Wouldn’t it be great if you could use any cool thing you find for slumping? Well, maybe not everything, but there are lots of things that CAN be used for slumping, as long as they are prepared correctly. Let’s look at a few examples and consider what we would have to do to successfully use them for slumping.
Terra Cotta pots are a very useful thing indeed, they can be used for pot melts, as well as floral formers in a pinch. Since glass contracts more than ceramic as it cools, it’s best to cover pots with fiber paper before using them as floral formers, the fiber paper gives a bit of squeeze room to the glass so it doesn’t break as it cools.
Terra cotta saucers can be used as slump molds with a good coat of kiln wash. If you feel the need to drill holes in it, use a masonry bit and make sure you follow standard safety rules in regards to dust.
Most stainless steel items are marked on the bottom, but not always. Some things to look out for with unidentified metal items:
Take a magnet with you, stainless is not attracted to magnets, if your item does stick to a magnet, it could be chromed or plated steel.
Stainless is typically thinner than aluminum, or pewter. If your item is quite thick, and not so heavy, probably not stainless.
Aluminum and pewter are both pretty soft metals, if you can, try a discreet scratch test to see if the metal scratches. Naturally, it’s best to buy the item before you do this. And, Aluminum and Pewter are also not magnetic, so use that test too.
Consider the price. Are you willing to do a test on a $1.00 piece? Just in case it really is stainless? Sometimes, it can be worth while to gamble if the price is right. And always test with scrap glass.
I frequently see incomplete cocktail shakers at the thrift store. This one is just $1.00, what a great price for a full size floral former. Rough up the surface with sandpaper and coat well with kilnwash or boron nitride spray.
a. coat well with boron nitride spray, which can go right over the glaze OR
b. sandblast off the glaze and kilnwash the mold.
Again, if you want holes, use a masonry bit and follow safety rules!
If you don’t do one of these two things, your glass will fuse to the glaze and it will be a big mess. A big cracked, broken mess.
If you aren’t already friends with your local ceramics store, you should be. Most ceramic supply stores carry a line of pre-made bisque ware at extremely good prices. These pieces are intended for ceramic hobbyists to glaze and fire. They can be used very successfully as slump molds, needing nothing but kilnwash. If you feel the need to drill holes in the mold, use a masonry bit, and follow dust safety guidelines.
Another option, although it is slightly more expensive, is to visit the local Color Me Mine or other ‘paint your own’ pottery chain. These stores are intended for drop in painting of ceramics by non-ceramic artist hobbyists. They have a different range of bisque ware, which they will happily sell to you.
Boron Nitride Spray Recommendations
I’ve used both MR97, and 1800 spray, and they both worked fine. The most easily found spray at this time is ZYP, which has mixed reviews from artists. Another option is Universal Mold Coat, which is mixed with latex paint and painted onto molds. I suggest ALWAYS testing the mold separator after you buy it to get a feel for it’s peculiarities and limitations.