learning what is required to cast glass

[Kara]

I have sculpted and cast bronze before. I have done the entire project from sculpture, mold making, wax, making the ceramic shell, pouring the bronze, chasing the sculpture and patina, to finish. I realise that there are simularities to glass casting. :teacher: I haven't had it explained to me about what happens after the ceramic shell has had the wax melted out of it, the process that remains to pour the glass in and how the process goes after that, like the annealing, wether you put it into a kiln. Any book recommendations?

[Dennis Brady]

I have sculpted and cast bronze before. I have done the entire project from sculpture, mold making, wax, making the ceramic shell, pouring the bronze, chasing the sculpture and patina, to finish. I realise that there are simularities to glass casting. :teacher: I haven't had it explained to me about what happens after the ceramic shell has had the wax melted out of it, the process that remains to pour the glass in and how the process goes after that, like the annealing, wether you put it into a kiln. Any book recommendations?

Glass Casting & Moldmaking by Boyce Lundstrom would be one of the best to start with.

[Planet Glass]

Have you considered pâte de verre? I am taking a 2 week-end class. We do the mold thing, then then we place crushed glass in a refractory mold, and allow it to melt in a kiln.

[Dennis Brady]

Have you considered pâte de verre? I am taking a 2 week-end class. We do the mold thing, then then we place crushed glass in a refractory mold, and allow it to melt in a kiln.

You can also do "freeze and fuse" castings that allow you to use anything (even jello molds) for mold casting.

[Planet Glass]

Does this work for large complex projects? I can see for pendants, but for a figurine?

[Planet Glass]

To answer your question, because of the high viscosity of molten glass, small detailed projects are best done by pouring crushed glass into the mold. The size of the frits and the kiln temperature will influence the final appearance of the glass, ie, how clear the glass will be, and the amount of bubbles within.

The frits are made into a paste with water and a binding agent, that can be white glue, gelatin, or gum arabic.

[Dennis Brady]

Does this work for large complex projects? I can see for pendants, but for a figurine?

In theory yes, but in practice tall objects can sag badly during firing. This effect can be minimized by using significantly faster ramps above 1000F (I use 1500 dph), but can't be completely avoided. They're usually better done in fixed molds. I've had better casting success pour filling molds or drip filling from a crucible (same method as for pot melts). Drip filling requires a relatively tall kiln (pottery kilns are excellent for this) but pour filling can be done with any kiln capable of producing enough heat to melt glass in a crucible.

Pouring molten glass into a mold is as simple as pouring molten metal. Just melt that glass and pour it into the mold. That's the easy part. The difficult part is producing a mold with enough sprues and vents to allow the glass to fully fill the mold. Molten glass is more viscous then metal and is thus more likely to trap pockets of air between the glass and the mold.

[Dennis Brady]

To answer your question, because of the high viscosity of molten glass, small detailed projects are best done by pouring crushed glass into the mold. The size of the frits and the kiln temperature will influence the final appearance of the glass, ie, how clear the glass will be, and the amount of bubbles within.

The frits are made into a paste with water and a binding agent, that can be white glue, gelatin, or gum arabic.

An alternative is to use glass with a lower viscosity (like Gaffer) which melts at a lower temperature and becomes thin enough to be cast into relatively fine detail.

[Kara]

Thank you I will read through this information and get the book. :magic: and like magic I will get back to asking more questions. Thanks

[Kara]

The best option for me to learn this would be a weekend course at pacific art glass in gardena, it's 2hours plus traffic. if youv'e been to LA or Orange county since Mexico moved here you would know the plus traffic means plus 1 hour or more to the 2 hours and that's just to get there, it's worst coming home. At $4.00 a gallon in gas, to sit in a parking lot. I think reading a book and forums are my best bet. Unless, anyone knows of classes towards Palmsprings, Even going to Las Vegas would be easier than the LA choice. I really want to learn it's really quite frusrating. The nearest stainedglass store doesn't teach it and that's 45 min. away.

[Dick Ditore]

Another good book is Pate de verre and kiln casting of glass by Dan Fenton and Jim Kerwin. We will be offering some casting classes. Just setting things up now. Not in Palm Springs, but easier to get to than LA!

Dick

[bert weiss]

Much lovely work is done by flower pot casting in to a refractory mold. With this technique, broken glass is placed in a pot which is heated such that the glass melts and drips down to fill the mold. Ceramic shell is not what is used though. When devising glass molds, you have to take in to account mold contraction during the cool down. Glass can break from the wrong mold setup. You also need to use a mold material that doesn't stick to glass.

Helen Stokes from Australia sometimes teaches her technique for this style of casting in the USA. She has a unique way of building her molds with fiberglass and investment. I have seen large goblets that she made this way.

I am not familiar with the book scene. Fenton and Kerwin wrote a book, but I don't know what techniques they cover.