Monday, June 8, 2009

Why Hard Glass?

Well, the weather outside is delightful... And I figure, why not take a moment to discuss the glorious benefits of hard glass?

This is prompted by the concerns of customers that our glass pendants are fragile. Well... Ours are actually quite strong, and can withstand a good amount of abuse, just short of dropping them onto a hard surface at some distance :) Paul and I perform strength tests on our glass designs before we sell them, because we have nieces and want to be sure our designs are safe. Most of my new designs are worn overnight to ensure they are not carelessly broken easily. Aside from a dragonfly wing jabbing into my neck(and not breaking, mind you), I’ve been very successful with this :)

I think people are just so used to the cheap imports that aren’t properly formed and annealed. This is a crucial step, and something to consider when you buy handcrafted local art glass vs. manufactured mass-produced imported glass. Yes, it’s cheap, but you really do get what you pay for. Our glass art is made to last, not the art equivalent of a single-use camera :)

Additionally, we use borosilicate glass in our Shepherd Creations (had to add that at some point, right?), which is more durable than “soft” glass. Glass itself is a fantastic medium capable of transforming into sculpture, beads, pendants, vases, just so many options in glassworking! Soft glass is created in so many more colors, but it’s much more sensitive to rapid heating and cooling, and you pay for it in the way of flying bits of hot glass when you treat it the wrong way. Boro is sooo much more easygoing, forgiving, and really quite durable. It’s what your traditional baking dishes are made of, and you know those don’t always break when you drop them either.

Which is melted with a furnace? The primary difference that gets folks confused is that boro glass is most commonly melted using a torch, at high temperatures around and upwards of 2,000 Fahrenheit. Soft glass, on the other hand, can be melted very easily at much lower temperatures, closer to 1,100 F. Soft glass is the kind used to make large vases and many of the chandelier sculptures you will see in Las Vegas, and it’s often done using a large propane or natural gas furnace. Its low temperature allows you to use just one gas, instead of needing oxygen to help it burn hotter like torchwork.

Soft glass can be used both with a torch and in a furnace, though the torch requires a much smaller flame to melt soft glass than to melt borosilicate glass. Flame work done at a torch also goes into the kiln for annealing, and soft glass is very susceptible to stress fractures due to rapid disproportionate cooling. Glasswork done on a torch needs to be kept warm throughout to avoid creating cooler gradients, and this applies to all kinds of glass, both soft and hard. Soft glass is often melted in pots and then kept hot and remelted while spinning in a furnace, then shaped and cooled, then annealed like borosilicate, just at lower temperatures. There are many types of glass; from super-soft leaded glass you can almost melt with a candle, to the hard glass we use that requires propane and oxygen both to achieve a clean super hot flame. We prefer to use a torch because we are in love with borosilicate. Can you tell?

This is meant to be a brief blog post on how I feel about boro on a late Monday night. I may be even more excited about it when I’m more awake, but we’ll save that for another time. Thanks for reading my blog, and post some comments sometime, won’t you?

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