TIG silicon bronze, ala this old tony, looks like it is helpful for low distortion build-ups. Maybe a combination of the screw and silicon bronze. I have had some luck with soft solder. Keep all contact areas large using plates/pins, and keep the flame off the interface. Brownell Hi Force 44 is good stuff and flows well with the correct flux. One may say that it is only good for about 10000psi or so, but that goes a long way with a plate and/or pins.