Tutorial on How to ‘Throw off the Mound’
Center the Clay for Throwing off the Mound
Throwing off the mound (or throwing off the hump as it is sometimes called) allows potters to make quantities of small pots or bowls very quickly. It is a technique that many production potters master and use as a matter of course.
When getting ready to throw off the mound, make sure to include placing a ware board next to the wheel so you can easily place the pots on it as they are completed.
You will want a fairly large quantity of clay. Wedge the clay into one lump, usually using between ten…
Open the Clay while Throwing off the Mound
Before opening the clay, it is a good idea to create a groove defining the area you will be working with. You want a mass of clay about the same size as a baseball, or about one pound of clay.
Work with the wheel at half or three-quarter speed, keeping the clay well lubricated. Open down to within about a half inch of the groove. This extra clay is needed, since most pots thrown off the mound are often trimmed so as to have a footed base. (This is done when the pot is leather hard.)
Throwing the Walls of a Pot while Throwing off the Mound
Throwing the pot’s wall is done the same way as if you were working directly on the bat. Work with the wheel at slow to very slow speed, keeping the clay you are working with well lubricated.
Be sure to begin the throw with your right hand positioned below your left, with your left hand beginning at the very base of the pot’s wall where it meets the floor. Compress the rim and remove excess liquid after every throw.
Remember to keep the walls as even as possible from base to rim.
Finish the Pot’s Form while Throwing off the Mound
Finish the pot as you throw off the mound just as you would finalize the thrown form on the bat. Stretch, flare, collar in, and smooth the shape as desired. Make certain to remove excess liquid from the pot’s floor, and compress the floor one last time. Compress the rim for the last time as well.
Wheel Trim the Pot while Throwing off the Mound
When throwing off the mound, do a preliminary trim of the pot while it is still on the mound. You will almost certainly be doing further trimming once the pot is leather hard, but removing as much of the excess now makes further trimming easier.
In addition, you will want to sharpen the definition of the groove defining the bottom of the pot. This will make cutting it off easier.
Cut the Pot off after Throwing on the Mound
Make sure your groove at the base of the pot is still well-defined. When cutting pots off the mound, use a very flexible line that won’t kink the way wires will. I prefer fishing line that is at least 30 pound test, with a preference toward braided line as opposed to monofilament line. By tying an old sewing machine bobbin at one end, I make it easier to keep the line from getting lost among the scrap clay.
As the wheel very slowly rotates, lay the line into the groove, being sure to keep the…
Remove the Pot and Continue to Throw off the Mound
Once it is finished and cut off, remove the pot by carefully lifting it free of the mound, using both hands and an even motion. Set it on the ware board that you have ready beside you.
Some pot deformation is usual, especially if you are lifting the pot with your hands. If you are doing a lot of work off the mound, you may want to look into getting pot lifting tools, or pot lifters. Check with your favorite ceramic supplier to see if they carry them.
After the pot has been removed and is safely set aside, center the new upper portion of the mound and begin the process again. With experience, many potters can throw a series of pots in which each pot only takes one to two minutes from centering to ware board.