[600MRG] Litz wire, anyone??

[James Hollander]

Dave,  can you tell us expected antenna current?  Besides physical fragility, you have thermal insulation on all the strands.  Would the I2R loss heat the insulated strands enough to make the weakest strands fail first, then divert current to the rest, etc, domino effect. 
     Re slipstick, suppose 2 skin depths in Cu at 475KHz is 0.2mm, or .008". 
 https://en.wikipedia.org/wiki/Skin_effect#/media/File:Skin_depth_by_Zureks.png 
The equivalent diameter D of copper tubing at least that thick would be equal to
    3.14 x D x 0.008" = (3.14 / 4) (.01")^2 x 692; or  D = 2.16".  
So a 2" copper tubing would be heavy and expensive but RF equivalent and thermally and physically more resilient.
      If you find out more or differently on this topic, by all means I'd appreciate hearing about it.   73, Jim H  W5EST