liambesaw

The best way to figure out how many pieces a mold will need, is to make them and fail. You'll find pretty quickly that more parts are needed in certain areas, and will then know the next time you make a mold what to look for. It's like @Chillysaid, every person would design a mold differently.

It is a really good wax. Luckily very close to me. Another great wax, but with different properties, is reed wax from brackers. Both are the best waxes I've used, and SPS crystal wax is a product that Mobil oil no longer makes (or at least that was the last news), so there is a limited life on it. You cannot let it freeze, I know that's not a big deal for you @CactusPots, but could be for others here. Reed wax is nice because it can freeze, but also is a decent wax in general. And is available into the future. I do hope mobilcer-a continues to be available, but I have a good back up just in case.

Can you use a respirator while you're there? Not likely necessary, but if you're worried about silica in the air, that's one way to keep using the studio and still feel safe. If dry clay on things is the worst it gets, it sounds like every studio I've been to. Silicosis is no joke, but there are measures you can take personally to prevent it. There's a lot of fear around it, which is understandable! But there are much more dangerous things you're exposed to in a studio that no one talks about. Silicosis is rare in potters now, because people are more aware of what causes it and how to prevent it. Be aware, but don't be paranoid.

You could always buy bisque tiles instead of trying to decorate ones that are already glazed. Those can be fun too, and no worry about making them or glazes not fitting over other glazes

There are a few cures for silicosis in trial phases now, actually discovered during the coronavirus treatment experiments during early pandemic. Good hope for those in our profession who have progressed to the point of COPD. Silicosis is not inevitable, it's highly avoidable with safe and conscious studio practices.

Glad to see I'm not the only one using woodworking tools! I use hole saws, drill bits, chisels, surforms, hacksaws, etc. For extruded stuff I extrude as long a form as I can and then carefully lay it straight on foam to dry up a bit, then cut into pieces.

OM4 is ball clay, so I think the slip would not behave the same. You can give it a try and see what happens though. I would guess the things you cast would be very fragile after casting.

I do it myself, but a friend has hers done by the kiln techs from our local pottery store and the cost is 400 including parts and labor. She has a 818 as well. So if you remove the cost of the elements, pins and connectors, that's around 200ish for labor? Seems expensive to me, but we live in the Seattle area which is very expensive in general. I recently changed the elements in my 14cuft oval kiln and it took me about 3 hours. Not too bad.

Freezing slip will cause water to leave parts of the slip, leaving drier clumps when thawed, but a little bit of time in a blender or magic bullet or whatever will set it straight. If it's casting slip, the water will separate and the deflocculant and other salts present (I'm looking at you neph sy) will crystallize. Would be a bit more of a task to thaw out casting slip. What will work fine at keeping mold out though, is a tiny pinch of copper carbonate.

Casting plaster is weaker now days, at work we switched from casting plaster to pottery plaster #1. Much better quality and strength, and quicker setting time too!

Just so you know for the future, this makes copper acetate, a water soluble copper salt, and is a more toxic and problematic version of copper for glazes. It will flocculate your glaze and may recrystallize over time.

That is... Scary as hell. If anyone reads this in the future, never SPRAY any metal salts, ever. They're all toxic, and don't provide anything special that you can't get some other way. The spray itself, toxic, the fumes from evaporating when it hits hot pottery? Toxic. And toxic in some of the worst, most heart breaking ways. Sheesh. But that's not fuming, fuming is introducing the salt (preferably as a powder) to the kiln during cooldown. Still hazardous, especially if firing indoors, but not nearly as hazardous as spraying the salt mixed with water!

Is fuming cobalt a thing? I didn't think kilns got hot enough for that

Tyvek is kinda neat, it allows air to pass but not moisture, doesnt seem like a good surface for wedging but I hadn't tried it, I prefer plain ole bare plywood

The cracks would have nothing to do with a lack of glaze, it's totally fine to fire with no glaze. It is some other cause. If you can describe the cracks it would be helpful