Tungsten circular current electrode
Signification, Tue Jun 25 2019, 03:01AMI am working on various spark gaps. This one is circular. and must be able to handle a capacitor-triggered spark (plasma) circular gap (one electrode). I need some very tough electrodes that can take a LOT of high current repetitive pulses and heat. Stripped 8 and 10 gauge magnet wire can be simply bend into a circle but gets eaten away much too fast (it works great until then).
I was thinking that the rod found down the middle of a spark plug would work (tungsten, beryllium, iridium, etc.), but how do I solve the problem of bending such material into a closed circular loop and attaching a wire lead to it--any ideas?
Re: Tungsten circular current electrode
Sulaiman, Tue Jun 25 2019, 05:03AM
Pure tungsten rods can be purchased via eBay etc.
e.g.
etc.
I have used similar for sgtc, if using more than a few watts the electrodes will need heatsinking.
Maybe a steel washer could be used as the outer ring ?
Nichrome wire or stainless steel wire may be an option ?
Sulaiman, Tue Jun 25 2019, 05:03AM
Pure tungsten rods can be purchased via eBay etc.
e.g.
etc.I have used similar for sgtc, if using more than a few watts the electrodes will need heatsinking.
Maybe a steel washer could be used as the outer ring ?
Nichrome wire or stainless steel wire may be an option ?
Re: Tungsten circular current electrode
Signification, Wed Jun 26 2019, 06:00AM
Thanks much,
I am going to look into it right away. ...ever heard of circular Tungsten loops?
Signification, Wed Jun 26 2019, 06:00AM
Thanks much,
I am going to look into it right away. ...ever heard of circular Tungsten loops?
Re: Tungsten circular current electrode
klugesmith, Wed Jun 26 2019, 07:02AM
Aren't tungsten rods for TIG welding generally brittle?
Some ideas that came up on another forum recently, for refractory wire that can be bent into a circle:
- stranded or braided tungsten wire (perhaps made as metal-evaporation filaments?)
- Tungsten-rhenium alloy wire, in standard percentages for thermocouple use, is allegedly more ductile than pure W. Here are some W-Re wire properties and diameters for sale:
- Niobium wire in many diameters is easy to get and easy to work with. That element has about the 6th highest melting point of all. Popular these days in jewelry and chain mail. Check out theringlord.com. Nb wire in many bright anodized colors, but plain is a bit less expensive.
klugesmith, Wed Jun 26 2019, 07:02AM
Aren't tungsten rods for TIG welding generally brittle?
Some ideas that came up on another forum recently, for refractory wire that can be bent into a circle:
- stranded or braided tungsten wire (perhaps made as metal-evaporation filaments?)
- Tungsten-rhenium alloy wire, in standard percentages for thermocouple use, is allegedly more ductile than pure W. Here are some W-Re wire properties and diameters for sale:
- Niobium wire in many diameters is easy to get and easy to work with. That element has about the 6th highest melting point of all. Popular these days in jewelry and chain mail. Check out theringlord.com. Nb wire in many bright anodized colors, but plain is a bit less expensive.
Re: Tungsten circular current electrode
Signification, Tue Jul 02 2019, 05:25AM
Thanks all!!!
@klugesmith:
Is Tungsten brittle? I really don't know, but this may be a bit telling.https://www.youtube.com/watch? v=K_LToWAZoSo
...hard to understand the speech.
Signification, Tue Jul 02 2019, 05:25AM
Thanks all!!!
@klugesmith:
Is Tungsten brittle? I really don't know, but this may be a bit telling.https://www.youtube.com/watch? v=K_LToWAZoSo
...hard to understand the speech.
Re: Tungsten circular current electrode
Signification, Tue Jul 02 2019, 05:30AM
Signification, Tue Jul 02 2019, 05:30AM
Signification wrote ...
Thanks all!!!
@klugesmith:
Is Tungsten brittle? I really don't know, but this may be a bit telling.
...hard to understand the speech.
Thanks all!!!
@klugesmith:
Is Tungsten brittle? I really don't know, but this may be a bit telling.
...hard to understand the speech.
Re: Tungsten circular current electrode
Signification, Tue Jul 02 2019, 05:32AM
Signification, Tue Jul 02 2019, 05:32AM
Signification wrote ...
Thanks all!!!
@klugesmith:
Is Tungsten brittle? I really don't know, but this may be a bit telling. from youtube.
...hard to understand the speech.
Thanks all!!!
@klugesmith:
Is Tungsten brittle? I really don't know, but this may be a bit telling. from youtube.
...hard to understand the speech.
Re: Tungsten circular current electrode
2Spoons, Tue Jul 02 2019, 10:37PM
Its brittle when cold. Heat it red hot to bend it.
2Spoons, Tue Jul 02 2019, 10:37PM
Its brittle when cold. Heat it red hot to bend it.
Re: Tungsten circular current electrode
Signification, Thu Jul 11 2019, 07:30AM
...finally got it! I used one of those 12mm laser module heatsinks (NOT the kind that uses the screws, but the type that makes full surface contact). I first wrapped the rod with stripped 16AWG Cu wire and hammered it in with a rubber mallet...very tight fit. Looks like 17AWG would be perfect. 18AWG--too small. The heatsink mounting holes were used as wire contacts.
Signification, Thu Jul 11 2019, 07:30AM
...finally got it! I used one of those 12mm laser module heatsinks (NOT the kind that uses the screws, but the type that makes full surface contact). I first wrapped the rod with stripped 16AWG Cu wire and hammered it in with a rubber mallet...very tight fit. Looks like 17AWG would be perfect. 18AWG--too small. The heatsink mounting holes were used as wire contacts.
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