Fusion Message Board

In this space, visitors are invited to post any comments, questions, or skeptical observations about Philo T. Farnsworth's contributions to the field of Nuclear Fusion research.

Subject: Re: Spot Welding?
Date: Oct 06, 7:48 pm
Poster: Jim Lux

On Oct 06, 7:48 pm, Jim Lux wrote:

>Silver soldering will outgas in vacuo for a while and may even pickup moisture when exposed to air, depending on how well you removed the flux agents. Silver soldering is more of an art and requires a hot acetylene/air flame as in a prestolite torch or an oxy/acetylene torch. Use the smallest tip possible and a micro flame.

Silver soldering isn't a problem for me (I have the stuff, and even a oxyhydrogen micro torch so there isn't a sooting problem), its just whether stainless (and the solder) would stand up to the temperatures. (Of course, there is that technique that was discussed of running a coolant down hypodermic tubing).. Spot welding seemed easier..

>I have mused over many grid making schemes. just a simple loop and hook followed by a crimp should suffice in any demo fusor provided the wire is properly annealed to avoid breaking when crimped.

Most of the tungsten wire I have is quite annealed (you can tie knots in it), but, somehow it seems that tying it together is a bit clunky.

>I have also mused over spot wleded "butt joints" which would be the ultimate ring system, but it requires a special jig be made to secure the wires for spot welding.

Right up there with investment casting a tungsten ring, I suspect...

I wonder how well graphite or carbon would work? Its pretty refractory, and the resistance shouldn't be a factor. Support and fragility might be an issue.

Or some sort of electric machining... Make it out of thick wires, and then etch it down

I'll probably just rig up a spot welder and use tungsten or titanium or stainless..