[R-390] Filters

[Bob Camp]

Hi

I suspect that the hypodermic approach only woks if you insulate the end of the needle with something. Since the voltage is low, it doesn't have to be anything fancy (paint, wax,…)

Bob

On Feb 17, 2013, at 10:39 PM, KA9EGW <ka9egw1 at britewerkz.com> wrote:

> The hearing-aid welding process I spoke of earlier, feeds the wire through a .003" ID glass tube.  A hypo needle sounds like it has possibilities...except for that it is conductive; dunno how much of an issue that is...
> 
> You're quite right, re-threading one of those drive-rod welders was a PITA job, and type 51S tweezers [like for example Techni-Tool p/n 758TW164] and a 10X eye loupe [Techni-Tool 298IN008] are almost a necessity...
> 
> Sorry [and slighty frustrated] I'm not coming up off the top of my head with anything else that comes right to mind...waitasec...how about those glass capillary tubes they let a little blood climb into then stick one end in a clay block to do a spun hematocrit?  Would one of those be small enough?
> 
> 73, Brian KA9EGW
> 
> On 2/17/2013 7:32 PM, Bob Camp wrote:
>> Hi
>> 
>> Feed it down a hypodermic needle or a glass tube.
>> 
>> Bob
>> 
>> On Feb 17, 2013, at 8:07 PM, quartz55 <quartz55 at hughes.net> wrote:
>> 
>>> Ugh.  I've spent the last hour trying to put the wire into the hole in the Teflon sleeve and I can hardly see the wire with +2.25 glasses and a magnifier lamp, much less hold it steady enough to get it welded without touching something else in the meantime.  I'm thinking I'm going to have to automate it somehow.  My sight is just not good enough and my steadiness is not there either.  I think it can be done, it just needs a jig to do it somehow.  The wire is so fine any time it touches something it bends and it's magnetic too, so if I drop it, it immediately goes to the magnet.  That's probably why it was outside the copper cup when I took the end cap off.  It's almost like I need to put the whole form into the cup with the wire in place while it gets welded.  And that means everything needs to be dimensioned correctly while it's inserted.
>>> 
>>> http://i251.photobucket.com/albums/gg287/DogTi/R390A/filtterwireinsert_zps320e9dba.jpg
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