- Choose the amount of clay you need for your slab. Remember, it should drape several inches over the mold in each direction (you will cut the excess away and be able to use it later)
- Flatten your clay by hand so it’s roughly 1.5” tall (and square)
Using the slab rolling machine, start moving the clay back and forth, lowering it about ¼” between each pass
- Be sure to use the correct slab roller material. The canvas is for dark clays, the smoother one is for light clays
- Rotate the clay 90 degrees each pass. If you’re doing anything round or square you want as square a piece as you can make. If you’re doing something rectangular, you can work it a little different to make it longer
- If using a hydro-mold: fasten the mold to your wheel head. The only difference between this and doing it on a tabletop is that the wheel is spinning while you work
- If using a regular mold: set it on a clean bench top and make sure you have plenty of elbow room
- Drape your slab slowly over the top of your mold, starting in the middle. Lower it down slowly to let it naturally sink and sit properly on the mold
Once you have set it down, release it and use your fingers to slowly press from the middle toward the outside edges.
- You are simply forming here and pushing any air out. Do not press and flatten the clay as you go. This is a gentle procedure.
- Use a needle tool to carefully trim the excess to about 1” below the bottom of the mold (all the way around). Ball up the extra clay and save it for future use
- Using a damp sponge, work your way continuously around the clay, smoothing it out and compressing the clay
- Now use a soft rib and do it again to really compress your clay
- Now do it with the sponge again to make it nice and get rid of any slip buildup
- Trim around the base of the mold with your needle tool, getting right against the mold but not digging into it at all. Your line will be a bit rough, that’s expected.
- Let it dry until the whole thing has lifted about ¼” to ½” (as the plaster dries out the clay)
Once it is leather hard to the touch, carefully lift the clay off the mold
- Note that this is the stage you will add foot rings, handles, feet, etc. So if you’re adding anything to the bottom of your piece, this is the time
- Note that this is the stage you will add your maker’s mark, stamp work, texture work, etc.
Using Hump & Slump Molds: Dan’s Quick Glimpse How-To
This is the process of using the slab molds (hump molds and slump molds) that I have available here at The Donkey Mud Studio.