Remember, there's only two things that can offer support when molding metal to the shape of whatever it's poured. Time is of the essence when you do it because of the solid state it will form when it hardens and cools, that is to say unlike water when heated that just turns into steam. Since it likes to adhere to a few different things, sand is the only substance to which most metals don't mix really well with, just make sure it's firm and compacted and quite possibly cooled. Think of wet sand and how it does pressed down together into the solidest lump. You'll not want any spaces for which the metals would run all the way through and follow these to their furthest-most point. You can also shape the sand in an outline so that the metal can be poured all the way in while the wood frame is just held there in place or suspended in space. That way there's no hammering needed, not even a tool. To say that it'll be heavy is a gross understatement of function since three cubits long in either direction is pretty substantial no matter if it has all that space in the middle. That's because there's unwillingness as we'd discussed before that when combined with the weight makes things pretty heavy to move from out of their place. You could've said that a lot of effort would be required to move it which makes it something which is harder to do. In the West, that is all perfectly good chemistry stuff and to those in the East, it means something else put that way thus. Thus, you'll want to say only that there's weight to the object that makes it harder to move and also takes up a good deal of space. In fact, this particular altar could only be moved by a sizeable crew. One person alone holding onto the handles thereof wouldn't been enough to move it but their death meant much to the presence above. Then for the dishes thereof, a simple shaping would've been enough for the sides thereof though when hollowing out, it would've required either more sand pressed down inside or else quite possibly the form or the use of a mold. Identifying a second substance though to which won't be adhered to when you're forming it out and making it of sizeable depth to make a good pot is somewhat harder to do and that being said, I'll let your own self educate you. Thus, the equation describing this relationship would look something like this in a few.
Size of your crew is weight added to movement that detracts from the space
Which is also the same as this once again.
Size of your crew added to weight and movement is a subtraction from space
Let's see if the calculations are as right as they should.
9 cubits is space
Movement required is all the way out the door or then to be added onto the floor
81 cubits roughly is the size of the cube even with hollowness
Each cubit is 20 pounds (estimated, I'm sure it's a lot more and to be accurate quite frankly you'll need a good scale) depending on the thickness of wood that was used comes out to 1620 pounds out in weight, though with hollowness, please run the numbers again.
80 let's say is the weight if we're adding up the total weights of the wood.
Then the brass also is heavy though with thinness, it's more than likely evenly spread. What if it's more like an estimated two to four times 80 pounds total there at the end. That would give us something like this, which is 320 in sum.
The size of the crew would've been four to eight men when added to you.
Though no one was supposed to be moving this stuff once it was all dedicated which means there's a certain gravity there. If each man could only be moving 50 pounds there in sum, is 6.4 men to lift all this up on a normal day though with the dedication and everyone quaking in fear of the Lord's taking, you'd have had a reduction in total capacity probably down more to 20. At this point, that's a requirement of 16 men there to you. Think of it if you will as a straight line that when it's perfectly balanced there's nothing moving for then. Though, when tipped in either direction, you can have something fall over on all of the men or else they'll succeed in moving it through. In fact in one particular section, that's exactly what happened with the ark of the Covenant when put on a wagon. That had killed just about all of its men and the only ones left were the oxen which drew it for then.
