Quote Originally Posted by cropwell View Post
My late next-door neighbour was a builder. His trick (and I suspect a trick common in the trade) was to give a good squirt of washing-up liquid into the compo mixer. It foamed up the mortar and made it lighter to handle and slippier off the trowel.

Of course for filling beams you really need high density, low elasticity, acoustic decoupling air.
Making foam concrete the DIY way is basically taking that a step further. I've been looking at it for possibly making raised garden beds. Suggesting it for damping a machine is primarily for the practicality of not being too heavy for one person to handle on their own, which is a consideration for all of my construction work.

Kit