CD 102.4 Mold Variants

By Al Klaus; posted July 17, 2021

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As our web master recently said "It's all about the wire ridge." So, I decided to take look at the wire ridges on my 102.4 lineup, and scanned the archive for different pics. What I found to my surprise was two different mold variants, but never documented side by side. So, here it is:

The right light aqua seems to be the more common wide U shaped wire groove, and a sharp to the touch wire ridge, with typical chipping. There are also very pronounced mold lines that start from the base and travel to the start of the dome. There is a dot on the inside of the dome, and very little dome glass.

The left dark aqua insulator has a more V shaped wire groove, less sharp, thicker, mint condition ridge. The mold lines on this are very weak, only seen on the skirt. Much more dome glass, no dot on the inside of the dome, but rings on the top of the dome.

Now the improvements in design are obvious. By making the wire groove more like a V, the wire ridge will be thicker, less sharp and less prone to damage. The only other mint one documented on the site, also has the more round wire ridge.

I only have one specimen dug from Lyndeborough, and it matches the more common U groove variant. But I think they were both made at Lyndeborough. The threads are an exact match, and have similar annealing cracks in them. The glass quality also looks the same. Maybe it was a design improvement made too little, too late, into production.

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