Welding Tips and Tricks

I have seen multiple ways to check for leaks, but what way is the best?

lucky wrote:I have seen multiple ways to check for leaks, but what way is the best?

If you suspect the hose is where the leak is, fill a bucket with water and submerse the hose, NOT the torch head. Then start the gas flow and watch for bubbles.

i use windex cut by half with water in a fine spray.
seems to work good, makes large bubbles if it leaking.
easy to spot.
craig

lucky,
What part of the torch are you wanting to test? Here is a short vid I did a while back when I discovered a leak in my torch head. For the cable I agree with soap and water or other substance that would bubble. The first thing you should do is open the valve on the bottle to pressurize the hose and shut the valve back off. If there is a leak your needles will drop off.
http://youtu.be/56wkDbqZvFk
-Jonathan

A gas leak in the line will PULL IN air, not release it, in normal operation.

You need to block the flow at the torch. Pull out the tungsten, and put your thumb over the cup to build positive pressure. THEN snoop the line with soapy water.

Steve S

Remember too that the leak might also be 'inside' the machine, possibly at the solenoid shut-off valve, or where the torch lead connects to the machine.

I strip the torch head and screw in a short back cap into the front and the back to seal it off, then you can do all the tests that the others have mentioned.

Len

Good idea Len!
Never thought about it before but the thread are same in both ends.
I've always used the thumb, no more

Otto Nobedder wrote:A gas leak in the line will PULL IN air, not release it, in normal operation.

You need to block the flow at the torch. Pull out the tungsten, and put your thumb over the cup to build positive pressure. THEN snoop the line with soapy water.

Steve S

I know what you mean, however I've have success using the method I posted in this thread.

Perhaps the pulling of air in is caused by a venturi effect? Maybe when the air outside the hose is replaced with water this would cause the gas pressure inside to now bubble out.

AndersK wrote:Good idea Len!
Never thought about it before but the thread are same in both ends.
I've always used the thumb, no more

+1

LtBadd wrote:

Otto Nobedder wrote:A gas leak in the line will PULL IN air, not release it, in normal operation.

You need to block the flow at the torch. Pull out the tungsten, and put your thumb over the cup to build positive pressure. THEN snoop the line with soapy water.

Steve S

I know what you mean, however I've have success using the method I posted in this thread.

Perhaps the pulling of air in is caused by a venturi effect? Maybe when the air outside the hose is replaced with water this would cause the gas pressure inside to now bubble out.

No. The factor at play is the difference between static pressure and dynamic pressure. In a good torch with the head flowing correctly, there's no positive static pressure in the line. The flow alone reduces dynamic pressure, such that leaks in the line will draw air in.

It's not the Venturi principle at work, though I suppose that has to be a part of it. It's tied up in Bernoulli's work as well as Reynolds'.

I don't fully understand it, but I've seen it in action often enough to accept it.

Steve S

Run a bead to get it warm, not too hot, push tungsten in, stretch a balloon over the cup, (a condom would work as well!!), step on the pedal once or twice to inflate the balloon/whatever. If it deflates quickly, yes, you have a major leak, and you can gauge just how bad it is. You can dip the torch in water as the pressure keeps water out, and, being quite warm it will dry out pretty fast.

I have a Thermal Arc Arcmaster 185, when it was new, it would hold pressure for more than a month, at least up to the valve internally. It now bleeds off a week or so, other things besides the hose can leak.

I havent actually done this, mine doesnt leak, just an idea.
-c-

Braehill wrote:I strip the torch head and screw in a short back cap into the front and the back to seal it off, then you can do all the tests that the others have mentioned.

Len

Neat trick. I have to remember that one. Thanks Len!

My valve isn't shutting off the flow all the way and allowing Argon to pass through the gas lense when I don't want it to. How do I fix this?

ryan.k.mcdaniel wrote:My valve isn't shutting off the flow all the way and allowing Argon to pass through the gas lense when I don't want it to. How do I fix this?

If you unscrew and remove the valve stem, you' should see a plastic "washer" in the end of it. This may be cracked, or even missing (unlikely, if it's never been removed before) or loose in the hole where the valve was.

Steve S