Mar 29
Wednesday
Radio Stratosphere
1000Z RESTORATION
Posted: Jul Sun 13, 2008 10:29 pm Reply with quote


1000Z RADIO HISTORY BEHIND THE FIND

I purchased my Zenith Stratosphere (serial #754322) on ebay from an antique dealer in the small California coastal town of Eureka on July 8, 2007. The radio was discovered in the summer of 2007 at an estate sale in Eureka. I was told by the antique dealer that the radio's second owner got the radio in the 1950's and restored part of the cabinet in what looks to be the 1950's or 60's judging for the age of the refinish lacquer on it.

I was also told that the radio's first owner was the Pacific Lumber Company's Scotia Lumber mill in Northern California in the 1930's and 1940's. The Pacific Lumber's Scotia Mill, where the Stratosphere radio was used, was one of the largest lumber mills in the United States at the time and mainly processed redwood lumber. The mill's Zenith Stratosphere was used in the employee lunch/break room and had been modified to allow a microphone to be plugged into the back so the radio's tuner could be used as a PA system for employee gatherings. I was told the second owner of the Stratosphere was the mill's electrician and that is how he came by the radio.

The antique dealer said that the 1000Z cabinet was kept inside of the owner's home, while the chassis was stored in shed type building and exposed directly to the moisture in the air from the nearby ocean causing the tuner to rust and the chrome plating to peel.

I purchased the radio without the amplifier and three speakers. It is thought that members of the seconds owner's family unwittingly pitched them in the local dump in the process of cleaning out the home in the estate sale.

THE SHIPMENT OF STRATOSPHERE TO NEW MEXICO

After getting over the initial shock of the purchase, I had to overcome a minor problem on the shipping. In most cases I have used Craters and Freighters or a major freight line to ship a console radio cross-country. Since Eureka is a fairly remote coastal town, it looked like a moving van was my only option. That option turned out to be pretty expensive. At the recommendation of the antique dealer, I checked with the local UPS store. It turned out that I could have two creates built on two pallets, one created for the cabinet and the other for the 1000Z's tuner chassis with its dial made of 6 layers of etched glass. If you break the glass on this dial you are pretty much SOL so I instructed my UPS store contact to foam pack the tuner using 4" foam on all 4 sides before crating it. The crates were trucked to Oakland, CA in a regular UPS brown truck and dropped off at their large freight division where the radio and chassis were loaded on to a larger freight semi for the radio's 3-day journey to southern New Mexico. The cost for the two crates was an amazing $237 and the shipping cost was just over $300.

THE RESTORATION OF ZENITH STRATOSPHERE #754322

The restoration of Zenith Stratosphere #754322 would start on July 21, 2007 and end on July 9, 2008. What ended up in my driveway in late July of 2007 was a complete cabinet, a heavily rusted radio tuner chassis, complete except for three missing tube shields. That was it. The mission was clear: I would have to find or reproduce the missing amplifier; tuning knobs; l 9” dial bezel; shadowgraph escutcheon; all three speakers; two, 12” Jensen A-12 Concert speakers; and the very rear 5” Jensen “Q” horn tweeter.

At first it seemed to be “Mission Impossible” but as I reached out to fellow collectors George Kaczowka and John & Jean Goller, I became hopeful I could find or reproduce the missing parts needed to bring my radio back to life.

In August of 2007 I received a call from a collecting friend who said he knew of a person who had the entire 1000Z tuner, amplifier and speakers for sale for $18,000. In the end, I learned that there were about four 1000Z chassis, amplifier with speaker sets out there.

Having the two major radio components that could not be easily reproduced, the elaborate inlay designed cabinet and the chrome radio tuner with its 6 layers of etched dial glass, was going to be key to my ability to get this radio play again.

THE RECREATION OF THE AMPLIFIER & TWEETER BOX

After asking questions on the website AntiqueRadios.com and talking to Stratosphere owners George Kaczowka and John Goller, I made the decision to reproduce the missing 50 watt amplifier from a traced pattern made from George's 1000Z amp. He had to take it all apart in order to remove the rust and repaint it. George's tracings and measurements gave me the needed information, right down to where the tube, capacitor, transformer and choke holes went.

George also provided all the measurements and tracings to reproduce the metal box that acts as a stand for the “Q” tweeter and houses the crossover electronics for the tweeter.
Once I had George's tracings, I copied them directly to a large format blue print. This allowed me to transfer the tracing information without redrawing the whole thing and running the risk of getting something wrong.

The next step with the reproduction of the amplifier was to find a machine shop willing to take on the project of reproducing a one-off copy of the Stratosphere amp and tweeter box. I found a local shop that mainly produced custom automobile parts and housings for commercial air conditioning units. I handed off my blueprint to the machine shop and they scanned it in to their Computer Automated Drawing (CAD) system and had my blueprint redraw allowing for binds and cuts in order to reproduced the amplifier and tweeter speaker box.

In a few weeks I had in my workshop copies of the amplifier and tweeter box. The originals Stratosphere amplifiers were copper plated so both pieces were sent off to be copper plated and painted using black gloss lacquer paint.

It was now time to turn the amplifier project over to Richard Majestic, an accomplished audio design engineer, who just happened to retire in my hometown of Las Cruces, NM. The challenge Richard had was to build an amplifier as close to the original as possible, using stock transformers and chokes. This was accomplished with some slight reconfiguration of the position of the transformers and chokes on the chassis.

If you want to know more of the technical information on the recreation of the 1000Z amplifier you can go to “Engineer's Notebook” PDF at the link below:

 Download the PDF here.

REPLACING THE MISSING STRATOSPHERE SPEAKERS

Two of the three Stratosphere speakers, the 12” A-12 Jensens, are fairly common; the third speaker, the Jensen “Q” horn tweeter is another story. The 12” A-12's were often used in the speaker cabinets of the Hammond Organs in the 1930s and 1940s. Zenith suspended the A 12s on a metal speaker pedestal with a special rear center speaker wire hook-up. The screw covered center hookups are unique to the Stratosphere speaker; so far I have not come across the same setup. The center covers are difficult to come by and when you do find them they are found on $2,000 Jensen theater speakers. I found my rare speaker covers for my Stratosphere in Australia on Ebay. The covers were in good shape and worked perfectly after I cut out the holes in the two A-12 speaker pedestals.

The Jensen “Q” horn tweeter is very rare and almost impossible to find. I've seen two “Q” tweeters sold on Ebay since I bought my Stratosphere, both for more than $6,000 apiece. Because of the extreme rarity and high cost I decided to go another route.

I already owned a pair of 5” Jensen “Q” tweeters from a parted out 1933 Scott All Wave XII set. These were the more common non-horn speakers used in 1930's E.H. Scott radios. From the rear the Jensen “Q” horn tweeter and the later “Q” tweeter look identical. In order to create a look-a-like “Q” horn tweeter, I fabricated a metal horn with an adaptor and attached it to the tweeter.

The next step was to find a Jensen speaker pedestal that would hold the look-a-like tweeter. I found on Ebay an early 1930's Jensen model 18 speaker on a pedestal that closely resembled the original “Q” horn tweeter pedestal. I had to cut the pedestal down by about an inch and create a center connector plate with a cover just like what was created for the Jensen A-12s.

REPRODUCING THE MISSING BEZEL & ESCUTCHEON

One of the great challenges on this radio's restoration was to find a Stratosphere owner that was willing to let me use their bronze dial bezel and Shadowgraph brass escutcheon to make molds from. I was very fortunate to find Jean and John Goller, who went out of their way to take their 1000Z dial bezel and escutcheon to the Smooth-On Mold Company in Indianapolis. Jean actually attended a class and Smooth-On helped her create the molds from their original 1000Z parts for my project.

Once I had the newly created bezel and escutcheon in hand, I airbrushed them a brass color and aged them with a tinting process to match the finish on some of my 1936 6-S-27 Zenith radio bezels.

FINDING REPRODUCTION THE KNOBS

The only thing that I know of that is reproduced on the 1000Z Stratosphere is the tuning knobs. Larry Bordonaro at Old Time Replications in Van Nuys, CA does a nice job of reproducing both versions of the 1000Z knobs for less that $200. The knobs come unpainted so they had to be painted a bronze color. It's my understanding that the original 1000Z knobs were made of wood and then bronzed.

THE CABINET RESTORATION

Without a doubt, the skyscraper inspired art deco cabinet created by furniture designer Frank Johnson is part of the uniqueness and beauty of the 1935 Stratosphere radio.

I was very lucky with my Stratosphere cabinet. I've owned a lot of radios and jukeboxes over the years and this cabinet did not have any chips, scratches or dents. One hundred percent of the veneer was on the radio and it was glued down. My good friend Brad Merchant from the Jukebox Garage in Phoenix, AZ has restored hundreds of 1930's and 40's jukeboxes and said that my 1000Z cabinet was the best cabinet he had seen in his 30-year history of restoring cabinets.

There has been a debate over the years regarding the finish on the Stratosphere. Some say the radio's finish is lacquer and others say it is shellac. My radio cabinet had about 40% of the original finish on it, which appeared to be shellac. The sides and top had been refinished in lacquer many years ago.

I asked Merchant about the use of shellac on this cabinet and he explained that in the 1920's, 1930's and even into the 1940's, furniture companies used shellac as a grain filler base coat in order to build up a smooth finish on uneven wood surfaces. This technique was used mostly on exotic veneers like the Australian laurel wood and Carpathian elm burl found on the 1000Z. On the 1000Z cabinet, finishers needed to build a heavy base coat over the uneven veneers in order to get a smooth flat finish like on the Walnut sides and top of the 1000Z cabinet. After cabinet finishers would build up the finish with a couple coats of shellac, thinned with about 50% alcohol, they would polish out the shellac to a smooth flat finish. This is sometimes called a French polish technique. Shellac is soft and tends to dent and scratch easily, so the final finish coats were shot on the radio using lacquer, which is very hard and seals and protects the cabinet.

One of the little known techniques the radio and jukebox manufacturers used was they dyed their veneers. Because of this you want to avoid sanding veneer. When you sand a 1930s cabinet's veneer, you sand away the original color in the factory wood. In order to avoid sanding the veneer on my Stratosphere cabinet, I used Stanley straight edged razor blades and slowly shaved the original lacquer and shellac finish. This process took over 100 straight blades and 50 hours to accomplish. The trick is to stop shaving the cabinet's finish before you get to the veneer. This technique preserves the original color and leaves all of the wood grain filed with the original finish. There were some areas where I used a quick strip method by brushing the stripper on and steel wool of the stripper right away. This had to be done in areas where there was heavy shellac build up on the cabinet.

After all of the finish was taken down, and just before reaching the veneer, I rubbed the cabinet with steel wool and wiped it down with a tack cloth. The cabinet was then shot with several coats of lacquer sealer. Since the original finish was still acting as wood grain filler, the finish buildup started right away. The cabinet was then shot with a special water-soluble red tinted stain. This stain is a very light coating, almost unnoticeable. For a slight contrast, the stain was applied heavier on the burl wood on the sides, front and sliding doors. At this point, all of the light colored wood inlay had a red tint to it. In order to get rid of the red tint, we took Q-Tips, wetted them and went over the entire inlay. After the red tint was removed from the inlay wood, the cabinet was shot with two more coats of lacquer sealer. We let the cabinet cure for 12 hours. Then it was taped off with green lacquer masking tape so the trim areas could be shot in black lacquer. After all of the black lacquer was shot on to the cabinet, the masking tape was removed and the cabinet was cleaned off. At this point, the cabinet was ready for the final heavy lacquer finish coats. Once the final lacquer coats were applied, the cabinet was left to cure for one week.

Once the finish cured for a week, a three-step process was used to rub out the finish. The cabinet was first rubbed out using 3M Super Duty Running Compound 05054, followed by 3M Imperial Hand Glaze 05990. In the final step the cabinet was polished with a felt-rubbing block.

The end result of the three-step process was a smooth, low gloss piano like finish. The entire cabinet restoration took over 70 hours.