Question Steel tank rack material advice

[Boarderguy]

I don't think you need it as strong as Boarderguy's drawing.

But you do you.

 

[Tracy]

I don't have a mig welder, just tig/stick.

I was thinking 7018 3/32 rod 90 amps.

Done as @Boarderguy showed in his diagram. At the least weld all four sides though 2 are for sealing and cosmetic reasons. The welds that provide the most structural strength are the top and bottom.

I'm wondering if I should get some like 1/2 angle to reinforce the bottom again as @Boarderguy showed or it that over engineering. Other option is to go one weld top and bottom and then go at put two on top of that one spreading it out.

The other concern is to much welding will cause distortion. Big plan for that is to do 1/4 inch welds moving around the unit as I go.

Welding all four sides will be fine. But the top and bottom would not be providing the most strength. Think of where your forces are.
It will be plenty strong for your purpose regardless of where you weld it, just pointing it out.

 

[formernuke]

Welding all four sides will be fine. But the top and bottom would not be providing the most strength. Think of where your forces are.
It will be plenty strong for your purpose regardless of where you weld it, just pointing it out.

Forces are going down with the weight of the tanks resting on horizontal. Granted most is more towards the center, but joint wise the top and bottom of the joints see the joint pressure.

 

[Tracy]

Forces are going down with the weight of the tanks resting on horizontal. Granted most is more towards the center, but joint wise the top and bottom of the joints see the joint pressure.

Pretend it is an I-beam instead of square tube. The stressed member is the vertical. Same thing with box tubing, but the vertical stress is split. If you weld top and bottom, then push down to failure, the box section will bow out the sides.
Again, none of this matters for holding a half dozen scuba tanks, you aren't going to be into the structural failure range of the tubing.

 

[formernuke]

Pretend it is an I-beam instead of square tube. The stressed member is the vertical. Same thing with box tubing, but the vertical stress is split. If you weld top and bottom, then push down to failure, the box section will bow out the sides.
Again, none of this matters for holding a half dozen scuba tanks, you aren't going to be into the structural failure range of the tubing.

I follow, to long since those classes . Still the joint I'm concerned over, but as long as I decent welding job I should be well within stress point.

 

[Tracy]

I follow, to long since those classes . Still the joint I'm concerned over, but as long as I decent welding job I should be well within stress point.

Yep. Comes down to the welder. You have a tig machine and you plan to stick weld it?
Make it pretty. Use the tungsten.

 

[formernuke]

Yep. Comes down to the welder. You have a tig machine and you plan to stick weld it?
Make it pretty. Use the tungsten.

I'm not good enough with tig to trust the joints yet.

I'm thinking of grinding the outside for looks. After all welding starts and ends with were I my grinder.

 

[Still Kicking]

I'm not good enough with tig to trust the joints yet.

I'm thinking of grinding the outside for looks. After all welding starts and ends with were I my grinder.

"Grinder and paint make me the welder I ain't."

 

[formernuke]

48 feet of tubing that needs to be cleaned prior to welding and painting. Yup where's my grinder.