Originally by Peter Duszkievicz, Tri-County RC Club, New Jersey
We all have to get to the field, and in doing so, we always move our airplanes. During the life of a model, it will get dinged up a bit, and eventually we all end up poking a hole in the wing, whether it’s in the car or hitting a bush. In this article, we will demonstrate a few easy steps to patch those holes in the wings.
To perform a successful patch on a wing, you will need the following:
- #11 blade hobby knife and scissors
- Covering iron
- Marker (Sharpie)
- MonoKote to match the patch
- Rubbing alcohol
- Trim solvent or acetone
To understand what we are patching, here are two pictures of the damage that we will fix. Both of the images below show the type of damage that we are working with.
- First, clean the surrounding area where the patch will be applied with Windex. For good measure, you may also want to use some rubbing alcohol to wipe down the area, making sure there is no fuel residue on the wing, and to give it a final thorough cleaning.
- After you have cleaned the area, use your hobby knife (with a #11 blade) to cut away the damaged area. It is best to cut a larger area, so the patch is easier to apply and conceal.
In the image below, a square has been cut out from the leading edge to the main spar and from one rib to the other. A straight line was drawn on the wing, so we could overlap a patch instead of cutting from rib to rib. The reason we did this was to minimize the work for diagonal strips that are shown (black and yellow), mostly because we were out of yellow MonoKote.
- Lastly, apply the patch. Before you start cutting your patch, turn on your trim iron so it gets hot and is ready for you to use. When cutting your patches, cut them large enough so that it over laps at least 3/8 of an inch. This will ensure that the patch does not shrink when you iron it on or hit it with a heat gun. Remember, patience here will pay off with a good repair.
When applying the patch, as in the two images below, spray a towel down with Windex and wipe it onto the wing around the border. The wet Windex helps to position and keep the patch in place as you begin to heat it with the iron. For the repair, we applied the white patch first. Hint: you always want to patch with the lightest color first so that the darker colors do not bleed through the lighter ones.
After placing the patch, begin to iron it on into place as follows:
- First, tack each corner just before the edge of the patch. As the Windex bubbles, move the iron forward towards the edge of the patch. Do this step for each corner.
- Using the iron, tack the patch at each center between the four corners. Work the iron towards each corner, and then out towards the edge of the patch. Do this for each side of the patch.
- After all the edges are sealed, gently run the iron over the patch itself. Start at the center and move out to either edge. Heat control is important here, so the patch will not excessively shrink or get wrinkles. Do this until the patch is nice and taught.
- An optional step—necessary for the patch in the last image (below) —is to apply any trim to match the original pattern. In the example shown, we used black MonoKote trim (the peel away kind) and trim solvent to apply it. Alternatively, you may use iron-on covering by applying trim solvent to the area where trim will be applied and then placing the trim on top of it. The wet trim solvent will allow you to work out any air bubbles, but you have to work quickly. Once the trim piece is in place, go over it with an iron set at a lower heat setting to ensure it is tacked on properly.
If you performed the steps correctly, the patched areas should look like the two images below.