CNC-kitchen on youtube does some great experiments in unique ways to reinforce 3d prints. His latest video is a slightly more involved version of the salt method where he casts the prints in plaster and then re-melts them. I have been looking at going one step further and using a burn-off filament to make a mold for metal casting.
Any system in equilibrium will tend to keep its shape or deform predictably if viscosity is high. I exploit that in a rapid printing method I've developed. It prints directly into a stable volume using various methods such as focused energy or a moving planar array. The potential active printing speed is limited only by the data transfer speed into the volume. A secondary locking step is passive and allows the system to lock (cure or cool etc) in place without further input.
Relating my process to the linked technique, some of the parts could have been made of plastic powder placed precisely in the salt. The baking step could still be performed and the parts would be almost identical.
Imagine 10,000 tiny hourglasses in an array that can switch between depositing plastic or salt. They switch on the fly to leave plastic in the salt matrix. You can see how the speed could go up dramatically.
I began building a proof of concept to print concrete in a sand matrix but never got that device working properly. It had a 6x6 array of 2“ square nozzles but I ran into problems with the mechanism to switch the nozzles between sand and concrete. I designed a second version that would have had better switching mechanism, but couldn't afford to build it.
He mentions grinding the salt - hyper fine salt is available as "popcorn salt" at restaurant supply stores. There may be anti-caking ingredients added it it that may not be desirable however.
https://www.youtube.com/watch?v=bG8dlxTX3AI&t