Volatile Organic Compounds) which are dangerous to us living things. If we can smell them, they're in our system. You need a respirator with the ability to filter them to be protected.



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