A recent post advised not to use teflon tape on plastic fittings, saying that it can crack them over time. Has anyone else experienced this, and does anyone know why this should happen? Thanks.
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Hummmm
Bob: This sounds like folklore to me. Most household plumbing comes with plastic fittings and mentions nothing about NOT using teflon tape. I also would like to know what is behind this.
Bob: This sounds like folklore to me. Most household plumbing comes with plastic fittings and mentions nothing about NOT using teflon tape. I also would like to know what is behind this.
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Peggie Hall/Head Mistress
Teflon tape is the ONLY thing to use.
And it will not crack fittings. However, overtightening them will crack a tank. Tighten plastic fittings NO MORE THAN a full turn past hand-tight, plus enough to aim an elbow in the direction it needs to go, even if threads are still showing. Test the tank for leaks...if it's leaking, back the fitting out and wrap with teflon tape. Do not use silicone...silicone only fills space--it doesn't seal a thing...and it WILL dry out and crack (the silicon itself, not the fitting)...above all, don't use any sealant such as 5200...you'll never get the fitting out again when you need to rehose. The only thing to use on plastic--or any other--fitting is teflon tape...and only if needed.
And it will not crack fittings. However, overtightening them will crack a tank. Tighten plastic fittings NO MORE THAN a full turn past hand-tight, plus enough to aim an elbow in the direction it needs to go, even if threads are still showing. Test the tank for leaks...if it's leaking, back the fitting out and wrap with teflon tape. Do not use silicone...silicone only fills space--it doesn't seal a thing...and it WILL dry out and crack (the silicon itself, not the fitting)...above all, don't use any sealant such as 5200...you'll never get the fitting out again when you need to rehose. The only thing to use on plastic--or any other--fitting is teflon tape...and only if needed.
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Eric
Teflon Tape
FYI , if you have ever read an installation instruction sheet for a Shurflo freshwater water pump, they advise against using teflon tape since it may clog the pump if pieces come loose. It was not specific but I assume they meant upstream from the pump. They also caution about the use of bleach in the water since it can harm the pump if too much is used.
FYI , if you have ever read an installation instruction sheet for a Shurflo freshwater water pump, they advise against using teflon tape since it may clog the pump if pieces come loose. It was not specific but I assume they meant upstream from the pump. They also caution about the use of bleach in the water since it can harm the pump if too much is used.
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Peggie Hall/Head Mistress
A word about bleach...
Bleach/chlorine IS harmful to the rubber and neoprene parts in water pumps...but the damage caused by an annual or semi-annual recommissioning as described in the article "Fresh Water Maintenance" in the Head Mistress forum is negligible compared to the deterioration caused by filling our tanks with chlorinated city water...because the effects of chlorine are cumulative...a tiny bit over time can do more damage than an occasional "shot." Occasionally we'll hear from someone whose fresh water pump has failed shortly after recommissioning with bleach...but it's always an older boat with an equally old water pump...and all that's happened is what would have happened within a short time anyway...just a little sooner. If the expected lifespan of a pump diaphragm is 5 years without annual recommissioning, WITH recommissioning, you can expect it to last 4 years and 10 months....which isn't a big difference IMHO.
Bleach/chlorine IS harmful to the rubber and neoprene parts in water pumps...but the damage caused by an annual or semi-annual recommissioning as described in the article "Fresh Water Maintenance" in the Head Mistress forum is negligible compared to the deterioration caused by filling our tanks with chlorinated city water...because the effects of chlorine are cumulative...a tiny bit over time can do more damage than an occasional "shot." Occasionally we'll hear from someone whose fresh water pump has failed shortly after recommissioning with bleach...but it's always an older boat with an equally old water pump...and all that's happened is what would have happened within a short time anyway...just a little sooner. If the expected lifespan of a pump diaphragm is 5 years without annual recommissioning, WITH recommissioning, you can expect it to last 4 years and 10 months....which isn't a big difference IMHO.
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Bob Zolczer
Teflon tape on plastic fittings
Sorry to cause so much confusion. The fellow across the dock from me has owned an A/C & Heating business for about 30 years. I just got finished repairing a fresh water leak. He advised me that he has seen many plastic fittings fail by cracking, especially where pipe goop and teflon tape are used. He told me that plastic fittings are designed to pressure seal by themselves. He claimed anything that would exert too much outward pressure would eventually crack the plastic. This may be due to overtightening, I don't know. He did say that any plastic fittings that he finds cracked or broken usually have had plumber's gook or teflon tape used. Thanks for the expert advice, Peggy, teflon tape would have made my repair an awful lot easier.
Sorry to cause so much confusion. The fellow across the dock from me has owned an A/C & Heating business for about 30 years. I just got finished repairing a fresh water leak. He advised me that he has seen many plastic fittings fail by cracking, especially where pipe goop and teflon tape are used. He told me that plastic fittings are designed to pressure seal by themselves. He claimed anything that would exert too much outward pressure would eventually crack the plastic. This may be due to overtightening, I don't know. He did say that any plastic fittings that he finds cracked or broken usually have had plumber's gook or teflon tape used. Thanks for the expert advice, Peggy, teflon tape would have made my repair an awful lot easier.
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Richard Owen
Teflon & Pumps
Recognizing the reason for recommending no teflon on pump connections would also imply that none be used anywhere upstream in the system since pieces could come free from any fitting upstream and end up in the pump. The point is really that when applying teflon, be careful not to have the tape too close (or actually partially closing off the end of the pipe) Properly applied, teflon will not cause a problem in the system because there will be no possibility of it getting in there. If the last thread doesn't get any tape on it, that's OK. It will still seal with the rest of the tape.
Recognizing the reason for recommending no teflon on pump connections would also imply that none be used anywhere upstream in the system since pieces could come free from any fitting upstream and end up in the pump. The point is really that when applying teflon, be careful not to have the tape too close (or actually partially closing off the end of the pipe) Properly applied, teflon will not cause a problem in the system because there will be no possibility of it getting in there. If the last thread doesn't get any tape on it, that's OK. It will still seal with the rest of the tape.
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