Tank hangers...would this work?

[Sparky57]

My 2 tanks arrived from Icondirect...21 g black and 38 g grey. Now I need to hang them below the floor. My father in law suggested I bend up a long clip out of heavy gauge stainless (sort of like a stetched out s, sorta like this shape ___|----- ) that goes around the outside flange of the tank, all around all 4 edges of the tank, and then screw the flange to the 5/8" floor with 40 or so screws.

This would prevent the tank from moving at all, would press is flush against the floor, makes it easy to remove if needed...Could Sikaflex it to the subfloor too for additional grab.

Any comments on this approach?

[barts]

That 38 gallon tank weighs 300 + lbs when full. When the trailer hits a bump, that load is increase significantly. From your description, I'm unable to get a clear idea of how the tank is secured, but I'd certainly follow the manufacturer's suggestions here. Absent any direction there I'd be inclined to support the tank across the bottom when full; it's fine to use lighter fasteners to support the tank during installation, but having a substantial support bolted in afterwards makes sense to me.

- Bart

[Sparky57]

Basically it would be a standard hanger approach,- the flange of the tank would sorta slide into a sleeve/hanger-- except the hanger would be screwed to the sub-floor, not welded to the frame. I suppose I could make a bracket to support the belly of the tank too.
Key question is around screwing the hanger assembly to the floor-- I think this would work, just looking for devils advocate advice around the strength of the screwed in approach.

Mark

[pbearsailor]

Hi Mark,

I'd sure be uneasy about using screws into the subfloor to support much weight.

If you welded angle flush with the subfloor and used studs on that, you'd have strength and would still have easy access for the tank. I think there are a few pics of something similar in my thread.

Like Bart said, that water stuff is heavy and you sure don't want to see your grey tank in your rear view mirror sliding down the road.

cheers,
steve

[barts]

Ah... googling quickly yields this.

Ignoring the tank strength issues, #6 or #8 fasteners are good for about 100# long term withdrawal load in 3/4" plywood. 1/2" plywood is only good for 50-60 lbs. This is a distributed load and you just need lots of fasteners - 40 seems adequate but not overkill by any means - if you put in more, it can't hurt.

Keep in mind that the plywood floor forms a diaphragm here; the floor should be supported by the steel floor frame all around the tank to prevent deflection and working. Note that the load from a tank like this is like two people standing next to each other on top of the floor and bouncing up and down in unison.

- Bart

[Sparky57]

Beauty. Thanks Bart. So a full tank, 38 gallons weighs 350 lbs, could be held in place by as little as 8 screws into 5/8ths fir ply if it was a static load. Adding some force of momentum then 5x that number should hold it. Also planning belly straps, so sounds like I am good (on paper anyway )...

[Protagonist]

Bolts all the way through the plywood, backed with large-diameter washers, and secured with locknuts, will not pull out as easily as will screws when the tank contents slosh around while you're traveling. This may not be possible for you, depending on what's on the other side of the plywood, but it's something to keep in mind if it's doable in this case.

Another possibility, if you must use screws… After inserting each screw, remove it again. Fill the screw hole with a marine adhesive that works with both wood and metal, such as 3M brand 5200 Adhesive. While the adhesive is still wet, reinsert the screw. This will make the screws a b**** to remove later (though hopefully you'll never need to), but will help increase their holding power.

[Sodbust]

What I know about weight,, road bumps a large pot hole can transfer over 5gs of force for a millisecond.. That would leap the weight number to 1500 lbs..

On all our plastic farm water tanks we use for spraying and such,, there life is much greater if the tank rests in a saddle to support all of the bottom of the plastic tank.. The rule applies to a 15 gallon tank or a 3000 gallons..

I would weld up a saddle,, and in your case just go to a fab shop and have a girdle made to fit the tank and reach to both frame rails... Just screwing it to plywood sounds like a train wreck down the road..

Sodbust

[Sparky57]

Ok- I was planning on strapping it too, I will use both but make sure the straps are heavy duty steel. I should be able to get those either welded or bolted to the frame.

Mark