Mild steel box section pricing

**reefy86** · 30-08-2021

Ah OK I figured that but going from my old drawing I think I had the frame at 4mm and then had the beams that the linear rails and ball screws being attached to at 10mm thick.

**John McNamara** · 31-08-2021

Re Damping.

This (Excellent) paper may interest you of you are thinking of building a machine and filling steel tubes with damping material. There are practical examples towards the end. Of note is the thin flexible layer between the concrete and the way it is sectioned within the tube in plastic bags in one case, it is not just poured in.

The machine designed in the paper, a tool and cutter grinder was actually commercially built by Star.

https://my.mech.utah.edu/~bamberg/re...mberg-PhD.html

Youtube "edge precision" to see one working.
https://www.youtube.com/watch?v=N2vPng7O5bQ

You can download the paper from MIT
https://dspace.mit.edu/handle/1721.1/88839

Regards
John

**Neale** · 30-08-2021

I added steel strips to the faces where the rails bolt on - good for fixing but no damping effect, I suspect.

**reefy86** · 30-08-2021

Sand is your friend for dampening but wouldn't surprise me if that's gone up 5 times the price too lol.

**Kitwn** · 30-08-2021

Originally Posted by reefy86

Sand is your friend for dampening but wouldn't surprise me if that's gone up 5 times the price too lol.

I've wondered if foam concrete would do the trick. Less weight and the air component of the mix is relatively inexpensive.

Kit

**cropwell** · 31-08-2021

Originally Posted by Kitwn

I've wondered if foam concrete would do the trick. Less weight and the air component of the mix is relatively inexpensive.

Kit

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.

**Kitwn** · 31-08-2021

Originally Posted by cropwell

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