Use mild steel filler wire, the type with the copper colored coating like mig wire has, for tig welding moly. I work at a place that makes experimental planes and that is what we use.
Also, try to track down Shaun Vesey or Jarrod Clendon. They had a nice cart wheel rig Shaun made from scratch in the 90's. They won a lot of races including (I think) a GP at Ohakea. I don't know what happened to the rig but if they still have it I am sure a few $'s will secure it. You will have to check the Wangarei (no 'h') phone book for a contact #
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