If you want to make a pinata with papier mache, as mentioned there are all kinds of things you could use as temporary formsAny forms made from a material that would stick to the papier mache though (rubber balloons won't stick at all or much) should be covered first with plastic wrap or aluminum foil before beginning the papier macheing process so the form can easily be removed after the papier mache driesIf you want to make a sphere (round shape) in particular, instead of covering a balloon you can make the sphere in two halves then tape them together You could use something like the back side of a large bowl or a huge light bulb or anything else you could find (or make) with a domed top Make two of those (let each dry fairly well before removing, then stuff lightly with bunched newspapers or something while they finish drying alone), then put the two parts together with tape, hot glue, whateverIf the edges of each hemisphere aren't even, you can cut them even with kitchen or other strong scissors.of if the pinata is thick/strong enough you can sand the entire bottom on a sheet of sandpaper on the floor/table, etc, firstYou may need a final layer of papier mache to smooth out the area where the tape is, but if you'll be covering the pinata with loops (or other shapes) of tissue paper or crepe paper, etc., you won't see that it's uneven(If you wanted to use a shoebox, you'd need to cover with plastic wrap or foil, then cover all but one side so you could remove the shoebox form when the papier mache driedYou could then attach a separate papier mache side, or you could try just laying the strips of papier mache across the open side until they're thick enough.)
In the UK there are spinning guilds/clubs in most areas with contact numbers on googleEnter words like Somerset spinning guild depending on your area.
