Compression supply valve tightness

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St. Paul, MN
Hey guys!
I am a DYI'er and I am generally comfortable with plumbing except the 'just feels right' parts. Compression valves are notorious for that.

I have 4 copper stubouts in my new bathroom that I put 5/8 compression valves on. I got the Proflo brand from Ferguson.
One thing I recognized is that the once tightend on those, there are more threads visible in comparison to Brasscraft or other brands, i assume this is just a brand differenece.
I put the first two ones on and made sure the pipe was cleaned, not damaged, and deburred. I basically when hand tight, then with wrenches until felt resistance, and then more than 1/4 to 1/2 turn and it was snug. Turned the water on and no leak or weeping on those 2. That was 1.5 month ago.
Last night i did the other two stubs and basically followed the same thing.
However had a tiny leak on one. So i kept going in increments until stopped. But i think i had to go another 1/2 to 3/4 past tight. No leaks since last night on both.
However I read somewhere that undertightned joints can fail at some point and the valve can blowout. Is that really a case with house plumbing? I know commercial uses tons of compression but residential water pressures are not that much.
As you can see in the images, you can see that one of my valves is tightened more than the other one. Do you see any issue here?


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Jeff H Young

In the Trades
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I always put a little pipe dope on the threads only of the angle stop. especialy chromeplated raw brass is semi self lubricated and might be ok . some say a drop or 2 of oil . When I did tract housing we would get leaks when guys put them on dry they would tighten till it squeeked. its a big problem put them on check and a few hours or days later a slight drip on cheap cabints made out of glue and saw dust. So Ive never changed my ways every compression joint a tiny amount of teflon dope not even all the way around nessesary as it looks sloppy if not wiped of well but thats how I and guys Ive worked with almost all did it.
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