Update: The mixing valve

When the mixing valve fiasco was finished, I knew—deep in my heart—that it was a temporary fix.

Really, everything is temporary.

But I knew the goo I used was not going to last as long as “real” plumbing.

Late in February, during a rainstorm and (while I didn’t think about it at the time) right after my room mate had taken a shower, I was down in the basement for something and noticed a puddle. It wasn’t big. It wasn’t actively dripping. So I assumed it was some new seepage or something; that spot in the basement is just inside where just outside there is a rain downspout and it was raining (also under the bathroom, but I wasn’t thinking about that just then). So I figured come spring I’ll need to address the gutter and downspout. Which I already knew; that particular gutter and downspout are pretty decrepit. The next day the puddle was gone.

But then Tuesday of the last week of February, while my room mate was taking a shower, I heard the normal “showering is happening” water noises, but also a distinctly separate “drip. drip. drip.” and I knew immediately what it was. I went and checked in the basement. Drip. Drip. Drip. Puddle. “Bollocks.”

So that Saturday, after the room mate moved out, (Back to China. I knew it was going to happen, which is why I waited for him to leave. Why inconvenience him to fix something that has been broken for weeks or longer when he is going to be gone in days?) I took the medicine cabinet out of my bedroom wall and looked. Here’s what I found:A picture of the mixing valve with the piping showing the leak

That pipe leading off to the right goes to the hand shower. Which I use occasionally to clean the shower, but which my room mate used every time he took a shower. (Also visible just below the valve is the charring from trying to do it the right way, with a blowtorch.) And you can see the water coming from both ends of the repair.

So I chiselled off the old putty (turns out what I’d finally used was the same plumbers epoxy: I’d just kept at it until I got it to stick. But it didn’t really stick, so it was pretty easy to chop through and pry off), pulled off the repair sleeve, and went to the hardware store. Because technology has moved on a bit since this was broken the first time; there are more options.

What I bought was a SharkBite Slip Coupling. Slip fittings have revolutionized the home plumbing repair field. When you’ve screwed up some copper or PVC plumbing, slip fittings are probably a good bet to fix it, especially if you’re not confident with the blowtorch (or for some other reason the blowtorch is not a viable option). The slip-coupler is designed for exactly this situation: bridging a spot where you have a couple of inches gap: you slide it deep onto one end, put the pipes into alignment, and slide it back off that end a little to bite onto the other end.

Unfortunately, if the pipes you’re biting onto are not pristine or not perfectly aligned, you may have trouble. I got the coupler slid deep onto the longer end. I got the pipes pretty well realigned. But the coupler wouldn’t go quite far enough onto the shorter end (which was in pretty bad shape) to seal. There was a bit of something on the backside of the pipe that I could feel, but I didn’t know what it was. Maybe solder? Maybe some glue? Whatever it was, it was keeping the coupler from getting deep enough to seal. Or maybe a nick or mar on the long end had hung up the coupler so it wouldn’t slide back over the way it is supposed to. Anyway, it wasn’t moving. So this is better…ish. One end of the repair is sealed. The other end is leaking worse.

Then I had an inspiration: Sugru. Sugru also didn’t exist when I was fighting this fight the first time. These days I keep a supply on hand, because Sugru is the coolest stuff ever. I checked with the Surgu web page. Which says it does stick to copper.

I got out a 5g packet, opened it up, massaged it into a ropey shape, and molded it around the spot where the coupler was not quite sealing around the copper. I pressed hard, trying to make sure it worked into the gaps as much as possible and sealed well against the brass and the copper. And then I went to bed. “Sugru cures pretty quick,” I thought, “but I don’t want to take any chances or be tempted to try it before it has a chance to finish setting up.”

And in the morning I tried it out for a minute or two: No leaks. I took a shower with it on: two small leaks. So I waited for it to thoroughly dry and added another portion of Sugru to seal those. While I was waiting the few hours my memory said Sugru takes to cure I re-read the instructions, just in case. Turns out it takes a few hours to skin over, but it takes 24 hours to cure to 3mm deep and longer for thicker applications. So that may be why the pinholes appeared after only overnight curing. So instead of risking, I waited until Tuesday morning to try it again. I figured if it goes to 3mm in 24 hours (Monday morning) it should be to 6mm by Tuesday morning. And there’s no way I put on a quarter inch layer, so it should be all done:

The repaired pipe, showing the sharkbite fitting and two different colors fo Sugru

I turned on the handshower and let it run hot for a few minutes: dry. Then I took a complete shower while the handshower still was running. After the shower: dry.

The next day I took one last shower before putting the wall back together. It started leaking again. Bollocks. I added a third round of Sugru. Waited a couple of days. Tried it again. It swelled up like a balloon, which then burst as I watched and shot hot water at my face. Turns out that a: Sugru sticks pretty well to copper, but not awesomely, and b: it’s flexible. If I had overwrapped the Sugru with something stiff to keep it from stretching, I’m guessing it would have been fine.

I sliced off as much of the Sugru as I could. I cut the coupler off the long end, and tried to work it off the short end. I used a lot of force, but no dice. I used the blowtorch to melt/burn the plastic parts out of the coupler and slid it off the pipe. So now I’m back where I started but with a wider gap.

I got a hand mirror and looked at the blob on the back: definitely solder. Definitely too far down the pipe to let the thing seal right. Despair. I decided to try again to sweat the stub out of the elbow and replace it with a longer stub, which I could then use a slip-coupler to get onto.

That didn’t work. Even with the protective mat, things got so hot the wood started to smolder.

But then yesterday I was in a different store, which sold a different brand of these slip fittings (Watts). And this brand needed a  bit less depth to be able to grab and seal. I bought one, slid it onto a spare piece of copper pipe, and drew a line around it with a Sharpie. Took it back off the spare pipe (this brand also works a little differently mechanically, and is easier to disengage and reposition), and held that pipe up to the short stub. Doable. Barely.

I grabbed some sandpaper and a utility knife, and sanded/scraped as much of the blob of solder off the backside of the pipe as I could. I took a regular slip coupler (not the deep-throat repair kind) and fitted it onto the short stub. It worked. I slid the deep coupler onto the long stub. I cut a short piece of copper to fit between them. Slid them all together. Held my breath. Turned on the water. It didn’t leak!

…at that spot.

Turns out while I was using all that force to get the failed first attempt back off, I had stressed one of the other repairs, and it was now leaking. A little. So I cut that repair completely out, went back to the store for a couple more fittings, installed them, and bob’s your uncle. All fixed:

The completed repair, showing the new slip-on fittings. And the new charring.

(You can still see a little of the red Sugru from the third round. And the new charring.)

A couple of bobbles, but 3 weeks is better than 8 months. Science Marches On!


A guy in his early 50s, living more or less alone in a 90-year-old house, trying to keep it all together.

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Posted in Plumbing

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