Looking for a place that sells weld in air tank bungs

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I have an air tank that has a .5" NPT fitting on it and I need a 1.25" NPT fitting. Does anyone know of any place around that sells bungs that I could weld in? I've googled the hell out of this with no luck.
Reply:try searching for a 'half coupler' on grainger's website.  i use these for bungs on occasion.  Make sure you get one made from the appropriate material, and rated for the appropriate pressure.  You could also search for a 'weld-o-let' in the right size.All the usual caveats about "I hope you know what you're doing" apply here.Benson's Mobile Welding - Dayton, OH metro area - AWS Certified Welding Inspector
Reply:Here.  Technically, I guess you want a thread-o-let.  I found these links with a few seconds searching.http://press.kscdirect.com/?p=3445http://kscdirect.com/images/PDF/A_18.pdfBenson's Mobile Welding - Dayton, OH metro area - AWS Certified Welding Inspector
Reply:Originally Posted by A_DAB_will_doHere.  Technically, I guess you want a thread-o-let.  I found these links with a few seconds searching.http://press.kscdirect.com/?p=3445http://kscdirect.com/images/PDF/A_18.pdf
Reply:Originally Posted by A_DAB_will_doAll the usual caveats about "I hope you know what you're doing" apply here.
Reply:Last time I looked at a hardcover copy of the McMaster-Carr catalog, it carried a large selection of welded-plumbing fittings, IIRC both in stainless and carbon steel. Should be easy to check online, if that company would be convenient to order from.
Reply:Go to a plumbing supply house and ask for a STEEL npt coupler."Where's Stick man????????" - 7A749"SHHHHHH!! I sent him over to snag that MIC-4 while tbone wasn't looking!" - duaneb55"I have bought a few of Tbone's things unlike Stick-Man who helps himself" - TozziWelding"Stick-man"
Reply:you dont want a coupling.you want a 1 1/4 by 1 1/2 bushing.
Reply:I'm not familiar with the term bushing, in this context.  Can you post a picture of what you're talking aobut boatbuoy? Originally Posted by boatbuoyyou dont want a coupling.you want a 1 1/4 by 1 1/2 bushing.
Reply:This is a (reducing) bushing. Threaded inside and out. However I was under the impression you wanted to remove the bung and replace it with a bigger bung or just hole saw a new hole and add a bigger bung. If that is correct then you want to go to a local plumbing supply house and get a "STEEL" npt coupling like this one I found at Grainger. Or look on Grainger web site, on left click on "plumbing", then in box above on left it will say "search within these results", type "coupling", then after the couplings page pops up type in the same box "steel" and you will get all of the steel and stainless steel couplings.Last edited by Stick-man; 04-24-2010 at 10:37 PM."Where's Stick man????????" - 7A749"SHHHHHH!! I sent him over to snag that MIC-4 while tbone wasn't looking!" - duaneb55"I have bought a few of Tbone's things unlike Stick-Man who helps himself" - TozziWelding"Stick-man"
Reply:Thanks Stickman.  The picture you posted makes sense to me as a bushing.  Maybe boatbuoy misunderstood the OP's desire to replace a 1/2" bung with a 1 1/4" bung.  I use the type of fitting you posted a photo of.  Actually, Grainger and other supply houses will sell a 'half coupler', so you don't have to cut it in half....Benson's Mobile Welding - Dayton, OH metro area - AWS Certified Welding Inspector
Reply:As mentioned above, if you don't KNOW what you are doing then don't do it!!!!!No joke, no kidding.  And in addition to knowing what you are doing, to have all the associated items in place as well.Things like ASME Pressure Vessel certifications, liability insurance, approved welding procedures, recertifying the pressure vessel, etc, etc, etc.It's not as simple as 'just' welding a new fitting in place.And btw, just -why- do you have a need or desire to replace the apparently existing 1/2 inch NPT port with an 1-1/4 inch NPT port?  Because that is a h-u-g-e change!  An air tank with a 1/2 inch NPT port is probably sized along with its motor and compressor pump for a certain flow rate.  Jumping to an 1-1/4 inch NPT port doesn't change any of the flow capacity from the compressor pump at all, it would only let you possibly get a bigger 'blast' of air out of the tank faster but then you would just end up waiting for the tank to refill anyway.And related to -knowing- what you are doing and the whole certified procedures and recertification of the pressure vessel, I don't -know- if an internally threaded pipe coupling is certifed for being welded.  A weld-on fitting obviously is made to be welded.Just because it sort of fits doesn't mean it's the right piece for the job!  The best laid schemes ... Gang oft agley ...
Reply:Forged A105 steel fittings are, generally, weldable. Cast fittings are generally not. Half couplings are sold specifically to be welded in place. After welding, you  will need to run the appropriate pipe tap to clean up the threads (many half couplings, and many weldolets, are supplied with only a partial thread to allow for this, since welding almost always distorts the fitting enough to need retheading.)DO NOT weld a threaded bushing in this application. They can be welded (and often are) for applications like a feedthrough requiring a male thread, but in this application, the half coupling is the way to go.As to safety: In a commercial application, this SHOULD NOT be done other than by a holder of an R-2 (repair and alterations) from the National Board. This would most likely be considered an alteration requiring engineering review. The wall on the air receiver is likely htin, and there will be a reinforcement requirement due to the hole. For your own use, this may not be required in many jurisdictions, but if there is a failure at some point, you might find that evidence of modification will be a show stopper for insurance and liability.
Reply:Here's a fuel transport tank project I just finished up using half couplings for connections for the filler neck and fuel pump.First picture is one of the two original ports removed as a part of modifying the shape of the tank.  The second photo is a 2" half coupler from grainger (forged steel, NPT thread) I welded into the tank.Note:  This application is an unpressurized, vented liquid transport tank, not an air receiver for a compressor.  It was washed and allowed to air dry, then purged with Nitrogen for 2 hours before welding commenced.  "If you don't know what you're doing, don't try this on your own." Attached ImagesBenson's Mobile Welding - Dayton, OH metro area - AWS Certified Welding Inspector
Reply:I've not run into issues with having to chase the threads on these couplings before.  Case in point, the half-couplings I used on the job I mentioned above were ready-to-go right from the start.  I installed the plugs because my customer is having the tank sand-blasted and repainted as a part of this whole project.  Those plugs threaded in with a little anti-seize without problems.  I like to weld fittings with a plug or nipple installed with anti-sieze because I seem to have fewer problems with thread distortion afterwards... Originally Posted by enlpckForged A105 steel fittings are, generally, weldable. Cast fittings are generally not. Half couplings are sold specifically to be welded in place. After welding, you  will need to run the appropriate pipe tap to clean up the threads (many half couplings, and many weldolets, are supplied with only a partial thread to allow for this, since welding almost always distorts the fitting enough to need retheading.)
Reply:Big difference between a (mostly) unpressurized fuel tank and a pressurized air tank.As you acknowledged, A_DAB.  If you don't KNOW what you are doing, then don't do it.  The best laid schemes ... Gang oft agley ...