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Plbg.com also known as the PlumbingForum.com. The popular plumbing tips, remodel and advice forum and blog. Ask any toilet, sink, faucet, pump, water quality and plumbing related questions.
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Author:
PlumberJoe (ID)
I hate plastic!!!! This past weekend I installed a new water pump and tank at the house to replace the old rusted setup. The new stuff is plastic where all fittings connect. Following instructions of using tape wrapped 4 to 5 times on the threads of the male fittings, then going 1.5 turns after hand tightening the fittings, every f'en fitting leaked! Even tighening a vit more did not help. As an 'experiment' I used a galvanised nipple between the plastics so it was metal to plastic using the same amount of tape and tightening procedure and had ZERO leaks. Unfortunately, I did not have enough nipples to complete the job and the stores were closed. Anyway, it really sucks having to reprime the system while fixing the leaks only to find out plastic to plastic sucks too.
QUESTION: What method will ensure no leaks the first time when tighening plastic threaded fittings together? Would it be appropriate to use pipe dope in addition to teflon tape?
I never had any problems as mentioned above doing metal to metal.
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Author:
packy
well, there's teflon tape and there's teflon tape.. some is thicker and better quality than others. the variety sold at the big box stores is very thin and 4 wraps is not enough.
i use blue monster tape, it is alot thicker. a dab of teflon paste ontop doesn't hurt.
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Author:
HelpMePlumb (FL)
You may have cracked the fittings. On plastic fittings I use no Teflon tape - sealant instead and don't overtighten cause that hurts, not helps.
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Author:
PlumberJoe (ID)
Thanks Packy for your reply. The reason why I want to use dope on top of tape is I had zero leaks for metal to metal fittings however I was told in the earlier days (10 years ago) never use dope on plastic. I was not sure why other than the dope can attack the plastci causing problems later on. As for thin tape vs thicker tape, I also tried more wraps of tape using various brands and struck out. As for all the plastic chinese made crap, it sould have stayed in China. Give me the good old American made steel anyday over the crap now on the market.
So, will dope on top of tape help? Or will it harm the plastic? Is the question..
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Author:
PlumberJoe (ID)
HelpMePlub, Doubt it very much. There are a lot of fittings and all leaked. When I used a metal nipple between the plastic and reusing the same plastic that leaked before, there were no leaks.
Edited 1 times.
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Author:
waukeshaplumbing (WI)
it all depends on what product you used & where you bought them
why did you get everything threaded??? thats the last method of joining pipes i would choose....and why did you throw galvanized metal in the mix??? thats the last material i would use....todays galvanized is junk...it will most likely rot in 10 years
tear it all apart...get a pex tool and redo it with Wirsbo Pex
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Author:
PlumberJoe (ID)
Please reread my opening post - To restate, the pump has threaded plastic ports for the fittings. the tank too. The plastic nipples are threaded on one end and barbed on the other end for plastic hose between the pump and tank. Sorry if I was not clear on this.All standard for the setup are purchased. The galvanized double ended threaded nipple was used in an attempt to see if it helps stop the leaks by using it between plastic and worked well. PEX plays nothing into this problem.
Edited 2 times.
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Author:
hj
quote; then going 1.5 turns after hand tightening the fittings
IF every male and female PVC thread was made "perfectly" then a "formula" such as that MIGHT work, as long as it was the correct formula. (Your "hand tight" is probably not the same as mine or anyone else's which is why a formula seldom works) OTherwise, you put the thread sealant on the male thread and tighten it as much as possible. Tape and compound should not be necessary, but the extra insurance probably helps.
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Author:
hj
Dope that uses the wrong oil, such as mineral oil, WILL soften the PVC. Use a compound which says it is safe for PVC and there is no such problem.
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Author:
joe plumber (NE)
I use blue teflon on plastic fittings .I have also used the white teflon tape .
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Author:
PlumberJoe (ID)
HJ, can you recommend by name an available dope compound found in the big box stores that will not soften PVC?
Thanks in advance.
Edited 1 times.
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Author:
PlumberJoe (ID)
Based on searches, it appears Hercules Megaloc Thread Sealant will be my best choice for a safe sealant for PVC/plastic. If anyone disagrees, please let me know otherwise I hope to find it at Lowes after work. I will try tape with sealer in an attempt to seal the crappy plastic fittings. thanks
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Author:
waukeshaplumbing (WI)
how about a new pump without plastic fittings?
ive never seen anything come with plastic fittings other than odd ball home depot stuff
buy something with brass
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Author:
Paul48 (CT)
Why not use teflon tape and silicone?
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Author:
PlumberJoe (ID)
You guessed it!! The pump was purchased from Home Depot. If it was earlier in the day, I ask you to pick my lotery numbers for tonight.
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Author:
hj
There are so many approved sealants that I do not know which ones they sell. BUT, the instruction on the can WILL tell you if it can be used with PVC.
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Author:
PlumberJoe (ID)
You are correct.A visit to Lowes, I discivered all the paste sealers they sell are compatible for PVC, plastic, all metals, my wife, etc.... although there was one that specifically stated not for ABS but was compatible with PVC.
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Author:
PlumberJoe (ID)
For anyone that is curious about the outcome: I used the Monster pipe thread tape in place of the crappy micro thin white tape and the appropriate pipe dope evenly spread over the male pipe thread after applying 4 layers of tape. I used the same tighening procedure which is hand tight then 1.25 turn using a wrench. the result: ZERO leaks at the water pump and tank connections. Problem solved.
Lesson: When dealing with inferior cheap Chinese made plastic thread parts, use good tape on the threads and a good dab of plastic/PVC compatible pipe dope. Actually, the lesson learned is don't buy the cheap Chinese made crap from the start. For this agravation, I am boycotting Chinese food for a week.
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Author:
PlumberJoe (ID)
Your advice worked. Did exactly as you recommended. The monster Blue tape is far superior than the cheap shi/t and the paste stopped the leaks like amodium AD stops the hersey squirts. thanks!
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