It's on the underside of the wing close to the joint with the fuselage. We did put a big piece of monokote that reached out around the trouble spot. I think we were hasty and didn't clean it off well. Now I have some ideas which will take time but at least we can try them. I think I said that it is an ARF. A good friend had it as a practice plane and gave it to me. It has a Smith tuned LA-46. Today, I flew it just one flight because my audience got bored with just one flight. But, it felt so good out on the end of the lines and stayed tight with overheads etc.
I will bet that doing what you did, only better, will work. This time thoroughly clean the monokote outside the damaged area and lightly sand it with say 600 grit where the new monokote will go. Then, really push the new stuff down with a booted iron from the center out. Then seal the edges with clear, it is going to stay - for a while. You will probably have to iron out the wrinkles every now and then. Don't try and do this with a gun. It won't seal the edges well enough and if you heat it enough to shrink much, the edges will not be glued down tight. If you are not overly concerned with the finish, go over the seams with a sealing iron.
You will know you have sealed it when a small amount of glue oozes from the seam. Wipe it off with an alcohol dampened rag before you paint.
For reasons that have nothing to do with sanity, most of my planes are monokoted from tip-to-tip, nose-to-tail. This works well for me wherever the covering comes in contact with heat. Believe it or not, there are a lot of hot places on an electric!
Good luck! Which ARF is it? - Ken
Ken
Oh, one more afterthought. On one plane that had a lot of area to fix, I used some Balsa Rite (I think that is the name - a film adhesive) before adding the new monokote. I rubbed it into the wood to get it in as deep as possible. Let it dry and added a second coat just before applying the monokote. Normally, you don't need the extra weight of supplemental glue with monokote.