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Upstream the author mentioned a possible future post on pipe joint compounds. Well, that’s what’s on the menu this time around. Again, if you are a plumber, you can skip this one too. Now, you might ask what’s so important about gobbing on pipe dope? Well, there’s more to this subject than meets the eye.
Even with the aid of PTFE ribbon tape, plumbers working with threaded systems still depend upon paste consistency compounds, for specific applications. On the shelves of suppliers you will see numerous brands trying to get your attention. Which one should you choose? Well, where do you intend to use it? On what type of piping? Will just one product cover all of your needs? These very questions will help you make the best choice. In this plumber’s experience not one single compound will cover all your needs. I will tell you what I’ve discovered over the years.
Not all compounds (all brands are blends, the sum of ingredients) are sanctioned for both metallic and plastic piping. As the author mentioned in his upstream blog, The Teflon Story, you have to be careful which compounds you apply to threaded ABS adapters (DWV systems) and involving faucets, around certain exotic content counter tops. So first, look ON THE CAN (photo 1) for any sanctioned uses and warnings. If you are working with ABS do your homework and make sure you see that specification spelled out. Ditto for PVC, although PVC is compatible with many more blends than ABS is. Some manufactured counter materials can be stained by some joint compounds (and certain brands of plumber’s putty) so it pays to work conscientiously and no drips.
For threaded steel fittings, both water and fuel gas lines, you have almost carte blanche. But regardless of which threaded material you wish to administer the compound, there is more than the compatibility issue, which I’ll get to next.
Tension, compression, and clean and dry threads are what allow quality PTFE ribbon tape to stay in place on male threads (as described in the Teflon Story). This clean and dry aspect remains the case also for compounds, with some additional twists, they being: consistency of the paste and how well it adheres to and transfers from the application brush to threads. This ease of loading the brush and the ease of transferring the compound to threads, especially female ones, are what makes plumbers brand loyal. Oily threads, both M/FM, inhibit you efforts to apply the paste and some brands just have a very unhelpful consistency and viscosity when it comes to loading the brush. For the brands that are difficult to load with a straight brush, you’ll find a ‘bent’ or angled brush makes a pesky chore almost a passable one. Conversely, compounds that have a “runny” consistency are easier to get out of the can but can be messier to use. (The author would rather tack towards runny than too stiff.)
The smaller the molecules of the medium you’re sending down the pipe, the easier/better they are to escape. Air under pressure is more difficult to contain than water under pressure.
Ready? Set! ……….
Some compounds have a set time and can be between 4 to 48 hrs where the viscosity changes from an easier to apply peanut butter consistency to that of fully cured rubber cement. This set time will vary depending upon ambient temperature and chemical content. The brand and viscosity/consistency that the author has used successfully for decades on threaded steel and brass (for both water and gas), under-sink threaded tubular brass waste slip nuts, and threaded female copper adapters (also for water) is the yellow Rectorseal No. 5. PHOTO 2.
This No.5 has a somewhat “nose tingling” aroma when you are working with it in a confined space such as under sink cabinets, but it loads and applies wonderfully. It has a slow set time.. When used on gas lines, the longer you can wait towards the listed cure time before air-testing, the better your chances of no leaks. When yours truly installed a new garbage disposer with a customer requested tubular bass continuous waste system (versus ABS or PVC), employing brass slip nuts, he needed to get the tools back on the truck and be down the road to the next job. Yet, I have had very good results (very few leaks) because I put PTFE ribbon tape on the male threads and No.5 in the slip nut female threads. Where No.5 is like a heavy syrup, other compounds, some of PTFE, are like cake frosting. And PTFE’s often do not have set times. I’ve found a couple of PTFE’s that were difficult to load and apply, and required some custom modifications to a standard acid brush to make use of. However there are situations where one type is better than another, and yet not just one blend solves your need every time. Presently my favored PTFE is Rectorseal’s T + 2. PHOTO 3
The ‘dope’ PtP was introduced to in the late 1950’s, and it’s still manufactured, is/was called (Key Brand’s) Key-Tite. PHOTO 4. (Key Brand is now owned by Cameron Co.) It’s in a white can with an old fashioned key on the label. Key-Tite is spelled in red letters and there are vertical green stripes on the can.
It’s also a green compound and nice smelling. Wonderful loading and application quality. Good stuff for water and fuel gas, but I can no longer find it in my locales. You might check the plumbing supply stores in your area. One of the best things about this one though is you never have to stir it even after long, long times in the can. Thus we can say no set time for this choice. (And, it will never dry out in the can between uses.). The product is an ‘Accessory’ for their WKM Valve line. If you are interested here’s a phone number 1+281-582-9500.
Got the Blues?
The author (while he’s thinking of it) would like to give you another tip. There’s one pipe joint compound (PHOTO 5) BLOCK ™ that over the years I became very appreciative of, even if it had only one, major place of application. That was W & O’s, bathtub waste and overflows. When you install a tub waste to a tub, and there is no ‘after finish’ access to the waste and overflow and p-trap, you in essence have ‘sealed your Knight up in the wall’. On traditional cast brass wastes, when the first generation rubber slip-nut washers, rubber tub-shoe-to-strainer gasket and rubber tub to overflow gasket, dry up and give-out (by shrinking and drying out) replacing them can be a real tussle. When ABS and PVC cemented W & O’s first came along I thought the rubber slip-nut problem was solved. But these plastic versions had/have other problems all their own. (Given the choice, I’d pic the brass.) The author eventually discovered a product, mentioned above, that was a smart choice even with the longer lasting beveled nylon washers. When installing virgin parts which are clean and dry, this product (PHOTO) seals the space between nut/washer/tube and Tee, develops a rubber-like final cure and resists failure from repeated heating and expansion and contraction. After full assembly it was applied (externally) to thin gaps between components and left to cure. In my book “Installing And Repairing Plumbing Fixtures”, the companion to “The PEX Expanded Plumbing A House”, you will see the tub waste and overflow parts involved, illustrated and photographed.
This ‘dope’ BLOCK is blue in color. It is manufactured by Hercules’s Company. In this plumber’s opinion there are a number of aromas associated with sanitary plumbing and plumbing chemicals that one could say was bordering on offensive. But I cannot say that about the nostalgic aroma of BLOCK. Its smell reminds me of new toys when I was a young boy, manufactured right after WW2. They were rubber. (The pleasure of entering the neighborhood 5 & Dime/toy shop, then, is much alike now walking into a fine-cigar store’s inner sanctum, even though I no longer use tobacco).
When having to tell my repair customer that I needed to cut holes in walls (‘inside, outside, and up-side down’) to get at the problem, it was never told without a very sincere, prominent “wish it didn’t have to be this way.” The chore of saying that was almost as unpalatable as the making of the holes. As a last gasp the author has reached through the smallest of possible openings, some existing and some PtP-ized to reach a waste and overflow, and/or p-trap, and attempt to rectify a leak.
Block, being of rubber, among a few other minor ingredients, has a consistency like real heavy pancake batter. It has a long set time, very dependent upon ambient temperatures, and yours truly only worked with it when set times could be fully met. (And, I gave up trying to use it without disposable gloves.) The author has cured some slip-nut leaks without disassembly, when the tub in question could be quarantined from water, for a long enough rest. On bone dry (sometimes with the aid of hand held electric heat guns) W&O connections, with repetitive exterior applications of BLOCK at slip-nut and gasket locations, I have postponed (sometimes for decades) needed fixture replacement due to gravity drainage leaks.
As mentioned above the weak links of W&O’s are still the rubber parts. (Shoe and Overflow), and in days gone by, the rubber slip-nut washers. Because of the rigidity of iron tubs, it was common (as mentioned upstream) to get 30 years of service from rubber in tub W&O’s. With today’s plastic tub/shower combo, even with cemented plastic wastes or nylon washers on the brass wastes, because of flexing of the ‘plastic’ fixture due to body weight, that’ no longer the case. And, is a good reason when employing “plastic” fixtures to consider the slower but surer assembly procedure using BLOCK.
Today, I don’t think you will find any new W & O’s boxed with rubber slip nut washers. The beveled nylon version slip nut washer is ubiquitous. But in some rare instances, you may find yourself working on an “oldie”. It was/is common to find properly maintained tubs to have rubber slip-nut washer wastes, twenty to thirty-some years on the job, two weeks prior to your leak call.
Brass Or Plastic
It’s really a pleasure to install a quality brass W & O, like a pop-up Kohler. Hefting and assembling the clean, shiny brass components somehow feels “superior” to cutting 1½-in. plastic pipe nipples and gluing on a tee and shoe. But what remains a bonus for the plastic option is the joining method: chemical welds. As long as the assembly is not abused (1/4-in. ‘drain snakes’)) and remains snuggly in place, the glued joints at some point become the strongest point. Trip levers/knobs and toe-taps tend to die first.
When installing a brass waste (preferably) to a new iron tub, on its side, on a carpet scrap, the author, leaves off the PTFE ribbon on the tee’s male slip-nut threads and applies a generous application of BLOCK to both the brass slip-nut cavities and the male threads of the tee and on and around the top of the in place nylon (or rubber) slip-nut washer. Then, just ‘snuggly’ tightening the slip nuts, the compound is forced around the beveled washer and ‘surrounded’ so to speak. Have ample rags handy to wipe up/off the excess BLOCK that squirms out around the tubing, and to clean the stuff of the jaws of your pliers. Next, on a following day, (I’ve explained to the homeowner the benefit of my madness), I apply another brush width, at the joint, around the overflow tubing where it passes through the slip nut on the tee and the tube of the shoe where it passes into the slip nut on the tee. Done. Now it’s a croissant and espresso break!
Just as it’s more difficult to do a ‘proper’ job of cementing larger diameter ABS and PVC pipe and fittings with the small brush in a four to six ounce can of cement, applying compound to larger diameter male and female threads with the small brush-in-cap is also at times irritating. The author recommends that if you only want to purchase one sized can, which will ‘go the furthest’ for meeting your need, I suggest a half-pint or larger. The brush is usually the same size of that of the quart can of compound. If ‘you’z in-the-biz’ the brush in ½-pint will work well with M/FM threads up to 2 & 1/2-in.
In the future I expect to see new compounds join the market and if they remain in the market for sufficient time to suggest there ‘might be something to it’, I’ll experiment with it first, before assigning it major applications. In the interim, those time tested brands mentioned in this article will see you through your present jobs requirements.
Peter Hemp is a San Francisco East Bay residential plumber and plumbing author and former R & D steam vehicle plumber. His hobbies are ocean kayaking and touring the Left Coast by bicycle.