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cappyjon431
January 21st, 2010, 10:47 AM
When I bought our dive op it came with 70 tanks, about a dozen of which had valves that needed repair/replacement. They have sat under my work bench for years, but I finally decided to replace the valves. It looks like these tanks had never been rinsed and after draining, the vaves are seriously hard to remove. I tried to loosen them up with a soft mallet, with no success. I put a pipe wrench on one an succeeded in removing the valve by tapping the pipe wrench with the soft mallet but scraped up the valve in the process. I would like to rebuild these valves, but I don't want to damage them in the removal process. What is the best way to get these buggars off? Thanks for any input.

Scared Silly
January 21st, 2010, 10:52 AM
Put your pipe wrench on and use a cheater bar instead of the mallet.

Belmont
January 21st, 2010, 11:04 AM
Put a piece of neoprene between the jaws of the pipe wrench, cheater bar is good but a few sharp blows with a hammer on the bar will help break the seal.

Scott
January 21st, 2010, 11:19 AM
Use a smooth jaw wrench and it won't leave the marks like a typical pipe wrench.
Smooth Jaw Wrenches (http://www.reedmfgco.com/index.html?screen=smooth_jaw_wrenches)

cbrich
January 21st, 2010, 11:48 AM
I would use an open end wrench that would fit the flats on the base of the valve, assuming the valve has flats on the base. But it sounds like you might be replacing all of the valves.

Spd 135
January 21st, 2010, 12:09 PM
If it is possible, put the valves (and tanks) in warm water for a while. This may loosen the scale that has built up.

Colliam7
January 21st, 2010, 12:19 PM
I would like to rebuild these valves, but I don't want to damage them in the removal process. What is the best way to get these buggars off?
Put a piece of neoprene between the jaws of the pipe wrench, cheater bar is good...
Use a smooth jaw wrench and it won't leave the marks like a typical pipe wrench.Other alternatives would include: a) use two pieces/strips of smooth (and softer) aluminum, instead of neoprene, between the jaws of the wrench and the valve, or b) use hard wood (oak) strips. Possibly less expensive alternatives to a new wrench. We keep aluminum shims in our bench vise at the shop for a similar purpose. And, Zeagle markets a wood box to support applying torque to regulators, with the same end in mind - avoiding scratching the metal. With the wrench, while I use a rubber mallet at times, my personal preference is a cheater bar if I can effectively secure the tank so it doesn't rotate.

NJDiver07866
January 27th, 2010, 01:17 PM
Don't sound like a drama queen, and you might have already thought of this, but just to be safe make sure the valve works. Take a bit of shop air and open up the valve and try to fill the tank. Check to see air goes in and out of the tank through the open valve. With old tanks you always have to be careful they are indeed empty. It could be the valve is bad and you think the tank is empty when it is really not. You can turn the valve open with the knob and it feels like it’s open but it’s not. So before you try to put an 8 foot breaker bar on it.. just do a quick check…

Good luck my friend

rcs9250
January 27th, 2010, 01:32 PM
For tough valves on SCBA's and some scuba tanks I made a wrench as pictured. I work in a machine shop so it was a real quick and dirty job. Sometimes making the tank immobile is a tougher task. A tank vise of course works well. I have seen people jack up a trailer with tandem axles and lower it slightly on the tank to act as a vise. Some have strapped them to I beams and telephone poles too.

cappyjon431
January 28th, 2010, 07:17 AM
Don't sound like a drama queen, and you might have already thought of this, but just to be safe make sure the valve works. Take a bit of shop air and open up the valve and try to fill the tank. Check to see air goes in and out of the tank through the open valve. With old tanks you always have to be careful they are indeed empty. It could be the valve is bad and you think the tank is empty when it is really not. You can turn the valve open with the knob and it feels like itís open but itís not. So before you try to put an 8 foot breaker bar on it.. just do a quick checkÖ

Good luck my friend

Definitely good advice, but I always remove the burst disk (slowly) before removing the valve. Loosening the burst disk a couple of threads is the easiest way I have found to insure the tanks are empty if the valve handle is inoperable.

DA Aquamaster
January 28th, 2010, 08:14 AM
Definitely good advice, but I always remove the burst disk (slowly) before removing the valve. Loosening the burst disk a couple of threads is the easiest way I have found to insure the tanks are empty if the valve handle is inoperable.If there is any possibility that the tank has O2 in it, do not attmempt burst disc removal and also do not attempt to try to remove the valve if you cannot get the valve open. The tank can and probably will explode as the friction of the threads creates an ignition source for the O2 and oxides in the tank.

In general use an open end wrench that fits the valve, if flats are provided on the valve. If no flate are provided and you have to use the face and back of the valve for "flats", use hard wood (oak) strips between the valve and the jaws of a pipe wrench.

Alos note that if the valve is hard to remove, the potential to gall the threads in an aluminum tank is significant and if that occurs you now have 30 pounds of scrap aluminum, not a scuba tank.

Leadking
January 28th, 2010, 11:22 AM
Use a smooth jaw wrench and it won't leave the marks like a typical pipe wrench.
Smooth Jaw Wrenches (http://www.reedmfgco.com/index.html?screen=smooth_jaw_wrenches)

Smooth jaw wrenches used to be called "monkey wrenches". Now you need to decide if it calls for a right-hand or left hand!:)

Wookie
January 28th, 2010, 11:44 AM
The best luck I've had without damaging anything is to: Turn the cylinder upside down in a machinists' vice. Clamp the hell out of the valve flats in the vice. If you do this, the cylinder will not slip, and the valve will not be dinged. Wrap a strap wrench around the cylinder and put a significant cheater on the strap wrench. I use the same strap wrench that I use on my Detroit Diesel oil filters. If after you apply all the torque you can apply and it still doesn't move, have your wife beat on the bottom of the cylinder with a rubber mallet to shock the cylinder. I haven't had it fail yet, and I don't round the flats of the valves either.

oxyhacker
January 28th, 2010, 11:48 AM
Or Moncke, to give credit where it is due ;-)


Smooth jaw wrenches used to be called "monkey wrenches".

knotical
January 28th, 2010, 05:39 PM
Or Moncke, to give credit where it is due ;-)
Neat; but alternatively, quoting:
Charles Moncke@Everything2.com (http://everything2.com/title/Charles+Moncke)

Charles Moncke was a London blacksmith; according to legend he invented the monkey wrench. A difficulty with this theory is that the British call a Ö wrench a spanner. In 1932-33, the Boston Transcript traced the invention to 1856, crediting it to a Yankee named Monk, employed by the firm of Bemis and Call in Springfield, Massachusetts.
We may never know.

Dive Raja Ampat
May 2nd, 2013, 12:28 AM
In Cambodia we used a large Tie Down Strap attached to a concrete telephone pole. We used a large crescent wrench and a cheater bar. Works real well, the trick is to keep the tank from moving.
if the valve is not working most times is that the hand wheel is stripped, replace the hand wheel and then bleed air .
Of course if the valve still works, the best test that the tank is empty is to have valve open and blow into the tank and should fill up to about 7 bar and you can feel on your cheek. the danger is if you let the air out fast you could have ice build up and still have lots of pressure so always a good idea to blow hard into valve to check, if the valve is cold, before you pop the top.
When you put it back together don't forget liberal amount of silicon in threads. For tanks with more that 32% Oxygen have a certified tech work on, Oxygen is what they use to fuel the space shuttle! (O2)

ajtoady
May 2nd, 2013, 07:12 AM
I would a) make sure tank is empty, b) try to get some soapy water into the tank, it shouldn't take a lot, and c) after getting soapy water in invert tank for a few and allow liquid to penetrate the valve threads. You are removing the valves anyways so a hydro, cleaning and vis is in order. If there is in fact a scale or oxidation in the threads soaking from the outside does not get past the O-ring. Last resort, after making sure tank is empty, cut in half for a cool little grill for burgers and hot doggies, yum!!!:D

sealark
May 2nd, 2013, 07:27 AM
The best luck I've had without damaging anything is to: Turn the cylinder upside down in a machinists' vice. Clamp the hell out of the valve flats in the vice. If you do this, the cylinder will not slip, and the valve will not be dinged. Wrap a strap wrench around the cylinder and put a significant cheater on the strap wrench. I use the same strap wrench that I use on my Detroit Diesel oil filters. If after you apply all the torque you can apply and it still doesn't move, have your wife beat on the bottom of the cylinder with a rubber mallet to shock the cylinder. I haven't had it fail yet, and I don't round the flats of the valves either.

Listen to the above post, if this doesn't work scrap the tank. best suggestion here...

rhwestfall
May 2nd, 2013, 07:31 AM
2010 thread....... think he is still working on the tanks? How many grills or wind chimes do you think he has by now?

sealark
May 2nd, 2013, 07:34 AM
I guess it helps to look at original post date.

captain
May 2nd, 2013, 11:19 AM
Never put the wrench on the sides of the valve, you can crush the metal into the O ring groove and ruin the valve. Always put it so one side of the wrench jaws are on the back of the valve and the other is on the front where the O ring is.


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