Propane tank leak - replacement/welding discussion

Topic: Propane tank leak - replacement/welding discussion (Read 3297 times) previous topic - next topic

Propane tank leak - replacement/welding discussion

July 14, 2017, 08:25:08 am

Now there is a propane leak in the welded area on my propane tank. Found by MOT.
Can these be drained and welded??

Re: Propane tank leak - replacement/welding discussion

Reply #1 – July 14, 2017, 09:34:10 am

Dan, do not see why not after draining and opening the valve while doing the welding. I think I would also unscrew the fill valve and take it off (if you can) just so you have NO fuel in there even though showing empty. It is a pressure vessel which has been certified so make sure the person doing it is a neat welder and grind the old weld out a bit before doing.
John H

Re: Propane tank leak - replacement/welding discussion

Reply #2 – July 14, 2017, 09:48:43 am

I would displace the residual propane with water before doing any welding on the tank, and have a CERTIFIED welder do the work.

Re: Propane tank leak - replacement/welding discussion

Reply #3 – July 14, 2017, 09:53:10 am

Quote from: Travelin' Man – July 14, 2017, 09:48:43 am

I would displace the propane with water before doing any welding on the tank, and have a CERTIFIED welder do the work.

Shouldn't the tank be tested and recertified as well if any welding is done on the tank itself?

Re: Propane tank leak - replacement/welding discussion

Reply #4 – July 14, 2017, 09:59:34 am

did a quick Google on propane tank welding leak

Welding Propane Tanks [Be Carefull!!] | Hearth.com Forums Home

Welding a propane tank | Hearth.com Forums Home

Something that should only be done by someone who knows what they are doing and understands the concerns. I would not take this to "Bubba's Welding, Bait, and Tackle Shop"

Re: Propane tank leak - replacement/welding discussion

Reply #5 – July 14, 2017, 10:12:58 am

When I weld on diesel or gas tanks I put dry ice in them to displace the fumes and oxygen with CO2. Water prevents a good weld, the steam pushes the weld puddle out. Agree with above it needs someone who repairs tanks for a living.

Re: Propane tank leak - replacement/welding discussion

Reply #6 – July 14, 2017, 10:15:44 am

Recertification.........yes.
I also like the idea of "Torching it off."

Re: Propane tank leak - replacement/welding discussion

Reply #7 – July 14, 2017, 10:19:55 am

If welding, the tank should be water filled to displace all remaining propane, then drained and argon purged prior to welding. The argon prevents any chance of a fire and also ensures the molten metal on the backside of the weld is not exposed to oxygen which would allow it to oxidize. The molten penetration will solidify much better if you purge, giving you a much stronger and cleaner weld.

That said, even though I am a skilled tig welder with a lot of experience, I would probably look for a new tank before I tried to repair one. The risk of future failure elsewhere is a possibility if it has already had a failure and risking a propane tank explosion or failure/leak down the line is just not worth it! Any repair would require removal of the tank, so swapping would actually be easier than repairing.

Re: Propane tank leak - replacement/welding discussion

Reply #8 – July 14, 2017, 10:51:34 am

MOT will not weld. Looking for used tank as many have been removed as many coaches have gone to all electric. Not sure what a new replacement tank would cost?

Re: Propane tank leak - replacement/welding discussion

Reply #9 – July 14, 2017, 10:56:39 am

Dan- get a guarantee on the new tank that it is not leaking before it is installed.

Re: Propane tank leak - replacement/welding discussion

Reply #10 – July 14, 2017, 11:23:34 am

A new certified tank is about $650.00. Wow. For an expense not expected but then there seems to be no end to maintaining a motorhome. A trip to Nacogdoches always is more expensive than my estimate. The thing with MOT they are very good at what they do.

Re: Propane tank leak - replacement/welding discussion

Reply #11 – July 14, 2017, 11:33:11 am

See if any businesses like this are in your area.

http://lpcylinder.com/

Re: Propane tank leak - replacement/welding discussion

Reply #12 – July 14, 2017, 11:41:03 am

NAC = 1 Coach buck per day, give or take 25%

Tim Fiedler

Sure Start Soft Start

TCER Direct generator-gas-prod 630 240-9139
Gen-Pro

Re: Propane tank leak - replacement/welding discussion

Reply #13 – July 14, 2017, 12:30:09 pm

Tks Craneman called ur referral and they are not certified to repair leaks in welded areas. Good try though.

Re: Propane tank leak - replacement/welding discussion

Reply #14 – July 15, 2017, 12:15:43 am

What size is your tank and where are you located - I may have a tank available at Oregon Motorcoach in a couple of weeks out of my U-320

Tim Fiedler

Sure Start Soft Start

TCER Direct generator-gas-prod 630 240-9139
Gen-Pro

Re: Propane tank leak - replacement/welding discussion

Reply #15 – July 15, 2017, 10:48:42 am

Propane liquid changes to vapor at 70 degree making 515x the liquid to vapor and then 15 to 1 air mixture and ignition source and you have a bomb. 1gal propane leaking changes into vapor is 515gals of vapor. Caution whenever dealing with propane.

Re: Propane tank leak - replacement/welding discussion

Reply #16 – July 15, 2017, 08:16:10 pm

Quote from: saddlesore – July 14, 2017, 11:28:15 pm

Short answer is NO!
Fed law prohibits any welding on a pressure vessel that has contained flammable substances. no matter if the tank is full or empty or empty and filled with inert gas for 10 years... the answer is still NO.

Where did they hide this law? As an Operating Engineer heavy equipment mechanic working the trade, we welded at least one fuel tank a week on bulldozers and scrapers. To think that you would have to shut down a $1,000,000.00 piece of equipment and wait for a $5,000.00 fuel tank to be delivered and change out is ridicules. We stick welded with 7018 and only lowered the fuel level below the damage. Threw in dry ice waited 5 min. tested with an oxyacetylene torch, never had a burp by the way and then welded.

Re: Propane tank leak - replacement/welding discussion

Reply #17 – July 15, 2017, 08:47:18 pm

Quote from: craneman – July 15, 2017, 08:16:10 pm

Where did they hide this law? As an Operating Engineer heavy equipment mechanic working the trade, we welded at least one fuel tank a week on bulldozers and scrapers. To think that you would have to shut down a $1,000,000.00 piece of equipment and wait for a $5,000.00 fuel tank to be delivered and change out is ridicules. We stick welded with 7018 and only lowered the fuel level below the damage. Threw in dry ice waited 5 min. tested with an oxyacetylene torch, never had a burp by the way and then welded.

Same on marine vessels, Capt hit the dock too hard and broke a seam on a 8000 gal diesel day tank. Lowered level to below crack and pumped in inert gas through vent. Used explosimeter with remote probe to monitor lower explosive or flammable limit inside the tank. and welded up crack. USCG approved method.
Jim C.

Re: Propane tank leak - replacement/welding discussion

Reply #18 – July 16, 2017, 07:36:03 am

I think the law says PRESSURE vessel, meaning fuel under pressure, LP, Natural gas, Hydrogen, etc.

TOM

Re: Propane tank leak - replacement/welding discussion

Reply #19 – July 16, 2017, 11:06:01 am

http://www.nationalboard.org/index.aspx?pageID=164&ID=440

Details repair of 27000 gal LNG railway car tanks that run at 300 psi. If you ever worked in a oil refinery, you would find literally thousands of tanks and miles of pressurized piping containing flammable substances. Gas would be $50 a gallon if the oil company had to replace every tank that needed repairs by welding.

Re: Propane tank leak - replacement/welding discussion

Reply #20 – July 17, 2017, 10:26:41 am

Appears the company who makes propane tanks for Foretravel made all sizes and shapes. Mine in the 02 is a weird shape. Looks plain to me. May have to build a tank . $$$$

Re: Propane tank leak - replacement/welding discussion

Reply #21 – July 17, 2017, 10:43:09 am

Quote from: Dan Stansel – July 17, 2017, 10:26:41 am

Appears the company who makes propane tanks for Foretravel made all sizes and shapes. Mine in the 02 is a weird shape. Looks plain to me. May have to build a tank . $$$$

Like Tim and others tanks have been removed to make room for batteries. Check at the mod centers for one.

Re: Propane tank leak - replacement/welding discussion

Reply #22 – July 19, 2017, 04:40:56 pm

Eric @MOT indicates that he is working on finding a 30 gal tank . Don't know cost yet. Only need propane for furnaces as hot water heater can be ran on electric. Coach is a 295 . Also on schedule to recover sofa. $$$ again

Re: Propane tank leak - replacement/welding discussion

Reply #23 – July 19, 2017, 06:05:40 pm

Ask him if my tank will fit from my coach, coming out in a week

Re: Propane tank leak - replacement/welding discussion

Reply #24 – July 20, 2017, 02:38:34 am

Quote from: craneman – July 15, 2017, 08:16:10 pm

Where did they hide this law? As an Operating Engineer heavy equipment mechanic working the trade, we welded at least one fuel tank a week on bulldozers and scrapers. To think that you would have to shut down a $1,000,000.00 piece of equipment and wait for a $5,000.00 fuel tank to be delivered and change out is ridicules. We stick welded with 7018 and only lowered the fuel level below the damage. Threw in dry ice waited 5 min. tested with an oxyacetylene torch, never had a burp by the way and then welded.

The key word is "pressure vessel-Flammable"
A diesel /kerosene/gasoline tank is not under pressure is it?
You can get a certified welder to replace mounting brackets, but not weld cracks in the tank its self.
The propane tanks used in RV's (permanent mount, not portable) have to be labeled & certified as such, ie: motor fuel-permanent mount- DOT registered.

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