Anniversary clock domes

Ken M

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Dome manufacture process?

I was talking to a friend today about glass domes, old and new. And he asked how they made them back in the old days, some having bubbles and defects. And I thought....I don't know! So I'm asking, how did they make those domes? Today, I expect it's all automated and defects are rare. Thanks!
 

shutterbug

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Re: Dome manufacture process?

Guessing, but probably glass blowing into a mold.
 

John Hubby

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Re: Dome manufacture process?

Ken, you've asked a good question. Glass domes are part of the history of "Anniversary Clocks" that is hardly mentioned in any of the literature on these clocks. Here's a brief summary that I put together after seeing your query.

The manufacture of glass domes for anniversary clocks "was" done by individual glass blowers in the 19th century, and for unusual shapes and sizes or short run production this practice has continued until today. For example, Ben Bowen (www.glassdomes.com) recently had a special production run to make oval glass domes for Gustav Becker skeleton clocks to the exact original specs, and I participated about ten years ago in a project to make 25 large oval domes for the Harder/JUF striker (about three times as big as the Becker domes). These were all hand blown into wooden molds made for the purpose. The wood molds are only good for short runs of about 35 domes, because the heat of the glass chars and ablates the wood so that the dimensions go out of spec after that many domes are produced. The molds are immersed and stored in water so they are totally saturated before being used for blowing. For info, the molds are quite expensive and hand blowing adds a good bit as well, so these aren't cheap. The "all-in" cost for the 25 striker domes was $450 each ten years ago. Molds for large volume automated blowing are made of metal and other materials depending on the finish desired.

Production of standard glass domes was automated early in the 20th century following the invention of a glass blowing machine by Michael Owens in 1895 in the U.S. and its use moving to Europe shortly after 1900. The following is from a brief History of Glass:
Increasing automation 1900-1925
Towards the end of the 19th century, the American engineer Michael Owens (1859-1923) invented an automatic bottle blowing machine which only arrived in Europe after the turn of the century. Owens was backed financially by E.D.L. Libbey, owner of the Libbey Glass Co. of Toledo, Ohio. By the year 1920, in the United States, there were around 200 automatic Owens Libbey Suction Blow machines operating. In Europe, smaller, more versatile machines from companies like O'Neill, Miller and Lynch were also popular.

Added impetus was given to automatic production processes in 1923 with the development of the gob feeder, which ensured the rapid supply of more consistently sized gobs in bottle production. Soon afterwards, in 1925, IS (individual section) machines were developed. Used in conjunction with the gob feeders, IS machines allowed the simultaneous production of a number of bottles from one piece of equipment. The gob feeder-IS machine combination remains the basis of most automatic glass container production today.
I have seen an article in a pre-WWI publication regarding glass dome manufacture that included illustrations of standard shape domes being made. At that time, and until the late 1930's in the U.S. and shortly after WWII in Europe the individual domes still had to be trimmed to length, that is why almost all pre-WWII domes have the flat cut bottom edge and are thicker. Also, the imperfections seen in many of these early domes (streaks, bubbles, etc) were due to the glass melting and feeding process that didn't have the sophisticated control systems developed later such as the gob feeder mentioned above. Continued improvement of the process (and the glass itself) reduced these imperfections and included the ability to make thinner section domes with fire-polished bottom edges as generally seen after WWII. You will find that most domes with clocks made after 1925 have very few imperfections, and the later fire-polished domes come off the production line ready to use and have the rounded bead at the bottom that offers better chip resistance.

Now you know just about all that I do regarding glass dome manufacture. :D
 

harold bain

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Re: Dome manufacture process?

John, long before there were anniversary clocks in need of domes, there were many French clocks made with larger dome requirements.
The company started by Michael Owens (Owens Illinois) is still around making glass:D.
 

John Hubby

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Re: Dome manufacture process?

John, long before there were anniversary clocks in need of domes, there were many French clocks made with larger dome requirements.
The company started by Michael Owens (Owens Illinois) is still around making glass:D.
Harold, that's right. Also, the sometimes "very" large and unusually shaped domes for all those clocks were hand blown back then and still hand blown today for the most part.

I visited the Jaeger-LeCoultre factory in Le Sentier, Switzerland a year ago and saw that they had developed a replica of the Reutter Atmos Model PO1 that has a relatively large rectangular base round top glass dome, so I asked if the domes were hand blown. Answer, "Oui".

O-I not only are still big in glass bottles but also in plastic (PETE) bottles. I visited a couple of their plants (back when I was still working for a salary) doing sales visits. They were one of our customers buying polypropylene raw material used for making bottle caps for the pete bottles. The machines they had then (mid-90's) produced in the order of 1,000 caps per minute, complete with the hard outer shell and safety ring, soft sealant layer inside, and an ink imprint giving a prize number or showing a drawing or whatever between the shell and the transparent sealant, each one different. Mind-boggling.
 

clksmyhobby

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Since my interest developed for 400-day clocks about 15 years ago, I have noticed several differences in the domes. Most are a clear glass or possibly crystal(?), but differ in weight and thickness. Some have what appears to be a flat cut or ground edge, and others have a smooth bead on the edge. Then there are the plastic type - Lucite, acrylic, Perspex, etc.


Older clocks in my collection (like from the '50s and before) have come with heavier glass domes without rolled edges. Some are just plain cut and some are ground smooth. The plain cut edges seem prone to having cracks and chips. Later mechanical and many quartz clocks have lighter weight domes with beaded edges. Some of the beaded edges have imperfections and will not sit flat on the clock base.


I had thought that plastic domes were just inexpensive replacements for broken glass or were related to the advent of quartz movements. But I have read that some mechanical clocks were originally sold with them. Experience has shown me that the plastic type can look as good as glass when cleaned and polished. Unfortunately, many came to me with cracks or deep gouges that show noticeably.


Would anyone care to share information about anniversary clock domes with respect to type, manufacturer, and/or dates of use?


Are there any clocks that should have specific domes to maintain original condition?

Thanks for any input you can supply.
 
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sjaffe

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A couple of comments: I believe the use of the plastic domes may have started somewhere around late 60's-early 70's. I believe that some manufactures switched to plastic because it was lighter (for lower shipping costs) and less likely to break in shipping. I have found the Novus products very effective for removing scratches in the plastic.
Stan
 

John Hubby

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clksmyhobby, welcome to the NAWCC Message Board! Thanks for your inquiry, this subject has been discussed at various times and in 2011 I posted a summary in post #4 of this thread regarding the development of glass blowing for domes. That covers much of glass dome history, and since then I've compiled a brief list specifically for 400-Day and other torsion clock domes. The following listing by years is based on my observations in recording data for more than 6,000 pre-WWII 400-Day Clocks and a very large number of post-WWII as well:

1840-1900: Entirely hand-blown glass. All cut bottoms, some ground due to imperfections on cutting. All relatively thicker glass ~ 2 to 3 mm.

1900-1930: Larger domes hand blown, smaller sizes blown using automated blowing machines with metal molds. All had to be cut to length, some ground to remove imperfections. Large domes 2.0-2.5 mm thick, smaller 1.75-2.25 mm.

1930-1939: Oval domes hand blown, large round domes blown into metal molds, smaller domes mechanized blowing. Start of fire polished bottom for small domes in mid-late 1930's. Large domes 2.0-2.5 mm thick, smaller 1.75-2.0 mm.

1947-1950: Essentially the same as in the 1930's with increase in number of fire-polished domes.

1950-Present: From 1950 virtually all smaller glass domes have fire-polish (beaded) bottom edge, dome blowing is fully mechanized. Large domes still have cut edge, most are ground smooth. Large domes 2.0-2.5 mm thick, smaller domes from 1.5-2.0 mm.

1952: First plastic (acrylic) domes introduced on novelty 8-Day torsion clocks made by Gebrüder Staiger. Within three years all makers have plastic domes on some models but glass is still dominant. These domes are from 1.5 to 1.75 mm thick depending on size with larger ones having thicker walls. The acrylic domes are sometimes slightly hazy and are relatively easy to scratch, may darken due to UV exposure.

1965: Polycarbonate domes began to replace acrylic domes, offering improved clarity, scratch resistance and chemical resistance. By 1970 all plastic domes are polycarbonate. Glass domes continue to be used for more than 60% of 400-Day production.

Since this is a continuation of the thread mentioned above, I am merging it with that thread to have this information in one place. The "Anniversary Clock Domes" title will be retained.
 
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clksmyhobby

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Great information! I've wondered about the process for a number of years.

This continues to be an amazing forum with an impressive depth of knowledge and experience.

Thanks for the thread merge, John.
 

John Hubby

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Are there any clocks that should have specific domes to maintain original condition?
Just noticed I didn't answer your last question. Basically I use the following guidelines to keep clocks in "as original" condition or at least as close as can be done using what is available on the market today:

1) Pre-WWII clocks should all have glass domes, no fire-polished edges until 1935 and later.

2) Pre-1904 clocks should all have hand blown glass domes, with slight imperfections such as bubbles, streaks, fine lines, slightly wavy. As best can be determined, 1904 was the first year that glass domes made by the Owens patent glass blowing machine were available to German makers. Prior to that time all domes for German makers' clocks were hand blown. These include:
>> S. B. Terry "candlestick base" 2 & 3-ball torsion pendulum (1852-1862).
>> Gustav Becker cylinder escapement (1872-1901).
>> Harder patent table model clocks (1877-1887).
>> JUF Harder patent table model clocks (1888-1901). JUF changed the movement design in 1901 to their own specifications.
>> Steinheuer & Rabe electrical remontoir torsion clocks, tripod table model (1890-1892)
>> Andreas Huber Harder patent table model clocks (1896-1904).
>> J. Christian Bauer patent pinwheel escapement clocks (1901-1902). These clocks were made by Carl Bauer of Fürth.
>> Ph. Hauck and W. Würth & Co. clocks (1903-1904). After 1904 likely used machine blown domes.

3) Some special clocks need hand-blown domes to original spec. These include:
>> DeGruyter patent table model striker (1884-1900). This is a perfect oval slightly tapered round dome, mentioned in one of my earlier posts here.
>> JUF table model striker (1905-1930). This clock had both an oval base and dome as well as a round dome. The oval base version is similar to the DeGruyter, the round base can use a short version of a louvre dome.
>> Gustav Becker skeleton model (1910-1911). This is a perfect oval tapered round dome with matching mahogany base. Currently available at www.glassdomes.com

4) Post-WWII clocks should all have glass domes to 1952. Earlier clocks and all louvre models will have cut bottoms, most of these will be ground. Fire polished standard and miniature domes are OK from 1949 onward.

5) After 1955, miniatures and some carriage models appeared with acrylic plastic domes or side panels but were not a large percentage until the mid-1960's. Standard size models continued to use glass exclusively until the early 1960's. From about 1965 polycarbonate started replacing acrylic. Overall (my best guess) plastic domes never exceeded more than about 40% of production with a lower percentage of standard size clocks having plastic and a larger percentage of miniatures and midgets.

There will likely be more to add here after everyone has read it and brought up examples that I didn't cover. All comments welcome!!
 
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mattw26

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I know this is an old thread, but I have a question about this. I just bought a German Kundo quartz clock that I received today. It chimes. Since it was advertised as vintage, I expected it to have a glass dome like my other Kundo clocks, but it has a plastic one. At first, I thought it might not be the original dome, but now I wonder if it might be the original. I paid $90 for the clock itself, plus shipping costs and taxes, which are expensive given that the item is fragile. I called the seller to have them help me set up the clock and they said they didn't know if it was glass or plastic. It has a flat spot on top, which suggests it is plastic and I can tell from the general feel and weight of it that it is plastic. I am attaching photos of the clock and dome. So I have two questions
1) Is it possible that the plastic dome is the original?
2) Would the clock be worth $90 with a plastic dome given the general condition of the clock?

clock face hour hand not aligned.jpg dome top flat spot.jpg full clock.jpg
 

etmb61

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Hi Matthew,

Just from what I can see I'd say your clock is a 1970s vintage, but since it's not a wine the term means nothing. The plastic dome is probably original. Plastic domes replaced glass for a time because of breakage.

Eric
 

mattw26

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Hi Eric. Thanks for the advice. I am a rookie collector that just got into this hobby so I am still learning as I go. It's good to know when this clock might have been made. I was disappointed that the dome was plastic, but if it is authentic, then it's ok for what it is. The clock looks nice and it chimes on the hour, which is why I bought it. The hour hand was slightly off, but somebody else on these forums told me I could fix it with a little bit of gentle force and I haven't had any problems since (knock on wood).

Someone on youtube told me that when they get a clock with a plastic dome, they generally replace it with a glass dome, which I suppose I could do.
 

etmb61

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Hi Eric. Thanks for the advice. I am a rookie collector that just got into this hobby so I am still learning as I go. It's good to know when this clock might have been made. I was disappointed that the dome was plastic, but if it is authentic, then it's ok for what it is. The clock looks nice and it chimes on the hour, which is why I bought it. The hour hand was slightly off, but somebody else on these forums told me I could fix it with a little bit of gentle force and I haven't had any problems since (knock on wood).

Someone on youtube told me that when they get a clock with a plastic dome, they generally replace it with a glass dome, which I suppose I could do.
It's not always economical to replace a plastic dome with a glass one. I have a Schatz 1000 day where the cost of the odd size glass dome is more than I paid for the clock with it's original plastic dome. Since you asked, in my opinion you've already paid too much for a quartz clock. I wouldn't throw more money at it for a glass dome.

Eric
 
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mattw26

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I see your point in this case. I went a little shop happy when I decided to start collecting these clocks and didn’t take the time to comparison shop and get a sense of the true value of these clocks. I probably should have asked the sellers a few questions, too. Lesson learned.

I like the idea of 400 or 1000 day clocks better from a value and historical standpoint, but I don’t want to completely exclude quartz clocks. Two out of the five clockS I have came from family members. One is a quartz dome with the Howard Miller branding, that I later found out had bought Kundo (or something like that). The other is a 400 day carriage clock. Those were both my inspiration to start collecting and are sentimental to me. The quartz clocks I bought had something unique about them that I liked (this one chimes, my other one is a nickel plated miniature). I’ve been looking mainly at Kundos thus far, but I’ve seen one or two Schatz clocks that caught my eye so I might expand my horizons a bit. Kundo and Schatz seem to be very popular among collectors and some of them are very similar to each other.
 
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