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Jul 29 12 2:56 PM

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Here lately, I can't seem to do a decent spray painting.  I keep getting bubbles, runs, or a "nubbly" finish.  I use rattle cans, but the problem is me.  Any good advice for getting a nice, shiny, smooth finish?

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#1 [url]

Jul 29 12 10:56 PM

I've used rattlecans for about 38 years. I wasn't too good with them at first, as there is always a learning experience with stuff like that. I have never used an airbrush in all the 45 years I have been building models. I have grown to get a decent finish with rattlecans, and have for some time now. The two models I have posted in the "Built Kits" section are just rattlecan paint jobs. 

Okay, to start off with, what kind of paint are you using? Hobby paints, hardware store paints, dollar store paints, etc. I know there are people who get good results with paint from Wal-Mart and places like that, but I've never tried that paint. I've always stuck to hobby paints such as Testors, and now Tamiya as well. I've also used Duplicolor spray paints with good luck. Most of what I prefer to use now is lacquer paints, but I have always used emamels in the past. 

Do you use primer before your paint jobs?

Enamels are going to run on you easier than a lacquer paint job, simply becase lacquer is thinner and it dries quicker. You still need to spray in thin coats though, no matter which paint you select. Of course, the last coat you'll want a little "wetter". I always clear coat over my paint jobs, but again you have to use light coats. Clear will run on you easier yet!

I've also read that many guys warm up their rattlecans in a pan of warm water for a few minutes. This thins the paint, and makes it flow out of the can, and on the body easier. Of course this is something else you'll want to experiment with if you've never done it before. The warmer paint will run a lot easier if you get it on too thick. I've personally never tried this, because I've never needed to. I guess I've developed my own method of using a rattlecan over the years. But it works well for me.

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#2 [url]

Jul 30 12 7:00 AM

First, do a scuff using at least 320 paper . Now ya don't have to "Dig " at the surface , just give the primer something to adhere to. Poly Styreene has oil like the Saudi's throw mo mo . Start at the top, hold the can at about 20 inches and keep yer eye on the invisible lines yer a makin. Overlap the lines .

Now that you're primer is dry, allow it to dry at lest a couple of hours . Rattle can primer has a high amount of either XLYENE or TOULOLOL. Both evavorate at a decent rate . Xlyene will attack Styreene in high amounts , so CAUTION is recomended . Rustoliuem is one such primer that will.

The Wal- Mart Color Place Primers can be troublesome as the quality or lack there of is "Spotty". Use the Martin Senior -Sherwin & Williams , Krylon, and Duplicolor LAQUER primers . STAY AWAY from Testor's SO CALLED primer , it's simply a Flat Grey Enamel !

Here , you can now sand LIGHTLY , with 320 or 400 paper and re shoot any flaws . Now lets move to a Top Coat . Start at the top, move , using OVERLAPPING strokes and keep the can about 18 inches away . If yer airbrushing, I copy Donn Yost's paint method as it works . Paint, one part , CHEAP LAQUER THINNER- TWO PARTS. Hey, you want a shine ? Donn's method works . Ive met Donn and I've watched him paint bodies .

Testors One Coat Laquer Clear is a nice , no hassle Clear . I can get a nice deep shine with generally four coats .

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#3 [url]

Jul 30 12 7:12 AM

Usually, I use Krylon spray enamel.  I have also used Martha Stewart latex spray enamel, to get a certain shade of aqua.

I have not used primer.  I probably should.

This weekend, I was spraying outdoors, because the weather was nice, and there was no noticeable wind.  However, when I sprayed, the air currents were often blowing the paint away from the model.  I would therefore change positions, but the currents would change.  The paint wasn't able to get to the model, so it went on "nubbly". 

I compensated by getting closer to the subject, thus the runs.  I'm not sure where the bubbles came from.

I did better spray painting than this when I was a kid.  An example is my 1930 Hubley Packard in Built Kits.  I didn't even use primer on that one.  But I did use Testors.

I should resume painting indoors, use primer, and be more patient.  I appreciate the advice, Les, and thank you.

BTW, what is your opinion of Krylon?

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#5 [url]

Jul 30 12 7:21 AM

Thanks, Ed.  In the past, I've had nice, glossy paint jobs, then decided to cover them with a clear coat, only to come out "nubbly".  What happened?  Should I have sanded the final coat of color before applying the clear coat?

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#6 [url]

Jul 30 12 7:56 AM

First, do a scuff using at least 320 paper . Now ya don't have to "Dig " at the surface , just give the primer something to adhere to. Poly Styreene has oil like the Saudi's throw mo mo . Start at the top, hold the can at about 20 inches and keep yer eye on the invisible lines yer a makin. Overlap the lines .
Now that you're primer is dry, allow it to dry at lest a couple of hours . Rattle can primer has a high amount of either XLYENE or TOULOLOL. Both evavorate at a decent rate . Xlyene will attack Styreene in high amounts , so CAUTION is recomended . Rustoliuem is one such primer that will.
The Wal- Mart Color Place Primers can be troublesome as the quality or lack there of is "Spotty". Use the Martin Senior -Sherwin & Williams , Krylon, and Duplicolor LAQUER primers . STAY AWAY from Testor's SO CALLED primer , it's simply a Flat Grey Enamel !
Here , you can now sand LIGHTLY , with 320 or 400 paper and re shoot any flaws . Now lets move to a Top Coat . Start at the top, move , using OVERLAPPING strokes and keep the can about 18 inches away . If yer airbrushing, I copy Donn Yost's paint method as it works . Paint, one part , CHEAP LAQUER THINNER- TWO PARTS. Hey, you want a shine ? Donn's method works . Ive met Donn and I've watched him paint bodies .
Testors One Coat Laquer Clear is a nice , no hassle Clear . I can get a nice deep shine with generally four coats .


-artformsdesign

Always interesting to hear how someone else does it. 320 sounds a bit gritty to me for a "scuff" of styrene (although I use a LOT of that stuff in preliminary bodywork). I prefer 400 or 600 for a basic "scuff." 20 inches sounds a bit far to me for rattlecan distance though you might be using a different kind of can than I've used. I think I shoot rattlecans at about 10-12 inches, maybe 14 or so. Only time I ever get anywhere near 20 inches is where I'm painting an engine block/heads and want a "pebbly" and not real glossy finish. I've had better luck with the Walmart Color Place gray primer than you have. I find the stuff goes on VERY smooth and thin and in most cases doesn't even need to be sanded. Plasticote #235 is also an excellent primer but will dry with a slightly pebbly or orange-peel finish that does need to be sanded. But it is VERY easy to sand and sands wonderfully with 3M #800 wetordry, used wet. Only takes about a half-hour to sand this stuff down to a wonderfully smooth finish this way on a typical 1/24 model car body. Great primer to use if you're painting with a very "hot" auto paint or something of the sort.

I DO agree with you completely about airbrush thinning. I too shoot about 2:1 thinner to paint. I simply don't understand how guys spray 2:1 paint to thinner, nothing that thick has ever worked for me. Also, when airbrushing of course you move in much closer than with a rattlecan, somewhere in the 3 to 6 inch range.

In painting, experience is your best friend. Every paint job is a law unto itself. Every different paint and every different temperature and humidity condition will require a slightly different painting technique and no one can tell you this stuff, you just have to experiment and learn it on your own.


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#7 [url]

Jul 30 12 8:00 AM

 
An important step is preparation before laying down the color coat. I first remove all imperfections in the body surface (i.e. mold lines, sink marks, etc). I wash the model to remove any mold release oils and oils from my skin. Next I lightly dust the entire body with primer, gradually building up to completely cover. I use a high quality primer; my preference is Tamyia fine white primer. I let the primer set up for about a week or longer. I follow up the primer by lightly sanding with 4000 to 6000 grit sand paper.

If you are using a spay can I suggest Tamyia or similar. These type of paints are formulated and thinned for plastic models. As with the primer lightly dust the entire body with a color coat, and lightly adding addition coats until body is completely cover in color. Be careful not to apply too much paint too quickly, runs and bubbles may appear. Allow the body to fully cure a week or so before handling

My current project is a Ferrari 250 GTO chassis # 3505. It will be pale green. In fact the real car was just sold for $35 million and is now in the United States (was in England). Anyway, the paint I will be using is Zero Paints from England. This paint requires a gloss coat. This requires using an airbrush, which I prefer to a spray can.

I will let you know how it turns out.





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#8 [url]

Jul 30 12 8:56 AM

    Also, what is the best length of time to wait between coats?  I was waiting an hour.

-mwcrowel


If you're using enamel paint, I've always had the best results waiting 20-30 minutes in between coats. Much more than that could cause you to have some issues like you were experiencing this last time. If you are using lacquer, usually only about 10 minutes between coats, if that. I've read where guys just let lacquer dry to the touch, and shoot it again. Personally, I use the 10-15 minute time period for lacquer coats.

As the others have stated, your prep is very important as well. There are varying but good methods that are used by the others, and they all should work well. Priming your model is a very good idea, if you haven't been doing that. I usually use 320-400 grit for bodywork, but around 600-1000 grit after initial mold lines and putty sanding is done, and after priming. 

I have always stayed about 10-12 inches from my subject when shooting as well. Much more than that cuases me to get a very orange peel paint job, that takes a lot of work to get looking better. Sometimes I've even had to strip and repaint due to too much orange peel. 

Your bubbles in the paint probably was due to the solvent in the paint getting trapped under too thick of paint. It's trying to "escape", but can't get through the thick paint quickly enough before the top layer starts to dry. I have seen this happen with enamels in particular, and mostly it's where the paint gathers around the wheel opening lips and bottom of the model. Rocker panels in particular. Temperature, humidity, and wind play a big role in this particular process, especially being outside.

I have had similar problems in the past, like you experienced painting outdoors. If you can do it, paint indoors where there is no chance of getting the breeze effecting your paint job. It doesn't take much to mess things up, as you've discovered!

Krylon is good paint, Mark. You should really prime under it though. I have to agree with Ed on the Testors primer. Unless you get some in the Model Master lacquer line, it is just flat gray enamel paint! I also agree with John about the Tamiya primer. It's some of the best for model building. The biggest drawback to it, is the price. It's quite expensive quantity-wise, compared to say a Duplicolor or Krylon primer (which I like quite well also). Hope this helps ya out a little.

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#9 [url]

Jul 30 12 11:00 AM

The trick in spray painting (whether can or airbrush) is to get the coats on heavy enough that they "flow out" smoothly, but not so heavy that the paint runs, sags, drips, or pulls away from sharp edges as it cures. This takes skill. I find it easier with an airbrush than a can--very easy to get too much on with a can.

Since I've learned how to polish out paint, I don't have to worry so much anymore about getting it on super-smooth. "We can fix it in the mix" as they say in rock 'n' roll. Polishing out paint is labor-intensive, time-consuming, and sometimes tedious/boring, but it really pays off, and a great paint job will be a joy on your shelf forever.

In other news (just since it's not worth starting a new thread about), yesterday the gas station had a "new" diecast I hadn't seen before--'70 Challenger R/T. It was red with white stripes and white "vinyl" top and the shape was pretty darn good. I'd have bought it except the "cheap" diecasts are now $20 and having been out of work for two years now, I'm about scraping the bottom of the barrel and just couldn't afford it. Oh well, I already have a Johnny Lightning diecast '70 Challenger in Sublime, so I can live without it.

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#10 [url]

Jul 31 12 9:17 AM

Gentlemen, thank you for this information.  There's enough here to call this a turorial, and on this project in question, a pot metal Banthrico 1950 Ford, saving or redoing the paint job according to your collective advice should go well. 
 
This is much appreciated.  I now see some of the mistakes I've been making.  Fortunately, metal is easier to repaint than plastic, IMO.
 
When the car is done, I'll post it in Diecast.

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#11 [url]

Jul 31 12 9:25 PM

An additional note to the benefits of priming your model, is that primer will also fill in small imperfections that there may be in the body. Light sanding scratches are a good example. In the case of your pot metal model, a good scratch filler primer such as Duplicolor Scratch Filling Primer would be a good choice if you don't have any real delicate detail to get lost under it.

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#13 [url]

Jul 31 12 11:03 PM

Hope you have good luck with it, Mark. I will be very interested to hear how it went. I get some of my Duplicolor from Meijer. The price seems to be pretty good on that kind of stuff.

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#14 [url]

Aug 1 12 10:45 AM

Two points of caution on using scratch or build primer. First, be careful as it is meant to fill and you can easily lose detail. Second, make sure it's Duplicolor and not Rustolium brand as the latter will crack when dry. 

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#15 [url]

Aug 1 12 11:56 AM

The issue so many model builders have with Rust- O- eliuem is the Xlene in it . Xlene is actually an Embalmbing fluid used in Funeral parlors . Yep great alcohol based drying agent , but Horrific on Poly Styereene plastics !!!!!!!!!

Uh stay with the Duplicolor or the Krylon, both are Laquer based ..............

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#16 [url]

Aug 1 12 1:55 PM

Another Rust-Oleum product modelers might want to use caution with, or better yet steer clear of, is their "Specialty" Plastic Primer. It says on the can that it's safe for styrene plastic, but I've had a reaction with it on my vintage 1967 palstic. Fortunately it was only on the engine blocks. I stripped it back off from them, sanded the valve covers and oil pans where it showed the most, and repainted with Testors enamel instead. That worked just fine. I used it on the engine in my Monogram 1986 Monte Carlo SS, and it did okay. Not-so-much when I used it on the '67 Ford engines. I won't chance it again.



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#17 [url]

Aug 1 12 2:03 PM


It's not only polystyrene that the build primer cracks on, it cracked on body filler on my 1:1. I don't use any primer on any polystyrene. I've never found a need for it. I've never liked Krylon either.  

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#18 [url]

Aug 2 12 7:55 AM

This is all good advice.  I will use caution with any of these products.  Fortunately, I don't plan to do any more painting on my plastic models, being satisfied with them as they are.

Upcoming paint projects are all metal:
the repainting of my Banthrico 1950 Ford and 1949 Pontiac, both pot metal;
the repainting of my remaining Hubley truck;
the painting of my Hubley 1930 Packard Roadster;
and the repainting of a 1940 Wyandotte pressed steel ambulance.

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#19 [url]

Aug 2 12 9:42 AM

       Another Rust-Oleum product modelers might want to use caution with, or better yet steer clear of, is their "Specialty" Plastic Primer. It says on the can that it's safe for styrene plastic, but I've had a reaction with it on my vintage 1967 palstic. Fortunately it was only on the engine blocks. I stripped it back off from them, sanded the valve covers and oil pans where it showed the most, and repainted with Testors enamel instead. That worked just fine. I used it on the engine in my Monogram 1986 Monte Carlo SS, and it did okay. Not-so-much when I used it on the '67 Ford engines. I won't chance it again.



-modelcarsz


I used to be assistant manager of several dealer body shops, so I have used every kind of primer and paint on my model cars. I am still looking for the perfect paint! I can to you NOT what to use rather than tell what TO use! You guys are right on one thing, never, ever use any paint by "Rust-Oleum" with the word "plastic" any where in the title! I was building a '72 Nova kit for another fellow, you do not need to know what that paint did to the surface of the body on that model!

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#20 [url]

Aug 2 12 11:21 AM

The very finest primer I've ever used was the lacquer by Model Car World, set up for airbrush. Went on VERY smooth, dried very smooth, very thin, nice light gray color that covered anything and served as a perfect base for ANY kind of paint, as nothing would touch it. It was obviously some kind of real-car paint. I think I read somewhere that it was Martin-Senour paint but just don't know. LOVELY stuff!

The second best primer I've found is the Walmart Color Place, which is almost as good in every way as the MCW stuff I just mentioned. Their other paints, not so much. They're not bad, they're just not great, but the primer is good stuff to work with.

Plasticote T235 is very nice, good stuff, too, but it goes on just a little thicker and really needs to be sanded out with #800 or #1000 paper used wet. I use it if it's on a body where the sanding won't be a big problem or PITA.

I have had much less good results with the primers from Rustoleum, Duplicolor, and Krylon. Nowadays I'll only use these as primers for engines, chassis, and interiors (i.e., where I don't mind a little "texture"), but not for bodies.

I'm talking here about priming plastic model bodies. Metal is much more forgiving.

I've used Rustoleum metallic paints (bought in an auto parts store, not a hardward store) as the color paint on several models with good results, as long as I had a good primer under them. Pretty easy stuff to use. The '99 Camaro I posted was painted with their Sherwood Green (Chrysler color) and it came out quite nice after polishing.

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