Saturday, March 22, 2014

Making Slip & Easy Hump Molds

To make slip I start off with scraps of my clay body and break them into as small of pieces as I can. I let them sit till they are bone dry.

I take them out of the bowl and put them in a ziplock baggy, seal it, and roll them till they are a very fine particle size.

I put the finely rolled clay back in a bowl and add water to cover the clay completely. If after several hours all the water is absorbed, add a little more water. At this point resist the urge to stir the mixture since this increases the amount of lumps. The idea is to end up with as smooth a mixture as possible.

I let the water and clay mixture sit till all the clay is evenly moistened, usually over night. The next day you can stir the mixture or usually I use a hand held mixer to blend up the slip mixture. Next I sieve the mixture and divide it up into pint sized containers with air tight lids.

Later I can use the slip as it is or add mason stains for colored slips. To mix in mason stains to a pint mixture (about a cup of slip) I start out with a teaspoon of mason stain and wet the mason stain in a small glass bowl with a bit of water. Then I add that to the container of slip till I think the color is good to my eye. Later I put a piece of tape on top of the jar of stained slip noting the amount of stain I have added for that particular color. For more details on mason stained slips click the link to Slip Slop Stain and Mixing Mason Stain Slips.

 Save those styrofoam trays which hold food from the grocery store, they make good hump or slump molds.

For these two plates I turned the trays over and rubbed them with Pam sprayed onto a paper towel. The Pam prevents the freshly rolled clay from sticking to the styrofoam and allows the plate to release more easily. For these two plates I rolled out a slab of clay and textured them.
Then I draped them over the upside down styrofoam tray, let them firm up a bit then flipped them over and let them dry on a piece of wallboard till dry. Don't let the plates dry completely on the hump mold since the clay shrinks (contracts) as it dries and that may warp the plate. Once they were dry I sanded the edges with a green scrubby (wearing a mask). Dry clay is harmful to the lumg so please wear a mask. These two plates are in the kiln being bisque fired. Thanks for reading and for all your comments..


  1. Do you use the slip in plaster or bisque molds, or just to decorate with slip-trailing?

  2. I use a coarse handheld kitchen grater to grate my firm clay for making slip. I just grate it out over newsprint and it dries in just a few hours. Dollar store graters work great.

  3. Fascinating. And looking forward to seeing those plates after firing.

  4. Hi Barbara, thanks, I don't use any molds or slip casting I mix this up to use on seams or to use with mason stains and decorating over the the piece I've made.

    Hi Marian, thanks, good idea about the grater, I bet that makes really small pieces of clay, but I try to minimize the amount of clay dust by keeping it in the baggy.

    Hi Elephant's child, thanks, not sure how I'll glaze them, we shall see.

  5. This was interesting & this could be used as a glaze over as well say to even out the coloring on a piece?? ...I want to take a pottery class this summer to make my own dishes & ceramic beads... :D I am doing some catching have made some beautiful pieces....

  6. HI Linda...nice to see you working again after getting settled. Good info on slip making.
    Happy Sunday to you!

  7. Interesting..thank you for sharing the steps.

  8. Hi Linda, thanks, this could be used for a non functional piece like a glaze would, but not on pottery used to eat from, this is just a liquid clay that I can add color to and paint on the piece of pottery, than I would put a clear glaze over the top.

    Hi Trish, thanks, so good to be back to making things with clay.

    Hi Dee, thanks, I hope some pottery folks can learn from what I show, that's how I learned a great deal about what I know about pottery.

  9. I use WD-40 instead of Pam. It doesn't leave a sticky residue or attract mice.

  10. Hi gnknapp, thanks, I used to use WD 40 but didn't like the smell plus some of my slump molds are wood and can also be used for food so I wouldn't' want to WD 40 on them. I dont' seem to get the sticky residue and my studio is in doors plus I have three cats. Ha.


I love suggestions, questions, critiques, thanks for your comment