Welding couplings on LP tanks.

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huffdawg

huffdawg

Minister of Fire
Oct 3, 2009
1,457
British Columbia Canada
Anyone have any welding advice for welding fittings on lp tanks . Filled my primary tank up to test for leaks and there were quite a few pinholes on the welds. :mad:

Was thinking of grinding down a little and then going over the welds. Then will pressurize tank with shop vac. and check again for leaks with soap and water solution.

Huff
 
If you welded cast couplings to the tank good luck! It took me forever to seal them up. You should weld pipe nipples into the tank then use a coupling.

Rob
 
I welded 2" pipe nipples on my tank. I didn't have any leaks at all. The hardest part is getting them lined up so that they are square. I had to make up a swing joint on one of them cause it was off a little and wouldn't line up with the incoming pipe. I will probably change it out next season and use one of the flexible SS braided hoses cause I just don't like it (I'm fussy I guess)

Whatever you do, make sure your tank is free of any propane before welding.
 
taxidermist said:
If you welded cast couplings to the tank good luck! It took me forever to seal them up. You should weld pipe nipples into the tank then use a coupling.

Rob
Click to expand...

Yup they must be cast cause the only ones that didnt leak were the nipples welded to the hole where the tank level guage was in .
Huff.
 
On that note, does that bad stuff (that goes boom) in a propane tank, rise to the top or fall to the bottom? Or a combo of liquid on bottom & gas at top, both bad? Just wondering if a fella has rounded up a couple of tanks, and they'll be sitting for a while, should they be sat with holes down or up.

We've got a stick welder here, that I can make pretty decent looking bubble gum with, but I'm not sure I should tackle something like this or not. On the flex hoses, that's another reason i started that flexible joint thread a few days ago - real hard to get two solid fittings to line up exactly right, especially with rounded surfaces like these.
 
huffdawg said:
taxidermist said:
If you welded cast couplings to the tank good luck! It took me forever to seal them up. You should weld pipe nipples into the tank then use a coupling.

Rob
Click to expand...

Yup they must be cast cause the only ones that didnt leak were the nipples welded to the hole where the tank level guage was in .
Huff.
Click to expand...
Can you borrow an oxy/acet torch from someone & braze the leaking fittings? Nickel arc welding rod would probably work too. Randy
 
Singed Eyebrows said:
huffdawg said:
taxidermist said:
If you welded cast couplings to the tank good luck! It took me forever to seal them up. You should weld pipe nipples into the tank then use a coupling.

Rob
Click to expand...

Yup they must be cast cause the only ones that didnt leak were the nipples welded to the hole where the tank level guage was in .
Huff.
Click to expand...
Can you borrow an oxy/acet torch from someone & braze the leaking fittings? Nickel arc welding rod would probably work too. Randy
Click to expand...

Yes I have acces to oxy/acet. and a miller 212 autoset with argoshield universal

Huff
 
Don't mess around, cut or grind the cast couplings out and do it right.
 
I have turned many propane tanks into water storage tanks and have always used the smooth steel couplers (not cast iron).

I have also started to weld the couplers on the tanks first, before putting holes in the tanks and then coming back with a hole saw to cut out the holes in the tanks after welding.

Every now and than I will get a leaker but for the most part I usually have very few leaks.

Brian
 
A bit amusing. I had a neighbor whose profession was welding cut and weld two 2" couplings into my LP tank. He used a hole saw to cut the holes for the couplings; then used a junky looking stick welder to do the welding, two passes. The job looked like a work of art. I asked him whether I needed to pressure test the welds before filling the tank with water, and he said "no." I then asked him what he welded. He said 3000 psi high pressure steam lines at the nuclear and big coal-fired electric generating plants in the area. Obviously, no leaks.
 
jebatty said:
A bit amusing. I had a neighbor whose profession was welding cut and weld two 2" couplings into my LP tank. He used a hole saw to cut the holes for the couplings; then used a junky looking stick welder to do the welding, two passes. The job looked like a work of art. I asked him whether I needed to pressure test the welds before filling the tank with water, and he said "no." I then asked him what he welded. He said 3000 psi high pressure steam lines at the nuclear and big coal-fired electric generating plants in the area. Obviously, no leaks.
Click to expand...

Were they cast couplings Jebatty
 
I didn't pay too much attention, but they looked like (USA made) steel couplings sold by a hardware store that specializes in pipe fittings.
 
huffdawg said:
Singed Eyebrows said:
huffdawg said:
taxidermist said:
If you welded cast couplings to the tank good luck! It took me forever to seal them up. You should weld pipe nipples into the tank then use a coupling.

Rob
Click to expand...

Yup they must be cast cause the only ones that didnt leak were the nipples welded to the hole where the tank level guage was in .
Huff.
Click to expand...
Can you borrow an oxy/acet torch from someone & braze the leaking fittings? Nickel arc welding rod would probably work too. Randy
Click to expand...

Yes I have acces to oxy/acet. and a miller 212 autoset with argoshield universal

Huff
Click to expand...
Use a oxy/act welding tip with cast iron flux if available & that should do it. If you welded these with your Miller Mig, well, I wouldn't have. Stick welding gets much better penetration on this type of weld. Mig welds tend to leak out the sides unless you are a really good welder. Good luck, Randy
 
Take it from me you will spend less time grinding them out and replacing with steel nipples then you will trying to fix the couplings. I weld pretty good and i chased leaks and ground and welded and ground ect ect. I got it to stop leaking but it took a while.

Rob
 
After years and years and years of welding pipe, let me tell you, get rid of the cast to steel. Use steel nipples or couplings.
You don't want to live with the fear of a leak with your system.
 
Epoxies are pretty amazing BUT not for this. Like others have said and yes it sucks to have to take steps back but do it right and weld in the right fittings. good luck feel your pain
 
huffdawg said:
This might sound stupid , has any one tried two part epoxy or jb weld .
Click to expand...



I bet it would work.........until Jan 25 when its -15* and your tanks are charged to 180* and it springs a leak. LOL.....start grinding!!!!!!!

Rob
 
If you don't have much brazing experience I would recommend doing as others have said & put in steel couplers. If you know how to braze well ther'es no need to go through the bother as brazed in fittings will not blow out with 30 psi, obviously. Randy
 
huffdawg said:
Always was a grinder! And quit laughing at me , my wife has been snickering for the last 24 hrs. :red:
Click to expand...


Not at you, with you because most of us have been there done that already. LOL


Rob
 
huffdawg take a look at this[PDF]
Adhesives for Heat Exchangerswww.permabond.co.uk/files/Download/MKT_Heatex_rev2.pdf

I used this on my heating system and forgot about it until I read your post. I think its going on 8 years. You would have to get rid of the water at the fitting and make sure its dry and then apply. Good Luck
 
REFire said:
huffdawg take a look at this[PDF]
Adhesives for Heat Exchangerswww.permabond.co.uk/files/Download/MKT_Heatex_rev2.pdf

I used this on my heating system and forgot about it until I read your post. I think its going on 8 years. You would have to get rid of the water at the fitting and make sure its dry and then apply. Good Luck
Click to expand...

Did you use this on your storage tank fittings

Huff
 
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