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Chip on old glass domes

Ken M

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Feb 28, 2009
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I've been noticing on older glass dome one chip, the same chip, on most of my older domes. Some have one or two more, but mostly there is just one chip, and they all look the same. Did they do that on purpose?
 

KurtinSA

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Seems like the chips would be coincidental in being similar...doubt it's by design. The chips are just another sign of patina.

Kurt
 

novicetimekeeper

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Seems like the chips would be coincidental in being similar...doubt it's by design. The chips are just another sign of patina.

Kurt
Patina has two distinct meanings. The tarnish on copper and copper alloys, and the smooth wear and surface finish from years of handling that you find on things like wood and stone.

It doesn't mean chips, which are damage, nor dirt, which is dirt.

At work we flame polish soda glass chips and on some glass we file with a diamond file to remove sharp edges.


Edit> If you look up the etymology it comes from the name of a shallow dish, which reflects its use as a name for wear from decades ot centuries of handling.
 
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KurtinSA

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Edit> If you look up the etymology it comes from the name of a shallow dish, which reflects its use as a name for wear from decades ot centuries of handling.
So having a chip in the edge of the dome doesn't reflect wear due to handling? I'm not really trying to argue one way or the other...that's just my perspective. I see the chips as a way of indicating that it is an older style dome. Very few of them survive and those that do tend to have some kind of imperfection in the edge.

Kurt
 

novicetimekeeper

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Yes, chips indicate inappropriate handling but they are damage, considered faults in condition. Patina is not a fault.
 

novicetimekeeper

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Patina has a different meaning on brass, bronze, and copper. Patination is the process of applying a chemical to the surface of a bronze casting to give it a finish, it can be a variety of colours. It isn't an indication of age, and removing it will devalue the piece. Likewise copper alloys can be treated to produce verdigris or or will do so over time and weathering, again, not a fault it can be a desired finish. (it can also be undesirable on a piece that should be polished but that is not the same thing)
 

tracerjack

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Wait, I’m confused. You (novicetimekeeper) wrote in post # 4 that patina had two meanings; tarnish on copper alloys and handling wear on wood and stone. Then, in post # 9, you wrote patina is a chemical process applied to copper alloys., which is what I experienced in bronze sculpture class. So, not tarnish? Can you explain? Perhaps you meant tarnish can be a desirable finish, which happens on weathered bronze, but Im not sure that’s desirable but more like unavoidable. I’m still of the opinion that if a 400 day clock not been neglected, it would have been regularly polished to maintain its shiny gold appearance. On the other hand, I understand why many choose not to polish off heavy tarnish, based in valid reasons, but I personally have difficulty describing it as patina.
 
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novicetimekeeper

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No, I said patination is a chemical process which applies to bronze sculpture. (Excessive handling can remove patination and reduce value)

The verdigris on copper can be achieved with chemicals or allowed to grow naturally as on a copper sheathed roof (which even the military would not polish)

Verdigris is not generally wanted on a clock, though I have seen a few modern clocks treated chemically to achieve it, and it is not always unwelcome on the dial and hands of turret clocks.
 

tracerjack

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It seems ‘patina’ is one of those words that gets attached to different specific meaning depending on which group is using it. In bronze class, artists is the best general term I can think of for the group, the result of applying chemicals to our sculpture (patination) was called ‘patina’. Not by us, but by our instructor, Rowland Cheney. In the world of horology, it has the same general meaning, but not exactly the same, which is what confused me. Appreciate your explanation.
 

novicetimekeeper

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It seems ‘patina’ is one of those words that gets attached to different specific meaning depending on which group is using it. In bronze class, artists is the best general term I can think of for the group, the result of applying chemicals to our sculpture (patination) was called ‘patina’. Not by us, but by our instructor, Rowland Cheney. In the world of horology, it has the same general meaning, but not exactly the same, which is what confused me. Appreciate your explanation.
true, but hopefully we can agree it doesn't mean chips in the glass.
 

KurtinSA

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Sorry I hit a nerve! I guess I don't have such a specific definition of patina. To me, patina means something shows its age. I have several older motorcycles that display a lot of "patina". They have rust, chipped paint, botched pin stripes on a fender, dents, etc. To me that just shows they've been around the block a time or two. YMMV.

Kurt
 
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novicetimekeeper

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Sorry I hit a nerve! I guess I don't have such a specific definition of patina. To me, patina means something shows its age. I have several older motorcycles that display a lot of "patina". They have rust, chipped paint, botched pin stripes on a fender, dents, etc. To me that just shows they've been around the block a time or two. YMMV.

Kurt
knocked about a lot isn't the same as patina. If you read auction descriptions they often mention condition consistent with age and use, they will less often discuss patina. Patina is a marketable quality.
 

Schatznut

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Getting back to the topic of the thread - of the domes I've seen that have chips, they all were ground flat on the bottom, leaving a nice crisp edge that is also prone to chipping. The domes that have a flame-polished edge are much less prone to chipping.
 

MUN CHOR-WENG

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The previous owner of this Kundo 4-pillar 400-day clock was aware of the problem of glass dome suffering chips at the edge. He took action to minimise this problem by wrapping a small band of plastic material around the entire edge of the glass dome. This seems to have worked well as the glass dome is still in good shape without any chip or crack.

1635390924586.jpeg


1635390965406.jpeg
Mun C W
 
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etmb61

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The chips probably led to folks wrapping the bottoms of the domes in pieces of chenille.
 

tracerjack

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I have one wrapped like that. It actually looks pretty good. It has gold grosgrain ribbon which blends in well with the brass bass.
 

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