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Re: about my processing

Posted By: SVP Neon Equipment
Date: Tuesday, 19 April 2011, at 2:04 p.m.

In Response To: about my processing (terlsworld)

> I burn the tubes to 580F,

Okay, that's about 304°C, which is good. What type or who's meter do you use to determine this?

> I am using voltarc
> glass 13mm with EGL 30-45ma electrodes.

The size and type of glass and electrodes does not usually play a roll in Hg migration problems, unless the electrodes are miss-matched (one bigger than the other or different brands on the same unit).

> I put a mercury droplet about 1&1/2 times the
> size of a BB in the tube.

Just as a wild guess - because I don't have a BB in front of me and I'm going by long-term memory how big one is - I would say you are using more than 500mg, which is way too much. All you need is less than 100mg.

> It has been my
> practice to process the tube and then roll
> the mercury in and seal the electrode. I
> don't wait to see if its going to light up I
> just assume it will and 99% of the time it
> does.

Unfortunately this is not the best practice. Once the Hg is in the tube and starts to vaporize, it turns whatever gas is in there blue. Even if you put a shot of air in the tube, once the Hg vaporizes the discharge will turn blue. So by dumping the Hg in the tube before burning it in, you cannot tell if it is a "good" tube or not until it's too late (the tube starts staining or dimming out).

> The mercury often gets trapped on the
> ceramic disk inside the elctrode.

Inside the metal electrode shell, or around the outside of the ceramic collar? Considering the amount of Hg you mentioned, either scenario is rather unusual. There can be different reasons why Hg sticks to the outside of the metal shell. What comes to mind immediately is dirty Hg and/or dumping the Hg on a hot electrode shell.

> Sometimes it rolls a bit past the electrode and
> usually stops at the first turn.

Does it stick to the glass at the first turn? Or is that just all the further you try to roll it? If it sticks to the glass it is an indication of dirty Hg and/or glass and the presence of contamination. As the others mentioned, you need to get some Hg on each electrode. If you are not doing this you will have problems even with a conventional transformer, but especially with an electronic.

> I then light the tube using the CPI6000 transfomer
> and over the course of an hour or 2 the
> mercury slowly makes its way to the other
> side.

Manufacturers of electronic transformers specifically recommend to use a conventional transformer to thoroughly burn-in the units before running them on an electronic. There are several reasons for this and they can probably advise you better than I can. But the fact remains, you should use a conventional transformer to burn-in the units, even red units. No matter how well a tube is processed there are always contaminants left in the tube. These contaminants affect the operation of electronic transformers, which may be part of your problem. Burning in, or "ageing", with a conventional transformer will "clean up" the remaining contaminants through a chemical reaction with the coating inside the electrode shell. Electronic transformers do not do this very well.

> When it gets there and the whole tube
> is burning nice and bright I figure its
> done. I haven't been physically rolling the
> mercury thru the tube. would that make a
> difference?

Yes. See above.

> For 13mm glass I use the formula
> 24 minus the glass size so I fill the tubes
> to about 11 to 11 1/2. for 12mm glass I fill
> to about 12 to 13

What are you using for a fill pressure gauge? Personally I think you are putting a little too much gas in. But assuming your fill gauge is accurate, we are kind of splitting hairs. I use 10mm pressure for 13mm glass and 11mm pressure for 12mm glass. This is based on old charts. Some newer charts recommend even less.

> I heard or read somewhere
> to add a tad extra gas for short tubes which
> is what I mostly make.

How short?

> So does that add any insite?

Yes it does.

> Do you think burning in with a
> magnetic transformer would make a
> difference?

Definitely!

Mark

SVP Neon Equipment

Messages In This Thread

• Massive Mercury Migration -- terlsworld -- Saturday, 16 April 2011, at 5:19 a.m.
  • Re: Massive Mercury Migration -- winslow -- Saturday, 16 April 2011, at 1:19 p.m.
    • Re: Massive Mercury Migration -- neontek -- Sunday, 17 April 2011, at 5:41 p.m.
      • Re: Massive Mercury Migration -- Winslow -- Monday, 18 April 2011, at 2:37 a.m.
        • Re: Massive Mercury Migration -- John Anderson -- Monday, 18 April 2011, at 3:58 p.m.
          • Re: Massive Mercury Migration -- Winslow -- Tuesday, 19 April 2011, at 1:26 a.m.
  • Re: Massive Mercury Migration -- SVP Neon Equipment -- Saturday, 16 April 2011, at 6:16 p.m.
    • about my processing -- terlsworld -- Sunday, 17 April 2011, at 5:06 p.m.
      • Re: about my processing -- neontek -- Sunday, 17 April 2011, at 6:03 p.m.
        • Re: about my processing -- Winslow -- Monday, 18 April 2011, at 2:45 a.m.
      • Re: about my processing -- SVP Neon Equipment -- Tuesday, 19 April 2011, at 2:04 p.m.
    • Re: Massive Mercury Migration -- neontek -- Sunday, 17 April 2011, at 6:50 p.m.

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