need a wing covering tip

Getting ready to cover the wing on my Shark .45. I planked the entire wing (built up ribs). I prefer silkspan over Carbon veil. A problem I've always had is the wing covering pulling up where the trailing edge of the wing meets the flap ends. It is never uniform and I think it makes it look bad. I typically wet my silkspan before covering, even on planked pieces. I prefer nitrate for undercoats and adhesion of silkspan. Any tips on how to get the covering to lay down and adhere on this problem area?

I assume you are covering the wing and flaps separately?
If so, it is done just like any other edge of the wing. Break the corner very slightly with fine sandpaper to ease the corner.

If you are joining the flaps before covering (like with cloth hinges), then i would cover over the wing and flap in one piece. When this has become fairly dry, I go back, carefully slit the paper over the hinge line (just don't cut the hinges) and dope the edges down. Gentle flexing "breaks" the dope and frees up the flaps. Dave Hemstrought gave me a tip years ago that seems pretty simple: fold 320-400 sandpaper and run this back and forth down the hinge line in the crease after you are done. I also use Nitrate up to color coats.
Bill <><

Bill: yes the flaps will be covered separatly, but the outboard 3" or so of the flap is separate and attached solidly to the trailing edge. It is this intersection, where the flow of the airfoil takes a sharp turn to a relatively flat flap end, I always have problems with. Even iron-on coverings lift here. Thanks

Mitch: Yeah, that can be a trouble spot. I slit the covering and wrap it considerably around the other side and keep rubbing in nitrate until it is stuck. I do make sure there are no sharp wood corners. They don't have to be sanded half round, but they do need a radius on their edges. I trim off until about 1/16th of the silkspan is still on the opposite side after it is stuck. When I go to the top, I can leave a touch more over lap on the bottom, but I still apply and rub until it is dry. Might take 5-6 or more coats rubbed in. No harm in slitting and over lapping the silkspan here as it sands out smooth real easy in the finish stages.
Bill <><

Mitch,

Do you dope the bare balsa before trying to apply the covering? If not a couple of coats of dope under the covering will help. Also when laying the silkspan, put a coat of dope on the wood just before you apply the silkspan then dope through the silkspan. Use your fingers to help seal it down and get the corners, be sloppy....

If you find a piece lifting after it is dry just poke a few holes with a pin, hit it with thin CA and rub it down with your finger. Just keep the finger moving or you will become part of the plane.

I would suggest you put the silkspan on dry over sheeting. When you put it on wet, silkspan will pull against the dope and move as you have described. If you wet it after the marginal dope has dried, this won't happen. You do want a good dope base all under the silkspan.

I think the problem you are talking about is the undercamber at the junction of the flap and wing. I have covered a few old time free flight wings which are undercambered, and I use a mixture of dope (nitrate works best) and Duco cement. Ambroid ar Sigment will also work. Not critical on the amount. Just squirt some glue in to the dope and mix. This is a pretty sticky mixture and will stick covering down in these trouble spots. Hope this helps.