[DCALLWELD]

On a job there is oxygen or acetylene bottles upside down in the concrete, they are used as bollards around shop doors.
They stand about three feet out of the ground and about two foot in. I need to weld pipes in-between them so people stop pulling up in-between doors and hitting the building. I don't think its such a good idea to weld on them do to pressure build up. (match in the gas tank boom boom.) My other option is to remove them from there existing location and set a smaller post in the concrete; one small problem the tanks are so close to the building i cant get a concrete saw in-between them the cut the bottle out.

I have thought of cutting some pipe collars and welding the horizontal pipes to them along with a nut to drive a bold threw to the bottle, this would hold them in place. NO real down pressure should be placed on them with the exception of a occasional lard ass taking a brake. IF they did ever have to protect the building they would transfer all pressure to the bottles.

Just wondering if any one else has ever pulled them out of concrete before ? I could overlap a chain around them to get pressure and pull straight up but idk if it would hold i know you can pull corner post out of dirt ( like fence work)


any ideas ????

[noddybrian]

Well that's a weird one ! - I would think they have used oxygen cylinders they sound too tall to be acetylene - unless yours are different they are noticeably different proportions - assuming they are oxygen I image they used out of test empty ones - this being the case if you drill a small ( maybe 1/8" ) hole into them initially to release any pressure ( use caution & stand aside of any potential release - use an air drill if possible) then open them out to tapping size for say 1/4" NPT get a length of pipe small enough to feed into this coupled to a bottle of CO2 use this to do a cheap purge on the cylinder & ensure interior is safe / inert now you can weld with confidence - when finished tap the purge hole NPT & insert a plug - must be other solutions - but I would say this will work without significant risk.

[Braehill]

First off only a jackass would put a cylinder upside down in the ground with the valve still in it. If the valve has been removed,which it should have been, it's now just a piece of heavy walled pipe with a cap on the end. If your worried about trapped gas in the cylinder you can drill a hole in it where you're going to weld the other pipe. This will give the pressure somewhere to go and the pipe you weld to it will cover the hole to keep water out of the cylinder.

Len

[Braehill]

we posted at the same time, I guess.

Len

[DCALLWELD]

Well both good points , should be safe as long as I put hole for pressure to blow off. As far as the old saying " Only a jackass would " I'm a fan of it, but have learned that jackasse's have dun the unthinkable before and I don't want to be a casualty of there ways.

[noddybrian]

Not sure if they would remove the valves or not - ours are thread locked into the cylinder & are tapered thread so are quite difficult to remove - but either way once vented they should be safe - as you say they're just pipe - I recycle old cylinders into all sorts of things when I need pipe - but I like to CO2 purge as I also use fuel gas ones ( OK - I know - not recommended ! ) these can be left vented for some days & still give a minor vapor flash if your unlucky - so I like CO2 - it's the only fairly cheap gas here & has the bonus of being liquid - so on fuel tanks etc I hold a cylinder inverted with a direct connected pipe ( no regulator ) & blast some liquid in - as it's heavier than air once expanding vapor is visible the entire thing is full & safe to cut / weld / whatever - I've been called " redneck " - but never " Darwin award" !!

[Braehill]

We have out of date cylinders "planted" as bumper poles all throughout the plant as we used to be a cylinder fill plant. We have used all kinds since we have the abillity to purge them and pull a vacuum on them, safe as can be then. The valves on most cylinders are easy to remove and if by no other method you can use an 8# sledge hammer to knock them off once the pressure is relieved.

Redneck was in full bloom when the old timers used to stand on the out of date cylinders and knock the valves off and launch them into the river so they didn't have to deal with the paperwork. More than one of them could have gotten Darwin Awards. Half the retirees from here also have mailboxes made from retired cylinder bottoms, some are quite nice, made from Aluminum Helium cylinders that they have to use to service MRI machines (Non-Magnetic for obvious reasons).

The ones by the truck docks are actually two cylinders welded together, one cut where it starts to neck down in the bandsaw and slipped over the neck of the other and welded. It can then be buried pretty deep and still have quite a bit sticking up in the air.

Len

[Otto Nobedder]

If you want to take safety to the best point, I'd fill the concavity at the top (bottom of the cylinder) with vegetable oil (non-toxic, as the valve is "most likely" gone), and drill a tiny (1/8") relief hole there, preferebly (as stated before) with an air drill, in case you get spray-back. There's not going to be anything explosive in the bottle (an acetylene/butylene bottle skinny enough to be confused with a pressure cylinder will only be maybe 36" tall, and impractical to bury more than inches and have a usefull barrier.)

Then weld as needed, and plug the hole with the method of your choosing. I'd cap it with mortar, round it off nicely, and repaint.

Steve S

[DCALLWELD]

Well good stuff fellas, think I'm going to give it a go , and hell if it goes wrong should be one hell of a show.
AS far as the last posting It was said to put vegetable oil in the concave part of the cap the drill threw it, if I understood correctly? what is the meaning of this?

[Braehill]

The vegatable oil would be used to cool the drill bit and be "enviromentally freindly" should it run down through the open hole in the now bottom end where the valve was removed.

Len

[DCALLWELD]

O Ok interesting , everyone is so eco friendly these days. just makes me laugh when the hippies tell me to stop burning diesel because it puts off carbon dioxide; AS I arrive home to 2/3 of the rain forest in my mail box in the form of junk mail. I'm not mocking the vege oil ide, it is a good idea and I will do it, it sounds easer to clean up.

[noddybrian]

If you use the vegetable oil may I suggest either using a very small amount or hose the cylinder down with cold water first - as if the end is sealed by the concrete or there is still a valve in it even a slight difference in temperature from when they were planted there can make a small pressure in the cylinder - not enough to cause any problem or concern - but probably just enough to spray said oil over you !

[Otto Nobedder]

If you use the vegetable oil may I suggest either using a very small amount or hose the cylinder down with cold water first - as if the end is sealed by the concrete or there is still a valve in it even a slight difference in temperature from when they were planted there can make a small pressure in the cylinder - not enough to cause any problem or concern - but probably just enough to spray said oil over you !

Actually, that's a benefit of the vegetable oil. It cleans easily, and has a high flashpoint (650ish, if I recall).

Steve