[WireNut]

This thread could easily go into turntable,plinth,tonearm designs.

[S Clark]

I've been thinking about lead shot (fishing weights) bonded with West Systems Epoxy.

What do you mean by lead wheel weights?

I broke up a bunch of these into smaller pieces and packed them into space around the edges of the box, leaving as little space as possible.  Then I applied the silicon caulking.  Split shot would do, or get a 25 lb bag of shotgun shot from you nearest hunting supply store.  I had access to free wheel weights. 

[WireNut]

I broke up a bunch of these into smaller pieces and packed them into space around the edges of the box, leaving as little space as possible.  Then I applied the silicon caulking.  Split shot would do, or get a 25 lb bag of shotgun shot from you nearest hunting supply store.  I had access to free wheel weights. 

S Clark. Just what I need 

But where can I find a bunch of these?

[S Clark]

Go to any independent tire store.  When they mount a tire, they knock off the old weights and can't reuse them.  Most sell them to scrap yards for whatever scrap lead goes for.  The big stores won't sell them to you because lead is toxic and they have corporate policies about disposal,, but little guys don't care.  10-15 pounds shouldn't be more than the cost of a burger and fries.  The scrap yards are giving about a quarter a pound for wheel weights as of today.