Painting Small Parts
by Darrol Cady

Painting fiberglass parts can be easy or they can drive you crazy trying to get the kind of finish that you want. I have been painting fiberglass racers, cowls, and wheel pants for many years. I have done it the hard way and now I do it the easy light way. I am going to share this with you.

The most difficult thing to overcome with fiberglass parts is filling the pinholes and not getting frustrated while you are doing it. I have tried the many things, like brushing the first coat of primer on the pieces then sanding and doing it again… It gets rid of some but not all. I have tried to fill them with primer by spraying on heavy coat of primer then using a brush to fill them in… Too much work and it is heavy. The method that I am sharing with you is a great system and is fast.

The first thing you should do is clean the parts with soap and water. The mould release that most the manufactures is water-soluble. The next step is to sand the entire piece to be painted. If there are some large areas that need some filling, use some of the new poly fillers, such as "Icing"… They are ready to shape in about 15 minutes and ready to feather out in about an hour. Do not forget to do the shaping before the cure is completed. After the cure, it is hard to sand. Do the shaping with 80 grit. The finer grits will plug and not get the job done. After it cures, then feather it out with finer paper.

If you have done the filling and sanding as above, you will have opened even more pinholes than you had before. Now take your air gun and blow the entire surface clean of all dust. Do it hard, so that you will blow any sanding dust out of the existing pinholes. Pinholes are not a problem at this step with this system. The next step is a little messy on the fingers, but it will wash off with soap and water. Use a filler like Model Magic, Dap, or just any of the water based spackling compounds that you can find at your local stores. First thin it out to the consistency of heavy mayonnaise. Now dip your fingers in the filler and rub the entire piece down. Don't try to fill any specific holes, just rub the entire piece down with small circular motions. Pretend that there are pinholes everywhere and you are pushing the Spackle in all of them. After you have the entire piece done, set it aside and let it dry completely. It can take a couple of hours. After it is dry, sand the entire piece down with a 220 dry paper. Now you have to be careful. You want to remove all the Spackle from the piece, but you do not want to make any new pinholes by over sanding.

When the entire piece is sanded, you should have little or none of the Spackle showing. You do not want any excess. Excess anything in the painting process is excess weight on the finished product.

The next step is priming. Spray a coat of 2-part primer on the entire piece. It should be a medium coat, not a heavy one. This coat of primer blends with the spackle and will now make it water proof, so that if you want, you can wet sand this coat. You want to sand most of the excess primer off with this sanding. You only want a thin coat of primer remaining. Try not to sand through the primer, but if you do it is not a big deal. When you are finished sanding, go back with primer and just cover the spots where you sanded through with a light coat of primer. The goal here is to get the entire piece smooth and one color for painting.

Like all painting projects, the work of doing the paint job is in the preparation. The painting is easy. I spray on a tack coat. I turn in the trigger restrictor so that I can control my first coat. I just want an even mist over the entire area being painted. I let this set for about10 minutes. I then open the trigger restrictor to where I can get enough paint to cover and gloss. At this point I am getting enough paint to get the full color of the paint I am using. I look at it at this point, and if it is smooth and glossy, I stop. If it is a little dry in spots, or trying to orange peel a little, I put a flash coat on the top… Not much. The flash coat is easy. I take the paint that is still in my gun and add some thinner to it. I make it will be too thin to paint with, but that is not the reason for the flash coat. It is to blend the topcoat with the base and level it all out. Be careful not to put too much on at this point. You can make a mess. It does not take much to make a big difference.

After you have them finished to this point, you can fix any blemishes that you may have in your finish… That is a little dust, pollen, or even bug feet… I paint outside.<G> You can sand any of those kinds of things with 2000 grit and then either hand polish or buff them to your liking.

There are many brands of paint that you can use. Automotive paint seems to work the best of everything I have tried. There are one step processes and two-step processes. See your local paint dealer for his sales pitch and what he recommends. Tony Stillman has the colors mixed to match most of the popular colors of covering film in smaller amounts. You might consider using his painting system. If you need some of the other products that go with it, you can get them locally.

When I paint, I prefer to have a nice looking LIGHT paint job. I have painted a complete Q40 racer and have only added an ounce and one half to the weight of the airframe with a 4-color scheme and clear coat. You can put lots of primer, lots of color, and lots of clear and make anything look like a piece of china. It is better to do it right and use less material to get the same results. If you want the china finish, then color-sand your last coat of clear and apply a second coat. With a light sanding and a power buff it will look like it came out of a mould.

Painting our small parts is not difficult. Do not be afraid to try it. You will be happy with the results.

Darrol Cady
PO Box 14273
Portland, OR 97293
Ph: 360-903-3520

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