These pretty lead crystal hearts are SO easy it (almost) feels like cheating. The first thing we need is a heart shaped lead crystal vase. I keep a sharp eye on thrift stores the month after the holidays, and save up whatever I find. This process works equally well on other types of lead crystal vases however, so if you don’t have a heart shape specifically, you can still use this info on other shapes of vases.
So, how do you know if it’s lead crystal? Well, you can do the time honored ‘ping’ test, flick it with your fingernail, if it pings with a ringing tone, it’s likely it’s crystal. Also, is it heavy for its size? This one may take some practice hefting other vases to get a feel, but crystal is usually thick and heavy.
Step 1: Cut the vase into slices
This will require a glass saw of some type. 3/8″ thick slices are a good target, any thinner than that and the slices will be quite fragile and you’ll lose some to breakage.
Step 2: Fire polish the hearts
For best results, clean the sawn surfaces of the hearts very well with a wire brush and dish soap, you want to get them as clean as humanly possible. Next is fire polishing. But before that, some back ground information about lead crystal and fusing with lead crystal.
Lead crystal is a type of glass that uses lead in the original batch formula to clarify the glass and to act as a flux. When I say batch, I mean at the factory when they are loading the furnaces with powdered ingredients to make the glass. This is important so that you understand that the lead is a molecular part of the glass structure. This is important because it allows us to use lead crystal in kilns without worrying about the lead ‘escaping’ or causing ‘fumes’. Home kilns simply do not have the energy or heat available to separate the ingredients of glass back out, so fusing with lead crystal will not cause problems.
The second thing to know is that the lead in the glass lowers the melting point dramatically, let’s look.
So, you can see that a fire polish temperature of between 1250 and 1350 is ideal. I used this schedule:
375/hr to 1350 h 6 minutes
9999 to 800 h 20 minutes
200/hr to 600 and then off
The nominal anneal temperature of lead crystal is around 800F. Because we don’t know the manufacturer of the vase, we are doing a little guess work. However, in our favor is the small size of the hearts, which should anneal at the natural cooling rate of the kiln, as they have very little mass or volume. By holding at 800 and cooling slowly, we make sure we cover the annealing range, even if we don’t know the exact temperature. For larger pieces of lead crystal, more study and investigation would be necessary.
Step 3: Enjoy! These sparkly hearts are a great Valentines gift, but they are popular any time of year, add a nice ribbon and keep a few on hand for gifting (or selling) occasions!