Quote Originally Posted by Kitwn View Post
John,
I haven't tried this but have wondered if polystyrene concrete could be used to damp the gantry without it getting too heavy. I found an article once (don't have it to hand I'm sorry) that described using up to 60% by volume of polystyrene beads (you can buy them for making bean-bag furniture) to make concrete for light-weight structures. It's still quite strong at that percentage and I think the density came out at a little over 1Kg/litre.
Hey. Thanks! That's quite interesting. I was thinking of something similar with perlite and concrete or epoxy. I was told that concrete may react with aluminium though somewhere but I can't recall where exactly. Does a anyone have any insight on that? On this note I was looking at some local companies that sell recycled tyres, chipped up for playgrounds. I was thinking that could make a good aggregate for a damping composite maybe, with either epoxy or liquid platinum cure silicone to bind the chunks together in a similar way to making epoxy/granite.

It sound like some tests might be in order, luckily I'm an acoustics specialist with oscilloscope etc here so could at least test a few solutions on a small scale.