Lesson 4: Painting

In this lesson, we're going to paint and detail our kit.

Preparation

First of all, you should decide how nice a finish you want. Some people choose to leave their rockets completely unpained, others need a perfect finish. I fall somewhere in between: I want a nice looking finish, but I'm not ultra-picky about the fine details.

For this lesson, let's try to get a nice finish, but not go too overboard. To do this, we will need to fill the spiral grooves in the body tubing and sand the fillets to a nice even radius. The first step is always to fill those darn spiral grooves. Below you can see that I used Elmer's Fill 'n Finish for the first pass. You won't fill them perfectly the first time, but try to get the grooves as well filled as possible.

Once the filler has dried, sand it off with 100 grit sandpaper. It's also a good idea to sand the whole body tube with 100 grit to scuff the surface for the primer. If you are using Public Missiles Quantum Tube, you will want to sand the surface with 150 or 220 grit, even though you didn't need to fill any spirals.

The next thing to do is prepare your nose cone for painting. Most kits come with plastic nose cones, which are often hard to paint with good results. Before doing anything else, scrub your plastic nose cone with warm water and soap to remove any mold release or other residue. Let it dry.

Molded plastic nose cones will have two seams from the tip to the base and may also have other mold markings. Use a razor knife to trim off any raised flashing and mold marks. Then, use 100 grit sandpaper to smooth the seam and mold marks as much as possible. Don't bother with the shoulder as it won't show when the rocket is assembled.

Lightly go over the entire nose cone with 100 grit sandpaper. You need to rough up the surface so that the primer can stick to it. This will often raise fuzzies that can't be sanded out, but these ill be taken care of in the primer step.

Finally, fill any remaining seams with plastic model putty. In the picture above you can see the nose cone filled and sanded and ready for priming.

Priming and More Priming

The priming filling and sanding steps are where you will determine how good a finish you get on your rocket. Paint doesn't fill defects, in fact it makes them stand out. The quality of the finish before you apply the paint is what will determine the final result. A perfect finish is achieved by making a perfect surface for the paint.

Safety note: spray paint contains volatile chemicals which are atomized in the air. Paint overspray and the volatiles in the can are harmful to breath. When priming and painting, use a paint booth if possible. If not, paint outdoors or where there is good ventilation with fresh air. Always use a respirator.

Now that all your parts are prepared for priming, wipe them down with a tack cloth to remove any dust. Shoot a light coat of primer over all pieces. The goal is not 100% coverage for the first coat, but just enough to start coating the surface. Wait a few minutes and apply another light coat. These two coats should make a good surface and show up imperfections in your spiral groove filling and fillets.

Note that I like Kilz® primer. This primer builds quickly and resists running and sagging. It's sometimes hard to find, but I've been able to buy it at K-mart and Orchard Supply Hardware.

Once your first coat of primer is dry (often as little as 15 minutes), it's time to look over the surface. You will find places where you didn't completely fill a spiral groove or where your fillet is not quite perfect. Fill any low spots first, using auto body spot putty or Bondo®. Once the putty has dried, sand the filled patches flat and sand off any high spots on fillets or the tube. It's OK to sand through the primer to get the surface flat.

Now it's time to prime your rocket again. Apply another light coat of primer and let dry. At this point you will see the remaining places where you need more work. Keep filling, sanding and priming until the surface is as perfect as you have the patience before. Remember that the paint will not fill defects and, in fact, gloss paint will make them much more visible.

When working with plastic nose cones, the primer will solidify the fuzzies from sanding the plastic and allow you to sand them down. This takes a while, but you can end up with a good result.

Once you are satisfied with your finish, hand sand the entire primered surface with 220 grit sandpaper. This will make a good smooth surface for the paint.

Painting Time

If you've done a good job with the surface preparation and priming, the actual painting will go easily and look good. Clean off any sanding dust from the surface of the body tube with a tack cloth. From now on, we need to keep the painting area very clean to avoid embedding dust particles into the paint.

Since most rockets are painted with spray cans, I will concentrate on those techniques here. If you have access to automotive paints and sprayers, you probably already know more about painting than will describe here. Some people also paint their rockets with air brushes. However, ordinary brush painting won't give you good results. If you don't have special equipment, you can still get very good results with spray cans.

I've chosen a scale rocket, so I want the paint job to look good and be reasonably prototypical. As always with matters of scale rockets, we turn to Rockets of the World, available from Saturn Press and various book stores. In the third edition, the Tomahawk info. starts on page 139. (RotW is a wonderful book and if you don't have it yet, I strongly urge you to buy it.) As we can see on page 140, the I.Q.S.Y. Tomahawk had a red nose cone with a black band below it, a white body and one black fin. There is also some bolt detail between the fins and on the black band and base of the nose cone.

When painting multiple colors, always start with the lightest color first. It's much easier for darker colors to cover lighter ones than vice versa. The Tomahawk is basically white with other colors in small places so I started by painting the booster and payload sections white. The nose cone was painted red separately and set aside.

With paint it's especially important to use light coats. The first coat should be little more than a light mist. The second coat should cover most of the details and the third and fourth coats should make the color nice and even. If you apply the paint too heavily, you will get sags and runs in the paint, which will require you to sand it off and start over.

Allow the base paint coat to dry fully. This can take up to a day, even in warm weather. Check your spray can for cure times. I like Krylon® spray paints, and many people like Rustoleum® paints. It's worth paying more for brand name paints because they are more forgiving on recoat times. Check the can to make sure the paint is "recoat any time" before you buy it.

When the base coat is dry, you can mask off areas for other colors. Plan your colors carefully so that you can do the minimum amount of masking. Use good tape for this. Regular "masking tape" doesn't necessarily provide a clean edge. I like the green 3M Fine Line tape for masking edges. This tape also comes in different widths for making stripes or other effects. When masking straight lines, use wide tape as it tends to stay straight.

Once your edges are defined with good masking tape, cover the areas of the body which are not to be painted with paper. Newspaper works, although the green paper rolls are very convenient. Use ordinary masking tape along the edges of the paper to stick it to the good tape. Be sure to cover the rocket well as overspray from spray cans travels surprisingly far.

Go ahead and paint your next color. This process can be repeated as many times as necessary to get all the colors you need for your rocket.

If you stick with the same brand of paint, you should be able to just spray the colors on top of each other with no preparation. This often means compromising on the actual colors you want, but you can usually get ones that are close enough. If you really are intent on getting prototypical colors, consider hobby shop paints such as Testors®. While these are expensive and come in small cans, they have an excellent color selection.

Decals

Your kit may come with decals or it may not. My Tomahawk didn't come with any decals and would be fine just painted. However, I like the last little touch that comes with some fine details. I decided to make my own decals based on the detailed drawings in Rockets of the World using decal film and my Alps printer. See the Making Decals article in INFOcentral for the technique. There are also several sources for custom decals.

There are two kinds of decals: water transfer and pressure sensitive. The water transfer decals are a very thin film on top of a paper back. When soaked in water, the film slides off the back and onto the surface. Pressure sensitive decals (really stickers) also have a backing, but they are thicker and when you peel them off, they are sticky without water. See the Applying Decals article in INFOcentral for decal tips.

In the last lesson (lesson 5), we will install the recovery system, check stability and pick motors to fly this baby!