Will sharp sand suffice for epoxy granite ?

[flanajb]

Hi,

I am struggling to source the required aggregate for making epoxy granite here in the UK and was wondering whether I can oven dry builders sharp sand and use that ?

The other question I have surrounds whether it is acceptable to make a 2700mm * 75mm * 150mm beam which I intend to use as the x- axis rail ?

I was thinking that I should insert some reinforcing bar of some sort so as to give it strength, but someone suggested that you should not do this as it will cause cracks in the epoxy when it dries due to the epoxy shrinking ?

Thanks

[janaf]

Sand, don't know.

Beam: all depends on what load you will put on it.

Reinforcing: If it is the 2700mm long beam I would definitly reinforce it unless maybe, maybe not if it is supported all the way along its length.

EG will not shrink if you use solvent-free epoxy as you should, It will cure in a chemical process, not dry up.

[preciseformwork]

Hi Flanajb, I'm no expert in this field; I build reinforced concrete structures. The steel will not cause the concrete to crack; with shrinkage. The steel actually works completely opposite and stops the cracking; as we put 'anti-cracking' bars in corners; as shear force is applied more in corners and causes more cracking.

Assuming it's 2.7m long by 75mm wide, 150mm deep; I would certainly reinforce with steel, and small little links, you will want a slightly larger aggregate would also help. Maybe a little single to give a bit more strength; sharp sand a little on the weak side. You might be able to tie some simple wire depending what sort of load you're putting on it.

I'm no expert at all; but would aluminum not be a better material for your requirements; lighter, greater tensile strength?