[ohohyodafarted]

Well gang it is now crunch time.

John Folsom and I have been formulating a game plan for our project.

As has been discussed previously, through our experiments with our Helium mass spectrometer leak detector, John and I have be able to determine that the pesky leaks that send most all the 15GP22 tubes to air, occur in the weld that joins the 2 halves of the ultor ring. John and I have discussed several approaches to "healing" the leaks, and the three approaches that seem to hold the most promise are:

1. Nickel plating
2. Frit Glass
3. Vac Seal

For the past several weeks I have been working with a local electroplater to try and devise a method to nickel plate the weld on the ultor ring. Today I got samples back from the plater and they "look" good, but we need to do a couple more experiments to see if this will actually accomplish what we want. So the first test will be to place the plated samples of the ultor ring in an oven at 650F for several hours to see if the nickel plating will hold up to the temperature of the rebuilding oven at RACS. We need to test the Nickel plating to see if it will have a tendency to flake off when we heat it in the rebuilding oven. I will be performing this test on Sunday afternoon. If the plating passes the test, then on Wednesday Feb 8th, I will be taking a 15Gp22 dud which as been tested for leaks and is marked where the leaks are located, to the plater to be nickel plated.

That nickel plated tube, and a second tube which has also been leak tested and found to have leaks on the weld, will then be packed up and air freighted off to RACS. The second tube that was NOT nickel plated will be a guinea pig for the VacSeal experiment. In this experiment, we will have RACS use VacSeal to coat the weld on the ultor ring and then cure the VacSeal in their oven for 1 hour at 500F. Then Racs will apply frit glass to both the nickel plated and the VacSeal tubes just as they did for the tube that RACS and Jerome Halpern successfully rebuilt 2 years ago and shipped to ETF convention. We have 2 rebuilt gun assemblies ready to ship along with these two tubes.

We also have a crate of 4 more 15GP22 duds ready to ship by ocean freight, and that crate will be leaving for France before very long.

Also in anticipation of Southwest Vacuum closing(the company that rebuilds the electron gun assemblies), John and I have sent a shipment of 12, 15GP22 guns and glass stems to Southwest for rebuilding, with instruction to rebuild as many guns as can be rebuilt within our limited budget of $3000.

We are hopeful that we can seal the leaks on the weld of the ultor ring, and that we will now be able to successfully rebuild the 15GP22 leakers. Only time and lot of money will be able to determine if we will be successful.

The one thing we know for sure is this, All along the entire tv restoration community had no idea that it was the weld on the ultor ring that was causing the tubes to go gassy. These defective welds are why, even before John and I made our attempts at rebuilding, the previous attempts 20 or 30 years ago failed.

Now that we know the leaky welds need to be addressed in order to get the tube to hold a vacuum for the long haul, we have a chance of finally solving the problem of the 15GP22's that will not hold a good vacuum.

A photo of the nickel plated ultor ring sample is displayed below for your eyes to gaze upon. Very shiny and smooooooth along the weld. Because of the way plating works, the nickel wants to plate onto the area that is closest to the nickel anodes that hang on the sides of the plating tank. That just happens to be the weld on the edge of the ultor ring. So the nickel builds up nice and thick and shiny and very smooth on the weld. Hopefully the nickel plating will seal the leaks in the weld.

We think we are finally very close to solving the problem and successfully rebuilding these tubes. Think good thoughts that the nickel plating passes the oven test on Sunday afternoon.

Bob and John