Re: Electrical connection to a Tungsten rod
Sulaiman, Wed Jul 03 2019, 11:59AM

I've successfully used the brass inserts with two screws that you find in 'chocolate block# electrical terminal strips
e.g.

Re: Electrical connection to a Tungsten rod
Signification, Fri Jul 05 2019, 11:03AM

@Sula...
Thanks for the tip. It looks like the 60A connector may work! One thing I am worried about: Since Tungsten is said to be so brittle (one of mine is only 1" long, 3/8" diameter, and 70%W / 30%Cu), and the clamp-down on the rod is not completely circular when tightened (by the screw), do you think the un-even clamp will possibly result in chipping/cracking if tightened enough to carry the full 60A?

Re: Electrical connection to a Tungsten rod
hen918, Fri Jul 05 2019, 01:40PM

I doubt it; the brass terminal is soft enough to deform and reduce the point load on the tungsten.

Re: Electrical connection to a Tungsten rod
MRMILSTAR, Fri Jul 05 2019, 03:04PM

With a drill and a band saw you can make your own custom clamps that are guaranteed to fit. I have made several out of aluminum but you could also use brass.

Re: Electrical connection to a Tungsten rod
Signification, Sun Jul 07 2019, 03:51PM

Also, I have a friend who likes guns. Since 3/8" is close to 9mm, I asked for a spent brass casing--It was a tiny bit too small to insert the rod. Now I need to try a .38" since that is a wee bit larger. So far I can't find one. Does a .38 mean 0.38"? Thanks all...

Re: Electrical connection to a Tungsten rod
2Spoons, Tue Jul 09 2019, 12:06AM

"A tiny bit too small" sounds ideal. Flare the opening, then force the shell onto the rod with a hammer. perfect friction fit.
You can probably buy 3/8" brass tube at a model shop, and use the same trick.

Re: Electrical connection to a Tungsten rod
Sulaiman, Tue Jul 09 2019, 08:09AM

Brass has about 4x the linear coeficient of thermal expansion of tungsten,
so a push-fit may fail.

Re: Electrical connection to a Tungsten rod
Ash Small, Mon Jul 15 2019, 10:12PM

Something that mabe worth looking at is copper or brass fuel, gas or water pipe fittings. Fuel/ gas pipe is avainable in 3/8", water pipe compression fittings are available in 10mm as well as Imperial/American sizes. You may need some copper foil or similar as a shim, but I'd look at what's available locally.

Re: Electrical connection to a Tungsten rod
Sulaiman, Tue Jul 16 2019, 12:24AM

The electrical connection of course needs to be good because of the high current.

If the spark gap is expected to be used at high current for a continuous period then cooling of the electrodes becomes vital also,
at least a fan-cooled heatsink, or a large heat spreader, for each electrode
preferably with air blasting through the gap.

Overall, a high current spark gap is a very noisy component.

Re: Electrical connection to a Tungsten rod
radiotech, Wed Jul 17 2019, 10:30PM

Could you treat the rod in an induction heater field inside a Pyrex flask
filled with hydrogen ?

The Chinese modules are cheap, and someone her hacked an induction cooktop a while ago.

Could this 'sintering' make your rod more ductile.

And do protect against the hydrogen blowing the flask to smithereens if it goes wrong.

Re: Electrical connection to a Tungsten rod
2Spoons, Thu Jul 18 2019, 02:00AM


Thats more likely to have the opposite effect and make it brittle.