75 Years Ago Today

75 years ago today, the first 200-inch mirror blank was cast at the Corning Glass Works in Corning, NY. The casting was unsuccessful as the ceramic cores on the underside of the mold broke loose and floated to the surface. I posted about this last year, but today I have some wonderful things to share.

Word got out prior to the casting and a great many spectators came to see the crew handle the molten glass to as they worked to fill the mold. Have a look at the photo and you can see just how close the crowd was to the crew.

Time Magazine's on-line archives has the story, Pouring Day, as it appeared in their April 2, 1934 issue. Be sure to check it out.

Here is the Corning Evening Leader from March 26, 1934. Be sure to click on it to enlarge and read the articles.

It is interesting to me that one of the sub headlines reads "Glass Works Officials Believe Efforts Have Been Successful" yet next to it is an article "Plan To Cast New Disc If Necessary". Of course the casting was not successful and the officials, namely Dr. George McCauley who was in charge of the project, knew that they would need to try again.

They went ahead and gave the big disc a rapid annealing. When it came out of the annealing oven it looked like this:

Not a pretty site, is it? While the disc was still molten the workers attempted to remove the ceramic cores that had floated to the surface. With plans underway for a second pouring, it was decided to re-melt the first pouring in an attempt to salvage it. Alas, during that process the disc was cracked.

So what do you do with a 20-ton failure? Put it on display and hope people come to see it. It became the first center piece of what is now the Corning Museum of Glass.

Last November I had the opportunity to visit, spend some time in the Corning Incorporated research archives and to finally touch the first 200-inch disc.


Of course Corning triumphed in the end. The second pouring, attempted 8 1/2 months later, was successful. That disc is still in use nightly at Palomar.

The failed disc is an impressive display at the Museum of Glass. Here are a few more shots to round out the post.

The front side of the disc:


The front side as viewed from below:

The back side of the disc:

Special thanks to Kris in the Corning archives for all the help she gave to me during my visit and for answering my many questions over the years. The old photos and the newspaper are a small part of the vast collection in the Corning archives.