Equipment/Glassworking
Class Red equipment: Do not use without specific training.
(More about equipment classes)
Contents
Glassworking - General
Summary
This is a kiln and hot torch to work with soft glass - fusing and forming rather than blowing although if there's interest in the latter let us know!
These are Category Red tools: induction is mandatory.
Owners
Health and Safety
Formal Risk Assessment: Glassworking
Glassworking involves both sharp, fragile raw materials and extreme heat. Most risks are obvious - sharp glass can cut you, and the hot torch and kiln can both burn. There are, however, a few non-obvious risks to be aware of:
- When working with the flame your glass will be glowing red hot or hotter, but very shortly after you put a rod down to work with something else the glass will cool to be visually indistinguishable from glass at room temperature. It may at this point still be hundreds of degrees centigrade! Do not pick anything up while someone is working at the torch without asking, you like your skin and want to keep it.
- Glass rods can stress-crack at the tip when heated. Point rods away from you and always wear eye protection - the glass won't travel far but you don't want it in your eyes.
- When using the kiln you will have to leave it to cool, unless you plan to be in the space for ten hours straight. Please leave some appropriate indication that the kiln is hot!
Other risks will be covered during training - working with hot glass is perfectly safe as long as basic procedures are followed.
Equipment
Our kiln is a Paragon SC2 kiln with an included bead door and window. This kiln includes a controller capable of multi-step programs with controlled rate heat up and cool down cycles. It has a maximum temperature of 1100 degrees centigrade, enough to fire some metal clays and work with most kinds of glass, but not enough to act as a metal furnace.
In addition to the kiln we have a HotHead gas torch, along with the appropriate connection kit to run off bulk Propane gas rather than the normal MAPP cylinders (these burn slightly hotter, but are much more expensive as they're not available in larger quantities). The torch is mounted on a height and angle adjustable stand suitable for bead work when sitting on the low stool that should be lurking around the glassworking station.
For bead working we have a variety of mandrels, bead release that can be cooked in the flame and a wedge shaped graphite marver.
For art glass and strip-work we have a set of cutting tools along with a slump mould for making very small (9x9cm) glass plates.
It is important that these tools remain exclusively used for glass, please resist the temptation to use the cutters, pliers etc for other materials!
Glass Stock
We have a selection of glass rod, sheet, stringer and frit.
The large pots of glass are bought as a random selection for about ten pounds per pot, they consist of offcuts of bullseye COE90 (coefficient of expansion, only important in as much as all glass in a particular piece should have the same number to prevent explosions!) in various thicknesses. Bullseye COE90 glass will tend to form 6mm thick sheets due to surface tension so stack your strip-work to that height.
In addition to this we have a small amount of specific colours of bullseye COE90 glass currently in clear 9x9cm sheets and larger plates of Makespace colours. We can buy at a discount from a couple of online suppliers even when ordering small quantities (a side effect of buying all the kiln and other hardware in one go!) so post to the list of you want anything in particular and we can order it.
For bead making we have a set of clear and a set of mixed coloured COE90 rods, along with tubes of frit and a selection of random stringer (1mm thick rod) glass for decoration. Prices for these are TBD, but will be printed on a sheet near the glassworking station when determined (something in the order of a pound per full rod, that would work out as around 20-40p per medium size bead, each of which would take about half an hour to make).
Location
The glassworking kit is in the corner of the main workshop nearest the stairs up to the cafe. Please keep work to the area covered by the steel sheeting - we're not working with enough material to cause a serious problem otherwise but it helps keep everything tidy. As it currently stands the station is only suitable for one person, or two if both are working together. It would be asking for trouble to try to have someone using the table to cut glass at the same time as someone was working with the torch, so please don't!
Scheduling
Unlike many pieces of equipment in Makespace the kiln requires a considerable amount of uninterrupted time to run. We don't have a formal booking system in place, so for now I suggest you email the list if you propose to use it. For example, if you're doing bead work you will be spending between half an hour and two hours (depending on how many you're making) using the hot torch, with beads being placed in the kiln at a holding temperature while the others are worked in the flame, then running an annealing cycle which will cool down under computer control for a couple of hours, then cooling to ambient before the kiln becomes available for other users. It should be possible to get two runs in a day, as long as the first is done in the morning, but no more than that.
While the kiln is a model which should be possible to leave unattended please ensure you can be in the space for the duration of its active firing cycle - it's fine to leave once the heating elements are off and the kiln is cooling to ambient but for now please hang around while it's actually firing. We may be able to revisit this at some point after it's had a track record of not bursting into flames etc etc.
How tos
How to make glass beads
If in doubt, consult the Kiln manual(s), and/or speak to one of the owners (or other trained users)!
Preparation
- Fire up kiln
- turn on, wait for "IDLE" to appear
- use Programme 1
- TODO which buttons to press in which order!
- Get bead release to correct consistency
- The bead release dries out over time. If it is too thick and lumpy you need to add water to it. Screw on the lid and shake the bead release well to get rid of all the lumps. It should be the consistency of a thick smoothie.
- get everything (mandrels, tools, glass) ready and laid out so you don't have to bend over hot flame to fetch it later
- wait till kiln is hot enough
Glassworking
- turn on flame
- TODO which way the valves work etc., where to put the lighter
- Coat the mandrel
- tilt the bottle before you dip
- dip only once, turn the mandrel while it is still in the bottle
- without touching the sides of the bottle, and pull out the mandrel
- without touching the sides of the bottle
- sit on the small stool, resting your elbows on your legs; rest the mandrel on your little finger, and use thumb and index finger to rotate it
- dry mandrel in flame
- heat glass rod evenly
- beware of splinters -- point rod away from you and other people
- the hottest part of the flame is [TODO]
- gently roll molten glass onto mandrel
- the glass rod should be in the hottest part of the flame, the mandrel slightly further away
- do not apply any significant force -- this will pull off the bead release
- do not let the glass touch the mandrels directly!
- when done, turn off flame and insert mandrel into kiln
- don't touch the walls and especially not the thermocouple at the back wall
- repeat as needed for as many mandrels as fit into the kiln
Wrapping up
- "skip segment": press button [TODO]
- stick around till the cooling process has finished, and the kiln returns to "IDLE"
- turn off kiln, and add note saying it's still hot (which it is!)
- leave mandrels in for another [several hours] so they can cool down to room temperature
- don't forget to pick up your beads later to make space for other people!
Finishing
tips & tricks for how to get beads off mandrel and what to do with them then:
- take the forceps from the toolbox to grip the mandrel (not the glassbead), and grip the bead with your other hand and rotate
- take care not to bend the mandrel! this is particularly relevant for the thin mandrels
- wash the beads to get the bead release off
- there are [these things with teeth on] to remove the bead release
- using a shoestring might work, too; at least for big holes
How to fuse glass together
TODO
Other uses of the Kiln
TODO
