[Mark C.]

All above ideas work well but for really settling glazes we have had great results with product called Magma
Its a bit of trouble to mix up but it works as nothing else does-even gums
we keep some mixed in sealed tub to add when we need it.
Mark

[neilestrick]

Epsom salts (magnesium sulfate) are my go-to for suspension issues, but you really do need have at least 8%, ideally 10% or more, of clay in your recipe, like EPK or Ball Clay. The idea is that the clay suspends well, but everything else likes to settle. The Epsom salts, a flocculant, get everything to stick to the clay, thus keeping it suspended. Without enough clay in the recipe you're just sticking together ingredients that will settle whether they're stuck together or not. Adding 2-3% bentonite (a super plastic clay) will help a lot, without affecting the glaze appearance. But it must be added to the dry mix and thoroughly mixed before adding water, or it will clump up really really badly.

[Graeme]

I use epsom salts - a couple of teaspoons per kilo of glaze. I've found it keeps glazes from settling into a hard lump in the bottom of a bucket, even if the glaze is not used for months, or even years.
That includes crystal glazes with no clay, or one of the raku glazes I use which is - frit 100 bentonite 5.
Cheers. Graeme

[trorison]

Epsom salts. I have found that adding 1.6% by weight to glazes that are heavy in Neph Sye or frit and light on clay works well. I adjust (lower) the 1.6% when I have a glaze that has clay and/or bentonite and still settles out. I do keep a solution handy for adjust after mixing but prefer to make a note on the next glaze batching to add it dry to the rest of the dry glaze mix. That way I have more control over time. When adding dry, I use hot water which I add by weight also. Usually start with 80% water by weight and adjust to the ingredients in the mix. So a 4540 gram batch (10 lbs of dry ingredients) uses 3632 grams of water to start and then adjust by adding a little more as needed. 3632 grams of water converts to 8 lbs.

[Deanna]

I remember reading an article in Ceramics Monthly (I think) in which it was stated that some glaze ingredients absorb water only over time; so that they don't settle at first, but later. I have a glaze that does this, it's a 4-3-2-1 glaze. I kept meaning to go back and read that article, and now I can't remember what issue it was in. Anyone know?

[perkolator]

I'm surprised nobody mentioned it, but you can add some CMC to the glaze to help with suspension. Definitely more expensive than Epsom salts or bentonite, but it works also and won't change the chemical makeup. We always keep a jug of prewet CMC in studio, mixed to a thick elephant snot consistency. It's a good thing to have in studio as it has many applications. One of the most beneficial things besides suspension agent is it will help the brushability of your glaze and will dry to a "coating" on your piece so the glaze is more resistant to powdering off on your hands when you touch it during kiln loading.

[Diana Ferreira]

I cannot remember who gave the idea to keep the Epsom salts in a suspension, but a big thank you again. I have a huge canister of it, and everyone in the studio uses it. We also use a hydro thingie to measure the SG of the glaze. We all use it now before we start glazing, to ensure that the consistency of the glaze is similar to a previous glaze day. I used to use it when I was still making my own slip, as I did not have a scale that I could use.