There are a couple of things to consider when heating gypsum (dihydrate) to plaster (hemihydrate),
Gypsum and plaster are poor thermal conductors - spread thinly on a tray/hot surface
micro-pockets of steam burst, emitting very fine dust - disposable oven/kiln or a big clean up
Water added to bulk anhydrate or hemihydrate forms a solid lump of dihydrate.
Keeping moisture OUT is required.
PS probably the cheapest and easiest way to get small quantities of the hemihydrate is to buy plaster ![;)](./images/smilies/wink.gif)
('plaster of Paris' is the purest type - I believe)
[Edited on 4-9-2022 by Sulaiman] |