50lb Best Mix - BMix - BMX - Mid Fire Cone 6 Pottery Clay - Rocky Mountain Clay Review (2026)

Who this clay body suits

B-Mix, often shortened to BMix or BMX, is one of the most widely used teaching clays in American pottery studios, and Rocky Mountain Clay's version keeps that same smooth, plastic character. It suits students learning to center and throw, since the clay is forgiving and consistent from bag to bag, and it suits studios that want one dependable body for both wheel work and hand building rather than juggling several clays. The 50lb size is aimed at potters who go through clay regularly, whether that is a home studio throwing every week or a class splitting the box among several students. Anyone doing occasional air dry projects, or without access to a cone 6 kiln, is better served by a different clay entirely.

Firing range and fired color

This is a mid fire stoneware rated for cone 6, which lines up with the most common firing schedule for home and small studio electric kilns, and Rocky Mountain Clay notes the body can be fired anywhere from roughly cone 5 to cone 7 while giving its best results at cone 6. In an electric, oxidation kiln it fires to a soft white, while a reduction atmosphere pushes it toward a light, stormy gray. That range makes it a genuinely all purpose stoneware rather than a body tuned for one narrow look, and it is smooth enough, with little visible grog, to take detail work and a wide variety of glazes and underglazes without fighting the surface.

Working with it and storing a 50lb box

The obvious trade-off with buying in 50lb quantity is weight. Shipping a box this size costs more than smaller bags, and it needs a cool, out of the way spot in the studio rather than a shelf, since a full box is heavy to lift repeatedly. In exchange, the per pound cost drops compared with buying 25lb bags one at a time, which matters for anyone throwing through clay every week. Like most plastic stoneware bodies, B-Mix wedges easily and holds its shape while trimming, and reclaiming scraps back into usable clay is straightforward with a standard slurry and dry-down process, so very little of the box goes to waste over a semester or a season.

How it compares with other stoneware bodies

Against Rocky Mountain Clay's own Speckled Buff Cone 6 stoneware, B-Mix is the smoother, whiter choice, better suited to work where you want a clean surface for glaze rather than visible fleck. Compared with Old Potters' Mid High Fire White Stoneware, which is also rated cone 6 to 10, B-Mix sits at the lower end of that range and is tuned specifically for cone 6 rather than stretching higher, which keeps its shrinkage and behavior more predictable if that is where your kiln always fires. Potters who want a body that goes noticeably hotter, into cone 10 territory, should look at those wider-range clays instead, since B-Mix is not built around that ceiling.

Verdict

For a studio or classroom firing to cone 6 and wanting one reliable, smooth clay for both throwing and hand building, this 50lb box of B-Mix is close to the default choice, and it is easy to see why it holds our score of 9.1 out of 10 among stoneware bodies. The only real catch is logistics, since a 50lb box needs storage space and costs more to ship than a smaller bag, so occasional hobbyists or anyone without steady studio access may prefer a 25lb size instead. Potters without a cone 6 kiln should skip it entirely and look at an air dry or low fire clay suited to their setup.

Frequently asked questions