Cracked or broken glass is distracting and always sad to see in a clock or barometer when it is so easy to replace and makes such a difference to the appearance.
It's cheaper to source FLAT GLASS from your local glass merchant or glazier assuming that you can fit it yourself but ask them to ground the edges to make it safe to handle. If you're a purist and want to use old glass taken from an old picture frame with its minor imperfections and slightly greyer appearance, you might find the local glazier reluctant to help because old glass can be brittle and unreliable to cut, but he might be persuaded to do it on a no-liability basis in case your piece of glass cracks while he's working on it. Flat rectangular pieces to match the panels found in the doors and sides of Vienna regulators, German springers and square-dial bracket and longcase clocks can be sourced locally, too. Take the old pieces to match the thickness because clock glass is thin by modern safety standards so your dealer might not stock it. If he can't help, try a picture-framing shop instead but expect to pay a 'high street' premium and don't opt for the modern non-reflective type! If that also fails, then I can supply replacements by post up to 250mm square in 2, 3 or 4mm thickness, or 6mm. Flat circular glass for mantel and dial clocks and some barometers can usually be cut locally, too. Expect to pay extra if you need a centre hole drilled (for a barometer set hand). On dial clocks, it's even more important to match the thickness of the original glass because thicker glass means more weight and more strain on the bezel hinge. Again, if you get stuck I can supply one by post in 2, 3 or 4mm glass up to 300mm diameter. Irregular shaped glass for longcase clocks with broken arch dials can be difficult to source locally but I can make these to order if you send me an accurate template.
Fitting glass to wooden cases and doors often involves nothing more than carefully prising out the wooden beading on the inside of the door, which is usually pinned in position rather than glued, and then pinning it back again to hold the new glass in position. Make sure it's fitted tightly or it will rattle every time the clock strikes. Circular glasses for dial clocks should be held with traditional plaster of Paris. You might need to experiment with the ratio of plaster to water as the 'standard' recommended mix tends to be too thin; you don't want to pour it into the bezel like you might into a rubber mould or it will seep past the glass - it needs to be stiffer. And you'll need to work very fast as it sets pretty quickly. Also bear in mind that plaster is quite heavy so the hinge will bear more strain.
Fitting glass to the door of a longcase clock is best done with brown putty but removing rock-hard putty from a fragile 200 year old clock door takes skill so it's better to send the door and I'll fit the new glass to it for you.
CONVEX GLASS is commonly found in mass-produced 20C mantel and floor-standing clocks with an English or German movement, in early dial clocks and in wheel barometers. Prices vary according to size and whether you need it fitted to your bezel. I can now also supply some square convex glass found in Art Deco clocks and even some rectangular convex glass but check the size with me first as there is a limited range.
BEVELLED GLASS is normally used in carriage clocks, four glass clocks, ships clocks, French clocks, barographs and in most aneroid barometers. Flat rectangular glasses up to 120mm in length and 3-6mm thick can be handmade to your exact specification. I just need to know the thickness, the length and width, AND the angle of the bevel (25°, 30°, 35°, 40° or 45°) if you want a good match. The top one in a carriage clock can be oval but I'll need the original glass or an exact template of the glass (not the size of the brass hole, which is smaller). Bevelled glasses larger than 120mm, suitable for four-glass clocks and barographs, can be made to special order. And do bear in mind that all of these are hand-crafted by a skilled artisan just like the originals. On a carriage clock some of the bevel is hidden on the sides by the rebate, but there's no rebate top and bottom so glasses I supply will have a fractionally shorter bevel top and bottom to compensate. That way, the bevel will look the same all round once fitted in the clock. The back door is different, of course, because the door frame has a rebate all round so if you want the glass for the door, tell me when ordering. Also , if it's a modern carriage clock, tell me if the edges are curved instead of straight, and the corners rounded instead of sharp, or it might not fit. Old glass tends to have a slightly grey hue and can be difficult to match so it more expensive. Modern glass has a slightly greener look about it from the side which the bevels pick up so if several glasses are chipped in the same clock, and you wish to replace all five for a perfect match, you'll get a discount. Normally, the finished glasses are shipped within a week so this is a very fast service without a premium surcharge. You should be able to fit carriage clock glasses yourself but I offer free advice or a fitting service if you need it.
Flat 6mm circular bevelled glass for, say, a ship's bulkhead clock, can be expensive if you want it fitted. Be warned, if you're determined to fit it yourself, make sure you give me the exact measurements. If you need a circular bevelled glass for an aneroid barometer, you will also need a centre hole for the set hand - I'll need to know the size. If you would like the existing set hand or a new one fitted, too, I can also accommodate that.
CURVED BEVELLED GLASS is found in oval carriage and four-glass clocks and can also be supplied to order but this is more specialised and therefore takes longer. It is also more costly - email me your requirements for a price.
OTHER GLASS. I can also hand-make small bespoke bevelled glass for other one-off projects unrelated to clocks, such as carriage lamps, lanterns, garden lights, and interior design projects. Just email me your specifications for a price, or send a damaged sample to be copied. For example, I have produced glass screens for gun sights fitted to many WW2 aircraft, including night fighters like the Spitfire, Mosquito and Beaufighter. My Gun Sight Mk2 replacement glass screen is hand-ground, just like the originals and it's the most accurate replica you will find anywhere. It's much more true to the original than the more expensive Canadian ones made on a CNC, which do not even feature a bevel edge, and so much more authentic than the poorly-fitting perspex ones selling for almost the same price, on which the bevel edge is highly-polished; mine have the smooth-ground finish of the originals, to reduce light reflections.