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Re: Bombing, Neon Products 'trodes



On Thu, 14 Dec 1995, ja wrote:

> Hello all,
> 
> I recall in past posts that some of you were using Neon Products 
> 'trodes.  I have used them for several years now with good success, but 
> have a weird phenomenon with their 12mm 50ma unit.
> 
> For me, this 'trode has always been hard to process, since it seemed very 
> easy to overprocess.  Evidence of the overprocess was simply a slight 
> ring of soot on the ceramic collar around the hole.
> 
> What's weird is that I've recently found that this ring of soot has
> nothing to do with overprocessing.  When it occurs, it can be _completly_
> removed by admitting about 3 torr of air and re-bombing a few seconds.  
> Like if never even happened.  It can happen even with underprocessed 
> trodes.  The only clue I have is the way is dissappears with re-heating.
> 
> I don't always get this soot.  It seems to happen during the final heating
> at 500ma.  I have been taking some notes to try and indentify the
> phenomenon, and it _seems_ to get worse at reduced pressures. 
> 
> In a nutshell, my bombing proceedure is:  warm tube, evacuate.  Fill with
> 3 torr air, warm, increase to 225ma or so, when temp. crayon has shifted
> color, go to 10x the 'trode rating (this case 500ma), reduce to 1 torr and
> bomb till cherry red. 
> 
> By the way, this soot seems to in no way effect the tube.  My shop sign's
> electrodes have this and have burned nearly 5 years with no aging effects
> at all. 
> 
> Anyway, does any of this make sense?  I know form repairing other guys 
> stuff that this light ring of soot happens to others too.
> 
>     -John Anderson
> 
> 
> 
John, That makes a lot of sense.  I have it too.  I am using Eurocomm 
electrodes which I like very much.  They seem to heat very evenly an 
completely.  I have noticed that ring around the collar area as well.  I 
bombard using about the same technique.  I can't explain it either however 
like you said, others are getting it too.  I thought that I may have been 
bombarding for a tad too long but at this point I am not sure.  I have a 
feeling you will see others noticing this as well.  Lets hope it doesn't 
effect the life of the tube.  
Maybe I didn't give you anything to chew on but I had to comment to let 
you know you are not the only one that had seen this happen.
Take it easy 
Howie
References: