Drilling and tapping a propane tank

[sparke]

I do not have enough ports for temp gauges and I can not find a welder. Has anyone drilled and tapped a propane tank directly? Are the tank walls thick enough? I am thinking of 1/4" hole for T&P gauges. Any other ideas? Was thinking of maybe installing gauge with a wire and bulb sensor through a tee at the inlet and outlet? Ideas are welcomed.

 

[ewdudley]

I do not have enough ports for temp gauges and I can not find a welder. Has anyone drilled and tapped a propane tank directly? Are the tank walls thick enough? I am thinking of 1/4" hole for T&P gauges. Any other ideas? Was thinking of maybe installing gauge with a wire and bulb sensor through a tee at the inlet and outlet? Ideas are welcomed.

Singed Eyebrows reports success with this in this thread:

https://www.hearth.com/econtent/index.php/forums/viewthread/58238/

--ewd

 

[Singed Eyebrows]

I do not have enough ports for temp gauges and I can not find a welder. Has anyone drilled and tapped a propane tank directly? Are the tank walls thick enough? I am thinking of 1/4" hole for T&P gauges. Any other ideas? Was thinking of maybe installing gauge with a wire and bulb sensor through a tee at the inlet and outlet? Ideas are welcomed.

I tapped into a 3/16" thick side with 1/8" pipe thread there were plenty of threads in this. You should have minimum 1/4" wall thickness & I personally would'nt hesitate to go up to 3/8 pipe thread in this. What works great & is very accurate is to use a long stem thermometer(off Ebay), available with 12" stems & greater. You tap the tank for 1/8" pipe thread, screw an appropiate length 1/8" pipe nipple into this(depends on your insulation thickness), put an 1/8 to 1/2 bell reducer on the nipple & screw the long stem gauge in. This is very accurate & reasonably cheap, Randy

 

[DaveBP]

For something like 1/8" or 1/4" tapered pipe threads the 5/16" or so thickness of the larger propane tanks will leave enough threads to seal well as long as the threads are cut cleanly and square to the surface.
Without a proper gage it can be tricky to know when to stop tapping into the tank. Keep checking with your proposed fitting as you cut a turn at a time until your fitting is started into the inside surface of the tank and it hasn't bottomed out on the outside surface. Use lots of real thread cutting oil and keep dribbling it on as you go (not just when you start tapping).
I wouldn't try to seal anything like the larger tappings for water supply and return. You need more threads for the cord or dope to work against.
(And I'm sure someone has got away with a 2" pipe fitting or something like that that hasn't leaked in 10 years).

 

[sparke]

Thank you for the input!