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Bragging rites for screwing up


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Sometimes you screw up and just have to share your stupidity with others.  I've been building a hydraulic press and today I finished fabricating the hydraulic tank.  Being the forward thinking type, I filled it with water to make sure that it didn't leak...several hours later and and I'm good.  Drained and dried, I filled it with hydraulic fluid only to discover several leaks. The viscosity of the hydraulic fluid is higher than water..... the molecular weight of the oil is greater than water. So what gives....cause inquiring minds want to know........Keith

 

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Different surface tension perhaps. Water is used to test for leakage UNDER PRESSURE (Hydrostatic) as is decreases viscosity under pressure the opposite of most oils. The other possibility is either the water evaporated faster then it leaked or there were inclusions in the weld that the oil dissolved. For a straight oil tank, if rewelding does not solve the issure, empty, clean well, then heat to about 350-450F and let cool. Then brush the joints with Lock-tite 290. This is the green wicking sealant. it will wick into the leak paths and set up. wont hurt the oil. The standard industrial practice is to weld new tanks and then brush all the joints as insurance especially in refrigeration recievers and so forth.

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Molecular weight is the usual measure of such things, so the op indicates that iisnt the case. But lubricants are formulated to be slick, and hydrolic fluid has a secondary function of lubricating the pump, valves and cylinder, not to mention the solvent and detergent properties that, as mentioned could desolve welding slag/flux 

an odd example of this is using mobil one (original formulation) motor oil. In older vehicles it would almost always cause leaks lol

Edited by Charles R. Stevens
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"Bragging rights" seems to indicate above and beyond typical issues: ER runs, massive fireballs, zoning compliance visits, mobs of neighbors with pitchforks and torches...I rather hope this ends up an empty thread!

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Actually in hydrostatic testing water is a much smaller molecule and lower viscosity than water.

In hydrostatic testing for the high pressure piping and pressure vessel water is almost always specified to test with. Cheap, environmentally friendly and with a small molecule and low viscosity it shows leaks much better than oil, especially when you get over a say 5000 psi. At 10,000 psi water's viscosity actually is decreased from ambient where most straight hydraulic oil is jello. The oil used by the 10,000 psi folks like Enerpac is primarily;y Kerosene as it does not increase viscosity as badly.

At 33,000 psi, the highest my lab at the Valve and fitting company could generate we used water. Of course I was burst testing at those pressures so the fact that the water could just run down the test cell floor drain was a real plus. That and the mist from a pin hole at that pressure makes for a great flamethrower when using oil if an ignition source is found.

A burst in 2.5" od by 0.340" wall DOM boiler tube sounded much like a half stick of dynamite when it burst.

Did I mention that my job for 17 years was to find every flaw and break everything I was handed? I loved that job:) Never found anything I could not break!

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Excuse me as I go change my britches, then to clean up the coffee I spweed across the shop...

​Oh me too. sometimes I laugh so hard tears run down my legs.

Frosty The Lucky.

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Now I suffer severe job envy Ptree. I'll be dreaming of breaking things tonight. <sigh>

I believe oil, especially hydraulic oils is effected more strongly by capilarity. I used to notice if you touched a bit of hydraulic oil with one finger in short order it had worked it's way to the other elbow and beyond. Silicone lubes, oil or grease were the worst, you couldn't keep it off you and it got on everything.

I didn't research it or ask the guys who answered all my hydraulics questions but it seemed if it was possible at all oil would find a way through. I LOVED DN-600 as a penetrating oil, the stuff would get between anything and was plenty slippery.

Frosty The Lucky.

 

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Easiest way to test for leaks is with compressed air and soapy water. Fill the tank with air and spray soapy water on your welds with a spray bottle. Any holes will bubble and carry on and will very easily be spotted. DO NOT however overfill the tank as it will explode! It doesn't take much. When I did mine I had the air gun in the return port with a rag around it and a rag in the suction port so the air was able to escape and not build up too much pressure.  

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Oh I forgot to mention the best trick I know of for sealing tanks. Put a vacuum cleaner in the filler and plug the fittings then paint the sealant on the seams. The vacuum will draw the sealant into any leaks, you don't have to find them first. Works a treat.

Frosty The Lucky.

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Did I mention that my job for 17 years was to find every flaw and break everything I was handed? I loved that job:) Never found anything I could not break!

 

LOL Sounds like the guy I go diving with. He describes himself as a "professional arsonist" as he works in the test lab for Kidde and it's part of his job to start the fires they use to test out the fire fighting foams they produce.

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I started at Westinghouse Air Brake Co, WABCO fluid power division in their engineering test lab while in school after the ARMY. Testing hydraulic and pneumatic industrial items. Also large ship controls. After a 2 years there I moved to Henry Vogt Machine Co in Louisville and ran the R&D lab. tested for the valve and fitting Div at first and then expanded to do boilers and ice machines and so forth. Now these were little modular heat recovery steam generators, that went behind turbine generators. These boilers took about 108 rail cars to ship:)

Once burst tested a header, 12" O.D. by 1.25" wall, with Vogt forged plugs welded into the ends. when it burt at about 20,000psi it drew a large crowd from the factory to see what had blown up:)

We hydro tested every product we shipped, and since we shipped about 100,000 valves a month imagine the hydro test dept. I built all of that automatic test equipment for VOGT for about the last 20 years I was there. Some were testing at 10,5000psi all day every day, running up to pressure and dropping, then up to 6750psi then dropping and a new valve in to be tested. cycle time was less than 60 seconds. You really have to have the right plumbing for that kind of thing:)

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