mammoth ivory scale back filler

[John L]

I have tried epoxy as a back filler for mammoth scales but am not satisfied. Any ideas here? Epoxy seems to be too gummy when grinding the rear flat.....expensive also. The material needs to be able to be colored also. Thanks

 

[blades&grace]

Bondo?

 

[Mark Behnke]

I was going to suggest Devcon but I think bondo is probably better.
Used to back turquoise with devcon.
http://www.midwayusa.com/product/647161/devcon-plastic-steel-bedding-compound-putty-1-lb

 

[Stacy E. Apelt - Bladesmith]

Bondo works well for filling smooth curves and single split/void areas.

I prefer to use structural epoxy resin (System Three T-88) that I have tinted to match the ivory. It will penetrate and fill pieces with lots of voids and splits. Tape up the other side and ends so it makes its own casting "bowl" and pour in the resin. If you have a vacuum table or investment vibrator, that will help the epoxy penetrate well. Use slow cure epoxy (24 hour), mix by exact weight, and allow to cure at room temp for 48 hours. It should make the backs solid.

On pieces that have thin splits and hairline cracks, I use thin CA, followed by medium CA,followed by thick CA - with the piece taped up as above.

If you don't tightly tape up the other side and ends, you will likely find the piece glued to the table top in a puddle of resin/CA, as the adhesive with find its way through the labyrinth of cracks and weep out the sides/ends.