Painting Models

[RetNavySuppo]

A gentleman in the control line forum asked about painting his model with Rustoleum or Krylon paint. It is too bad we lost the reservoir of knowledge in the Flightlines Forums as there was a wealth of info there on this subject.

Let's see if I can remember some of it. Also, I have personally experimented with these paints.

Rustoleum

Soild colors are fuelproof but clear and metallic colors are not glow fuelproof. However, there are a few "buts".

If you are in a rush to fly, don't use Rustoleum. Its fuelproof properties grow the longer you let it cure after application. If you paint today, you shouldn't go flying tomorrow. The common wisdom is to wait at least two weeks. You'll see why if you do a simple experiment. Paint something today and set it aside for a couple weeks. Then paint something else a couple weeks later and wait a day or two. Then compare the two pieces. The two week old piece will have a harder and less tacky finish. You can feel the difference. Also, it is fuelproof only up to a certain point. It's risky at above 15% nitro or even 10%.

Rustoleum brushes well, but since it dries so slowly, it attracts a lot of dust and loves to run if you are heavy handed with the paint. What I do is dilute it with mineral spirits and brush on multiple thin coats. The thinned stuff dries faster too. Also, I can wet sand between coats for a really smooth finish. Spraying Rustolem is a bear. The overspray gets everywhere (and farther away than you would think) and takes hard scrubbing with solvent to remove it. However, a sprayed Rustoleum looks real nice. You can spray outside but then you have to contend with the wind and stuff floating in the air. By the way, Rustoleum will dissolve white foam (don't ask me how I found out that tidbit of knowledge - grrrrrr!).

Krylon

Krylon is not fuelproof to glow fuel but holds up well if you are using a gasoline engine. It sprays great but watch out for the overspray. However, it is not as bad as Rustoleum. It also eats foam.

Alternatives

Top Flite (MonoKote) and the makers of Ultracote put out spray paints that are supposed to match the colors of their iron-on coverings. The Top Flite stuff is pretty good and is similar in ease of use to Krylon. It is supposed to be fuelproof up to 15% nitro (according to the label on the can). However, some modelers have complained of quality control problems, i.e., particulate matter forming in the can which then gets sprayed on your finish. This can actually happen with any spray paint, so test each can on a piece of scrap, each time you use it. I have only tried the Ultracoat paint once (black) and wasn't too impressed. I tried it over Ultracoat plastic covering and it didn't stick very well (despite proper surface preparation). The Top Flite paint does a much better job.

I found something at Home Depot that is an excellent fuel proofer. It is Minwax's Helmsman Spar Urethane. It is available is brush or spray and comes in gloss, semigloss or flat satin finishes. It brushes well and evens out well as it dries (very few brushmarks if you thin it a bit). I painted several coats of this on my engine test stand. A few months ago some 15% fuel leaked out of the fuel tank and sat there probably for weeks before I noticed it. The puddle had completely dried out. I cleaned it up with some real alcohol (not rubbing alcohol) and there was no effect on the finish of the test stand whatsoever. Great stuff!

Now for the "buts". It doesn't come in colors - drat!!! It is not completely clear. It has a pronounced amber hue to it. However, I have used it successfully over darker colors of Rustoleum and Krylon with excellent results. It might not look right over lighter colors like white or yellow. Brushing is easy (especially if you thin it a bit with mineral spirits) but spraying can be a pain in the rear because of the overspray.

I have tried other clear polyurethanes (such as those from Minwax) but I have been disappointed with their lack of "fuelproofness".

By the way, the gentleman in the control line forum mentioned that he wanted to paint a Dolphin. I don't know what that is. However, the type of surface you want to paint also has an influence on what you use for paint. For instance, I mentioned that Krylon and Rustoleum will dissolve white foam.

That's about all that comes to mind at present. I am sure others will have additional thoughts.

[Britbrat]

Thanks RetNavySuppo. Tremclad is also just like Rustoleum & it gives an excellent gloss

[fox4ever]

Hey thanks for the info. Your right, everyone needs more information on subjects like these Lee

[stetto]

...Also, for anyone within range of one, an auto finish store will "rattlecan" any color of the rainbow in auto-grade polyurethane. I've used some, and it is as durable as it comes--but <shrug> at a price...I used to go to Spaceage in Mesa AZ, and the options are nearly endless...The auto grade clearcoat is an option for those who wish to color their plane with a less expensive product.

Another option is to go to your neighborhood Sherwin Williams or ICI (Glidden) paint store and have them tint you a quart of industrial alkyd. You have to cup-spray or airbrush, but those finishes are highly fuel proof as well, and can be tinted...(edit--OK, yes you can brush alkyds as well, but instead of thinning I'd suggest Penetrol, an oil-based flow agent...)

[jetmex]

I'll go ahead and post my how-to on painting monocote covered airplanes with Rustoleum.

First, why Rustoleum? Because it's cheap and available just about everywhere. It is fuelproof up to about 15% nitro and gasoline resistant, which is just fine for most sport fliers. And, it will keep your airplane from rusting, guaranteed!! ;D The brushables can be mixed to get whatever color you need, and I think they now make generic camouflage colors (gray, olive drab, tan) as well. The one downside is that it does take at least a week to cure fully, and the silver and clears are not fuelproof.

To start, cover your airplane with a light base color, I like to use the dove gray if I'm going to paint an entire airplane (this is based on using monocote, Ultracote works just as well). Just an oh by the way here, I do mainly warbirds, so modify your base color accordingly. You can also use silver or white. One of the neat advantages of using the silver is, that as the paint wears and chips, you get a realistic weathering effect. The disadvantage of silver is that I have yet to get a really nice cover job with that color. It might be me, but I can never get it shrink really tight, and it tends to wrinkle pretty badly. If it's a multicolor camo, I'll cover the model with the lightest of the main colors, usually tan or gray, and then go from there. Same with a civilian type scheme.

As with so many things, preparation is the key to a good paint job. Shrink the covering good and tight, then scuff it lightly with 00 steel wool or fine wet sandpaper. Easy does it, you just want to knock the gloss off, not sand a hole in the covering! Then wipe down the entire surface to be painted with alcohol or acetone. Don't touch it before you paint, the oil from your fingers will keep the paint from sticking.

Mask straight lines with the blue, low tack 3M masking tape. It's great stuff--leaves good straight lines and won't leave any residue when you pull it off. Irregular camo patterns (such as the RAF WWII schemes) can be masked off in several ways. 1. Frisket paper--available at a lot of craft stores and hobby shops that carry plastic models. It's adhesive backed -- cut your pattern, stick it on and paint. It can get expensive for larger models. 2. Sticky back shelf paper works for this also, the cheaper the better. 3. Butcher paper or newspaper. This can be done two ways--you can use double sided scotch tape to stick it to the surface, or you wet the paper with water, lay it in place and paint. Don't let any excess water dribble on your paint job, you want it just wet enough to keep it stuck to the surface. If you use newpaper this way, don't leave it long because the newsprint will bleed off onto your model. Mottled camouflage can be done freehand (practice first, spray patterns vary) or you can cut an irregular hole in a piece of paper, hold it a few inches from the model and spray through it. Changing the angle of the spray can will alter the shape of your blotch. 4. If you have kids, then you probably have a can or three of silly putty lying around. Roll it between your hands into a round ribbon shape and stretch it to length, then use it to lay out your camo pattern. Neat thing is, it can be used again, the paint won't hurt it.

After you've masked, wipe down the surface again. I usually spray in my garage, toward a fan aimed to blow the overspray outside. Move your cars, the stuff goes a LONG way! Spray several light coats instead of one heavy one--it minimizes runs and makes for a smoother finish. Let each coat dry for a few minutes before spraying the next one. When you're happy, let it set for a few minutes, then pull all the masking off before the paint dries, so you don't lift it at the edges.

You may get some dust while the paint is drying, but it hasn't been a problem for me, I'd guess it would depend on where you live as to how bad it can be. A clean paint area goes a long way toward minimizing that problem. I usually let the paint cure at least a week before applying decals or trim, then off to the field I go!

Of course, all the above can be modified as necessary to fit your needs.

If you did the prep work well, the paint should last for quite a while. I hope this removes some of the mystery from the process, and if any of you do try it, post some pics and let us know how it comes out!

[RetNavySuppo]

Another alternative is to use clear Monokote which is specifically designed to be painted.

Jaime, I have read in a lot of places that the flat colored Monokotes are difficult to work with. What has been your experience? Also, what do you do about the inevitable wrinkles? Can you reshrink a painted Monokote suface?

An additional comment on Rustoleum. I wet sand the Rustoleum to get out dust particles or hairs or to remove brush marks if I am not satisfied with the finish. I use thinned Rustoleum - it requires 2 or 3 coats but it levels out better (i.e., fewer brush marks). If you are going to wet sand Rustoleum, it is best to do it within 24 hours of application. The Rustoleum gets harder as it cures and after a few days, it is a bear to wet sand.

[jetmex]

I've never used the flat monocote--I've always found it easier just to paint the stuff. I've heard it's harder to use than the regular stuff. I'm also considering switching to the iron on fabric type coverings (Coverite or Solartex), since I've heard they are easier to work with and can be painted just as easily.

You can reshrink the monocote after it's painted, just go easy with the heat. It is possible to blister the paint if you get it too hot, and after Rustoleum cures, it can be a bear to sand down and touch up. On the warbirds, it not that big a deal, since the full scale airplanes were usually touched up like that. It could be a real pain on a nice striped civvie paint job, though!

Just another thing here--I use the spray cans since I don't have a decent airbrush any more. I haven't tried to hand brush it but it sounds easier than spraying (not nearly as much masking, I suspect)--what kind of brush do you use? I usually try to find a scheme that can use the colors that are available. I haven't tried the Rustoleum camo colors yet, if someone does, please post your results here. Also, does anyone have any experience with the Chevron brand flat camouflage sparay cans? Got a Spitfire that will need a paint job sometime in the next century..... ;D

[RetNavySuppo]

I have tried spraying Rustoleum, but the overspray problem is a pain in the rear. The overspray goes even further than Krylon (actually Krylon's overspray is not that bad, but Krylon is not fuelproof). Even when I spray say, the top of a wing, the overspray gets on the BOTTOM of the wing. I suppose if I masked the heck out of the object I am spraying, it might work.

I have tried spraying outside, but as my home is on the highest point in our area, I always have a bit of a breeze, or more. I suppose I could spray in the garage but my handyman painted the entire inside of the garage a nice bright white. This, combined with the fluorescent lighting, makes the garage look like a pristine operating room. It would be a shame to get Rustoleum overspray all over it. Besides, I need to see where and when my wife nicks the garage wall with her car. When you are married to the perfect wife, you have to look hard to find something to ping her about.

Brushing Rustoleum is not bad if you remember a few things. I use only camelhair brushes of various widths (available from Tower Hobbies). Mostly, I use the 1-inch widths. You have to put Rustoleum down "wet". This can be a pain sometimes because Rustoleum loves to run. If you try to stretch out the amount of Rustoleum you have on your brush, it will get very "sticky". Thinning the Rustoleum alleviates this somewhat, but you still have to be careful.

The brush you use is real important. New brushes are out of the question. New brushes have too many bristles and many of the bristles are loose. My most prized brushes are many years old and have only about 1/2 to 2/3 of their original bristles. These bristles are well-anchored, having survived so many uses and cleanings. Rustoleum is a MAGNET for loose bristles.

With Rustoleum, surface prep is important, especially if you are using thinned Rustoleum. Wet sand with very fine sandpaper (600 grit). Scratches on the surface you are painting will take 2-3 coats of thinned Rustoleum to hide. It's best not to have those scratches there to begin with. If your surface is real smooth, thinned Rustoleum gives good results.

Regardling Solartex, it easily stains unless you clearcoat it or paint it another color. I have sprayed clear dope on it with good results. The dope also keeps it tight. I spray dope right in the middle of my shop. The good thing about dope is that it is so volatile that by the time dope overspray hits the ground or another surface, it is already just dry dust. Then all I have to do for cleanup is a quick swipe with the shop vacuum or a quick swipe with a damp paper towel. That's all there is to the cleanup.

One last thought. I have had so much success brushing/spraying the dopes I get at Aircraft Spruce Specialities (I make the 90 minute drive down there once every few months), that I am moving away from Rustoleum. The brands they carry are Randolphs (which I think is now defunct) or Certified Coatings or Classic Aero. With the use of some reducer, these dopes brush real well and leave few or no brush marks and dry real fast. These are full-scale aircraft, professional quality, dopes and work real well on our models. They also seem to be more fuelproof than modeling dopes such as Aerogloss. They are certainly worth looking into.

[stetto]

One word re: brushing RustOleum, RetNav: Penetrol...

[RetNavySuppo]

Eric-R,

How about a few more words on Penetrol - what does it do, how to use it, and where do I buy it?

[stetto]

Penetrol is what they call a "wet edge extender" for oil based paints. You can usually find it in quarts and gallons in paint stores and some hardware stores.

Added to oil paint in moderate amounts keeps the paint from "roping up" or dragging on your brush or your work surface. In fact, the use of Penetrol can virtually eliminate those unsightly brushmarks, allowing the paint to lay down more evenly.

Remember that a heavy coat of paint is going to run or sag unless being applied to a flat surface that's laid down...Penetrol allows you the time to apply a thinner coat while maintaining that wet edge that keeps the finish consistant. I personally swear by the stuff when painting doors and trim...

www.floodco.com/Products/penetrol.cfm

[jetmex]

One word re: brushing RustOleum, RetNav: Penetrol...

Ya know, Eric, you almost sound like a painter or something....... ;D ;D ;D

[RetNavySuppo]

Dr. Paint (Eric-R),

I picked up some Penetrol today and mixed some up with some Rustoleum Royal Blue and painted the side of an orphaned fuselage that I had prepped. It looks like the Penetrol takes the place of thinner - I had been using Odorless Mineral Spirits. What a difference! It does brush real easy now with little brush drag. Thanks for the tip.

However, I also have more air bubbles in the brushed on coat than before and they aren't going away. I don't know where these air bubbles come from. I let the mixed paint sit for a couple hours and it looked completely smooth. I had this same problem when I used the Rustoleum undiluted or diluted with the mineral spirits. It seems that the air bubbles are more prolific the thinner the paint, no matter what I use as thinner.

I occasionally see the same problem when I use polyurethane, but to a much lesser degree. Yet, on the other hand, I never have this problem with dope. I am using the same camelhair brushes for all paints (my brushes are always well cleaned).

What is your diagnosis and recommended cure?

I would love to use the water-based polyurethanes (no fumes, easy clean-up, choice of colors), but they completely turned me off because of how poorly they performed in my tests of "fuelproofness".

[stetto]

Hmmm, that's a poser. I usually get bubbles in a brushed on coat of paint if I'm brushing too fast. Once the bubbles are there it's hard to get them out because repeated strokes push the bubbles back into the finish. With the Penetrol you should have time to "lay off" the coat, by which I mean you can go back over the applied coat once or twice with an unloaded brush to even the work, and done slowly enough should in most cases alleviate a lot of bubbling...

If you aren't already applying the paint s-l-o-w-l-y, try it once. If that isn't working, remember that brush angle has a lot to do with bubbles too. If you're too perpendicular to your work--LOTS of bubbling. If you lay the brush down too far against your work--DOH! About a 30 degree angle is best, and don't force the brush, let it do all the work.

BTW, RustOleum Royal Blue is one of my favorites. I hope this helps, and remember that you can always try different amounts of Penetrol and brushing techniques on a sample til you find your own "sweet spot". I've used a lot of Penetrol, and I've found that in some cases you can't use too much!

[tperry2054]

Try using a hair dryer, not heat gun, and direct the air over the painted surface at an angle. Try on a scrap piece to get a feel for the technique.

This tip was picked up when I covered furniture with polyurathane.

Tom

[ctdahle]

And Another one