Paint Help Needed

[strevo]

Hey guys. I'm using the Model master 2-part lacquer spray paint for the first time, and I'm wondering how loing I need to let the color coat cure before I put the gloss clear top coat on. I was thinking that the lacquer would dry much quicker than enamel , but I put one coat on and left it overnight (about 20 hours) to dry, and it felt dry to the touch, but when I had to turn it over to paint the bottom, the top got gouged into the paint by the silicone supports I had it sitting on. Should I be waiting longer before it's totally dry? I appreciate your help. Thanks.
-Steve

[Don Garrett]

Steve, need more info before answering this one. Lacquer is what we call a "hot" paint. It can produce some disturbing results when applied over plastic with no seal coat or enamel primer . It's a great product but we need to know if you are mixing apples oranges. Your allowed drying time sounds like you may have made your first "dust coat" too heavy... lacquer should flash or kick over between coats....where as enamel skins over and the material under the skin coat takes forever to air dry.

[hot ford coupe]

I've used the Model Master lacquers alot. Don's dead right as usual on the way to apply it. In fact, I learned how to do it from him. You have to use multiple dust coats and use a really good primer underneath. Model Master's gray and white primers are excellent for this but you also have to do it with multiple thin dust coats. Tamiya primers also are really good as well as their paints. I tried different techniques with the two part paint system and I found that if you put on thicker coats, the paint definitely does not dry right. In fact, I got it to a point where the paint didn't even set at all. Now at this point you may feel like you'll get more orange peel with the thinner coats but that's o.k. Once you get enough coats onto the plastic, you can do some light sanding between coats but go lightly. Then you'll do the same thing with the clear coats and put enough on so that you're polishing the clear coat and not the color coat. This is especially important when you use a candy type paint with an undercoat. I did a tutorial on basic painting a while back. If you look in some of the archives, you might still find it there. It has a few diagrams which may help with some of the other painting problems as well.

[strevo]

Don,
I used a good high-build automotive primer underneath, followed by seveal dust coats of the model master white primer , so interaction with the base material shouldn't be an issue. For the color coats, I was following the can's directions of 2-3 light coats with 2-3 minutes in between, followed by a heavier coat. Maybe I was putting it on too thick or too fast I guess? I was keeping the spray cans in a digital oven a 90 degrees F. Hopefully the paint I have on there now will dry OK. I have it in the oven at 95-degrees to see if that will help it dry any faster, but so far, no luck. If it hasn't dried by tomorrow I might just sand it all off and start again with very light dust coats. I'll keep my fingers crossed that I don't have to do that though.
-Steve

[xken]

Strevo, an old rattle can trick I learned back in the '60's was to hold a can under running hot water a little while then shake and you will feel the temp go cool, then hold under water again and do this repeatedly until you cannot feel any temp change. This does two things, warms up the paint for better flow and drying and also creates a little more pressure in the can and gives you a much better spray pattern than a cold can. Just make sure you dry the outside of the can before painting.

Ken

[hot ford coupe]

I would definitely do what Ken is saying. It's very easy to do. I usually never do it like the can says because I always wind up with problems. I let a little more time for the first few coats to gas out a bit more before I go to further coats. That way, I'm not sealing in a bunch of the solvent. Also when you spray too thick a coat of paint too soon after a few dust coats, the solvent rich thick coat can cause dissolving of the first few coats resulting in a really whopping thick coat that sets like old enamel . Some folks can get a good finish in a day or two. In my case, I don't rush things because every time I try to get something painted quickly, I always screw it up. If I have to err, I err on the side of longer time. Another thing that I learned from a guy at my last hobby shop was that you shouldn't worry about spraying a perfect final coat. He said with lacquer , you're always going to wind up smoothing and polishing out the paint. If you let the final coat dry for about a week or two and then you polish, the surface is rock hard and will polish out really well.

I remember years ago, there were guys who would spray on a lot of coats even on 1/24 scale models. No joke but this one guy who won a contest for 1/24 scale models sprayed on 149 coats of lacquer and hand rubbed it out. The finish was amazing but with that much paint, I think he wound up with a model somewhere around 1/16 scale.

[xken]

Between laquer and enamel , laquer drys through solvent evaporation from the bottom up; enamel on the other hand forms a skin and drys top down. I have seen enamel put on so thick that three days later you could still score it with your fingernail. That is why they bake enamel to harden it faster.

Ken

[little gü]

Hi there.
Some of you may say, I`m a barbarian but I remember painting my son`s R/C car body from Tamiya maybe 15 years ago.
I did it with acrylics , that I use for the paint - and airbrush -jobs on 1/1 cars and motorcycles.
No sanding , no filler ( because I don`t know how fast he will destroy it) only two coat`s BMW blue - spraymask - flames - two coat`s clear acrylic with hardener ( how you call it in US? catalyst?. no problems.
The basecoat dries very fast with a special thinner . The clearcoat dries overnight ( in vienna we don`t have 20 hour-nights like strevo) he he he.
I`ll show you some pic`s, if I discover it in my playground chaos
little güüüü

[strevo]

I definitely agree about warming the spray cans before using them. I use hot water at home, but when I'm at work, I use the digital oven to heat the cans to 95-100 degrees. This is much more accurate than the hot water, and you avoid having to dry the can before you spray. I just make sure never to get the can anywhere near 120 degrees to be safe. The oven is also great for drying the paint quicker. This is definitely not recommended at home since the average home oven isn't very accurate, and won't go down low enough to ensure the can won't blow up.
-Steve

[little gü]

Here are two pictures from my son`s R/C car.
No filler, no sanding - only acrylics over plastic.
a quick one day job.
little gü

[hot ford coupe]

Ausgezeichnet!! You do great work.