Anyone have model car building experience?

"TheJWT" (thejwt) 02/24/2014 at 21:57 • Filed to: None

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My friend and I have been building our respective cars over the past few weeks, and a few days ago, we got around to spraying the body and chassis. We used Semi-gloss black for the chassis, which came out great, but when we painted the bodies, we ran into trouble. We both got extremely bad orange-peeling, and we can't seem to figure out why. We washed the bodies before painting and did all the necessary steps; the only thing I can think of is that we painted outside when it was a little chilly. We both used Testors spray cans, mine was gloss white and my friend's was gloss black. Does anyone with more experience than us know what the problem could be?

AthomSfere > TheJWT 02/24/2014 at 22:14

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All metal? Light coats or did you douse them in spray paint?

aplaiddinosaur > TheJWT 02/24/2014 at 22:16

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In my experience, painting a model car is always a hit or miss thing. There are ways to fix a bad paint job (wet sanding, etc.) but it is usually much more difficult than on a real car due to all the detail in a small space. The trick to getting a good paint job is really just laying down the right amount of paint. You need to spray on enough for the paint to "gel" together, but not too much that it starts to run. Trust me, it's quite a fine line. In your case it sounds like there may not have been enough paint on the car. I usually try and do a few light coats within a few minutes of each other. It is also helpful to paint with warm (room temp) paint and let the body dry inside. I've painted cars outside in the cold and been successful before

Destructive Tester > TheJWT 02/24/2014 at 22:19

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It's been a while, but as I recall the Testors likes to be applied over a primer. The air temp most likely didn't help but if you need to spray when it's cold it can sometimes help to CAREFULLY heat the paint using a pot of hot water. DO NOT put the can into the hot water on a heating surface; heat the water, remove the heat source, then heat the can until it is warm NOT HOT to the touch. Shake the can to stir the paint then heat it a little more in the water to ensure even heating. I'm no expert in polymers, but I believe a little heat makes the paint and solvents mix more evenly ensuring a smoother application. As I said; I'm no expert, that's my hypothesis based on observation. If you are really an expert and I'm incorrect, I'd be curious to hear why it works.

I can't stress enough how important it is to allow the heated water to heat the can while not exposed to a heat source. It doesn't take much heat, figure around 100-110 F which means the heated water should feel like mild bath water and the can should be warm but by no means uncomfortable to the touch.
To the Safety Nazis who are going to jump all over this, I'm not advising them to heat he paint to anything more than a summer day in the average garage.

TheJWT > AthomSfere 02/24/2014 at 22:20

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Everything is plastic, and I put on a few light coats

Destructive Tester > TheJWT 02/24/2014 at 22:21

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Also, if you screw-up a paint job try soaking the body in a tub of un diluted Fantastic all purpose cleaner for a few days. I've found it will remove the paint without damaging the plastic in any way. It's also a good way to pre-wash a kit prior to paint to remove any release agents or skin oils.

TheJWT > Destructive Tester 02/24/2014 at 22:22

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I'll definitely try that next time, I just thought it was odd because the semi-gloss black went on really well in the same conditions

TheJWT > aplaiddinosaur 02/24/2014 at 22:25

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Yeah I'll probably have to play around to find out what works and what doesn't. When I was spraying the body, the paint didn't seem to be sticking to the car, so I added more coats which didn't help

If only EssExTee could be so grossly incandescent > TheJWT 02/24/2014 at 22:27

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Try primering the bodywork before spraying, as well as a clearcoat afterwards. It really helps improve the finish as well as the durability of the paint down the line. Also, many light coats will provide a much better result than one thick one. It should look like you're just "dusting" it, if you can't still see the color underneath after the first coat it means you're spraying too thickly.

I also try to avoid the Testors sprays. They spray way too heavily for my tastes and take forever to dry. Instead I use Duplicolor Enamel that can be found at my local NAPA. The cans are $5.xx each but they are huge and last forever.

Destructive Tester > TheJWT 02/24/2014 at 22:28

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That's the funny thing about paint chemistry, I've had different colors of the same brand of paint have reactions. We won't even get into what I've had clear coats do...
That's where my other suggestion on the Fantastic comes into play...

Destructive Tester > TheJWT 02/24/2014 at 22:34

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Also please be careful, patience and caution are your friends when you're heating a pressurized cylinder...

If only EssExTee could be so grossly incandescent > Destructive Tester 02/24/2014 at 22:36

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The worst is the so-called "clear" coats that yellow over time.

Destructive Tester > If only EssExTee could be so grossly incandescent 02/24/2014 at 22:39

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At least in that case you get to enjoy a nice paint job, I've had clear coats crackle a smooth base coat on contact...

JACU - I've got bonifides. > TheJWT 02/24/2014 at 23:18

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If you're in it for the long haul, consider upgrading to using an airbrush. You expand your color options tremendously, and once proficient you can work up your finishes in extremely thin layers.

Old-Busted-Hotness > TheJWT 02/25/2014 at 07:58

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Along with the other tips, the most important thing is to practice. You'll use up a bunch of paint but you'll learn how it acts.

I'm pretty good now, after 45 years of model building:

In case of Kinja: