I have a lot of dry clay I have saved to reuse. Most of it is in smaller pieces, I'm working my way to making it into powder. I'm thinking of getting a rock tumbler to make small batches of powder since most of the pieces are pretty small anyway.
Currently, i put the powder and sometimes granules into a bucket and pour white vinegar and very hot water over it, sometimes mixing immediately sometimes waiting for it to cool. I always let it rehydrate for at least a few days before drying on a plaster board.
Currently I mix the clay by folding and flattening, as this is easier than wedging for me. I'll wedge smaller pieces, but for these larger ones I'll pop the air bubbles and smooth it out. So far it's been ok but I'll sometimes have a bubble I missed until I am nearly done shaping on the wheel.
Does anyone have suggestions for how to decrease the air bubbles trapped from rehydrating? Would a vibrating paint mixer work?
You do not have to make it into a powder you can just rehydrate the bigger pieces and that will work fine. I will typically just break up clay I am reclaiming into quarter sized pieces and let it rehydrate for like a week. I'll mix it as it is dehydrating, maybe once every couple days. Then when I want to reclaim I will just pour off the extra water and put it on plaster.
You do not have to wedge it all at the same time. You could do whatever mixing method you want, then wedge small portions for throwing. I think the air bubbles are coming from the folding.
I've had larger pieces that just didn't rehydrate while everything else is a wet mess. I'll use very hot water (our water heater is set to 180f) and vinegar, giving it at least a few days to a week to rehydrate. That's why I started trying to get everything into smaller pieces or even powder. I've had the fewest air bubbles with smaller pieces or powder. I think air is trapped in the clay that doesn't come out when soaking.
How coincidental to see a pottery post the day after I spent a night binging videos about clay!
I haven't done pottery since middle school but this guy has a ton of videos about making/reusing clay. Sorry for commenting without an actual answer but maybe you can find some tips on that channel? From what I saw he wasn't too concerned with breaking it up super fine. In one video he just smashes up the dried clay in his driveway. I didn't see anything about air bubbles aside from kneading it really hard to get rid of them