water tank design

.125 minimum thickness. 1/8th inch. Frankly..Id go to 3/16th inch. or even .250...1/4"

Shrug...your choice.

If it was only 8" deep..Id say 1/8", with some cross members.

But you are asking Sheet Metal to hold 200 gallons of water.

Shrug

Gunner

"Somewhere a True Believer is training to kill you. He is training with minimum food or water,in austere conditions, day and night. The only thing clean on him is his weapon. He doesn't worry about what workout to do--- his rucksack weighs what it weighs, and he runs until the enemy stops chasing him. The True Believer doesn't care 'how hard it is'; he knows he either wins or he dies. He doesn't go home at 1700; he is home. He knows only the 'Cause.' Now, who wants to quit?"

NCOIC of the Special Forces Assessment and Selection Course in a welcome speech to new SF candidates

Why so deep? It's just to catch molten "swarf", right? My intuition is that an inch or 2 of water would be plenty. Bob

I agree with him. I think you'll need reinforcement along the top rim as well of course.

Fine if you don't mind the extra cost and weight.

I welded a tank out of thinnish (don't remember exactly) steel, about

2'X2'X4' tall. TIG tacked the seams every 6" or so, then TIGed the seams solid. Lots of heat but only very slight warping. When the steel wouldn't hold up with 160F water, I built a second version out of stainless. I'd don't think warping will be an issue with yours. 10X6X say, 1 foot of water plus the tank will weigh about 2 tons. Does it really need to be so deep?

Wayne

It's not a simple problem. I used the formulas for the deflection of plates from Roark's when I had to do this about a year ago for a tank for a black oxide line. My customer hasn't installed the tank, so I don't yet know how I did.

I didn't know this existed 'til now or how it works -- I use a Mathcad version of Roark's for most calculations.

Keep in mind water weighs 64 lbs/cu foot, make sure you have a suitable structure and foundation to carry that weight to the earth.

Stuart

You could use thin metal and build a plywood and joist floor under it designed for the 83 Lbs / sq ft live load.

jsw

On Sun, 17 May 2009 17:36:54 -0500, the infamous "Karl Townsend" scrawled the following:

With 16" of water to push on it, you'd have (6x10x1.333' = 78 x

64.5lbs/cu.ft.) 5,013 pounds of water in the tank. I vote with your guess, or heavier, depending upon the amount of stiffeners you put in the sides to keep it from oil-canning. I'm too lazy to get the Audel Millwright's book from the bedroom. (It's late; G'night, Karl.)

Shirley, ewe jest!

-- No matter how cynical you are, it is impossible to keep up. --Lily Tomlin

1/8" with no reinforcement will probably rip along the edges :-). 16" deep x 6' x 10' of pure water weighs 4992 lbs, and that load uniformly applied to a 6x10' sheet of 1/8" steel results in a bending stress of 91 ksi and a calculated deflection of 6.8". I'm no engineer but just doodling with a cross support every 2', 6' long, supported at the ends, each taking 1/5 of the 5000 lbs, using 3" square tubing (makes it possible to get forklift forks under it) would result in a deflection in the middle of each tube of .056" and a maximum stress of 4.6 ksi for a safety margin of at least 10. So that's the kind of supports I'd be thinking of. For comparison 3x3x1/4" angle is about 1/3 the stiffness and 3" tall x 2" wide x 1/4" tube is 2/3 the stiffness. A very useful program for this kind of stuff is Engineering Power Tools from The free version works but is missing some advanced beam deflection features, among others, and it's only about $50 for the full version and well worth it IMHO. Oh, and of course my estimate completely ignored the weight of your grid structure.

Couldn't you weld it by stitching 2" then moving a couple of feet away and doing another 2", etc, to keep the local heat buildup under control?

----- Regards, Carl Ijames

On Sun, 17 May 2009 16:13:39 -0700, the infamous Gunner Asch scrawled the following:

Doublecheck your figures. Water's 8.3lbs/gal and 64.5lbs/cu.ft. That's 7.5 gallons per cu.ft. x 78, or 585 gallons if filled to the top.

-- No matter how cynical you are, it is impossible to keep up. --Lily Tomlin

Let the Record show that Gunner Asch on or about Sun, 17 May 2009 16:13:39 -0700 did write/type or cause to appear in rec.crafts.metalworking the following:

"A pints a pound the world around" - water is approximately 8 pounds to the gallon. 200 gallons is three quarters of a ton.

As an engineering guy I knew once wrote "Overstressed systems will eventually become unstressed. But wouldn't you rather do it in a controlled manner?"

- pyotr filipivich We will drink no whiskey before its nine. It's eight fifty eight. Close enough!

Very good indeed. I was simply pondering without resorting to a calculator.

Thanks!

Gunner

"Somewhere a True Believer is training to kill you. He is training with minimum food or water,in austere conditions, day and night. The only thing clean on him is his weapon. He doesn't worry about what workout to do--- his rucksack weighs what it weighs, and he runs until the enemy stops chasing him. The True Believer doesn't care 'how hard it is'; he knows he either wins or he dies. He doesn't go home at 1700; he is home. He knows only the 'Cause.' Now, who wants to quit?"

NCOIC of the Special Forces Assessment and Selection Course in a welcome speech to new SF candidates

Not in UK it isn't. A UK pint is 1.200949 USA pints, so a UK gallon is about 10lbs. In both languages, 1 cubic foot of water weighs about 62.43lbs, so the proposed (80 cu.ft) tank would hold about 4994.4 lbs (2.23 tons) of water

Well,I did say "approximately". Now I'm going to have to go dig the reference out and check. (As to the "pints a pound" bit - my response on first hearing that was "Man, beer is expensive!") Hmm.. 8 pints to the gallon, 8.345 pounds of water to the US gallon, or .133 cubic foot to the gallon US, so ... whip out ye old calculator, punch, punch, punch, ... well, dang, he's right.

I got 2.5 tons of water, "close enough". Still more than I first estimated, and still enough to over stress a system 8-)

tschus pyotr

"I am always willing to learn. I am not always willing to be taught." WSC

- pyotr filipivich We will drink no whiskey before its nine. It's eight fifty eight. Close enough!

[Next morning, as the coffee slowly takes effect] The 1981 edition has only simple algebra such as figuring rafter lengths. I don't see any structural calculations at all.

It's still a useful book that describes a wide range of general handyman skills such as how to frame a house, plus ones more specific to metalworking like the right and wrong ways to install a bearing with a hammer.

jsw

Just something to think about... Livestock water tanks are only made of 20 gauge steel even the 10' round ones. Granted they are corragated somewhat and have a metal pipe around the top for reinforcement but still it should give you an idea on what will work. Jesse

BTW the livestock water tanks are 24" high.

Here is a link to a livestock tank manufacturer:

I built my water tank out of 14 ga hot rolled and it held fine till I got tired of that black water mess. I started exhausting the dust from my machine into a chamber where most of the dust fell out of suspension and then into the great outdoors. Steve

As long as you use a support frame around it 10 gauge would work just fine. The portable ponds we use in the fire service are nothing but a canvas tarp with a lightweight support frame. 1500 gallon units are 10'2" per side and 28" deep. A typical support frame will bow 4" in the center of a 10 foot side. Those are 1/2" tube with 1/8" strap bracing every 2 feet or so. Replace the canvas with steel and make the support frame out of

2X2 box and you shouldn't have a problem. Your looking at almost 600 gallons of water at that size.