ms_manic_minxx wrote:I always have tons of excess fumaric acid, even after washing (with distilled water), and it doesn't seem to fully get lost until the freebase step.
Based on this, SWIM thought she had already performed water purification. SWIM hopes that minxx wasn't trying to wash off fumaric acid with water.
With the last water purification/rextal that SWIM did, he reduced the water volume a bit much and left it in the fridge and in room temp for a while using a small custard dish. He ended up with a hard disk of deep red fumarates (full-range from jurema) which broke into shards and bottled. Most of the time, he just does a hasty rextal by evaping completely on a wide shallow dish, moistening the surface lightly before scraping (if this isn't done, it is very difficult to scrape up, and you'll make a mess), scrape the wet fumarates into a pile and pop it back in the dehydrator; if SWIM does this right, he gets rocks, otherwise, it turns out a bit sandy. Sometimes, if there's enough fumarate concentrated in a small area and is hot enough, it will form a goo, and this goo can be worked around to solidify into very dense and solid rocks.
Freezing the mixture of limonene and FASW to induce separation of the limonene from the aqueous solution (so it can be decanted without aid of a separatory device) also precipitates out excess fumaric acid prior to freezing solid (perhaps not all of it, but most...still needs more testing). Freezing is a great, multi-purpose preliminary step when dealing with FASW, in SWIM's experience