Museum restorations
The art of restoration is a specialty given to people that are devoted and passionate in their field of interest. All finding pleasure returning something to its former condition and function rewarding. With glass restoration there are limitation in the expectation of visual repairs. Dishware, stemware and some glass sculptures can only be displayed and no longer used. There may also be other limitations and conditions after the restoration is completed depending on the subject being restored. While I’m not involved with restoring 800 year old one of a kind items. The process is identical were your trying to conserve as much of the original and introducing as little newer material as needed.
Glass restoration
By- Len Daley
Restoration of glass globes with reverse painted or crystal etched shades is very popular using a non yellowing optical bonding process.. You can google some of the museum restoration companies for the process which takes a special skill set that I also perform . The results on crystal cut glass work are impressive in most cases looking like a hair or the line between bifocal lenses when the break is clean. On painted glass the results are more noticeable because the paint along the crack is missing or scalloped. Often because the paints are on the inside of a shade a sliver of light is visible at the breaks. Very small or missing fragments are not reused. On colored glass the results also look like a hair on the glass depending on the color and or textures. Areas where chips of glass and fragments are missing will be visible and filled in with the bonding. Structurally after my work is completed the glass shades are extremely strong, secure and functional again. The pictures below clearly express the minor lines with some of the wide uses of bonding glass.
Len why can’t you hide the crack lines? In most cases you will feel the line with your finger nail as it will appear as a hair line on the glass. The simplest way I can express it would be to say. When glass is bent the molecules are frozen bent under heat to a shape. When a panel is cracked the molecules in the glass can expand back to their original form. This causes the glass pieces to relax no longer controlled by the original bending or shape formed by the heat. Lining the pieces up can never be perfect again. Clients need to understand a little bit about the technical aspects of glass. The nature of glass in most cases express the transmission of light going through it. As light travels the glass absorbs some of the lights rays holding or letting the light traveling through the glass. Any obstruction (crack) to the original molecules when the glass was created will obstruct the traveling light and reduce the original clarity. When expressing the process to clients I will often say “even diamonds have flaws”. Again my work is strictly related to lighting and glass only.
Slag glass lamp panel restoration
Slag glass is becoming extremely difficult to resource and find. In my lighting work I have found my glass resources are becoming limited. Over the past 50 years that I have worked in glass I have seen many glass companies and rare glass colors disappear. Just recently one of the last manufacturers from 1880’s stopped making glass in 2018. Having their glass furnaces turned off will put more demand on glass restoration and less on glass replacement. The example above shows what I’m trying to explain. Basically in the example your looking at is a five color slag glass mix discontinued back in the 1940’s. The option in this case was limited to custom bend a best matched color or using a chemical optical bonding process very similar in dental work. While the process is extremely difficult and time consuming in this example conserving the existing broken glass was the best option for the lamps historical value.
Below are two examples of a mustard color which was discontinued and became more of a popular caramel color in the early 1900’s. Because this color was discontinued I often express the bonding process. The first example also reflects the conservation bonding approach because the back texture (rough ripple) was also discontinued. Depending on the lamp and its historical value. If I cant best match the glass color, texture and density I try to conserve as much of the original glass panel as possible.
Clear glass restoration
In this example the lamps shade is clear with a commercial frosted etch design on the exterior. Making a new one is impossible and finding a duplicate would take a life time. The bonding process enables the client to have a strong and functional shade and retain the emotional attachments with the original lamp.
Cast glass restoration
Cast glass is formed in a mold most often by machine. Colors in some cases are formed with the original base layer of glass. Sometime the a color is added to the exterior before the original cast glass is cured. The two bankers lamp globes shown obscure the light from traveling through the glass. But the break is visible on the light green surface and not visible on the dark surface. In contrast a large 24 inch white cast bathroom globe also shows no visual lines. Again clients need to understand the bonding process is only used to make the glass product strong and functional again.
This uranium (green) vase shape I believe was used with a floor lamp base. The glass is a mouth blown shape with both ends cut and ground. I don’t have much information but assume a pipe ran through the vase shape with a vase cap or fitting holding both ends in place. The seven pieces are prepped to receive the bonding before starting. I then need to know exactly which pieces go first and which one goes last to avoid fitting problems. A mock up with clear tape is sometimes performed before most glass bonding projects. If you look closely at the last few pictures on an angle with the camera you can barley see the fracture lines with this type of glass. In some spots just like a scratch on glass you can feel the lines with your fingernail.
Reverse painted glass restoration
I was very pleased with this Handel reverse painted cast shade. The exterior has a glue chip surface common for many Handel shades. The textured surface helped blend in the glass bonding restoration. Minor missing fragments of the painted surface let a little light through.
Another example of a cast glass shade with reverse painting on the interior. Few missing painted chips. The very lower edge had what I call a spider crack. Where multiple cracks merge at one spot. The spot required filling with the bonding materials to avoid sharp edges.