1/4 Pex Compression Fitting Question

Old 05-14-16, 09:22 PM
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1/4 Pex Compression Fitting Question

Using Sharkbite's 1/4" Pex (3/8 OD) with a Brass Craft compression connection. I've used compression connections with copper many times no problems with correct tightness. First time with pex. The BC catalog states to use 3/8" plastic sleeve with 1/4" so I bought a few BC sleeves and did a few trials with test length of pex to get the feel. It seems like I never get to a point where the compression feels snug around the pex. If I wrench down on it to get the feeling of tightness, the pex deforms. If I just snug it, I am able to rotate the pex in the fitting. Not sure of what the sweet spot is.

Any advice before I put it into the system. I know I can always get it partial and if it leaks snug it some more, but then my worry would be I didn't snug it enough and I would stop the leak but over time the fitting would fail.

Thanks for all input.

http://www.brasscraft.com/pdf/0302_B...gs_Catalog.pdf Page 15

Shop BrassCraft 3-Pack 3/8-in x X Compression Adapter Fitting at Lowes.com

Kinda sidebar additional question:
The same BC catalog says plastic "tubing" requires an insert of the type

however the same page breaks out pex separately and does not mention a insert for 1/4" pex. I read this as there is plastic tubing 1/4" that is not pex that requires the insert and I am correct in not using an insert in my pex.

Just not sure of the the nomenclature regarding "plastic tubing".
Old 05-16-16, 11:35 AM
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I believe deforming the pipe a bit is expected with compression fittings. That's why they can't be reused since it actually compresses both the compression ring and the pipe.

But I would definitely lean towards just getting to the 'tight' point and tighten it from there. Once you get a leak-free joint, I think it's highly unlikely to start leaking again in the future. As you imply, you can always tighten it a bit more - you can't really 'loosen' these fittings and too-tight can cause leaks just as easily as not tight enough.
Old 05-17-16, 12:41 AM
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Thanks for the input Zorfdt. That is probably what I'll do.

Just surprised no one on this board has used compression fittings on pex. Of course I never have so......
Old 05-17-16, 08:45 AM
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I've used pex, and compression fittings. But I don't trust compression fittings ON pex so I use an adapter between. But then I was slow to trust sharkbite fittings, too...

I think the "plastic tubing" they are referring to is the white poly tubing like is used to connect a refrigerator to the water supply.

Why not just stick to fittings made with pex barbs? The peace of mind gained by using the entire engineered system rather than "will fit" is worth the extra couple bucks per, IMO.
Old 05-17-16, 08:48 AM
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So I have not actually used them with PEX....but the last brasscraft 1/4 turn lav stop I installed came with both brass and stainless steel tubing inserts and the instructions said to use the stainless insert for PEX....
Old 05-17-16, 03:34 PM
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if it leaks snug it some more, but then my worry would be I didn't snug it enough and I would stop the leak but over time the fitting would fail.
Here's my approach to compression fittings. I install many and don't have call backs.

- Only use a brass ferrule on copper tubing, not plastic

- For 3/8" and 1/4" plastic tube, use a plastic Delrin Sleeve and insert.
The Delrin sleeve is a plastic compression ring/ferrule

- Wrench tighten the compression nut until tube will not slip out easily, the sleeve grabs just a little, then tighten one full turn to 1-1/4 turn. Do not over tighten.

- If tightened correctly, the joint should not leak upon installation and will not be susceptible to leaks over time, you're done

And not to confuse, but the 3/8" doesn't technically require a Delrin insert, but it doesn't hurt either. The 1/4" always requires the insert.

I'm not sure how you are rotating the tube as a test for tightness, but that is not a test normally performed. You can trust these fittings without any tests except to check for leaks. When I was first learning plumbing, I discovered I could rotate almost anything, and things didn't go so well. Leaks O'plenty
Old 05-17-16, 11:34 PM
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Gotta thanks carbide for the magic sentence "read the instructions". Without my glasses I thought it was just so much legal junk but printed in the box was actually the instructions (I hate having to wear glasses to read).

I think guy and handyone are also correct in that plastic tubing requires the insert. 1/4" Pex being it's own special animal apparently does not.

No pex barbs for 1/4" pex , apparently the 1/4" pex is special animal in the pex family

handyone, I was grabbing the pex with wrench and seeing if I could twist it just to get a measure of what a small amount of torque did to grabbing the pex pipe when I was playing with some short lengths of pipe as a trial. I tried it per the instructions and it seemed to hold. Next stop actually putting it in the system!

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Thanks all for input....moral of the story put my d**n glasses on.

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