heat resistance of pipe dope

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I am putting a threaded bronze ball valve in a 1/2" copper water line.
So I am using threaded adapters between the pipe threads and the copper tube.
I intend to use pipe-thread compound on the threads when I install the adapters. Then I would wrap the valve with a wet rag and solder the tubing ends of the adapters onto the copper tubing.
The pipe threads will get hot during the soldering operation.
What kind of pipe dope is supposed to be resistant to this kind of heating?
The line carries drinking water.
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On 2/13/2009 8:15 PM Matt spake thus:

I'd use teflon tape and not worry about it.
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Before you start heating Teflon tape up to the temperature that melts solder you might want to read this article;
http://www.yourlawyer.com/articles/read/9769
Cut and paste the address into your browser
EJ in NJ
David Nebenzahl wrote:

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On 2/14/2009 8:00 AM Ernie Willson spake thus:

Why should I do that? All I have to do is click on the link. Are you using some kind of antique newsreader?
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And your point is???
EJ in NJ
David Nebenzahl wrote:

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On 2/14/2009 12:18 PM Ernie Willson spake thus:

First of all, it would be copy and paste, not cut and paste.
Second of all, no modern news/mail clients require you to do that; your link appears as a clickable link in your message, so all I've got to do is click on it. No need to copy and paste.
By the way, you might also try not top-posting: bottom posting makes more sense, and is the norm here.

>

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Thanks for all your constructive help
EJ in NJ
David Nebenzahl wrote:

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Ernie Willson wrote:

Thanks again for the article on teflon.
Now I will try to rehabilitate you with respect to top-posting:
A: Because it ruins the order in which people normally read text. Q: Why is top-posting such a bad thing? A: Top-posting. Q: What is the most annoying thing on usenet and in e-mail?
:-)
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Well, it can become a "religious" issue.
Anyway, any rule has its exceptions. Like when there's a LOT of text sitting there to write beneath. Sort of a pain to force someone to page through all that to get to your bit. (As when for some good reason you don't want to elide a bunch of that stuff first.)
David
PS: you want to get into a REALLY religious issue, lets talk about cross-posting!
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Mine does. "Mutt".
But then I'm using a "shell account" to access the net, meaning I dial in, log-in, and arrive at a unix (well, net-bsd) prompt. No gui.
So cut-n-paste (just SOUNDS better than "copy-n-paste", though of course that is what you're really doing) it is.
(Paste into LYNX browser, also non-gui, no pictures either.)
However, makes me think I should ask if there's some hack that will shortcut that somewhat.

David
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Ernie Willson wrote:

Teflon when it is heated to temperatures which, at their low end, are only slightly above normal cooking temperatures. C-8 has been shown to cause tumors in rats and fumes from Teflon coated cookware can cause what is known as "polymer fume fever," a condition which has been shown to kill birds even at low temperatures but which DuPont claims is harmless to humans if the cookware is used at a temperature of up to 500F. When Teflon is overheated (above 700F), fatal cases of polymer fume fever in humans have occurred (at 842F). In 2005, however, the Environmental Protection Agency stated that tests on laboratory animals linked PFOA to liver, pancreatic, and testicular cancer, reduced birth weight, birth defects, and immune suppression.
Thank you.

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On 2/14/2009 8:00 AM Ernie Willson spake thus:

Point well taken; I have no doubt that teflon is yet another nasty chemical inflicted upon us by the money-mongers who *always* claim that they're harmless and that civilization would collapse if they were to be banned.
Having said that, I don't think that sweating on a couple connectors for a valve is going to inflict a lethal dose of fumes on the torch-bearer.
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And you are likely right. I just point out because someone might have a problem if there a lot of joints in a confined space. Simple awareness of this possibility might prevent a serious accident.
EJ in NJ
David Nebenzahl wrote:

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Why can't you just sweat all the way through? Does the ball valve have provisions for sweating? If not, get one that does. What happens if the thread leaks, how do you take it apart?
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Mikepier wrote:

You can get valves that can be soldered directly to copper tubing, but then you will ruin the valve seals if you overheat the valve while soldering.
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I have only used valves intended to be soldered into the line for several decades without a single problem, this includes regular valves with rubber washers and now the ball valves. They are made to take the heat, and only specifiy that you should have them open when soldering. If you overheat them, you are probably burning off the flux and oxidizing the copper and brass, resulting in a bad soldering job anyhow. Probably resulting in a leaker.
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Mikepier wrote:

Maybe I am not understanding your questions.
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I have never cooked the seals on a valve while soldering it, but I have cooked the hell out of pipe dope on several occasions, to the point where the threaded joint leaks. You are better off with a sweat valve, and you can save the cost of the threaded adapters.
JK
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Big_Jake wrote:

Could you describe your technique? In particular, do you wrap the valve body with a wet rag?
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I use a good torch (Turbotorch) with MAPP gas. I clean both sides of the joint with open mesh sand cloth, and apply a generous amount of flux - I prefer Oatey #95 tinning flux. I apply more heat to the valve than the pipe, to draw the solder into the joint. Finally, as the tinning flux starts to turn silver and bubble, I apply the solder, working around the joint - I prefer Oatey "Silver" lead free solder.
You can wipe the joint with a wet rag as soon as you are done to cool it down. If you are worried about the valve, you can take the stem out while soldering, unless it is a ball valve.
The breakthrough for me was getting away from 95/5 solder, which I could never get to flow right. The tinning flux actually has powdered solder in it, which seems to really make the job go quickly. I can't imagine being able to apply enough heat to the end of the valve with a wet rag wrapped around it. I have, however, wrapped a wet rag around a male or female adapter that is near the point I am soldering, to keep from cooking the pipe dope out if it, but never while soldering to the adapter. You might be able to solder using an acetylene torch with a wet rag around the valve, but as I said initially, I have never cooked a valve bad enough to ruin it.
JK
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