I'm wanting to make a homemade mud pit using ball and kaolin clay purchased at a pottery store. It would be indoors in a large tote/storage container. I'm hoping to add water and just put the lid on the container when done using it until next time. If anyone has maintained an indoor clay pit, what steps did you take to ensuring it stayed safe/pleasant to use? Bleach? Chlorine? Is there a certain amount of time a pottery clay mix would last before needing to be replaced?
I had a heated one ton mudbath in my house for many years. I found that using chlorine was unnecessary, clay is anaerobic so nothing tends to grow in it and as long as it is mixed up regularly nothing should grow on the surface.
The main problem is that a large mass of clay tends to dry out both on the surface and in any corner where it is not regularly stirred up. You do not want the clay to solidify in a corner as it is difficult to get mixed back up. The easiest way to prevent it drying out on top and forming a crusty residue that would feel like grit if it gets mixed in is to always cover the surface in some way, such as with a cover or plastic and to leave a thin top covering of water on the surface.
Note that a mudbath can accumulate body hair over time and if enough gets in there, you will eventually notice it to the touch. This can be minimized by washing out muddy clothes to retrieve mud in a separate bucket instead of directly into the mudbath and then mixing water into the bucket to liquify the clay and then strain it.
I'm also using a bit of chlorine in mine. I have it since January and still looks fresh. When not using it for couple weeks the clay and water seperates a bit so that stall water on top can use the chlorine. Also, I'm heating the storage bin with heating pads coupled with an inkbird to manage the temperature. It's pretty nice to have access to 100F clay year round. I have an inflatable pool beside that bin and I scoop the clay back in that bin after use. Best wam room improvement ever.
I've not had a giant vat of the stuff (which does sound absolutely sublime, though!) but the small totes/buckets/containers I do have - I've never noticed an issue. So I can't speak much on the 'maintenance' side.
On the 'clay' side, though - I would just say mix up a small sample of the clay you intend to use and see how it works. Maybe you already have and found its what you like.
But if it were me, I would throw some bentonite in there to give it some 'body' and some 'slipperiness'. Pottery store should have it, too. (My local pottery shop knows me as 'The guy who buys the 50lb bags' - while most potters seem to buy 1lb increments!) Anyway, just a thought!
Adding bentonite to clay makes the clay look more glossy and causes it to not stick as much to the skin. Some like this effect, I do not as it makes the clay less sticky on the skin and more watery in texture. I recommend trying a small amount of bentonite first to find out if you like the effect.