Instructables
Picture of How to make a slump Mold for Ceramic hand building
 The slump mold is a great way to make bowls without using a pottery wheel or using the pinch-pot method. The molds are super super easy to make and well worth the time.
 
Remove these adsRemove these ads by Signing Up

Step 1: Materials neeeded

Picture of Materials neeeded
P1070199.jpg
P1070200.jpg
P1070201.jpg
P1070207.jpg
You will need:
Pottery plaster. It HAS to be ceramic grade, otherwise it will dissolve in water very easily. (please wear a NIOSH mask when working with dry plaster. Avoidance of lung cancer is so very worth it...), 
Water,  
A non-important bucket,  
The objects you want to make the mold from (must be flexible plastic, unless you want to cut it up to get your mold out),  
A scoop,  
A spray bottle of vinegar (not pictured),  
A scale,  
Something to stir your plaster with.

Step 2: Mix your plaster and pour

Picture of mix your plaster and pour
Mix your pottery plaster (you did get pottery plaster, right? NOT the cheap stuff from the craft store?) according to the directions. If there are none, it is usually about 1 lb of water to 1.5 lb of plaster mix. This is where the scale comes in... 
This stuff sets pretty quickly, so use your stick to stir stir stir and get all the lumps off the bottom as quickly as you can and then pour it into the molds.
Give the mold a couple of good taps (not hard enough to spill the plaster) on a sturdy surface to get any bubbles out from the bottom.
I used 1.5 lbs of plaster and was able to make one good sized mold and one rather shallow one.

Step 3: Remove bubbles

Picture of remove bubbles
 If bubbles bother you or you are planning on using all sides of the mold, spray the mold lightly with the vinegar to pop the bubbles.
scoochmaroo4 years ago
What do you do with this?
skeletal dropkick (author)  scoochmaroo4 years ago
 You use it for hand building with ceramic clay. check out my next instructable to see... :)   www.instructables.com/id/How-to-use-your-slab-roller-and-slump-mold-to-make/