[Bob Shaw]

Sounds pricey.

I've got a 20kg box of hot melt glue. I might give that a go.

[awerby]

I doubt that the glue would improve the machinability of wax much - if at all. It's rather gooey in its pure form, so it's unlikely to harden the wax. PLA filament is rather pricey I agree, but it's also available in pellet form much cheaper, as well as in the surplus prints I mentioned that seem to be proliferating out of control.

[Bob Shaw]

The stuff I've got is industrial glue for plastic (I think). Its very hard as it comes.

Having said that, its glue. So when it gets hot it gets tacky.

Worth a small batch just to see.

I agree about scrap PLA though. That sounds promising.