Thursday, September 10, 2009

kickin it old school.

I mixed up a bunch of clay yesterday. I took a couple photos that were not all that fantastic but I'll share them anyways. Clay mixers and pugmills are very expensive, so this is the way I've mixed my clay since I've left college. I've gone through stints of buying pre-mixed clay but have never been happy with those clay bodies.

Weigh out the materials....(my batch is 220#s dry.)

Mix it all with some water, start with feldspar & silica, then kaolins and ball clays, fireclays and grogs are last. I use a drill with a sheetrock mixer on the end...if you're really broke you can use a hoe or a big stick. It's more efficient to use a larger container(horse trough like windy ridge) and mix more slip at once but my space is constricted so I use a large 35 gallon trash container.


These are a couple of my drying racks, 2x4's with chicken wire attached to one side. I cut some bed sheets in half and pour the slip into those. One batch of clay fills one rack, it's about 300# of usable clay when finished. I use a bucket to transfer the slip from the barrel, but you can get high-tech like Ron Philbeck and use a sump pump to transfer the clay, saves the back! Take note of the respirator on the ground...save your lungs too.

Here it takes 1.5-3 weeks for the clay to start to become usable. Mixing one batch took me 27 minutes from weighing out the materials to getting the last bit out of the barrel. One batch of this clay equals 2 batches in the bluebird mixer. Anyone will tell you that clay mixed with this method is infinitely better than mixer-mixed clay. To test this theory I mixed a batch in the Bluebird mixer and let it age for just over three months. From both types of clay I made pots to be altered and squished and pots that needed handles. Clay from the mixer was consistently short and cracked while pushing the walls of pots and pulling handles, the blunged clay did not. Just in case anyone was curious. Enough said.
Later.

7 comments:

Peter said...

Thanks for that really helpful information. Must give it a try. I'll be printing it out and putting it in my studio!

Ron said...

Mixing clay!!! I'm getting geared up to do so myself. Gotta go buy my dry materials next week. That whole Bluebird idea was short lived. I decided to just buy enough commercial earthenware to make it through till my blunged clay gets made. I agree 100% that it's the best way to mix clay.

Chris C. said...

Does the grog settle out to the bottom or stay suspended?

Chris C. said...

Forgot to ask: Do you wedge it once it comes out of the racks or just start using it right away?

brandon phillips said...

you have to add the grog last so it doesn't settle. the slip should be thick enough that the grog will stay in suspension. the edges dry at a faster rate than the middle of the rack so it does need to be wedged for even mositure content but the mix itself is relatively airless.

Dirt-Kicker Pottery said...

Is it less expensive than buying ready to use clay? I pay about $25 for 50 lbs of Laguna clays.

brandon phillips said...

yes, mixing your own will always be cheaper money-wise. but if you use only a small amount of clay or only have limited time to spend working then it's probably not worth the time or effort. It's purchased in bulk by the ton and by the time it's mixed it costs about $7 per 50#. I use 2-3 tons per year so there is money savings to be had for me. I purchase it in bulk by the ton for the university and myself so we can both realize the bulk discount. the other reason i mix my own is because i haven't found a suitable clay body for my work and kiln...nor do i trust a pre-mixed clay body that I can't tweak if need be.