Glass Bead Making : Full Professional Grounding Introduction Class Pt. III

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Work Room chat:
I think I won't be announcing the release of my written tutorials through The Work Room's blog post anymore. I just felt that it has the effect of cluttering my jewellery journal! :P Instead, I'll just add the icons on the right sidebar which will link you to the source and just email me for anything else la! ;)
Update: Hhhhmm....ok, maybe not. Cuz that would involve some alteration to the blog layout... :/
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Part V,Part IV.Part II, Part I

Apart from the torch setup, understanding the properties of glass is also part of the game. I won't be going into details on the chemical properties and what not cuz even I don't know them in details. I only know enough for an understanding of lampworking, and even this I did not know about during the class. It was after reading Making Glass Beads by Cindy Jenkins and coupled with my experience throughout the class that I finally know what I did wrong. (The funny thing while attending all these classes is doing what I shouldn't be doing which ended up me learning what I should do but rather what I shouldn't! LOL....)

I've mentioned about the COE of glass before. And just a recap, it's the coeficient of expansion, simply put as the rate at which the glass contract and expends. I didn't quite understand this while I was doing glass fusing with Uncle Ghee back then. Only that you must use glass of the same COE while fusing them or risk cracking them up!

But now, after the lampworking class, I totally understands now! :D

Well, basically, as glass cools from its molten state, the outside cools much faster than the inside as the heat travels so slowly through it. Because of this difference, stress is set up between the outer cooler layers and inner hotter ones and we all know what stress can do! It cracks you up! Well, not you but yeah, the beads cracked.



This was a necklace that Diana made which cracked on the plane to New York. I think it must be during the time when she first started making glass beads because she did in fact went to America to further learn on glass bead making because information was scarce in the UK back then. Erm, like how I flew to UK to learn also? LOL..... XP



Which is why these beads cannot be guaranteed for sale if you do no anneal them. Therefore, having a kiln is a must in lampworking. Even if they do not crack now, it's just a matter of time before they crack. A small entry level kiln averages around £300. (Yes, you may add this amount the the previous one)




Although it has been said that beads no larger than 10mm might be able to survive by firing it with the orange flame (oxygen) for a good some minutes and then plonking it into a terra cota pot with vermiculite. Well, it's still better to anneal with a kiln lar....



What annealing does is holding the beads at a temperature for a period of time long enough so that it evens out any tensions caused by working it.

The interesting about hot glass is that one part can be stiff whilst another part is runny. This allows one part of the bead to be worked on at a time while the rest is stiff, providing very good control.(Trust me, it's not easy to control molten glass!) That is how encasement is done without movement of the underlying core. Encasement is where you see the patern sinks into the surface of the bead. Encasement is done by adding a layer of clear glass on top of the pattern. Erm, something like having a glass frame around an object?





Now, you need to also study the flame from the torch when you work with glass and fire because glass behaves differently at different temperature and the temperature is different at different parts of the flame.





This is at the cool outer part of the flame, used for keeping the bead warm but still stiff because warm glass cannot stick to cold glass. Also, you use the part to warm up your glass rods before melting them. Directing them to the hotter part of the flame directly will cause thermal shock and glass to crack. Something like running glass jars from the fridge with warm water?





The part of flame where the glass rod is the slow heating part of the flame, used for gently melting the glass. And the part where the bead is, is the outside of the flame. This is where you let the bead cool between operations so that the bead can be stiff to work on and yet warm enough not to cause thermal shock.






This, (somewhere at the centre of the flame) is the fast heating part of the flame for heating the outer skin of the bead.



And this?





....... is a bead I made which cracked from thermal shock because I let it cool to suddenly and did not keep it sufficienly warm during operations. :P