Stupid workbench idea?

[Screwdriver]

If you want a massive bench i.e. very heavy then at the sort of thickness/volume you are talking about, concrete won't add that much mass.

If I was going to make a massive bench, I'd use a thick top, form say a 4-6 inch deep box and fill it with all the junk/offcuts of steel I would otherwise have to dispose of. Weld each piece in place as you go, then if you insist, fill it with concrete. Potting compound,epoxy or even bitumen might be better for filling the voids but could be expensive depending on volume.

A quick calculation suggests a 25kg bag of cement would weigh about 275kg if it was made of steel. You wouldn't want to pick up a bag like that, let alone drop it on your foot.

 

[Gwil]

Aye, but within reason....

Beyond simple reason lies genius......and, sometimes, spectacular success or failure. But it's human nature to push the envelope.

 

[angellonewolf]

hope you got a good floor if you build out of steel and fill it with steel

 

[Screwdriver]

hope you got a good floor if you build out of steel and fill it with steel

Well it's not my workbench

As it happens I do have a rather nice welding bench waiting for its legs.

Link to this forum, It is still waiting...

 

[slim_boy_fat]

Link to this forum, It is still waiting...

Time to stop messing with vices etc, extract the digit and crack on! . Don't forget the write-up

 

[Dcal]

If you want a massive bench i.e. very heavy then at the sort of thickness/volume you are talking about, concrete won't add that much mass.




A quick calculation suggests a 25kg bag of cement would weigh about 275kg if it was made of steel. You wouldn't want to pick up a bag like that, let alone drop it on your foot.

I would check your sums, the volume of the 25kg bag will reduce considerable when you add water.

25kgs of cement will make 12 litres of grout.
I am suggesting reinforced concrete is the way to go and that weighs about 2.5 ton a cube so 12 liters will weigh about 30kgs ( the water required for hydration also plays a part with the increase in weight.)
Steel had a weight of about 7.8 ton a cube so 12 liters weighs about 93kgs.
If you need extra mass there are ways of getting it with concrete. For example you can use iron ore (Magnadense) for the aggregate, which will make concrete which weighs 4.5 ton a cube.
I've used it for submerged gravity foundations where the reduction in weight due to the buoyancy really makes a difference.

Having said that I don't think the added mass is required but I do think reinforced concrete, where the steel and concrete works.togeather is needed and will work great.

 

[Maker]

I say do it, we can all point and laugh "I told you so" if it fails but I don't think it will tbh, it's an interesting idea which will make for a very heavy solid workbench.

 

[Screwdriver]

I would check your sums, the volume of the 25kg bag will reduce considerable when you add water.

I didn't calculate the volume reduction of a bag of cement, a certain poetic license needs to be taken into account so you can visualise a bag made from solid steel.

But yes, steel is "only" four times more massive. At least it won't shatter

 

[Dcal]

3 and a wee bit more but we won't fall out over that.

Steel is best I'm not arguing that -
but steel costs about £800 a ton so that's £6240 a cube.
Concrete is say £100 a cube or about £40 a ton.
A bit of steel and a bit of concrete working as they should, seem a good idea to me.

I don't need another bench (meaning I don't have room for another bench) but I'd be happy to do a test on mass concrete covered with a bit of steel plate, reinforced concrete covered with steel plate and wood covered with steel. All same thickness
I've some 5mm laying about so what about using that as a control?
What's a reasonable size for a destructive test?

 

[Screwdriver]

I think thinforth is about to beat you to it. I suggested filling a worktop with welded up scrap so thats not only free, it also saves a trip to the dump.

But its a digression really because i would never do it myself, I'd just go for a thick steel top and wood substrate if I wanted to damp out vibration.

I once toyed with the idea of a concrete kitchen worktop. Looks great but man what a hassle! With this steel/concrete workbench, something thinforth hasn't considered yet is that after building this half ton monster, he's going to have to flip it over.

 

[bigegg]

with this steel/concrete workbench, something thinforth hasn't considered yet is that after building this half ton monster, he's going to have to flip it over.

I'm going to guess: engine crane.

He already said flipping won't be a problem.

 

[Screwdriver]

I'm going to guess: engine crane.

He already said flipping won't be a problem.

My apologies, I see he says its "not an issue".

I'm guessing he hasn't tried anything like that yet. I turned that big chunk of machine bed over and let me tell you, it's a lot more tricky than it sounds. Ok, so lift it up with the crane. Then what?

I had all sorts of trouble (one man operation) largely because I hadn't thought it through either. Even at 300kg I just assumed it would be relatively easy with cranes blocks and stuff. I guess it would be easier if you were prepared to drop it otherwise I would say it is a non trivial operation!

 

[gaz1]

im posting this as it saves me typing it out the table appears to be 1m x 1m

other reference is its a nice idea for an outside table with lights

dining table for a client 60" x 60" x 1..5" 5 - 80 pound bags of concrete