3D printing a PLA chess set for alu/bronze casting

Each piece takes 2.5 – 4 hours to print at the high resolution which I require to produce a good finish. The printed pieces will be attached to a tree, then encased in jeweller’s casting medium inside a steel cylinder. When set, the cylinder is heated to 200-300ºc to melt and vaporise the PLA, producing a cavity in the casting medium, into which the molten metal will be poured. The mould is baked for about 6 hours to thoroughly dry and harden it before the metal is poured into it.

There are 16 pieces in each army of a chess set. So 64 hours of printing for each colour. Plus failures. So far, in about 5 days of printing, I have produced the whites. That has taken almost 1kg of PLA, one roll. PLA is not expensive. I paid about $AUD22 per roll, including postage. Lately prices have risen to around $AUD30 per roll.

These are examples of a print run failure. This run was almost completed after 24 hours, when for some reason it just stopped. It was overnight, possibly a short power outage. Another run failed due to poor plate adhesion, again near the end of a run. I solved that issue by turning up the temperature of the extruder to 220ºc and the temperature of first few layers of the platform to 70ºc.
An army of pawns. One spare.
Half ready for casting. Now printing the opposition (in black PLA, only because that is what I have on hand, plus it might be another photo opportunity.). Can’t wait to see these in aluminium and bronze.