Glass, and products made from glass, are created on a Glazier's Bench. Potash, lime, and sand are heated on the bench to form melted glass. The melted glass may then be worked into a number of different products: glass rods, glass jars, sheet glass, glass pipes, and glass torches. By using white sand instead of regular sand, you create jeweled glass, which is used to make fine glass rods.
You can also make mirrors from sheet glass and silver powder if your Sheet Glass Fabrication skill is 7; and if you have Lab Construction 1, you can make thermometers from glass rods and quicksilver.
A Glazier's Bench runs on charcoal. The temperature of the bench (in degrees) is displayed in the window, and at any time you can choose to add 2, 6, or 12 charcoal.
Adding charcoal causes the Glazier's Bench to slowly heat up over a period of about 100 seconds -- the more charcoal you add, the faster the temperature increases. The temperature will remain constant for another 100 seconds, and then begin to cool off. (There is no way to cool a Glazier's Bench apart from waiting.)
If, during the heating-up phase, you add charcoal a second time, then the temperature of the bench will jump dramatically at the end of the heating-up phase. These jumps are useful when you are first starting the bench, to get it quickly to the temperature you need, but are usually disastrous if you cause one while you are making an item.
While glazing, you will need to maintain the temperature of the bench within certain ranges; if the temperature goes outside this range, the item you were fabricating is destroyed.
Every Glazier's Bench functions slightly differently, though it is not character-dependent, and the difference can be easily measured and accounted for.
The bench runs in heating cycles of 100 TeppySeconds, with a cycle starting each time you add charcoal. After adding charcoal, the temperature of the bench will rise a certain amount each 'tick' (10 TeppySeconds) for a certain number of ticks. The total amount by which the bench temperature rises after adding 2 charcoal is called 'HV' (Heat Value). This value is different for each bench.
If you do not add any more charcoal within 100 TeppySeconds after the last time you added charcoal, the temperature will start dropping a fixed amount every tick. This value is called 'DV' (Drop Value).
You can have multiple cycles going at once; the effects are added together. However, for any two cycles that overlap by more than 10 TeppySeconds, the temperature will jump at the end of the first cycle in proportion to how much time the two cycles overlap by. That is, if you add 2 charcoal, wait 1 tick, and then add another 2, the temperature jump will be far greater than if you waited 6 ticks. The actual amount of the jump seems to be the overlap (in TeppySeconds) times the amount the bench would normally rise in 1 tick.
To calculate the HV and DV for your bench, add 2 charcoal, and record the temperature changes. For example, you may see the temperature increase as follows: 0, 14, 28, 42, 56, 0. You can't calculate DV from this, since it went straight to zero - the DV may have been greater than 56. But from this data, the HV of this bench would 56.
To get DV, get the bench temperature up to at least 400 or so, and then watch the temperature drop. For example, if you add 2 charcoal, wait 1 tick, and then add 2 more, you may get the following numbers (notice the jump): 0, 14, 42, 70, 98, 112, 1368, 1211, 1054, 897, 740, 583, ... In this case, the DV is 157.
In order to make glass items in a Glazier's Bench, you must have melted glass present in the bench. Each bench can hold a maximum of 50 melted glass, and you cannot create a glass item unless you have more than 19 melted glass in the bench. So your first step is to melt lime, potash, and sand into melted glass.
Each unit of melted glass requires 2 potash, 1 lime, and 10 sand. If you need to make fine glass rods, use white sand instead of regular sand. (Note, however, that you cannot have both regular glass and jeweled glass in the same bench.) In order to create melted glass, the bench temperature must be at least 3200 for regular glass, or at least 4400 for jeweled glass.
Once you have melted glass, you can start creating glass items. While creating rods, jars, pipes, sheet glass, and torches, the temperature must stay between 1600 and 2400. If if goes outside of this range, the project is ruined, and you lose the melted glass used to create it.
Remember to watch the bench temperature! Use a timer (either a kettle or Tanith's Windows-based timer app, and set it to roughly 1m45s) to keep track of when to add charcoal.
Sheet glass takes 120 seconds and is difficult to make; if you fail, the sheet breaks and is lost. Success or failure is based on your Sheet Glass Fabrication skill which, like Stone Blade Fabrication, starts at 0 and can eventually go as high as 7. Your skill level has a chance of increasing every time you failed to make a sheet of glass, so it will take some time and materials to get your skill level above 0. At skill level 7, you will no longer randomly break sheets of glass, and you will also gain the ability to create mirrors at the Glazier's Bench.
To create mirrors, your Sheet Glass Fabrication skill must be at level 7. You will need 1 sheet glass and 200 silver powder for each mirror, and you must keep the bench above 5000 to insure that the silver powder doesn't blow away, ruining the mirror.
Note: The sheet glass you use for the mirror must be in your inventory, not in the bench!
To make thermometers, you must have the Lab Construction 1 skill. You will need 3 glass rods and 10 quicksilver for each thermometer. While making the thermometer, you must keep the temperature above 2400. The bench used to (and perhaps still does) tell you that you need to keep the temperature above 1600 -- this is technically true, but there is still a chance of losing the thermometer between 1600 and 2400. The lower the temperature is below 2400, the higher chance you will have of losing the thermometer. Making a thermometer takes 60 seconds.
Note: The glass rods you use for the thermometer must be in your inventory, not in the bench!
As a side note, Lab Construction 1 is very expensive. It will be far cheaper to simply find someone who has the skill to trade with, as there are people who will trade thermometers for at or near cost. If you do decide to get the skill on your own, consider spending 2 mentor points to halve the cost with Scholarship.
(See also: Guides)