It's not a lot, because I printed it with an infill of 10%. You can increase it, and make it around 40% or 50%. Some people also use sands to make it heavy. For now it doesn't bother me and I think because I'm putting other things on top of the tray, it doesn't move around easily.

To give a more solid feel and "woody" sound[1] you might try filling with epoxy or expanding foam.[2][3]

[1] https://www.youtube.com/watch?v=-gwXJsWHupg

[2] https://old.reddit.com/r/3Dprinting/comments/3hewrd/has_anyo...

[3] https://old.reddit.com/r/ResinCasting/comments/9v03mp/fillin...

or clay.

https://youtube.com/shorts/9YKbf5pJy9M

It can be a bit painful to get hold of, but I’ve been experimenting with micro-suction sheets, which allows you to “stick” things down to smooth surfaces, without adhesives (the material surface is full of tiny pores that act as millions of mini suctions cups). And allows you to easily remove, and re-stick them later without leaving any goop behind.

It’s a nice way to stop these types of 3D prints from sliding around in surfaces, without having to resort to weights or lead shot, which it way more painful to integrate that you would expect.

https://sewelldirect.com/products/airstick-microsuction-tape

Silicone sheets should also work well for this.