DO not use foil, wastes your dope and the aluminum is horrible, far worse than the dope for you. Then keep torching till the hole smooths out. Once you have your round bubble end, heat one point with the torch grazing the edge horizontally above the bubble when it is red hot keep the fire to the spot and blow until the hole pops. Blow into the end, not hard enough to pop it but with enough strength for it to expand into a bubble. A glass cigar tube heated till glowing red from a torch.
