Forging a Balloon shape

[art925]

Good one for you all.
For a local competition, I want to forge some balloon shapes then enamel them, so probably best to go without two halves and solder together....so what shape do I start with please?

Many thanks!
Les

[china]

Are we talking truly round or actual balloon shape either way, I would start with a flat disk and slowly draw it out to the desired shape, or use a dapping/dopping set to create two round halves the gently strech one half to get a balloon shape
might have to create a custom shape mould for the elongated half, I'm sure some other ways will come to light as there is always more than one way to skin a cat ( or make a balloon)

[ps_bond]

I might also consider clamping the metal between 2 thick sheets of hardboard (bolts with wingnuts on the corners) with the profile cut out and chasing it effectively in air to form it.