If you have to use that instead of the candle, try widening out the area. Also did you use anything to remove wax from the area before hand? The wound should be square instead of a V for that repair to work best.
Even mineral spirits should remove the wax from the surrounding area... You mentioned sanding but you didn't say anything about removing the sanded crap from the area. Sand if need be, wire brush, but you'll have to use some sort of solvent to give the epoxy something to bond to.