Capping off a propane line: need tips and tricks!

[profdant139]

After great effort, I just now found my very slow propane leak (and I will soon prepare a fascinating 😉 report on the many things I learned while trying to find it). Bottom line – the leak is at the point that the external barbecue fixture connects to the propane system.

What I want to do is remove the barbecue fixture – we never use it. And I want to cap off the stub or nipple that "tees into" the propane line. The pipe is galvanized. It appears to have an ordinary pipe thread -- not a flared brass gas fitting.

I am planning to unscrew the existing reducing bushing (I think that is what it is called) and replace it with a galvanized cap. I will use teflon gas tape at that joint.

My real question is this: I don't want to put any stress on the other galvanized propane lines underneath the trailer. I will hold back on the galvanized nipple with a pipe wrench while unscrewing the existing reducing bushing. The bushing is very rusty -- I anticipate having to use a lot of force to unscrew it. I'm planning to spray it with WD-40 a day or so before unscrewing it, to try to loosen the threads.

Does this sound like the right approach? I am not a plumbing or propane expert, as you can tell.

Thanks in advance for your suggestions!!

[profdant139]

It looks like my local Lowe's has a selection of black iron. Galvanized might work, but why take a chance?

Again, continuing thanks for all of the helpful comments!!

[Lantley]

smthbros wrote:
"Galvanized pipe can flake and clog orifices an small openings within your appliances."
This is no longer an issue due to a change in the galvanizing process which happened several decades ago. None the less, it would be wise to check with the governing authority for your jurisdiction. Until about 30 years ago, copper was unapproved for natural gas piping in my jurisdiction. It is now approved.

You maybe right that it is an old tale at this point nevertheless many jurisdictions do not allow galvanized pipe

[smthbros]

"Galvanized pipe can flake and clog orifices an small openings within your appliances."
This is no longer an issue due to a change in the galvanizing process which happened several decades ago. None the less, it would be wise to check with the governing authority for your jurisdiction. Until about 30 years ago, copper was unapproved for natural gas piping in my jurisdiction. It is now approved.

[Lantley]

profdant139 wrote:
If the pipes are black iron and not galvanized steel, can I use a galvanized cap to cap off the line? The metals are not so dissimilar that they will cause electrolysis, are they?

And if I need to get a black iron cap rather than a galvanized cap, who would carry such an item?

Sorry if these are naive questions, but I have stepped outside my comfort zone here.

Galvanized pipe can flake and clog orifices an small openings within your appliances. Small pieces of the galvanized material flakes off.
Don't be obsessed with using galvanized pipe. Black pipe fittings are readily available.
Galvanized pipe is not used for gas work due to the potential for flaking and clogging.

[profdant139]

If the pipes are black iron and not galvanized steel, can I use a galvanized cap to cap off the line? The metals are not so dissimilar that they will cause electrolysis, are they?

And if I need to get a black iron cap rather than a galvanized cap, who would carry such an item?

Sorry if these are naive questions, but I have stepped outside my comfort zone here.

[Edd505]

Chris Bryant wrote:
Should be black iron, not galvanized, but other than that, it’ll be fine.

That was my thought, gas = black iron. I prefer the yellow tape, less mess.

[profdant139]

phil, this was not an extend a stay. Just an ordinary external bbq fixture. Not sure why the leak formed -- I am going to examine it closely after I remove it. Right now, there is no way to see the area with the leak -- it is about an inch below the bottom of the trailer.

Gonna get some of that PB stuff and let it sit for a day or so before I move ahead with removing the fixtures.

[TurnThePage]

I think when I did it 10 years or so ago, the fitting came of pretty easily, and I just screwed a cap on with teflon tape and a little grunt. It's held up fine ever since.

[pnichols]

profdant139 wrote:
After great effort, I just now found my very slow propane leak (and I will soon prepare a fascinating 😉 report on the many things I learned while trying to find it). Bottom line – the leak is at the point that the external barbecue fixture connects to the propane system.

What I want to do is remove the barbecue fixture – we never use it. And I want to cap off the stub or nipple that "tees into" the propane line. The pipe is galvanized. It appears to have an ordinary pipe thread -- not a flared brass gas fitting.

I am planning to unscrew the existing reducing bushing (I think that is what it is called) and replace it with a galvanized cap. I will use teflon gas tape at that joint.

My real question is this: I don't want to put any stress on the other galvanized propane lines underneath the trailer. I will hold back on the galvanized nipple with a pipe wrench while unscrewing the existing reducing bushing. The bushing is very rusty -- I anticipate having to use a lot of force to unscrew it. I'm planning to spray it with WD-40 a day or so before unscrewing it, to try to loosen the threads.

Does this sound like the right approach? I am not a plumbing or propane expert, as you can tell.

Thanks in advance for your suggestions!!

I'm curious regarding the source of your leak ... was that an "Extend-A-Stay" adapter fitting that developed a leak?

If so, I was thinking about installing one in motorhome's propane system for use of a 5 gallon propane tank to supplement the main tank on long campouts - plus maybe also power our outdoor BBQ ... but have held off because I didn't want to introduce another potential leak source into my propane system.

Here's a link with a photo as to what an Extend-A-Stay adapter is for a built-in propane tank, which may be similar to what you have on your TT for use with an externall BBQ:
http://www.rv-project.com/projects/extendstay.php

[philh]

Pipe dope ONLY goes on threads... not on the flange like the idiot (a master plumber to boot) that installed a water heater on my first travel trailer before I bought it.

[mapguy]

Galvanized pipe is not used for propane or natural gas service. Use black iron cap and use a gas rated pipe dope like Rector Seal for the best results. Teflon tape is very difficult to use and insure that you have no minuscule leaks. That is -unless you over tighten the fittings as is very common.

[wa8yxm]

There is a different dope for gas threads (I think it is yellow in color) and they generally use "Black Iron" pipe.. any hardware. ANY hardware department. Just take the old fitting in so you have the right size.

[LarryJM]

MrWizard wrote:
i prefer 'Kroil' or 'PB blaster' much better penetration, bushing will come out easier

I agree "PB Blaster" (My preference) is XXX times better than WD40. Best to let the PB Blaster work for a day or two reapplying as necessary to keep fitting wet. It takes time for the PB Blaster to really be effective so it's not a quick one step process.

Larry

[profdant139]

Some great tips -- thanks! I hope to avoid becoming a "pipe dope."