Alumina Hydrate or Oxide

[Chris Throws Pots]

The studio where I work has a bin labeled "ALUMINA" but it doesn't say whether it's hydrate or oxide. I'd like to mix up some alumnina wax to help prevent lids from sticking and am curious if:

1. Does it matter if it's hydrate or oxide? 
2. If it does matter, what test can I run to determine which it is?

If it's relevant, I've made kiln wash and wadding using this many times over the years. And when I've ordered it to replenish the bin, I've always just asked for alumina.

[Callie Beller Diesel]

It will typically be hydrate, but if you need the information, it's probably on the purchase reciept.  And no, it doesn't matter for alumina wax. 

[Min]

3 hours ago, Chris Throws Pots said:

what test can I run to determine which it is?

Fire some and weigh the LOI. Alumina hydrate is Al2O3.3H2O and alumina oxide is Al2O3 so the hydrate is going to have a higher LOI, about 30%

Like Callie said for wax it won't make a difference, might actually be able to use less if you have alumina oxide but since you use so little it's a bit of a moot point. If you were to use it in glazes for some reason (unlikely) it could make a difference. 

[Mark C.]

My guess is as everyone has said  Alumina Hydrate  and it will not matter.

I like to dip my wax sponge (smaller cut sponge piece)in a small bowl of powder Then apply to touch points between where ware touch.I find it settles out of wax pretty fast.

[Chris Throws Pots]

Thanks all! How much alumina should I use?

[neilestrick]

I use a teaspoon or two in a 6oz. bottle of wax. It helps to add a little water, too. You don't have to be precise with this.