Dropping out

Every once in awhile you want to run away, escape the confines of daily life, and let fate rule.  In other words, it’s time to drop out.

Fig 1.  My first 3 Drop Out Vases

In this instance, I was ready to try a new technique in glass fusing.  I wanted to make a different kind of vase, other than a draped handkerchief style.  I had seen pictures of cool vases that looked thinner with truly cylindrical walls but didn’t know how to make them.  So began my intro to dropped vases.

With a dropped vase, you start with a thick flat sheet of glass and suspend it over a ceramic ring (circular or square) that has a hole in the middle.  (The ring needs to be on stilts above the kiln shelf)  Heat the glass up in the kiln to around 1330F.  The center of the glass will slowly drop down through the ring.  This creates the basic vase form. 

Now for some details…

The general rule of thumb is that every 3 mm of glass can drop ~2 inches.  Knowing this, my first attempt used 2 layers of 3mm glass.  Base layer was a 8″ clear plate.  The top layer was a mix of blue and purple segments along with some grape frit to fill in any gaps.

Fig 2.  Glass segments laid out before full fuse.

I did a standard full fuse sequence (to 1460 F) to fuse this into one thick glass plate.

Now I was ready for the drop out phase.  I propped the 8″ glass disc on my ceramic ring with a 4″ center hole.  Since my glass was 6 mm thick, I theoretically could allow for a 4″ drop.  However, I was very nervous and opted to only use 3″ posts.  I was afraid my glass would drop too much, thin too much, and actually collapse or open a hole in the center.

Fig 3.  Set up in kiln before drop fuse cycle.

For my first attempt, I only went to 1300F and held for 15 minutes.  I was peeking into the kiln quite a bit.  I discovered it was really hard to tell how far down the glass was drooping.  Was it hitting the kiln shelf?  Once you think it’s dropped enough, you need to drop the temp as fast as possible to an annealing temp of ~950F.  If you hold at high temps, the glass will continue to melt and let gravity do its thing.  To speed the cooling, I opened the kiln top several times until the temp was down to around 1100F.  I did find out that even Kevlar gloves will start to singe if you hold them near the kiln opening too long!  A bit too toasty for my comfort.

Fig 4.  The final product placed in an iron stand.

Once everything was cool, I was able to see that I freaked out too soon.  The glass had dropped but not enough to really hit the kiln shelf and form a flat base.  That’s ok.  I had a nifty iron candle stand I pressed into service.  You will also note that the vase lip is rather wide and has dimples.  To support the weight of the dropping glass, the lip on all molds will tend to be wide.  My particular mold had small holes throughout the lip to add additional dimension (or dimples).

That was fun!  Let’s try again. 

Round 2 featured 3 layers of fully fused glass.  This thicker starting point was a boost to my confidence that the drooping glass had enough material to drop to the kiln shelf.  I used 3″ posts again but went a little hotter, to 1330 F, and held longer, for 20 minutes.

Fig 5.  Much better!  This vase can stand on its own or in a stand (as shown).  It also has enough volume to hold a votive candle.

Now I was ready to really go for it!  Last attempt used 3 layers of glass but I boldly used 4″ posts.  I was going to let this one drop further.

Fig 6.  Finally, a full drop out vase, complete with a foot.

Note that a foot formed by allowing the droop (or slump) to continue beyond the point of initial contact with the kiln shelf.  A little longer and things might have gotten dicey.  Remember, the foot cannot get wider than the ceramic ring’s hole or you can’t pull the glass vase out!

To succeed in dropping out, you do have to let go of your fears and just go for it.  It can be scary but you’ll figure things out.  I’m ready to get even wilder – more layers and larger drops.