Will my legs be strong enough
 

I've got some 80 x 80 x 2mm sections long enough to use as legs, will this be strong enough to take the weight.
As I am going to be a bolted frame, can I weld 5mm plates to 2mm section, just tacking at the edges or will it burn through.
I'm a very newbie to welding..... gonna borrow one this weekend, never used one before?
cheers
Andrew

Changing from the plans can always be fun... But it always opens a can of worms.....
Dont just tack.
80 x 80 x 2mm would take the weight applied if fully welded.
2mm can burn through while you are learning to weld often easier to start on 3mm+
Usually weight is an advantage in the base and helps it stay put for accelerating the bits that move, or fill with cement :)
Cheers
David

Thanks David.

I've done some calcs and each 720mm leg will weigh 4.7kg, so I'm going to fill with dry sand, that will add 6kgs to each leg.
Steel arrives this friday and will start welding this weekend.
I just wanted to use up these ( 8 off ) 80mm by 80mm by 1800mm steel sections rather than take them to the scrap heap.
Will weld all around, thanks for your advice.
Cheers
Andrew

You might consider using the thin wall tube for diagonal braces, or building a storage shelf under the MM, rather than primary structure. If you have any flex in the thin wall you will need to add extra diagonals.
I suggest you practice your welding first :) rather than learn on such a nice machine as a MM.
Cheers
David

Good Point on the thin wall.
Welding will be fun to try.
Thanks
Andrew

Steel arrived today.
Not used metal before. very dirty stuff ! lol.
As my materials had to be cut from 7.5mtr lengths, I now have the off cuts.
So, I have a lot of 100 x 50 x 3mm left over, I will use that for legs.