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Author Topic: Tip for fixing leaky plastic plumbing fittings  (Read 2950 times)
Dallas
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« on: December 18, 2006, 08:18:20 PM »

Hey all!

Installed a new toilet in our bus the other day and it worked great for a few days, then the day before yesterday, I noticed the floor was wet around the base of the throne. I thught that maybe I had missed or something in the middle of the night. (At least that's what Cat would accuse me of).

I dried it up as well as I could but later in the day, it was soaked again. I was kind of afraid I had cracked the mounting flange like I had on the old toilet, but I determined that the water was coming from the nylon/plastic fitting on the vacuum break where it connects to the incoming water line.

I took it apart, wrapped it with teflon tape, put it back, and it was worse. So I took it off again and looked at it carefully. Hmmm, some dummy, while installing it had cross threaded it. I tried plumbers putty, pipe dope etc, but nothing would cure the leak. There was always that drip, drip drip after about 30 minutes.

I, being economy minded as we all know I am, (Cat says I'm Cheap!), I hated to go buy a brand new 90° threaded fitting, so I looked around and found some butyl tape that was left over from a roof vent I'd installed on a camper. I thought to myself, well, why not!

I got a small piece and worked it in my hand until it was warm and pliable. I then pushed it into the threads on the fitting as tightly as I could.

When I put the fittings back together, Viola! no leak. It's now been over 12 hours and still no dripping.

I don't know if this is a recommended usage for this stuff or not, but, since no one should be drinking from that area, I figured it couldn't hurt!

Just my tip for the day.

Dallas
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Dreamscape
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« Reply #1 on: December 19, 2006, 03:36:11 AM »

Dallas,

Glad it worked, at least for now.

It seems that us Bus Nuts have lots of leaks, FUEL, OIL, WATER ETC., ETC., ETC..

A very much written about topic as of late.

Some one should write a book about that stuff, are you game?  Grin Grin

Installed a new toilet in our bus the other day and it worked great for a few days, then the day before yesterday, I noticed the floor was wet around the base of the throne. I thught that maybe I had missed or something in the middle of the night. (At least that's what Cat would accuse me of).

That never happens, right?

Happy Trails,

Paul

Dreamscape
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gumpy
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« Reply #2 on: December 19, 2006, 04:56:14 AM »

If it leaks again, get yourself some teflon paste. Wrap the fitting with 3-4 wraps of teflon tape, and apply the paste over the tape. Screw the pieces together, and let the paste set up for about 24 hours. That should cure it.

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Craig Shepard
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« Reply #3 on: December 19, 2006, 05:32:13 AM »

Or blow two bucks on a new fitting  Cheesy
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« Reply #4 on: December 19, 2006, 05:34:05 AM »

Most Plastic fittings they recommend NOT to use teflon tape.  FWIW Smiley
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Dallas
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« Reply #5 on: December 19, 2006, 06:08:35 AM »

Or blow two bucks on a new fitting  Cheesy

Len,
For shame!
You mean actually spend $2 on a fitting to do a 15 minute job?

When I could save $2 by working for an hour and a half fixing what I screwed up in the first place  Grin Grin Grin Grin Grin Grin
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gumpy
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« Reply #6 on: December 19, 2006, 06:10:06 AM »

Most Plastic fittings they recommend NOT to use teflon tape.  FWIW Smiley


Who is "they"?

According to the Plastic Pipe and Fittings Association (http://www.ppfahome.org/index.html) it's ok.

"What type of thread sealant should I use on threaded plastic fittings?
You are always safe to use PTFE Teflon tape (3 mil thickness). If a specific fittings manufacturer recommends a specific brand of thread sealant then it is acceptable to use it on their fittings only. There are many different types of thread sealants on the market and even though some may say they are acceptable for use with plastic fittings they may not actually be chemically compatible. Even some Teflon paste sealants can cause premature fitting failure due to chemical attack. "
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Craig Shepard
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« Reply #7 on: December 19, 2006, 10:01:14 AM »

I bought a roll of silicone tape for a leak on mine.  Worked like a charm.  Stuff is easy to use too.  Just stretch it out and roll it on.  It sticks to itself.

Jimmy

But if you don't want to spend money, and your original solution fails, I suppose you could always just tie some used up underwear around it. 
 Grin
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« Reply #8 on: December 19, 2006, 03:42:13 PM »

Lasco the largest manufacturer of plastic fittings recommends no teflon tape.

But I was referring to Sealand toilets and tetford as I believe both toilet mfgs state no teflon. But hay I stand corrected.

 I followed your link and I read it said it was okay to use the 3 mil but right below it said to follow MFG recomendations.

I personally think when using teflon tape on plastic fittings people tend to put to much and crack the fitting. That is why the toilet guys say no.

Good quality plastic to plastic fittings USUALLY  do not need teflon IMHO

Cheers
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« Reply #9 on: December 19, 2006, 04:39:37 PM »

The way Cat says your cheap, makes it sound like something bad. Like pervert or lazy!! It is suppose to be a compliment.
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Dallas
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« Reply #10 on: December 19, 2006, 05:58:28 PM »

The way Cat says your cheap, makes it sound like something bad. Like pervert or lazy!! It is suppose to be a compliment.

Jim, I keep trying to convince her I'm not only cheap, but easy too! Trouble is, she doesn't believe me!
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« Reply #11 on: December 19, 2006, 06:00:32 PM »

I used to work for  Goodrich Aerospace, and they had a subsidiary that I visited that makes teflon tape.  The plant manager gave me a tour of how its made, and how to use it.  Evidently it works not so much by filling in the base of the threads like most sealers do, but rather by making the threads slippery so the fitting is actually tighened tighter than it would be, so the threads seal.  As a result of this, he said when you do use it, you should never wrap it more than one time around (some overlap is ok), because the fluid or whatever you are trying to seal can leak out in between the plies of tape.

To use teflon tape on already slippery plastic that can be overtightened does not make sense knowing how it works.  

The paste type does actually fill in the gaps, and that is what I always use when I really need it to seal the first time.  Even oil base paint works well here.

I have found this to be true in the years I have used various sealers, and it was certainly true on the drain threads on my poly water and waste tanks for the bus.
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Jim Stewart
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« Reply #12 on: December 19, 2006, 06:20:01 PM »

Personally I avoid teflon tape like the plague - there are lots of better alternatives but the decision to use teflon or not depends on the type of seal.  NPT fittings seal by interference on slightly tapered threads - that is an appropriate situation to use teflon.  Anytime you have a flange or flared type fitting with straight threads then teflon is definitely not appropiate because the object is to compress the shaped fittings together to make a seal rather than to have the seal effected by the threads themselves. 

Rather than using teflon tape I use something called Tru-Blue Rectorseal.  It is a pipe dope that remains flexible on the threads but skins up where exposed to air.  It is suitable for a wide range of fluids - I'm not sure about petroleum products but it is great on the other liquids we encounter and on propane.  It also makes fittings easier to take apart when that inevitably happens.
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« Reply #13 on: December 19, 2006, 06:23:05 PM »

My favorite is also the Rector seal.  Bob, is correct in his statement about the type of fitting.  Flare fittings should never have a sealer added to them.  If they leak, you must fix the pipe / flare itself - bandaids don't work on this type.
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Jim Stewart
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« Reply #14 on: December 19, 2006, 07:37:34 PM »


I personally think when using teflon tape on plastic fittings people tend to put to much and crack the fitting.


That is quite true, and in the link, it also alluded to that. it's very easy to break the fitting if you over tighten, and the teflon makes it easy to overtighten because it reduces the friction.

The problem with not using tape and paste, is that some of the fitting manufactures don't properly taper their fitting threads, and so as you tighten it, you never actually get any tension on the threads. Also, when putting plastic on plastic, the friction without teflon will often seize the fitting before it's actually water tight, and it will leak.

It's definitely a fine line between getting it tight and breaking it.

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Craig Shepard
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