FAQ - Cleaning your view port

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Richard Hull
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Real name: Richard Hull

FAQ - Cleaning your view port

Post by Richard Hull »

View ports get fogged to nearly opaque over time in any fusor. This demands an occasional cleaning of the inside surface due to deposition of mostly grid material and any other evil lurking in the fusor.

Most of us use the rugged tungsten grid assemblies. Tungsten is unusually tenacious and chemical cleaning is just not possible for the most part. The deposits must be abraded from the glass. I have generally posted on this in past posts, but I have found a rather rapid way to take care of this situation. My viewport over the last two years has become so occluded that only a yellow hot grid could be seen through it. In the past, I have used a paste fine abrasive and a cloth and 1-2 hours of hand work to clean my port.

I now use a 1/2-inch diameter wooden dowel in a drill press loaded with an aggressive black metal polish to rapidly, (less than 1 minute), to do the job. The black stick abrasive was found at Harbor Freight. I chucked the dowel in my drill press and while running I forced the wet dowel end into the stick to pick up the compound. I then placed the occluded glass face-up on a pad of cloth on the drill press base as a cushion. I then held the 2.75 conflat by hand and put a little Xerox glass cleaned into the conflat well over the glass to help distribute the compound as the dowel was carefully and with very little pressure onto the glass. As this gentle rotating dowel did its job, I moved the conflat around by hand so the dowel scoured the entire surface. On the first 30 second operation, I could easily see through the glass! I cleaned out the compound with more Xerox glass cleaner and then placed the glass on a pure with piece of paper. This allowed me to see areas that needed a bit more attention. I repeated the above process 2 more times before 100% transparency was noted.

Caution! - It is imperative that the lightest of touches is needed when pressing the dowel on the glass. I later used jewelers rouge as a backup fine polish on a fresh dowel.

Note: 100% clarity is what I mean. This is the 4th cleaning since 2004 on this viewport. The normal brown solarization so common to long operated X-ray tubes remained, of course. There is no real solution here for this malady. One must live with it or purchase a new $75-$100 viewport. Heavy solarization will affect the colors viewed through a cleaned view port. Again, that is tuffski-stuffski, don't like it?...pull out your wallet.

Images below.

Richard Hull
Attachments
Lens cleaner and tube of stick abrasive used in the effort
Lens cleaner and tube of stick abrasive used in the effort
Closeup of dowel with polish end showing
Closeup of dowel with polish end showing
Progress may have been a good thing once, but it just went on too long. - Yogi Berra
Fusion is the energy of the future....and it always will be
The more complex the idea put forward by the poor amateur, the more likely it will never see embodiment
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