RE: Mini F-16 vintage project consideration
I would lay down 1 layer of 2 oz cloth with epoxy over the mandrel and let it cure.
Next step would be to wind fine music wire over the layer of cloth, possibly using an entire length of it. The trick would be to keep it tight and to solder both ends. Then I would glass over the wire with 4 or 6 oz cloth and call it good.
A solid, 1 piece mandrel might not want to cooperate with releasing the part, so I would make the mandrel out of 2 pieces of wood with a pair of shims at the parting line that are easily removed.
If this idea didn't pan out, at least you would still have a reusable mandrel to try different layup schemes with.