Pressure Testing welds on hydraulic line

[robstaples]

Looking for direction or recommendations on how to pressure test a 3/4 inch Aluminum schedule 80 pipe with out getting hydraulic oil in a possible leak... making the repair that much harder. Pressure will be limited by over pressure releaf at 1500 psi
The application is rear pto pump feeding front fel snow blower. Pto pump is rated at 2000 psi /20 gal per min. Have had it previous mounted on two tractors using hoses and do not like the messiness of 3/4 hoses for lack of a better term. All tractors have cabs.
So I purchased weldable 3/4 NPT ends to weld on the schedule 80 pipe. The plan was to TIG but the ends heated faster than the pipe and I ended up MIGging them. So the plan is to mount along side cab , tucked close , and have quick connects to be able to leave on year round.

Thought if I had just one small leak at high pressure, I could use that as return line.

For testing , I could individually bobble test with air pressure up to 150 or fill with water and push with a dive tank or welding gas pressure but lots of fittings issues.

Looking for suggestions. This pic shows approx position and end fittings

 

[ptsg]

Aluminium pipe for hydraulic application? Doesn't sound like a good choice to me.

Why not use the proper steel tubing intended for hydraulic hardlines?

 

[LouNY]

What ever tubing or pipe is used do a hydrostatic pressure test if you are worried about leaks,
a hydrostatic pressure test can be done to several thousand PSI with safety.
Any leak will dump the pressure off almost immediately with minimal danger.

Use a hydrostatic test pump do not use high pressure gasses,
many pipe line or pipe fabrication shops will have them and you may be able to borrow or rent one.

Or buy an inexpensive one, even a hydraulic porta power pump will work with water for a while and then can be cleaned lubricated and resealed cheaply.

 

[Rebeldad1]

switch to steel pipe. If you arnt sure of your welding cap 1 end and check with air pressure.

 

[robstaples]

Thanks LouNy, did not know about inexpensive hydro testing. Have one on order. If the aluminum pipe or welds fail badly, I’ll switch to steel or back to carefully routed hose.

 

[mrmikey]

Just curious, why did you go aluminum pipe instead of mild steel or s/s hydraulic tubing, it'd be a smaller o/d. I wouldn't use aluminum for hydraulic especially where it's vulnerable to damage, just my thoughts............Mike

 

[true temper]

Use a pressure washer.

 

[Fallon]

High pressure testing with air is always a bad idea. It compresses to a massive spring & explodes when something fails. A fluid can't compress & only transmits power, but doesn't store it. A hydraulic leak will spray & can pierce skin doing nasty things. But if it ruptures the pressure drops instantly & doesn't explode violently.

A grease gun can hit 8,000-10,000psi on most lever or electric guns. If you properly purge all the air from the lines you shouldn't have to pump that much.

You could use water if you didn't want to contaminate bad welds with petroleum.

As others noted, I'd look at steel instead of aluminum. Stronger, but more importantly easier to weld & less prone to fatigue or stress cracking.

 

[4570Man]

I understood your post to say you want to test the welds for leaks not test the working pressure of the pipe. I’d just hit it with shop air and spray soapy water on it. That pressure is of no danger of exploding and if it holds that leak free it should be fine.

 

[Fallon]

I understood your post to say you want to test the welds for leaks not test the working pressure of the pipe. I’d just hit it with shop air and spray soapy water on it. That pressure is of no danger of exploding and if it holds that leak free it should be fine.

Ya, a few PSI & soapy water will show cracks or holes in the weld. It wouldn't show a really weak point. Makes for a great first test on high pressure stuff. I generally do the soap tes on all my gas lines & my shop air line fittings.