Knowledge Base

Frequently Asked Questions

Products

Product Qualities

Production

Other

Products

What should I do differently when I use SilverCoats™?
Mirror calls for a little extra care when used in stained glass projects, and SilverCoats are no different. You want to protect the silver coating from chipping during construction and from deterioration over time. Either avoid grinding or use a special mirror bit on your grinder (Mika ME-5F or ME-6F). If it's a copper-foil project, remove flux and patina as soon as possible. Then, remember to use a sealant. Your supplier stocks these inexpensive shellacs (Sprayway Mirror Edge Sealant is a popular brand). Follow the instructions, lightly spraying the edges and back surface of cut pieces. As with all mirrored glass, use a mirror mastic where adhesive is called for. These little precautions will assure that your SilverCoats stay looking brilliant in your projects.
Why did you discontinue that product?
There are any number of reasons why we choose to discontinue a product. It is never a simple decision, and it's always more complex than just "slow sales" There's usually a compounding production-related factor, such that equipment or scheduling limitations, combined with poor demand for the product, lead us to choose to "discontinue" production.
Do you ever bring back discontinued products?
Certainly. There have been many cases of products being reinstated to the standard line. It usually means we've solved the production issues that originally led to it's demise and feel demand is strong enough to warrant making it again.
Why are some of your products unavailable for extended periods?
Normally it's due to our inability to accurately predict the future. The nature of our process requires us to run an extended color cycle. That is, the colors must be run in a set sequence, and it takes months to go through the cycle. So, when we make red, for example, we make enough to stock and sell for the entire length of the color cycle—until we get back to red again. Sounds simple enough, but the longer the cycle, the harder it is to accurately predict sales volumes.

At other times, our capacities have been so overburdened that we've chosen to skip certain products in the cycle in favor of others. Knowing that we're going to be out of something, we might to choose to produce clear Waterglass® and skip orange. These are tough decisions, and they are extremely rare.
How do you decide on which new products to make?
We listen. Our market research is as sophisticated as chatting with glass users on the phone, at trade shows, and so on. Have some ideas? Needs? Daydreams? Give us a call, or better yet, send an Email!
Why don't you make a transparent black?
Black, by definition, is the absence of light. All light is absorbed. Anything that transmits light wouldn't be black anymore. We could make a very dark gray, but the darker it is, the less light it would transmit. Everything's a tradeoff.
Can I get a custom color made?
Probably not, but let's talk about it. On things we have the ability to do, we will do, with a sensible minimum order. For example, customers can order an iridescent coating or a smooth texture where one isn't normally available. But that's quite different from an altogether custom color. Our response to that depends entirely on what the color is, how much you need and your time frame. You'll have to call with specifics to get a better answer.
Can I get every color you make in any texture?
Not at this writing. Artique®, Rough Rolled, and Waterglass have broad color selections but generally we limit the production of rolled textures (Hammered, Granite, etc.) to colors that sell well enough to justify carrying the inventory.
Do you make Glue Chip?
No. Glue chip is a cold-glass process, that is, it's a treatment done to glass sheets long after they're produced. Many glue-chip manufacturers do use Spectrum glass, though. See the Dictionary for an explanation of how Glue Chip is made.
Can I order custom sheet sizes?
Extra thick or thin glass? At this writing, we can and often do produce, on special order, sheets of extended length, but not width. We regularly manufacture sheets measuring 24 x 60 to 24 x 72 inches or longer, custom order. Equipment limitations keep us from making sheets wider, however. Same goes for extra thick or extra thin glass, though we have some limited capabilities there. Call for more details.

Product Qualities

What causes the comet-shaped marks on the surface of some of your opal glasses?
We call them "seed tracks." In some particularly gaseous glass compositions, a bubble will form in the stirring bay ( the pool where glasses of different colors are stirred together). That bubble pops as it's drawn through the sheet-forming rolls, creating a "track" on the sheet surface. We make every effort to keep them to a minimum.
Why do you call it "T-Glass?"
When color changes are made in a continuous furnace, there is a transition that must take place between them. Example: In transition from blue to green, various hues of turquoise and teal are created inadvertently. Years ago, we called this "transition glass," or "T-Glass." As time went by, "T-Glass" came to refer to any glass product that falls outside our standard tolerance due to variance in color, texture, mix characteristics, or light transmission.
What's the best way to cut Waterglass®?
Score the glass on the back side (the flatter side) to ensure an even, uniform score. Don't forget to reverse your pattern if you want the wavy side out in the finished project.
Why does Baroque cut "differently" than your other glasses?
Baroque is very unique. In it we mix together two or more glasses of intentionally mis-matched compositions. The glasses, of slightly different expansions, "resist" being mixed together and don't homogenize easily. Thus, the characteristic reamy pattern and high-contrast mixes. Due to the nature of Baroque, the sheets have slightly more internal stress than other Spectrum products. Which means greater care is in order when cutting.
Some Spectrum sheets aren't 24 inches wide ... whyzat?
Sometimes the glass runs narrow, simple as that. Rather than throw it away, we put a few extra sheets in the case to make up any lost square footage to the distributor. Distributors vary in their methods of selling Spectrum® sheets that are less than 24 inches wide.
Why are most Waterglass sheets narrower than 24 inches?
The Waterglass® texture is created by stretching the molten glass ribbon as it exits the sheet-forming rolls. Grasp two ends of anything with some give and stretch it. Gets narrower, right? There 'ya go.
Why does the Waterglass texture seem to vary somewhat from color to color?
Different colors, even different densities of the same color, have different heat-retention properties, and thus, different viscosities at the same stage in the sheet-forming process. These properties directly affect the texture that results when the hot glass ribbons "stretched." We make adjustments aimed at consistency of texture, but you will see some differences on close examination.
Is there a front & back side to the glass sheets?
Absolutely! How can I tell which is which? In some products it's obvious, in others, less so. Generally speaking, the shinier side is the top or front side of the sheet. Rolled textures are always textured on the back side of the sheet.
Why do some products have more seeds than others?
In glasses that aren't intentionally seedy, the seed count and size varies with the nature of the glass composition. Some glasses, notably ambers, champagnes and purples, are naturally more gaseous in nature than others. Gas in the glass equals bubbles in the sheet.

Production

How do you make Waterglass®?
It is produced by over-stretching the glass ribbon as it emerges from the Forming Rolls, while it is still hot enough to shape. This stretching forms the natural "ripply" Waterglass surface.
How do you make Baroque?
Baroque is a "reamy" glass, whose texture is produced by stirring together two glasses of carefully mismatched compositions. See Cutting Baroque.
How do you make Iridescent Glass?
Immediately downstream from the sheet forming rolls, the hot glass is sprayed with a liquid metallic crystal that bonds to the surface, creating the colorful, shimmering reflections.
How do you make Ripple Glass?
Spectrum Ripple is also a natural texture. We operate the top and bottom forming rolls at different speeds, which sets up a 'jumping' tension between them, causing the dynamic ripple texture to form.
How do you make Seedy Glass?
Compressed air is forced into the molten stream in the forehearth channel. As you might guess, this makes the glass 'bubbly.'
How do you make Hammered, Granite, Ice Crystal, etc.?
These are rolled textures. Their patterns are embossed on the bottom forming roll, which textures the sheet as it passes through.
How are your Gold Pinks made?
We use a pink glass frit made from gold oxide. Frits are color-concentrated glass chips that can be sprinkled into the forehearth and melted right in the molten stream.
What do you mean by "Continuous" process?
The Spectrum process combines the four principle phases of sheet glass production (raw material introduction, melting, sheet forming and annealing) into one continuous process. Base glasses are melted in continuous furnaces, which are always full of molten glass. Raw materials introduced into the furnaces push molten glass out, forcing it, stream-like, down the forehearth channel, past the ladling bay, where secondary glasses are added by hand, and on to the stirring bay, where the combined glasses are hand-stirred together. Continuously moving, the glass then flows between the sheet-forming rolls and into the annealing tunnel. It's the only process of its kind in the world. Read more.
How do you actually get the color in the glass?
Color is created as part of the basic raw materials. Virtually any metallic oxide creates color in glass. Some of the most common are cobalt (blue), copper (blues & greens), manganese (purples), sulfur (ambers) selenium (reds & oranges), cadmium (yellows), chrome (green), fluorine (white opal) and nickel (gray).

Other

I bought a sample set awhile back, and it's never been updated like you promised ...
Ahem.... No, really, we make every effort to notify all registered sample set owners for every Sample Set Update. We publish the Update availability in our quarterly newsletter, The SCORE, and here, in our web site. You become a registered owner by returning the postage-paid card that came with your set. Updates normally happen in September, though we've been known to do interim updates during particularly prolific new-product years. Need to bring your Sample Set up-to-date? Refer to Samples for complete information.
How can I get my work published?
We'd love to see your work, and will consider it for publication in The SCORE, other publications, or here in our web site. We've even been known to use unsolicited work for posters and Spectrum T-shirts, or in our trade show display. Remember, though, get good photographs. We see a lot more bad photos of good work than the opposite, and simply can not use them. Incidentally, we also keep photo albums of art work using Spectrum in our offices, and share them with visitors and the like. If you'd like to be represented, just send the shots!
Why can't I buy my glass directly from you?
We make a lot of glass, and have to depend on a distribution system to buy in bulk, break down that bulk, and move it to retailers who take the same job a step further. Every step in the chain serves a critical purpose and meets a critical need. We protect those companies (distributors and retailers) by not selling directly to their customers, because we need them—to accomplish effective, wide-scale distribution of our products.
Do you give tours of the factory?
Every day, no charge. Actually, weekdays only, 8-4. We prefer you call in advance to let us know you're coming, and there are a few guidelines we like to communicate to you in advance (age restrictions, etc.) But the tours are really cool, and everyone enjoys them. Please come -- or take our Virtual Tour.
Can I get back issues of THE SCORE?
Sorry, we don't keep back issues. Here on the web, though, we intend to make past patterns available, as well articles of wide interest. If there's a particular item you need (pattern, article copy) and you don't find it here, contact us—we'll do what we can.
Can your glass be tempered?
Sure, but it might break in the process. Tempering is the process of putting the stress that we've so carefully annealed out of the glass, back into it. Successful tempering depends on the particular glass's ability to stand up to induced internal stresses. So, fairly simple glasses will temper fairly well (smooth cathedrals) and more complex ones may give you major headaches (Baroque). All you can do is try it on a small scale, experimenting with the tempering process, to find a set of time-temperature relationships that give you acceptable results on the given glass you're trying to temper. Acceptable results would be a rate of loss (breakage) in the tempering process that you could live with. The trial & error process will require close cooperation of the tempering facility you're working with.

Bottom line: art glass of any kind will not temper as dependably (low breakage rate) as float glass, because it's not near as "perfect," or flawless. But it can be done, and is done, fairly frequently. Consider lamination, too, when safety glass requirements need to be met.
What do your stock numbers mean?
Is there any rhyme or reason to them? We'll refer you to our explanation of our system: Classification.
Do you have patterns available of the glass work you feature on the site or in publications?
We have obtained permission to use the images as we have. You need to do so also. Please contact the artist/studio that produced the work.
Why don't you label your sheets?
Good question. There's really only one good reason: we sell to quite a few large-scale manufacturing firms. These companies are real producers, and any added step in their production process costs them time and money. Labeled sheets would mean them taking the time to remove each label, and they are decidedly against it. Segregating our production between labeled & unlabeled, to keep manufacturers from getting labeled product opens up a can of logistical worms that we don't want to touch. One of these days we may find the perfect compromise, but until then....