Invisible mending for glass collectors, not fraudsters

You may have noticed that several of the pieces of glassware we have offered for sale - as part of the detailed description - include notes about any damage which may be present, any restoration which has been carried out, and a note to the effect that it may be possible to restore them to a near flawless condition.

This is a service which we can undertake on your behalf working with trusted associates who have perfected a method by which damaged glassware can be returned to its original splendour. This is done using a restorative process which avoids the potentially damaging procedures of grinding and polishing to recondition chipped or flaked areas; as you can imagine, to evenly re-grind the foot of a glass which has a quarter inch chip on its edge requires the removal of that same measurement around its full circumference, thus irrevocably altering the original proportions of the piece which cannot possible retain its original balance and “feel”.

Reducing the diameter of the foot also means that its original concave profile also has to be recreated – albeit across a smaller diameter; this is achieved by further grinding to the underside of the foot, which visibly reduces the thickness of the glass. This may be sometimes be detected as one may observe score-marks – like spokes – which radiate out from the stem on the underside of the foot. Sometimes artificial wear and tear will then be added to the new “wear line” around the circumference of the foot in an attempt to replicate the condition of a piece which has been slid across table tops and bars, cleaned, polished, balanced on stone mantles and unsympathetically curated by sundry disinterested custodians or inebriated alehouse habitués over centuries of use.

Rather than using these essentially destructive techniques, we prefer to endorse a procedure - painstaking and highly skilled in its own right - which uses a specially formulated epoxy resin to effect the repairs by replacing damaged areas. These resins are not simply “off the shelf” solutions, but are chosen from a wide range of different grades which are paired with the original piece to provide the closest possible match in appearance, shade and finish. They can also be tinted using additives that provide the most exact match to the target piece – be it the subtle grey shades of “clear” flint crystal, or the more strident hues of coloured glassware (blues, greens, reds – any of the popular antique casts…)

This matching process crucially also includes an analysis of the refractive index of the piece. In simple terms, this ensures that when light passes through both the original glass and the resin insert, it is refracted at the same angle and will, therefore, present what appears to be an entirely uniform surface to the casual observer (if you want to get all technical and swan about in a lab coat, clipboard in hand and looking terribly well informed, the propagation of light through the two constituent parts will be as near to identical as is possible, based on the determination and calibration of analogous phase velocities in both substrates – so there).

A drawback of using these resins is that - in their uncured state - they are very fluid, but need to be presented against the intact part of the piece being repaired in such a way that as little work on the cured inset as possible is required to avoid any further imperfections being inadvertently imparted. In order to do this, a silicone mould is taken from another part of the original which most closely matches the form of the area to be repaired, in to which the resin is introduced layer by layer until the full extent of the void within the mould is filled.

The resin insert is then left – in position - to cure for 48 hours at a carefully controlled temperature; the curing process has the additional benefit of bonding the insert to the original so there is no additional adhesive required; you need only reflect on childhood repairs to Subbuteo figures or crockery – hastily reassembled before parents were aware of the breakage – to know what a give-away the presence of inexpertly applied glues can be; there is no scope for such incrimination with a bonded insert !

Once in place, the genuinely artistic aspect of the repair comes to the fore with the polishing of the insert to replicate the surface of the once-again complete item. This has the effect of both matching the patina of the infill to the appearance of the original glass, and allowing the conservator to replicate any existing striations on the sound part of the piece. This polishing is done by the use of increasingly fine glass papers and then varying grades of silicone carbide polishing cloth, before a final burnish with a metal polish rub is used to impart the required lustre.

It should be noted that inserts created with these processes can be fairly readily detected under very close scrutiny, but the piece will certainly look sufficiently complete for display purposes. It is not the intention to make the repairs entirely invisible, as this would inevitably lead to the possibility for repaired items to be sold as undamaged and complete, with the additional value inherent to any object in such purportedly pristine condition. They can also be easily revealed by exposing the restored piece to ultra-violet light, at which point the insert will be made immediately obvious. This resin-based restoration is a service for the owner who wishes to enhance an object that would otherwise be sadly diminished by damage, in the full knowledge that such restoration has been carried out, rather than offering the potential for obfuscation. This is sadly not always the case for other procedures which claim to deliver a repaired item intended be indistinguishable from an entirely undamaged equivalent – that is a service not to the owner, but only to a potential seller – and a gross disservice to any unwary collectors !

Both approaches to restoration have their merits depending upon the nature of the piece requiring restoration. Chips to lustres if a suitable replacement pendant or droplet cannot be found are better being ground and polished when the chips are small. We prefer chips on the bowl of wine glasses to be filled, not ground, and small chips on the feet of glasses to be polished where the loss is minimal.

Before going on our website, all glasses are carefully checked for any restoration, and it is always noted in our description of the glass. If we state that there has been no restoration, that is a representation on which you are entitled to rely. Where we consider restorative work may be carried out with advantage, we will also note that.

Filled and colour tinted restoration is universally accepted in the world of the porcelain collector. We want the same to be true for the world of the glass collector. It is inevitable that some glasses will have suffered damage and restoration over their many years of service, but it is our firm belief that the proper course is to make its existence clearly known to our clients and that this should form a basic practice standard within the antique trade.

(errr - and yes, it's The Mending Song by the mice on Bagpuss - bonus points for anyone who spotted that)

an example of a repaired glass as listed on our site

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