Testing hydraulic tank for leaks, recommendations?

davedj1 · Jan 28, 2013

I had to weld in some bungs on my tank and I would like to test for leaks before I proceed. I can't use air as there is a large hole in the top for the filler, I don't want to use hydro oil (too hard to drain it off in the event I need to do some touch up welding). I hate the thought of using water but that may be the only solution, or how about vinegar? Vinegar might actually be the answer!
thanks,
dave:dance1:

Gary Fowler · Jan 28, 2013

Just use the API tank fabrication Code for checking for leaks. Clean the tank weld area free of any oil on the outside using acetone and let it dry. Then Just spray or brush the inside with diesel and let it set for 24 hours. If any leak is there, the diesel will penetrate thru and you will see the oily film form and if any dust is blowing around, it will adhere also. This is how they check the annular plate weld (this is where the bottom plates join the vertical walls) on API (petroleum) service tanks prior to filling them with water for strength test.
If diesel wont leak thru, then hydraulic oil which is much thicker wont leak either. Next to doing a dye penetrant test, this is the best way although you do have to wait for a spell to see if it weeps thru.

puckgrinder85 · Jan 28, 2013

I would be leary of using air pressure, it doesnt take much to deform areas and 90* corners arent made for holding pressure. I know, that you know it would have to be regulated way down, just throwing it out there. This is the reason they hydro test air/gas tanks.

davedj1 · Jan 29, 2013

The problem is that I can't access the inside other than pouring something in. The tank was pre made, I just added a 1" bung to the bottom side for the supply line to the pump. I'm afraid if I use any type of oil and if I do have a pin hole leak, I can't drain it and clean it enough for it to safely weld on it again.
thanks,
dave

wdchyd · Jan 29, 2013

I don't know if this would be of any help but welding on the bung first before cutting the hole thru is what the gas co around here does to pretest the integrity of the weld before drilling out the hole

they first weld on the bung, screw on fittings to test under pressure, then remove the test fittings and drill out the hole inside the bung

I TIG weld all my root passes first for a leak proof weld

wdchyd · Jan 29, 2013

It may be easier for you just to cover that hole on top and pressurize with air....you don't need much pressure to test

Gary Fowler · Jan 29, 2013

wdchyd said:
I don't know if this would be of any help but welding on the bung first before cutting the hole thru is what the gas co around here does to pretest the integrity of the weld before drilling out the hole

they first weld on the bung, screw on fittings to test under pressure, then remove the test fittings and drill out the hole inside the bung

I TIG weld all my root passes first for a leak proof weld

That is the way we test hot tap fittings also. I assumed from the OP write up that he had already cut the hole and made the weld.
You can likely just visual the weld and assure that it wont leak. Look closely for pin holes or slag pockets, Grind the suspect areas and remove any defects. If you find everything to be solid weld metal with no cold lap at the edges and no pin holes, then it likely wont leak.we

Gary Fowler · Jan 29, 2013

wdchyd said:
It may be easier for you just to cover that hole on top and pressurize with air....you don't need much pressure to test

Mix a soap solution and cover the area with it, take a rag and hold it in the top with your blow gun and blow air into the tank. Its ok to allow it to leak out at the rag. 2 psi is plenty for the air test and 5 will likely expand the walls. It doesn't take much on a square sided tank to blow it up to a round shape. If you feel the sides expanding, then you are pressured up plenty.