Throw it away or get your money back then buy Delta products.
Sealing straight threads
- Thread starter CleRob
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salguod
Member
That's not terribly helpful. Grohe makes quality products and my understanding is that this kind of straight thread is used commonly all over the world, it's just not common here in the US. There isn't much info available on it online either, likely because Google is showing me US oriented content. I'm confident I'm missing something in what I'm doing, but I'm struggling to understand what.
Grohe's customer support has been helpful, but they don't have technical data on general sealing techniques for straight thread, which is what I need.
Straight threads are not good for plumbing without a gasket of some type at the bottom of the threads.
As you’re finding out.
Good luck with your “ quality “ stuff.
Some of Grohes stuff is junk. They were bought out a few years ago.
I gave good advice. I’ve seen $50,000 in damage from a dripping handshowers connection in a wall.
salguod
Member
Trust me, I understand. I just spent $20K on a surprise DIY bath remodel (contractor estimates were 2x-3x that) because the contractor who did the original work put walls around 3 sides of a 2 threshold shower pan. There was 18" X 40" of subfloor missing from the water damage.
Unfortunately I'm at a point where it'll cost me a lot (hundreds at least, probably thousands) to tear out what I have and go with something else. New shower wall, updated wall plumbing, remove and reinstall the shower glass, paint, etc.
I really need to make this work, and I should be able to based on it being used all over the world, so I need to figure out how.
salguod
Member
It's not the hand shower, it's where it exits the wall. I've got a female npt drop ear in the wall, a grohe npt to straight adaptor threads into that, and that's where my trouble is. The adapter has to be cut off flush with the wall and something called an S union threads into it. Because it's cut off, no way to use a sealing washer.
Then the mixing valve is attached to the S unions, with a sealing washer.
Thankfully, the leak is inside the shower and not the wall, so it's obvious and relatively harmless.
I'm thinking that I'm going to try the sealing cord one more time, and if that fails, go with the Permatex or something like it. I was hoping to hear from OP if it's still good a year plus later.
Then the mixing valve is attached to the S unions, with a sealing washer.
Thankfully, the leak is inside the shower and not the wall, so it's obvious and relatively harmless.
I'm thinking that I'm going to try the sealing cord one more time, and if that fails, go with the Permatex or something like it. I was hoping to hear from OP if it's still good a year plus later.
Use a regular pipe nipple from the drop ell in the wall and install a Delta handshower ell onto the nipple. Then your hose and hand shower wand.
https://www.amazon.com/Delta-Faucet-50560-SS-Handshower-Stainless/dp/B000KQ5XU6
salguod
Member
One of us isn't understanding the other, likely me, so I thought a couple of pictures would help.
This is the Grohe unit. Mixing valve outside the wall. Hot and cold enter it and that's where it's leaking.
The straight thread is behind the escutcheons, which thread onto the adapters. You can see the drip forming in this shot.
This is the Grohe unit. Mixing valve outside the wall. Hot and cold enter it and that's where it's leaking.
The straight thread is behind the escutcheons, which thread onto the adapters. You can see the drip forming in this shot.
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I’ll go back to my original recommendation.
Throw it on the dumpster or get your money refunded
I wish you the best.
Throw it on the dumpster or get your money refunded
I wish you the best.
In continental Europe and Russia straight threads on iron water pipes were common. Thread was sealed with linen yarn wetted in oil-based paint, plus a jam nut. The nut likely generates an axial force on threads sealing those. Pipe length is easy to adjust, and it lasts forever. Otherwise, you need a sealing interface (cones), O-ring or gasket. I believe you can get Teflon yarn to play with or roll it out of tape and add a jam nut. But manufacturer is supposed to provide you with adapter to US piping or proper designed seal, so send it back and get Delta as other suggested.
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Ludington
Well-Known Member
I installed new washing machine valves, and they came with straight thread. I had a terrible time getting them to seal. I wish this post had existed then. I ended up using a lot of Teflon tape and forcing the connection onto them. It did seal, but obviously incorrect. I'll know for the next time what to look for before I buy straight threads again.
Get a plumber to do the work. I have dealt with a few of these and don’t like them but there are quite a few extenuating circumstances that could apply And make it difficult to impossible to install properly. Just because it doesn’t leak doesnt mean it is right.
Every plumber up to anout 30 years ago carried candle wicking with them for these situations.
Still have some on. Y truck and use it on old brass lines.
salguod
Member
Grohe supplied sealing cord, but it failed, I assume due to user error. I bought Loctite 55 which is the same stuff and it sealed for 2 months but is now leaking.
Your mentioning a jam nut is interesting. This has no jam nut and no space for one. My current theory of why it's failing is that I've been trying to bottom the union in the adapter and perhaps the axial force is creating space on the back side of the thread, allowing it to leak. My thinking is a straight thread needs no axial load to create even spacing on both sides of the thread and no uneven loading. That's just a theory and, of course, different than what you are saying.
My thinking is to try the sealing cord one more time, trying to avoid axial loading. If that fails, I'm going to a thread locker / sealer like the Permatex 57535 mentioned above.
As I said, replacing the unit will cost me thousands in rework, I'm not ready to go there yet.
Ludington
Well-Known Member
Teflon moves under pressure, and the thicker it is, the less is resistance to the force. This is where linen helps. Somebody mentioned candle thread -similar material. You can soak it with Teflon paste. And only as a last resort -you can seal thread with thermal two part filled epoxy, hard to find, needs to be before expiration date and thread require degreasing prep. You may get it in small packs. It will make a permanent, weld like joint.
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Ludington
Well-Known Member
salguod
Member
The first few minutes of this video shows what I have. When it shows the S union, I have the first one, without the shutoff valves. It also has scored thread so I didn't have to rough it up.
It's interesting, I did manage to find a couple of posts from outside the US a couple of months ago. Just like the US posts tend to not understand why anyone would use straight thread and this sealing cord, they wondered why the US bothered with the tapered pipe thread when this worked so well. That's why I'm confident there's a way to get it to work. I guess it's all about what you are familiar with.
It's interesting, I did manage to find a couple of posts from outside the US a couple of months ago. Just like the US posts tend to not understand why anyone would use straight thread and this sealing cord, they wondered why the US bothered with the tapered pipe thread when this worked so well. That's why I'm confident there's a way to get it to work. I guess it's all about what you are familiar with.
salguod
Member
I took it all apart, applied the Loctite 55 sealing cord and reassembled, stopping a half a turn short of bottoming. It's sealing for now. Of course, it sealed last time - for a couple of months.
Since I had to shut the water off, I did what I should have done in the first place and put an access panel in the wall behind and added shut off valves for the shower itself. Now if I have to do this again, I can at least work on it without shutting the whole bathroom off.
Hopefully you won't hear from me again, meaning it's sealed.
Since I had to shut the water off, I did what I should have done in the first place and put an access panel in the wall behind and added shut off valves for the shower itself. Now if I have to do this again, I can at least work on it without shutting the whole bathroom off.
Hopefully you won't hear from me again, meaning it's sealed.
