Be sure to take the above advice about making the mateing surface between the wing and fuselage flush. You should also reduce the size of the nylon bolts. Use 8-32 as maximum (you can really get by safely with 6-32 nylong) if you plane weighs less than 8 pounds. The 1/4-20's that usually come with kits is much to large and strong. The structure will break before the bolts will. I use only 10-32's on my 15 to 20 pound big birds and have never had a failure other than when I have had a case of dumb thumbs and then the bolts broke before structure just as they should.