Pipe joint compound question

Old 02-09-07, 12:17 PM
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Pipe joint compound question

Hi, Im installing a new fuel oil tank. At the local plumbing and heating supply house I inquired as what to use to seal the pipes (for the fill, vent, supply valve, etc) to make them fuel oil safe. They sold me a little tube (2 oz.) of "pipe joint compound, item 12-102 Utility chemicals)It is a gray gooey substance. I used it on all the threads like I was instructed. It seems fine. The question I have is this. Is this stuff supposed to dry or get rubbery or something? Its been days since I did the job and the excess around the joints is still in a wet state. This is outdoors and its cold out too. Is this normal for it to remain creamy. How long do I have to let it "dry" before I can use the pipes for their purpose. I dont want to fill the tank only to find that the bottom feed valve is leaking from where it screwed into the tank. Was this the proper product? Is the cold weather causing this? If this is the wrong forum, admins feel free to move it.
Old 02-09-07, 03:44 PM
Join Date: Mar 2006
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There are probably hundreds of "pipe joint" compounds and most are incompatible with at least some usages. Whether or not the compound you bought is suitable for fuel oil I cannot even hazard a guess. It should state on the container (tube) if it is suitable with fuel oil.

That stated, many pipe joint compounds remain in a "plastic" state forever to allow future disconnection of the piping. This is not a fault of the product but instead a benefit.

For fuel oil I like "Permatex number 2" compound. This is dark brown and remains flexible. It seals well and is compatible with fuel oil. It is a thick paste-like compound that is hard to remove from your hands so you may want to wear gloves.

Permatex number 1 compound is more of a reddish color and will harden to the point that it is extremely difficult to "break" the joint.

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