Tulwar Hilt Resin Substitute.

[Atlantia]

Hi Norman.
It depends what you want to achieve. The original resin must be some natural substance, although I'm not sure what. I believe it is made malleable with heat, so if you wish to 'create' a substitute which has similar properties, then perhaps a base using some kind of D.I.Y roofing pitch/tar that sets hard (the type roofers use to lay flat roofing felt etc).
If you wish to achieve something more solid, then fibreglass resin is good.
However, I would caution that some experimenting is a good idea first as a handle full of set resin can be difficult to remove/alter.
Also, if using fibreglass resin, then I would add particulate matter to give it a more 'authentic' look.
I would suggest doing some experiments, for instance getting sawdust, sieving it to get the really fine particles then dyeing it with a thin wood dye, letting it dry and mixing it into the resin to get a better texture and colour.

A more simple and forgiving mixture would be the old wood glue and dyed sawdust mix, but it will take a while to dry.

Regards
Gene