Substitute For Epk In Soda Wadding

[Kristin_Gail]

Accidentally used the all but a tiny bit of my EPK today, mixing up a bucket of glaze.  But I really need to mix wadding tomorrow!  I use 50% EPK and 50% Alumina Hydrate.

 

I have Glomax - can I substitute this for all of the EPK?  There's an article here at Ceramic Arts Daily saying I can substitute half of the EPK with Glomax.  Wondering if I could substitute all of it?

[neilestrick]

Glomax is calcined kaolin, so it won't have the plasticity of non-calcined clay, which you need to form the wadding balls. Do you have any ball clay? Try 15% ball clay, 35% glomax and 50% alumina in a very small batch and see if it's enough clay to form the wadding.

[Kristin_Gail]

I do, indeed!  OM-4 Ball Clay.  I'll go give 'er a whirl.

 

I forgot, I do also add a bit of plain flour to my regular 50/50 mixture.  Would the ball clay make it unnecessary for me to add the flour?

 

Thanks, Neil.

[Mark C.]

The epk is the binder (sticky) for the alumina

Flour does nothing as it burns off-use it for cookies and bread.

Mark

[Colby Charpentier]

The epk is the binder (sticky) for the alumina

Flour does nothing as it burns off-use it for cookies and bread.

Mark

 

This was worth a good laugh! Cookies and bread, huh?

 

Flour is a filler, like sawdust or any other organic material that will burn off in the firing, it's used to "open up" the wadding so it easily chips off after a heavy atmospheric firing. In most situations it's not necessary, but there are times...

[Benzine]

 

The epk is the binder (sticky) for the alumina

Flour does nothing as it burns off-use it for cookies and bread.

Mark

 

 

This was worth a good laugh! Cookies and bread, huh?

 

Flour is a filler, like sawdust or any other organic material that will burn off in the firing, it's used to "open up" the wadding so it easily chips off after a heavy atmospheric firing. In most situations it's not necessary, but there are times...

Well, if you don't use the flour, in the waddings, you can market the wares as "Gluten Free".....

[Kristin_Gail]

You guys are silly.

 

I did, last time, try two different wadding recipes - one 50/50 EPK/Alumina Hydrate + flour, the other a smaller percentage of Alumina Hydrate (notebook is in the shed, but I think it was 70/30) with no flour.  The second was very difficult to remove from some pots.  I had thought it was the ratio that did it; didn't realize it could be the absence of flour.

 

Will make a small test batch this morning.

[neilestrick]

The flour will lighten it up, making the wads less dense and easier to break apart. It will do nothing to prevent sticking, that's the alumina's job. The clay is the binder that allows you to form the wads and holds them together in the firing.

 

I used to use a wood kiln wadding that was equal parts by volume 20 mesh silica sand, fireclay, and flour. Super crumbly!

[Mark C.]

For my last salt fire on the Island of Molokai a few weeks ago I mixed up a approx 50/50% epk and alumina and it released just fine and that was in a sticky salt environment

Any filler will lighten it up-I never had an issue that I wanted to lighten it up-I want to remove the wads as one as they pop off- the more alummina the easier to release.

Mark

 

PS. As far as filler you could use the flour and bake some muffins in the wood ports on the way up-as sawdust will get stuck in your teeth.Choclate chips are also a good additive

[Kristin_Gail]

Mixed up a test batch - held together great!  Same with a 2KG batch.  Now, they're all going to repel soda and pop right off, right? 

 

No, really.  Thanks so much, again, Neil!