Fidelitech
New member
In the shop now there is existing PVC pipe and I need to connect to brass fitting. Best way to seal this is???? Just use teflon? or is that special goop to use when mating these two.
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PVC to brass fitting??
- Thread starter Fidelitech
- Start date
72Tunaboat
Well-known member
Teflon tape will work fine.
DHS
Well-known member
Rector Seal or another pipe dope. With the brass pipe fitting we get at work they recommend dope when screwing PVC on to Brass.
tcianci
Well-known member
If the pipe is for hot water you want to be sure to use a connector designed for this purpose, they are avaiable in unions and adapters. Just gluing a threaded fitting to the PVC and then threading on a brass fitting will result in leaks because of the thermal "crawl" of the plastic pipe as it is heated and cools again. I actually installed on of those fittings on the pvc hot water line in my garage tonight, I fought slight drips from the connection of the PVC to the brass compression adapter at the faucet for years, even re did the whole connection with new fittings of the same configuration, got the same leaks in a few days. I'm hoping that this thing works like it's supposed to!
Charles (in GA)
Well-known member
you can glue a PVC fitting that has either male or female iron pipe thread on the other end, from there you can screw on a brass fitting that also has iron pipe thread. DO NOT waste your time with thread tape, it simply won't seal on PVC to metal, or PVC to PVC pipe thread fittings. Use thread dope instead.
Charles
Charles
DHS
Well-known member
when transitioning from PVC to metal, always screw a male PVC thread into a female metal thread. Screwing male metal into female plastic can cause a crack or split in the female plastic fitting when you tighten it up.
If you are at a supply house they also have Banded Females that have a stainless metal band around the outside where threads are to prevent this. But MRB is right its best to just use a male adapter.
1pfieffer1
New member
- Joined
- Sep 18, 2009
- Messages
- 3
Pipe dope and thread tape are lubricants not sealants. Threaded joints are in and of themselves what makes the seal, not the lubricant. The lubricant simply allows the joint to be completely tightened so it functions correctly.
you can glue a PVC fitting that has either male or female iron pipe thread on the other end, from there you can screw on a brass fitting that also has iron pipe thread. DO NOT waste your time with thread tape, it simply won't seal on PVC to metal, or PVC to PVC pipe thread fittings. Use thread dope instead.
Charles
DHS
Well-known member
Pipe dope and thread tape are lubricants not sealants. Threaded joints are in and of themselves what makes the seal, not the lubricant. The lubricant simply allows the joint to be completely tightened so it functions correctly.
I'm not 100% sure about that. Even RectorSeals site sayes (RectorSeal® No. 5® pipe thread sealant is a soft-set, slow drying compound which seals, lubricates, and protects threaded pipe and fittings.) I have heard that before though.
72Tunaboat
Well-known member
Pipe dope and thread tape are lubricants not sealants. Threaded joints are in and of themselves what makes the seal, not the lubricant. The lubricant simply allows the joint to be completely tightened so it functions correctly.
So..what you're implying.. is that I can just squirt some oil on a threaded pipe and it will 'lubricate it' enough so it can be threaded tighter. And the threads will seal it?
BS.
I agree that these products do lubricate, but they also are a big part in the seal. If you try to tighten a fitting with no dope or tape, it will not seal(no matter how tight you get it).
Just my .02
1pfieffer1
New member
- Joined
- Sep 18, 2009
- Messages
- 3
I did some researching about the matter. Here is what Wikipedia has to say........
"The taper on NPT threads allows them to form a seal when torqued as the flanks of the threads compress against each other, as opposed to parallel/straight thread fittings or compression fittings in which the threads merely hold the pieces together and do not provide the seal. However a clearance remains between the crests and roots of the threads, resulting in a leakage around this spiral. This means that NPT fittings must be made leak free with the aid of thread seal tape or a thread sealant compound. (The use of tape or sealant will also help to limit corrosion on the threads, which otherwise can make future disassembly nearly impossible.)"
So, I stand corrected. I also need to have a chat with the Master Plumber who taught me when I was in school to get my license..........*******.
"The taper on NPT threads allows them to form a seal when torqued as the flanks of the threads compress against each other, as opposed to parallel/straight thread fittings or compression fittings in which the threads merely hold the pieces together and do not provide the seal. However a clearance remains between the crests and roots of the threads, resulting in a leakage around this spiral. This means that NPT fittings must be made leak free with the aid of thread seal tape or a thread sealant compound. (The use of tape or sealant will also help to limit corrosion on the threads, which otherwise can make future disassembly nearly impossible.)"
So, I stand corrected. I also need to have a chat with the Master Plumber who taught me when I was in school to get my license..........*******.
I agree with a few of the comments above:
1. Where possible, buy a pre-made adapter that includes a 'glue on' PVC end and a "screw to" brass end. That's the best possible solution.
2. Failing that, make sure that you have a: a) male PVC screwing into female brass (otherwise, the male brass will eventually split the female PVC); and, b) use thread dope, not thread tape.
I speak from experience of the "hey, what's that sound of gushing water coming from the basement the night after my plumbing project" sort.
1. Where possible, buy a pre-made adapter that includes a 'glue on' PVC end and a "screw to" brass end. That's the best possible solution.
2. Failing that, make sure that you have a: a) male PVC screwing into female brass (otherwise, the male brass will eventually split the female PVC); and, b) use thread dope, not thread tape.
I speak from experience of the "hey, what's that sound of gushing water coming from the basement the night after my plumbing project" sort.
Kjbakke2
ALLIANCE MEMBER
pipe dope is the way to go