Hi Dick,
Sorry to hear about your ARFs minor wing damage. Your ARF P-40 should get you in the air in a few days, so you can still fly in the nice early fall WX. There is no reason for delay due to the lack of balsa for minor repairs. There are several other materials that have been used to build good flying models. Ones I have used:
1. Foam. for minor repairs, any kind of scrap Styrofoam will do. From any packaging, insulation sheets, etc. It is light, strong and easy to shape. I have 30 lb. planes that have all foam ribs.
2. Corrugated cardboard from any box. Ribs don't have to be very strong, they are really there more to hold a shape than provide any strength.
3. Foam board. A great model building material. Stationary stores have it, and many other stores as well. I have had several planes built entirely out of it.
4. Corrugated plastic sign material. Any sign shop sells it, and/or will have scrapes that will work. Find a store that sells "For Sale" signs, they are often made from this, so are many real estate signs. In LV we used this to make some good flying RC combat planes. VERY easy to work with, fuel proof, strong, and relatively light.
I'm sure there are others. Please don't let a minor repair hold you up. Of course, you can always replace your wheels with skis and fly all year round!
The ARF P-40 is an excellent plane. I am very happy with mine.
Regards,