I have to add 3/4 oz of weight to the right wingtip of my .46-size WM P-51. I have to figure out how to CLEANLY hack into the fiberglass wingtip, add the weight, then CLEANLY patch it up. Any ideas?

My temporary solution is to stick on 3/4 oz of lead to the bottom of the right wingtip on the CG. I've read that these things have a tendency to fall off in flight, so I sealed it with clear monocote (photo attached).

Is this an acceptable? So far it has stuck on for 2 tanks on the ground, including taxi practice and practice take-off runs. The plane has not flown yet. Will the altered airflow at the wingtip have any adverse effects?

Thanks,
Juice

Looks good to me.
That is the bottom side, right???

Juice,
get thee 3/4 oz of BBs or split shot. Drill a small hole in the wing tip slightly larger than the weights. Coat each piece with epoxy and drop through hole with wing vertical so BB or shot falls to trailing edge. Add some additional epoxy for insurance and allow to cure. Shake it good tomorrow to insure nothing is loose. Check balance and seal the hole. Subtract a BB or two to compensate for epoxy.

Geistare... Yes that's the bottom side.

vinnie... That's the kind of tip I'm looking for. Thanks.

Juice