Teflon tape vs. paste
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Have used both, for me paste is easier than tape though.
Paste is easier to apply. My well head is made of fittings with a 4 ' length of 1 1/4 ID plastic hose.
Originally Posted By: Ducked
Originally Posted By: MarkM66
I'm drawing a blank on when either is needed in an automotive world.
The tape gets used a lot in my little automotive world, as an anti-seize, thread sealer, and lubricant supplement, especially on brakes.
I prefer the tape because I can get it. I don't know much about the paste because I can't.
Lately I substitute polythene for the general antiseize duty (for example, on wheel studs), but I still use PTFE on brakes, especially around the bleeder threads.
My caliper slider pins are silicon-greased and wrapped in PTFE tape, but I'm unsure if this is a great idea because of the slight risk that overheating could break it down and form fluoric acid, which isn't nice.
I never use type on a brake system. They're all sealed by the flare. Never saw tape used on slider pins... nor would I
Originally Posted By: MarkM66
I'm drawing a blank on when either is needed in an automotive world.
The tape gets used a lot in my little automotive world, as an anti-seize, thread sealer, and lubricant supplement, especially on brakes.
I prefer the tape because I can get it. I don't know much about the paste because I can't.
Lately I substitute polythene for the general antiseize duty (for example, on wheel studs), but I still use PTFE on brakes, especially around the bleeder threads.
My caliper slider pins are silicon-greased and wrapped in PTFE tape, but I'm unsure if this is a great idea because of the slight risk that overheating could break it down and form fluoric acid, which isn't nice.
I never use type on a brake system. They're all sealed by the flare. Never saw tape used on slider pins... nor would I
Tape and paste are rated differently for working temperature.
We have customers that specify both and we adjust product ratings accordingly (usually de-rated for paste but it is product dependent).
Also, we typically specify 24 hours curing time for most paste sealing products.
We have customers that specify both and we adjust product ratings accordingly (usually de-rated for paste but it is product dependent).
Also, we typically specify 24 hours curing time for most paste sealing products.
Originally Posted By: Imp4
Also, we typically specify 24 hours curing time for most paste sealing products.
Curing time? Are you saying that the paste itself actually seals a joint? I thought it was metal-to-metal interference and the paste or tape only facilitated the thread closure. I have a hard time believing that cured paste holds back city water pressure in my pipes.
Also, we typically specify 24 hours curing time for most paste sealing products.
Curing time? Are you saying that the paste itself actually seals a joint? I thought it was metal-to-metal interference and the paste or tape only facilitated the thread closure. I have a hard time believing that cured paste holds back city water pressure in my pipes.
I use paste often, for gas pipes; for water white Teflon tape.
Many towns will fail you if you use paste for gas instead of tape. White tape is also illegal for gas, yellow is required, however some towns will fail you for using yellow.
Paste lubricates the threads as you turn the pIle but yet seals however pipe is narrower at the end and thickens as it goes in so when you tighten pipe it gets tighter, that is where the majority of sealing comes from.
Many towns will fail you if you use paste for gas instead of tape. White tape is also illegal for gas, yellow is required, however some towns will fail you for using yellow.
Paste lubricates the threads as you turn the pIle but yet seals however pipe is narrower at the end and thickens as it goes in so when you tighten pipe it gets tighter, that is where the majority of sealing comes from.
I prefer paste 99% of the time. I only use tape for air hose fittings or on PVC pipe.
Originally Posted By: JLawrence08648
Paste lubricates the threads as you turn the pIle but yet seals however pipe is narrower at the end and thickens as it goes in so when you tighten pipe it gets tighter, that is where the majority of sealing comes from.
I don't understand how paste would seal. For example, if you assemble a joint without dope or tape and it leaks that means there is a clear path for the gas or liquid to escape the threaded joint. If you instead assemble the same joint the same way with dope you have the paste in that clear path and it somehow holds back the pressure in the system? No way. The only thing that will seal a tapered pipe joint is metal-to-metal contact and the dope or tape lubricates the joint during assembly so the interference fit can be made.
Back to joint compound "curing", that just never happens. In my 17-year old house I have disassembled pipe joints where the old compound is still pasty, it hasn't cured. You can go up to any of the pipe joints in my house now and easily wipe away the excess compound from around the perimeter of the joint. So unless you're using some sort of anaerobic sealant that actually cures I still don't see how that could possibly seal a joint. In fact, when when assembling pipe joints it sometimes happens that it isn't tightened quite enough and it takes a half-turn more to stop dripping. That shows me that it has nothing to do with the sealant "curing" and everything to do with driving the threads together tighter until an adequate seal is achieved.
Paste lubricates the threads as you turn the pIle but yet seals however pipe is narrower at the end and thickens as it goes in so when you tighten pipe it gets tighter, that is where the majority of sealing comes from.
I don't understand how paste would seal. For example, if you assemble a joint without dope or tape and it leaks that means there is a clear path for the gas or liquid to escape the threaded joint. If you instead assemble the same joint the same way with dope you have the paste in that clear path and it somehow holds back the pressure in the system? No way. The only thing that will seal a tapered pipe joint is metal-to-metal contact and the dope or tape lubricates the joint during assembly so the interference fit can be made.
Back to joint compound "curing", that just never happens. In my 17-year old house I have disassembled pipe joints where the old compound is still pasty, it hasn't cured. You can go up to any of the pipe joints in my house now and easily wipe away the excess compound from around the perimeter of the joint. So unless you're using some sort of anaerobic sealant that actually cures I still don't see how that could possibly seal a joint. In fact, when when assembling pipe joints it sometimes happens that it isn't tightened quite enough and it takes a half-turn more to stop dripping. That shows me that it has nothing to do with the sealant "curing" and everything to do with driving the threads together tighter until an adequate seal is achieved.
fittings for water: PTFE tape + paste
fittings for NG: paste
fitting for fuel/oil: paste or curing sealant
The majority of sealing is done by the threads (NPT) however tape/paste/sealant does provide a certain level of "sealing". For example: hand tighten a black iron fitting for gas (0.5 psi) and it'll likely leak. but that same arrangement with a bit of dope and it won't. However try that with 100psi air or water and it will still leak unless tightened sufficiently.
fittings for NG: paste
fitting for fuel/oil: paste or curing sealant
The majority of sealing is done by the threads (NPT) however tape/paste/sealant does provide a certain level of "sealing". For example: hand tighten a black iron fitting for gas (0.5 psi) and it'll likely leak. but that same arrangement with a bit of dope and it won't. However try that with 100psi air or water and it will still leak unless tightened sufficiently.
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Originally Posted By: kschachn
Originally Posted By: Imp4
Also, we typically specify 24 hours curing time for most paste sealing products.
Curing time? Are you saying that the paste itself actually seals a joint? I thought it was metal-to-metal interference and the paste or tape only facilitated the thread closure. I have a hard time believing that cured paste holds back city water pressure in my pipes.
Pipe threads are most commonly tapered, hence "NPT" (National Pipe Tapered standard) and do an effective job of "sealing" by itself. Using tape or dope is just an extra safety measure.
Originally Posted By: Imp4
Also, we typically specify 24 hours curing time for most paste sealing products.
Curing time? Are you saying that the paste itself actually seals a joint? I thought it was metal-to-metal interference and the paste or tape only facilitated the thread closure. I have a hard time believing that cured paste holds back city water pressure in my pipes.
Pipe threads are most commonly tapered, hence "NPT" (National Pipe Tapered standard) and do an effective job of "sealing" by itself. Using tape or dope is just an extra safety measure.
I recall the airlines banning the use of teflon tape after problems were encountered in hydraulic systems because of tape fragments contaminating servos and such.
Originally Posted By: kschachn
Back to joint compound "curing", that just never happens. In my 17-year old house I have disassembled pipe joints where the old compound is still pasty, it hasn't cured. You can go up to any of the pipe joints in my house now and easily wipe away the excess compound from around the perimeter of the joint. So unless you're using some sort of anaerobic sealant that actually cures I still don't see how that could possibly seal a joint. In fact, when when assembling pipe joints it sometimes happens that it isn't tightened quite enough and it takes a half-turn more to stop dripping. That shows me that it has nothing to do with the sealant "curing" and everything to do with driving the threads together tighter until an adequate seal is achieved.
Rectorseal #5 and a few other compounds like Oatey's Great White don't really set per se - they're oil based and stay soft. The former is interesting in the fact that it doesn't have PTFE but it behaves like it does. It's the benchmark for gas pipe dope from what I've heard. I used it for a few gas connections at the parent's house.
The newer PTFE-filled compounds don't have solvents in them and are cleared for CPVC pipe. They still don't set but the added PTFE probably helps with mechanical stability.
Now, if it's on an engine or something that gets hot with vibration, I use Loctite 567/Permatex High-Temp Thread Sealant. Reason being is that you have vibration and holes that run into fluid passages.
Back to joint compound "curing", that just never happens. In my 17-year old house I have disassembled pipe joints where the old compound is still pasty, it hasn't cured. You can go up to any of the pipe joints in my house now and easily wipe away the excess compound from around the perimeter of the joint. So unless you're using some sort of anaerobic sealant that actually cures I still don't see how that could possibly seal a joint. In fact, when when assembling pipe joints it sometimes happens that it isn't tightened quite enough and it takes a half-turn more to stop dripping. That shows me that it has nothing to do with the sealant "curing" and everything to do with driving the threads together tighter until an adequate seal is achieved.
Rectorseal #5 and a few other compounds like Oatey's Great White don't really set per se - they're oil based and stay soft. The former is interesting in the fact that it doesn't have PTFE but it behaves like it does. It's the benchmark for gas pipe dope from what I've heard. I used it for a few gas connections at the parent's house.
The newer PTFE-filled compounds don't have solvents in them and are cleared for CPVC pipe. They still don't set but the added PTFE probably helps with mechanical stability.
Now, if it's on an engine or something that gets hot with vibration, I use Loctite 567/Permatex High-Temp Thread Sealant. Reason being is that you have vibration and holes that run into fluid passages.
Originally Posted By: MarkM66
Originally Posted By: Ducked
Originally Posted By: MarkM66
I'm drawing a blank on when either is needed in an automotive world.
The tape gets used a lot in my little automotive world, as an anti-seize, thread sealer, and lubricant supplement, especially on brakes.
I prefer the tape because I can get it. I don't know much about the paste because I can't.
Lately I substitute polythene for the general antiseize duty (for example, on wheel studs), but I still use PTFE on brakes, especially around the bleeder threads.
My caliper slider pins are silicon-greased and wrapped in PTFE tape, but I'm unsure if this is a great idea because of the slight risk that overheating could break it down and form fluoric acid, which isn't nice.
I never use type on a brake system. They're all sealed by the flare. Never saw tape used on slider pins... nor would I
On the nipples I mostly use it for anti-seize effect, though it may also reduce air suck when bleeding, when, pretty much by definition it is not sealed by any flare.
I've never seen tape used on slider pins (before I did it) either, but then I don't watch that many Youtube videos so I'm not claiming a "first".
Doesn't bother me. I'm unsure of the flourine release thing, but someone recently posted a pic of Volvo brake grease with PTFE in it recently., so its good enough for the Chinese....
Originally Posted By: Ducked
Originally Posted By: MarkM66
I'm drawing a blank on when either is needed in an automotive world.
The tape gets used a lot in my little automotive world, as an anti-seize, thread sealer, and lubricant supplement, especially on brakes.
I prefer the tape because I can get it. I don't know much about the paste because I can't.
Lately I substitute polythene for the general antiseize duty (for example, on wheel studs), but I still use PTFE on brakes, especially around the bleeder threads.
My caliper slider pins are silicon-greased and wrapped in PTFE tape, but I'm unsure if this is a great idea because of the slight risk that overheating could break it down and form fluoric acid, which isn't nice.
I never use type on a brake system. They're all sealed by the flare. Never saw tape used on slider pins... nor would I
On the nipples I mostly use it for anti-seize effect, though it may also reduce air suck when bleeding, when, pretty much by definition it is not sealed by any flare.
I've never seen tape used on slider pins (before I did it) either, but then I don't watch that many Youtube videos so I'm not claiming a "first".
Doesn't bother me. I'm unsure of the flourine release thing, but someone recently posted a pic of Volvo brake grease with PTFE in it recently., so its good enough for the Chinese....
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Originally Posted By: MarkM66
I'm drawing a blank on when either is needed in an automotive world.
Oil pressure and coolant temp. sensors are normally pipe thread, a lot of them come with sealer already applied. I had to replace a cylinder head on a 4.7 and Chrysler spec'ed paste for a few of the bolts.
I'm drawing a blank on when either is needed in an automotive world.
Oil pressure and coolant temp. sensors are normally pipe thread, a lot of them come with sealer already applied. I had to replace a cylinder head on a 4.7 and Chrysler spec'ed paste for a few of the bolts.
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Originally Posted By: AVB
Originally Posted By: MarkM66
I'm drawing a blank on when either is needed in an automotive world.
Oil pressure and coolant temp. sensors are normally pipe thread, a lot of them come with sealer already applied. I had to replace a cylinder head on a 4.7 and Chrysler spec'ed paste for a few of the bolts.
Thanks. I forgot about those being pipe threaded.
Originally Posted By: MarkM66
I'm drawing a blank on when either is needed in an automotive world.
Oil pressure and coolant temp. sensors are normally pipe thread, a lot of them come with sealer already applied. I had to replace a cylinder head on a 4.7 and Chrysler spec'ed paste for a few of the bolts.
Thanks. I forgot about those being pipe threaded.
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