At 1:35, it's pretty tiny. I assume you are not very experienced with scuplting, so are looking for another approach. I would buy some silicone sealant in the tube, usually used for sealing windows and cracks around the house hold. Check the back label for suitable type. If you can afford casting resin, get a small A/B kit, if not then A/B epoxy liquid cement will work.
- With the silicone, make a little mold of the index finger of the other hand. Being carefull to be able to remove the 'one piece' mold from the hand after the silicone cures, without breaking more fingers off. Usually takes around 12 - 24 hours to cure.
- Then cast the ring finger with the A/B epoxy or resin.
- After the epoxy cures, pull out of mold and glue in place of missing finger.
Otherwise, the easier way: if the figure will be holding something in the subject hand, try sculpting the finger onto the object the hand will be holding with your favorite epoxy modeling putty.
Hope this helps, actually, I hope this made sense.
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