Rolled glass

What is rolled glass?

Rolled sheet is made by passing molten glass through rollers to achieve some uniformity of thickness and sometimes to give pattern or texture to the surface.

• It can be rolled horizontally in a continuous sheet similar to float glass, but supported on rollers instead of molten tin. The surface and thickness will be somewhat more uneven than float. Sheets will be cut to size and the edges will be sharp. Spectrum sheet is made this way, as is Viridian DecorPattern, (formerly Pilkington Texture)
• It can be drawn vertically before passing through rollers and cut to length. Artista is made this way.
• It can be ladled onto slabs and passed through rollers as separate pieces. All or some of the rounded edges may be retained or cut off. Bullseye and Uroboros is made this way.

Important:  rolled glass has no tin deposit on its surfaces. Tin deposit is confined to float glass.

Edge of stacked rolled single colour art glass

Rolled glass is made in a wide range of grades, including

1. Products by Bullseye, Schott-Desag, Spectrum, Uroboros and others with various levels of certification as to compatibility.

2. A wide range of sheet of similar colour but lacking any warranty as to compatibility.

3. An extensive range of coloured and textured glass for leadlighting.

4. Commercial figured or textured glass, both coloured and obscure.

All of these products are soda lime glass with varying COE. All are suitable for slumping or bending as a single piece, but many require testing before fusing two or more pieces together. 

Stringer (strands of varying diameter) shards (broken pieces of glass) frit (finely pulverized glass) are used as decoration or for colour contrast.

These will generally be made from sheet or from the same melt as the sheet.

Patterned ‘clear’ glass

This glass can be:

• Commercial sheet with a composition similar to clear float, so can be worked at similar temperatures; but may not be compatible with clear float. Viridian DecorPattern products are of this type.
• Part of the range made by art glass producers. May have different COE to other products from the same maker.

All of these glasses can be bent, slumped or fused.

Firing can affect the pattern: the higher the temperature the greater the change.

• The combination of patterns and processes are too numerous to detail, but one example of what can be achieved is:  

Two pieces of reeded glass, fused together with the reeded faces touching but at right angles to one another can produce a regular pattern of bubbles where air has been trapped in the spaces.

Coloured glass

This type of glass falls into a number of categories:

• Commercial patterned or textured sheet.
• Coloured ‘art’ glass as used for leadlighting.
• Tested compatible/fusible sheet.

All these glass types are suitable for kilnforming. They can all be bent and slumped.

There is the same compatibility problems as with other glass when fusing. They may have different COE or viscosity curves: may not ‘fit’ together.

They can slump or fuse at up to 20°C, 30°C, even 40°C lower than float.

Different colours of the same ‘type’ glass may work best at different temperatures.

If your imagination and ‘eye’ can conceive a way to combine disparate types or colours, give it a go: but, TEST FIRST.

 A problem peculiar to fused coloured glass is where a mix of light and dark colours are fused together and exposed to extremes of cold and heat: such as in windows facing north or east in the southern hemisphere (south or east in the northern). With dark next to light, the dark piece can absorb heat so much more rapidly than the light or clear piece that differing expansion rates can crack the panel.

Putting it behind a sheet of clear float can greatly reduce the risk. This is one up for leaded panels over fused.

This is much less of a problem with painted panels where the colour is only ‘skin deep’, only on the surface: the underlying glass all has the same heat absorbing ability.   

Coloured ‘art’ glass

This form of art glass comes in a wide range of colours and at widely varying prices.

• At the top of the price range are  ‘Tested Compatible’ (TC) products, where one pays the maker for doing the compatibility test.
• Next down in price comes the products which may appear similar to TC sheet but which do not bear a TC label. They may bear other labels which may imply some assurance of compatability.
• Lower again is the wide variety of leadlighting glass which was used for kilnforming before the ‘hobby’ market expected instant results and no failures; for which they were prepared to pay.

Which level one chooses will depend much on ones budget and one’s spirit of adventure. They are all available from outlets supplying the leadlighting craft. 

It is important to remember that a label signifying some level of compatibility applies only to those sheets bearing the same label, and not with sheets bearing any other label: still less with a sheet which looks the same but doesn’t bear any label at all. Maybe the label has fallen off, but equally possible is that it never had one at all, and for a reason.

With the exception of those sheets bearing a makers label, glass of similar colour or pattern may be made by more than one manufacturer. The likelihood of them being compatible is uncertain.

When in doubt. TEST.

Be aware of how glass manufacturers describe their glass standards. One maker uses two labels, 'Tested Compatible' and 'Fusing Standard'. This latter term is really a marketing blurb without meaning, as there is no 'standard' governing glass for fusing. This same maker advises in the fine print to test for compatability, so buyer beware!

Locally available glass ranges

Here is a listing of rolled sheet available in Australia. Others can be added at any time. They can be new products, or existing products re-named.

For fusing, where the compatibility tests have already been done, the range of makers is small but the colour range is vast. The individual sheets will carry a label certifying to it being compatible with other sheets bearing the same label.

Other sheets not bearing such a certifying label can be equally suitable for kilnforming but the user will need to do their own compatibility tests. 

The makers of most of these products produce data sheets to help you use them.

Youghiogheny Glass, made their ‘Easy Fuse Float Fit’ range compatible with the COE 82 float from PPG of Carlisle Pa. (formerly Philadelphia Plate Glass), but still advise compatability testing.

Wise advice, considering the chances of getting float of known COE; and particularly from that particular maker.

PPG is also the maker of ‘Starphire’ float, so it’s possible that the colours could be used with it. However, as Starphire is becoming somewhat of a generic term for the type, the piece one purchases could not be COE 82 material at all. TEST.

Early 2008 saw the arrival of the Shearer “Slump and Fuse Colours” range with a COE of 84.

There are now available in Australia ranges of fusible glass having COE of 96, 94, 90, 84, 82: all claiming some level of compatibility within their product range. Where will it end.

Avoiding confusion in the studio

Certified Compatible sheet often comes at a high price. At the studio level the need for accurate identification of each piece of glass becomes more critical the greater the number of disparate ranges with which one works.

Equally important is that each merchant has foolproof systems in place to ensure correct identification of every piece from receipt to delivery. The end user has a vested interest in seeing that this occurs.

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A colourful collection of rod and tube.

As well as those from Bullseye Spectrum and all the other suppliers of kilnforming sheet, there are available other brands of glass rods stringer and frits for bead making, in soda lime or borosilicate. They include Moretti (Effetre)  Kugler Kokomo Northstar Glass Alchemy, and can have COE up to 104 and as low as 33. Woe to the kilnformer who uses these products for decoration on sheet glass.

Information on glass suppliers