Shutoff Valve Leak Only When Hot

I have a shutoff valve that gets a pin size amount of a water bubble around one spot of the threads on the inlet side when I run a few minutes of hot water to the sink. It does not leak any other time. Do I dare attempt to tighten the nut (probably compression) or leave it alone as there is no steady leak?
Actually, I am confused as to why it would only leak once the pipe heats up with a run of hot water?
Thanks for your time and input.
Ben
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Tighten it slightly. Will probably fix it.

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Ben wrote:

Hi, How about redoing it with some Teflon tape? Tony
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I've thought about redoing it with some tape, but never had much luck with reusing a compression fitting.
I'll probably try giving it a little snug while holding the shutoff valve tight so the outlet compression fitting does not move.
Any comments on why it only leaks under the hight hot water temperature?
Thanks for the reply,
Ben
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Ben wrote:

Different materials expand and contract at different rates.

--
Joseph Meehan

Dia duit
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