[jchcollins]

A few questions on gold Bulova cases:

What is the difference between "14K Gold Filled Case" and others - such as I know the few 18K cases that were produced by Accutron are often referred to as "solid gold." Are the 14K filled just gold plated? Did Bulova make a 14K case that was more solid or heftier than "Gold Filled"?

My 218 is 14K Gold Filled, and just recently I noticed one small place where it appears the gold has begun to chip, at the bottom of one lug. You have to be in fine-tooth mode to find it, but I know it is there. Is this something to worry about or will it get worse? Note this watch (an M9) was an everyday wearer for probably at least 25 years out of it's nearly 44 so far, and I still wear it probably at least 3x a week.

Thanks.

 

[skypilot]

Gold filled and gold plated etc generally mean a layer of gold applied over a different metal, usually brass, and applied by various methods. These are subject to the gold wearing off exposing the metal underneath.
Solid gold, not to be confused with pure gold, means just that, gold that has been mixed with other metals such as silver depending on the color you want. I t won't wear through because the metal under the surface is the same as the metal at the surface.
Bulova didn't make their own solid gold cases, they had them made by various providers.
I might suggest a tutorial on the subject done by Ulackfocus of this forum in his series Horology 101.

 

[oliverb]

Others will chip in too but here is a simple explanation. "Rolled Gold", "Gold Fused", "Gold Filled" and "Electron Gold Plated" are all forms of layering gold over a base metal - usually brass. Sometimes micron gold electroplating is done over stainless steel but I don't think Bulova did this for Accutrons. Solid gold cases may be found in 10K, 14K and 18K. All are basically just different percentages of gold in the alloy. Pure gold (24K) would be too soft and easily damaged. You can check the Net to find out about how the various forms of plating are done. White gold plating is a little harder than Yellow/Rose gold plating because of the other metal in the white gold alloy. Same should be true of solid white gold.

Acids in perspiration will slowly erode any type of gold plating. Constant wear will also do the same. I wouldn't worry about the spot of "brassing" you found on your case. It's perfectly normal on an older watch. It is pretty rare not to find some erosion on a vintage watch that has seen frequent use.

 

[accutron]

Others will chip in too but here is a simple explanation. "Rolled Gold", "Gold Fused", "Gold Filled" and "Electron Gold Plated" are all forms of layering gold over a base metal - usually brass. Sometimes micron gold electroplating is done over stainless steel but I don't think Bulova did this for Accutrons. Solid gold cases may be found in 10K, 14K and 18K. All are basically just different percentages of gold in the alloy. Pure gold (24K) would be too soft and easily damaged. You can check the Net to find out about how the various forms of plating are done. White gold plating is a little harder than Yellow/Rose gold plating because of the other metal in the white gold alloy. Same should be true of solid white gold.

Acids in perspiration will slowly erode any type of gold plating. Constant wear will also do the same. I wouldn't worry about the spot of "brassing" you found on your case. It's perfectly normal on an older watch. It is pretty rare not to find some erosion on a vintage watch that has seen frequent use.

Let's not forget the 9K cases made for the British market

 

[oliverb]

Let's not forget the 9K cases made for the British market

Interesting. I didn't know that. I couldn't remember the exact amounts of gold in the different karat ratings so I just looked it up.

-9K is 37.5% gold
-10K is 41.7% gold
-14K is 58.3% gold
-18K is 75% gold
-24K is 100% gold

Karat rating is actually based on the number of "parts" of pure gold in the alloy. So 9K would be 9/24, etc. with 24K being 24/24 parts pure gold.

Some folks have complained about 10K gold turning their fingers (skin) green. Others don't have a problem with it. My mom has an allergic skin reaction to anything with 10K gold.

 

[PeterHBne]

Interesting. I didn't know that. I couldn't remember the exact amounts of gold in the different karat ratings so I just looked it up.

-9K is 37.5% gold
-10K is 41.7% gold
-14K is 58.3% gold
-18K is 75% gold
-24K is 100% gold

Karat rating is actually based on the number of "parts" of pure gold in the alloy. So 9K would be 9/24, etc. with 24K being 24/24 parts pure gold.

Some folks have complained about 10K gold turning their fingers (skin) green. Others don't have a problem with it. My mom has an allergic skin reaction to anything with 10K gold.

I do love you precisenous.

 

[SAM2]

Back in the 60s, I worked in a shop where we made gold plated electronics for the Gemini Spacecraft but all I can remember is that it was an exacting and sometimes dangerous process. A cocktail of acid potassium gold cyanide was used and great care was taken. I remember reading that one of the watch case foundries on Long Island became a Superfund site after it closed. Very little of that experience is of help to my understanding of how watch cases were actually plated, except that the chemistry would have to be similar and that it must have been a two stage process. Those marked "18K Heavy Gold Electroplate" appear to have been first plated inside and out with a thinner coating that may have had less gold content. The outside of the case would have been dipped in a solution with the 18K gold for a longer time. In the shop where I worked, a tar like substance was applied to areas of metal parts that we didn't want plated. The Heavy Gold Electroplate Accutron cases must have undergone a similar process but the bond between the case and the first layer seems to be much stronger than between the two gold layers. I have one ladies M5 that has some chipping at the edges where the two layers meet but the color of the gold in both layers is virtually the same. I had some success polishing the edges of those chips using nothing more abrasive that a Cape Cod Cloth. It is tedious but I have nothing better to do this time of year and if Bob Piker is able to get the movement running again, it will have been worth the effort.
I was never good at percentages and all I need to know is that rolled gold (RG) is not electroplating but rather a heat fusion process and gold filled (GF) is the same but better. Isn't there a mathematical formula to calculate the gold content of GF and RG jewelry? Not that any of you would ever admit scrapping an Accutron.

 

[akkatron]

SAM2 how are you so cool? That is very informative. I've always been curious about plating techniques

 

[Luckyme]

I am no expert on metals or watches. I have a 214 Spaceview with a 10K GF bezel. I also collect Victorian jewelry which has many pieces made of "rolled gold" which is just one process of applying gold over base metal.

My two points are this...the amount of wear and tear *chipping, loss of gold) a gold plated watch will get is dependent on how much it is in contact with the elements, inc. skin acids, and the thickness of the plating.

I can't answer the latter about the Accutron bezels, but I CAN say that after wearing my watch for the day, I always give it a good wipe down with 99-100% alcohol with a micro fiber cloth. This cleans of any residues inc. skin oils and acids. I also every other day, or as needed, carefully with a micro cloth, gentle rub down the watch AND crystal with a jeweler's rouge cloth and polishing cloth. My watch shines like mint new, and the crystal looks like it just came out of the factory!

Of course banging your watch around, or letting it get run over by a train might do damage to the finish even the above won't fix!!

 

[netsuke]

Back in the 60s, I worked in a shop where we made gold plated electronics for the Gemini Spacecraft but all I can remember is that it was an exacting and sometimes dangerous process. A cocktail of acid potassium gold cyanide was used and great care was taken. I remember reading that one of the watch case foundries on Long Island became a Superfund site after it closed. Very little of that experience is of help to my understanding of how watch cases were actually plated, except that the chemistry would have to be similar and that it must have been a two stage process. Those marked "18K Heavy Gold Electroplate" appear to have been first plated inside and out with a thinner coating that may have had less gold content. The outside of the case would have been dipped in a solution with the 18K gold for a longer time. In the shop where I worked, a tar like substance was applied to areas of metal parts that we didn't want plated. The Heavy Gold Electroplate Accutron cases must have undergone a similar process but the bond between the case and the first layer seems to be much stronger than between the two gold layers. I have one ladies M5 that has some chipping at the edges where the two layers meet but the color of the gold in both layers is virtually the same. I had some success polishing the edges of those chips using nothing more abrasive that a Cape Cod Cloth. It is tedious but I have nothing better to do this time of year and if Bob Piker is able to get the movement running again, it will have been worth the effort.
I was never good at percentages and all I need to know is that rolled gold (RG) is not electroplating but rather a heat fusion process and gold filled (GF) is the same but better. Isn't there a mathematical formula to calculate the gold content of GF and RG jewelry? Not that any of you would ever admit scrapping an Accutron.

To your comment that gold filled is better than rolled gold, would that mean there is more gold content in gold filled?

 

[SAM2]

To your comment that gold filled is better than rolled gold, would that mean there is more gold content in gold filled?

Yes but it is not that simple. In a perfect world, an item that is marked Rolled Gold has a ratio of 1/40 gold to the total weight of the object so marked and a Gold Filled item would have the higher standard of 1/20. Consider two watch cases of the same weight, a GF case would have a gold layer that is twice as thick as one that is Rolled Gold. That makes Gold Filled the better of the two when it comes to watch cases that are expected to last a lifetime.
The same would apply to those vintage expansion bands but remember that only the caps have a gold layer. Still, one that is Gold Filled could be expected to last longer than one that is marked Rolled Gold.
Back in the day, companies like Bulova could be trusted to adhere to those standards. In today's world and with the price of gold what it is, some watch makers have coined new names for the process of applying gold to watch cases and bracelets that may have very little if any gold content. To some, gold is a color rather that a precious metal.

 

[netsuke]

Yes but it is not that simple. In a perfect world, an item that is marked Rolled Gold has a ratio of 1/40 gold to the total weight of the object so marked and a Gold Filled item would have the higher standard of 1/20. Consider two watch cases of the same weight, a GF case would have a gold layer that is twice as thick as one that is Rolled Gold. That makes Gold Filled the better of the two when it comes to watch cases that are expected to last a lifetime.
The same would apply to those vintage expansion bands but remember that only the caps have a gold layer. Still, one that is Gold Filled could be expected to last longer than one that is marked Rolled Gold.
Back in the day, companies like Bulova could be trusted to adhere to those standards. In today's world and with the price of gold what it is, some watch makers have coined new names for the process of applying gold to watch cases and bracelets that may have very little if any gold content. To some, gold is a color rather that a precious metal.

Thanks for that clear explanation. It seemed logical to me that 'filled' would have more gold content.