Tapping a new port into an air tank

[rabler]

I have read several times that they are heat treated. Maybe for very large tanks which would be costly to put into a giant heat treatment oven they just make them thick enough to not matter?

Heat treating can be used for changing the hardness of the metal, or for stress relieving built up internal stresses caused by (amongst other things) the thermal expansion and contraction from the heat of welding. I'd **guess** that it may be a stress relief process.

 

[matthewsx]

Yep. I hear that term thrown around a lot more often that explained, so I was trying to put some reasoning behind it specific to this case.

Here’s some education for those inclined.

https://courses.washington.edu/me354a/chap6.pdf

FWIW, I’m with the take it to a certified pressure vessel welder or replace it camp. You may be able to weld it successfully, but it’s one of those things where the consequences of getting it wrong are exponentially larger than the cost of doing it right.

JMHO,

John

 

[strantor]

Well here's some safety presentation slide show material if anyone needs it. I am going to pressure test it next week outside with a very long air hose and I'll let you all know if it blows up.

 

[tq60]

Fill it with water and plug all of the fittings.

Put a gage and zerk someplace and use a Grease gun full of water to pressurize it to test pressure.

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[markba633csi]

Looks good to me

 

[682bear]

Pressure test it with water... NOT air...

I think the standard is to test them to 1.5 times the operating pressure.

I'll repeat... do not test it with air. It's too easy to use water to chance it.

-Bear

 

[strantor]

I have access to a hydrostatic test pump (hand pump), might as well do it right if I'm going to do it.

 

[Weldingrod1]

You need a 1.5xworking pressure proof test before you air that thing up... water, please!

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[woodchucker]

I see a couple of pin holes.
Camera can show things that are hard to see.. it can also hide things that are easy to see.

 

[durableoreo]

I don't think heat treatment is an issue in small air compressor tanks. But whatever you do, hydrostatic testing is absolutely required. It's easy and does not require expensive equipment. It will simplify your life to have certainty that the work is sound.