Here goes with repairing dogs legs.
Above are a couple of Britains hollowcast hunt dogs - both having a missing lower left leg when found. I have already drilled into the leg - and fitted a pin, cut from a peper clip. Note that the pin is deliberately slightly longer than the remaining legs - as it goes through a hole drilled into a tailor-made stand (base) which I made for each dog. ( You can see the pin on the right side dog). This is my "bone" for the leg.
The left dog has had the leg remodeled by using an epoxy putty to form around the pin - just as flesh would around a bone.
Here's the other dog - whose leg has been remade in a similar fashion.
When the epoxy putty has cured - I give each dog a justification coat of matte paint - which will help show up any minor flaws - which can be modified, by sanding or filing to remove material - or adding more if necessary.
Here's where I am with these two - not too bad - but maybe a bit of sanding back required in a day or two - once everything has solidified. Also note that I deliberately left one dog with a short tail ( snapped off from the original curled one) , as it reminded me of my favourite dog Angus ( now sadly, gone), who had a tail very much like it. Guess what I will call them when they are done??
Curly and Angus, of course!
Hope that helps a bit.
When I next get a horse with a hole in it - I'll do another show and tell. But for now .................... here's a tell version.
Cut a piece of tissue paper about two or three sizes bigger than the hole - and crumple it up into a rough ball. Push it into the hole with something ( a straightened paper clip will do. When it's inside it will un-crumple a bit. If you lose it - do it again with another piece. When you can see it inside and preferably touching the inside of the horse - run a little super-glue (the runny kind) into the hole. It will quickly set off - and be stuck inside the horse. You can add smaller pieces of tissue paper now - if you want to save the putty - and keep the layer thin.
When you are satisfied that the hole is now shallow enough (aim for a couple of millimetres) - you can begin putting in small pieces of epoxy-putty into the hole to build up to the surface of the horse. I usually put in a touch more super-glue for the putty to quickly stick to. Build up the putty to slightly proud of the surface - and leave it to set off HARD. This may take a day or two - depending on how deep the putty is, (that's why it pays to use the paper first - so you have a thinner layer of putty to solidify.
Once dry - you can file/sand it down until you are satisfied with the surface - when you can put on a justification coat of paint - which will help show up any faults or irregularities - just as I have done above with my two dogs.
Hope that helps too Dave - jb