Western Electric OST - pre #122

[wds]

I picked up my second pre-122 ost.  These are made of hard rubber - quite smelly, approx 80 ohms resistance, and the caps are larger than the 122, 143,144 - they fit my we long pole receiver.  The caps even have the same profile as the long pole caps.  I was told these might be #112 receivers, but I can't find any information to confirm it.  Does anyone know what these might be? 

Also, is there a way to remove the light brown coating on this receeiver?  The top is original, and when you remove the cap everything on the inside is original color.  The light brown almost seems like some type of corrosion on the hard rubber.

[unbeldi]

I picked up my second pre-122 ost.  These are made of hard rubber - quite smelly, approx 80 ohms resistance, and the caps are larger than the 122, 143,144 - they fit my we long pole receiver.  The caps even have the same profile as the long pole caps.  I was told these might be #112 receivers, but I can't find any information to confirm it.  Does anyone know what these might be? 

Also, is there a way to remove the light brown coating on this receeiver?  The top is original, and when you remove the cap everything on the inside is original color.  The light brown almost seems like some type of corrosion on the hard rubber.

I have observed this brown coating on other hard rubber items too, for example on hard rubber key knobs.   I thought it was dirt at first, until I realized that it wasn't, when I tried to clean it with acetone.  This turned the items even more brown.
It probably is a residual from break down of the rubber.   I solved the issue by treating the knobs with black spray paint and preventing it to dry into a gloss by rolling on paper.  This essentially only stained the surface black.

I think on larger surfaces I would try to polish the surface to proper smoothness, and then use black shoe polish to stain it and finish it.

Isn't the brown most prevalent in the areas where one would expect the most skin contact?

[unbeldi]

Visually your receiver looks very much like a 122.
Here is the timeline of the most significant bi-polar receivers:

1890:  early bipolar type 108;  rare: only ca. 530 made
1894:  improved types, Type 110
1895:  Type 111
1896:  Type 112
             Total 110, 111, 112 production: 860,000
1902:  Type 122;  high production: 5.5 million
1912:  Type 144;  very high production

However, the illustrations in the source show two or three types that look pretty much the same as a 112 or 122, but are not detailed with a type number.

Source: AT&T (1975): Engineering and Science in the Bell System

[wds]

I have the Ron Knappen charts and books, but still can't figure out which model number these are.  Also, the serial number on both of them are over 4,xxx,xxx.  The light brown one is 4,150,260.  If the serial numbers started at 1, then this can't be a model 112, and probably not a 122 - or there were many more produced than Ron's chart indicates.  Very puzzling. 

[wds]

This receiver does look similar to the 122, until you hold them side by side.  I think the reason I got this one for a reasonable price is that no one recognized this as being different than the 122. 

[unbeldi]

I have the Ron Knappen charts and books, but still can't figure out which model number these are.  Also, the serial number on both of them are over 4,xxx,xxx.  The light brown one is 4,150,260.  If the serial numbers started at 1, then this can't be a model 112, and probably not a 122 - or there were many more produced than Ron's chart indicates.  Very puzzling.

What do those charts indicate?

[wds]

I was referring to Ron Knappens charts, and the quantity of receivers made.  He states that 2.8 million of the 122, 123 and 134 receivers were made, and if mine is a #112, and only 862,000 were made, then I'm guessing the serial numbers must not have started at 1.  Or a lot more were made than is indicated on the chart. 

[wds]

As to the light brown color - I doubt that the light brown "rust" is from skin contact.  The color is uniform on the entire cap, even the areas that wouldn't touch the skin.  I think it might have been caused by exposure to something else.  Do you suppose I could remove it with a light sanding?

[unbeldi]

I was referring to Ron Knappens charts, and the quantity of receivers made.  He states that 2.8 million of the 122, 123 and 134 receivers were made, and if mine is a #112, and only 862,000 were made, then I'm guessing the serial numbers must not have started at 1.  Or a lot more were made than is indicated on the chart.

Does the author list sources for those numbers?
While the AT&T/BTL books often summarize more concisely than I wish, the discrepancy in count for the 122-type seems excessive, and in such a case I would side with primary sources. While the BTL books are really primary either, they are a lot closer to the source, the authors had complete access to the AT&T archives.

Knappen also does not seem to consider the 108 a bipolar type, while BTL does.  It should be pretty obvious what it is when one has one.   Anyone?

[unbeldi]

As to the light brown color - I doubt that the light brown "rust" is from skin contact.  The color is uniform on the entire cap, even the areas that wouldn't touch the skin.  I think it might have been caused by exposure to something else.  Do you suppose I could remove it with a light sanding?

skin oils, cosmetics, hair treatments, all likely have a tendency to spread and penetrate the surface layers uniformly over time, so I would expect material deterioration to be greatest near the ear and less toward terminals or the cord exit.  No one would hold the receiver by the end and probably not often in a closed fist either.

Perhaps the deterioration is aggravated by manufacturing problems, varying temperature during vulcanization or inconsistent material composition, or lower quality of latex.
Hard rubber is made with the addition of sulphur and bis-phenols and others. I suppose the brown stuff could be a result of bis-phenol reacting with moisture to form phenol alcohols, which are all brown. This can also be observed on heavily used Bakelite surfaces, which form tiny pits of brown stuff, or a brownish surface coat.  I have seen many Bakelite handsets that had this. Cleaning and rubbing the pieces with metal cleaners leaves the rag usually yellow to dark brown.

I seem to remember someone on this forum indeed sanded and polished hard-rubber receivers to a new looking shine.

[unbeldi]

Searching the forum yielded this:

http://www.classicrotaryphones.com/forum/index.php?topic=14433.msg150903#msg150903

There, Jeff explains his restoration of a 122-type RX and posted a PDF file with pictures of his results.

W.E._122W_OST-Receiver_R.pdf

[Sargeguy]

If it is an earlier WE receiver, I would not restore it-i'd leave it as is.

[Dan/Panther]

I recently restored a Pony in very bad shape. Maybe some of my info can help.
D/P

Here is the link.

http://www.classicrotaryphones.com/forum/index.php?topic=15192.0

[AE_Collector]

Unbeldi:
Is this portion of your reply #2 a typo?
Should be "Total 110, 111 , 112 production: 860,000,  not 110, 111, 123 production: 860,000

I didnt want to fix it in case I am WRONG!

Terry

1896:  Type 112
             Total 110, 111, 123 production: 860,000

[unbeldi]

Unbeldi:
Is this portion of your reply #2 a typo?
Should be "Total 110, 111 , 112 production: 860,000,  not 110, 111, 123 production: 860,000

I didnt want to fix it in case I am WRONG!

Terry

1896:  Type 112
             Total 110, 111, 123 production: 860,000

oh, thank you.  Now, why didn't I see that?
I corrected it.  Thanks very much for the alert.