Repairing Old Damaged Glass


Repairing Old Damaged GlassGlass is fragile and prone to breakage, so it seems logical that it’s less possible to repair. A piece is either in prime condition or it’s damaged. And while repair is difficult, it’s not impossible.

There’s one example of a piece broken into a thousand fragments being skillfully repaired. On February 7, 1845, William Lloyd, after going on a drinking binge, smashed the Portland Vase, a fine example of ancient cameo glass. Restorers did such a fine job of reassembling and mending it that scarcely a trace of the breakage is visible today. This was, of course, a priceless piece, and the need of preserving an example of what had long been a lost art was great enough to warrant the corresponding expense.

Granted that few, if any, collectors have much chance of owning a Portland Vase. Sometimes it’s advisable to let a piece of broken glass remain that way or discard it—a few minor defects in an otherwise fine piece of glass can be minimized. To accomplish this requires skill and a wide variety of glass working tools. Such repairs aren’t for the amateur, but must be done by a professional restoration expert with a properly equipped shop. What a good glass repairer can accomplish in eradicating blemishes caused by time and use is incredible. With grinding and polishing wheels, a skilled restorer can remove all traces of nicks and chips.

Take, for instance, a wine glass marred by a slight nick on the rim. Skillful grinding and subsequent polishing will cause this to disappear entirely.

The same repairman can also regrind a glass lamp base that has slight chips along the lower edge. The same can be done with a piece of lacy Sandwich or pattern glass.

Replacing Decanter Stoppers

Repairing Old Damaged GlassClosely related to this work is a repair possible with decanters. Sometimes a stopper of the same type and period as the bottle doesn’t fit properly. If it’s too large, the repair is relatively simple. A restorer can grind the base of the stopper smoothly and evenly until it fits the neck of the bottle. Even the opening of the latter can be slightly enlarged by grinding. If the base of the stopper is too small, a sleeve of glass must be applied and then ground so that a firm fit may be insured. This repair is naturally not as successful, because it’s always obvious.

For those collectors trying to replace a decanter’s stopper, it’s important to match it to the tint of the decanter. In the case of Irish glass, there’s a difference in the tint of decanters made in Waterford and those made in Cork. Those from the former have a slightly smoky, bluish tint while those from the later a straw or amber tone. These fine differences in tone are only apparent to the average observer by close comparison, but if a stopper from Cork were to be fitted to a decanter that originated in Waterford, this slight difference in tint would immediately be emphasized and the original purpose defeated..

Grinding and Polishing Old Glass

Repairing Old Damaged GlassIn grinding and polishing glass to remove slight chips and nicks, a collector should be sure that the piece so treated should be rare and fine enough to warrant the expense of restoration. There’s also the chance that the piece may break or crack in the process. For example, a Stiegel-type sugar bowl has a very slight chip on the finial of the cover. Should the owner take the risk of the cover breaking during the restoration process or should he or she leave it alone? The chances of the cover coming through in perfect condition with blemish completely smoothed away are 99 out of 100. But there’s always the chance that even in the hands of a skilled glass grinder that it will break.

Curing Sick Glass

Sometimes a piece of old glass is quite free from nicks or chips but the surface has begun to disintegrate, giving a slightly cloudy or frosted appearance. If it has gone beyond the initial stages, it’s an example of sick glass. There are two causes for sick glass. Either the proportions of the batch from which the piece was made were incorrect, or the piece has oxidized from chemical reaction. The latter may have been due to the glass having been left for years in a damp cellar, having been buried in the earth, or having been used overlong as a container for some liquid.

Extreme examples of sick glass are sometimes very beautiful, such as the iridescent pieces recovered from Egyptian, Grecian, Roman archaeological sites.

Repairing Old Damaged GlassUnfortunately, in normal pieces of sick glass, there’s seldom any iridescence, but only a cloudy, frosted tone. In the initial stages, this condition can be rectified by repolishing, provided the restorer can reach both sides of the piece to clear the damaging cloudiness. Plates, bowls, drinking glasses and similar shaped pieces lend themselves to this treatment. If the disintegration is only on the surface and has not permeated the material, such work is usually permanent. Otherwise, it’s of only temporary benefit, and the telltale cloudiness shortly reappears.

Old flasks and bottles, with a mild cloudiness, cannot, because of their shape, be sent to the re-polisher, since he has no means of reaching the inner surface of the glass with his bluffing and polishing wheels. On the other hand, some collectors have developed an ingenious technique for treating bottles so afflicted, and it is reasonably successful. They take a pliable green twig, and attach a swab to one end, then dip it in a good grade of clear, colorless mineral oil and patiently work it around inside of the bottle. They rub each cloudy spot until it disappears under the action of the oil. After treating the bottle or flask, they tightly cork it. If the owner of the piece removes the cork for any reason, the cloudiness will return as soon as the oil has evaporated.

This treatment is, of course, not a cure. Sometimes, the oil finally gives the glass a slightly yellow cast. Bottle collectors often find dried sediment in their bottles. If they can’t remove the sediment with liberal doses of good soap and water, they can fill the bottle with either a mild acid or alkaline solution, and let it stand for a day or two. It may be necessary to use first one and then the other. If the sediment is acidic, the alkaline solution will produce a chemical reaction that will loosen it. If the substance is alkaline, the acid solution will have the desired effect. In no case should a powerful reagent be used. Vinegar and washing soda, both inexpensive and mild, are excellent mild reagents.
Repairing Old Damaged Glass

Dealing with Dried Sediment

If sediment still remains, a collector can fill the bottle about a quarter full of clear water and add about two tablespoons of fine steel shot, followed by corking the bottle and shaking it thoroughly. This scours the inside effectively. If shot isn’t available, clean bird gravel used with less water can be substituted. It’s important not to use lead shot since it’s not sharp enough to be effective, and if there’s any trace of chemical in the bottle, the result may be a coating of lead solution. This isn’t only difficult to remove but, in extreme cases, can ruin the bottle or flask.

Article By Bob Brooke

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