How To Build A Teardrop Trailer/Joints
There are many ways to cover the seams in the luan skin on the teardrop body. Builders use aluminum, wood, and RV trim bought commercially.
However, for our simple teardrop trailer we will create a moulding over the seam with Bondo. Step one is to apply masking tape on either side of the seam. Once that is done, mix some bondo according to the directions and apply a thick layer (about 1/8" thick) across the seam and over the edges of the masking tape.
With this technique, you don't have to worry about doing it all at one time. In fact its better not to try because you need to pull the masking tape prior to the bondo starting to cure. So as soon as you are done applying it, start pulling the tape. If the Bondo starts to cure before you pull the tape, chunks of bondo may come off the edges.
When you pull the tape it will leave the nice straight edge. You can continue on with masking tape and more Bondo as required to cover the entire seam. After you are finished, let the Bondo fully cure. You can then carefully sand the bondo smooth so that it looks like a moulding. You can try painting it if you like but try it on a test piece first. Its really better just to leave it plain. Later you will apply urethane varnish over the trailer and over the Bondo seams.