hi

i am kind in process of learning and doing stuff. so not all the materials and all the equipment in the house
so i'am trying to improvise and find solution from existing materials and tools that i have.

i'am planing to do mould, but i dont have gelcoat.

so will thickened resin with fumed silica do the job instead of gelcoat.
i am talking about the mould for just a couple of uses.

One thing to remember is that gelcoats are formulated to remain tacky until the backing layers are applied, giving a strong chemical bond between the gelcoat and the backing resin. If you just use thickened laminating resin to make your own gelcoat it will cure hard with a waxy surface if left too long. This will prevent the backing layers bonding properly. Just let it cure to a tack before applying the backing layers and you should be ok.

Carbon Copies Ltd

It depends on what kind of resin you will use, for polyesters: what wozza said, if you use epoxy then that's not an issue since they don't contain the wax additive.