I agree with you on the Teflon tape. I was a Navy Diver, and all the instructions I was acquainted with while working on dive systems stated that Teflon tape is not a sealant; it is a lubricant. Granted it does have sealing properites, though that is not it's designed purpose.
Hi Grayfurnaceman, I'm just writing to say "THANK YOU" for all of your awesome videos. I appreciate your efforts as I have learned a lot...thanks for sharing. You're one of the best teachers I have ever had!
I agree. It is much easier for me to understand something if I actually see it than if someone just talks about it, and I know a lot of people who are the same way.
Another Great Video ! Although I knew you would do a Great Job of breaking it down, I'm always amazed at the extent of your Detailed Information for small and seemingly simple issues. Please keep these coming, although I rarely comment, I always Like, & Look forward to Each of Your Videos! Thanks For Sharing your Great Info !!
Nice video on the cut away! I usually use pipe dope for sure on gas line but usually use Teflon tape for water have had pretty good results? But I'm not a plumber or pipe fitter or anything just for repairs I still have galvanized pipe in my house and soon going to pex for my water supply! Most of the galvanized is as old as the house of course except for a few new repairs I had to do. But a small repair seems to become a little bigger one with new pipes to old one's. In most cases any way.
Always wondered about this subject. Super great video and explanation. In 1972 I bought a pipe cutter; pipe threading kit, and a can of pipe dope that has an applicator brush in the cap. I still use all 3---but not very often. Have done a lot of gas pipe over the 40 years with no issues--including installing a furnace in 1972. The dope is a blackish gooey stuff which loses moisture over time. The can states to add alcohol to revive it. Once dry on a joint, this stuff is like cement. It also now stinks in the can. I have pondered the thought of pitching it out, but always end up keeping it on the shelf. To keep it going, I put its container inside another to seal and save it. It's like a petroleum based substance. All pipe I see these days is marked "Made in China."
grayfurnaceman Oh shucks, I am so sentimental and this stuff is nearly as old as me...since age 21. PS---comment on seeing Made in China pipe---yeah, I usually buy such stuff at the box stores. ..
How about a video on how to clock a pipe fitting. How much is too tight? 90% of the time I work with pipe fittings it's almost more than 3/4 of a turn away from where I want it and I have to really crank on it get it back to the spot I want.
In addition to a sealant the dope also acts as a lubricant to cut down on friction which allows you to tighten the joint with less effort to get that thread to thread interference fit.
There is thread called CS hydril that makes up with no dope and is a gas tight seal.We used it in the oil feild but its too expensive and NPT works just as well in most cases.
The threads on brake bleeder screws are also tapered, which is a real pain when you break one off. Some calipers are really expensive and it's a shame to have to replace one just for that.
*Hold on there, spelunkerdbuddy. Are you **_sure_** brake bleeder threads are tapered? Of course the tip is tapered to seal off the brake pressure, but I do believe the threads aren't tapered.*
Speaking of iron pipe fittings stay away from the garbage quality fittings made in China. I was piping for compressed air in my shop and a few of the elbows cracked right down the casting seam when tightened (they weren't overtightened either) and they expect these to be used on propane or natural gas? Scary stuff. I use Ward made in USA fittings now.
Great explanation! Just curious why you don't like Teflon tape. Have you seen a lot of failures with it or something? I haven't used pipe dope very much because when I need to fix plumbing or gas pipes I usually need it fixed quickly, so my go to for years has been Teflon tape. I have never seen it leak when it is correctly wrapped and the connection is tight, although it can be a pain to use.
"Crane experiments on defects in threads. A piece of eight-inch pipe was threaded for a distance of 2 and 1/4 inches. The pipe was then put into a lathe and mutilated. In the threaded part, three grooves were turned,each 3/16th of an inch wide and to the bottom of the thread. The tops of the remaining threads with the exception of the one at the end of the pipe were turned off, giving them a flat surface 1/32" wide. Next, at 3 points on the circumference of the tapered threads, flat spots were filed,1" long and 2" wide, extending 1" on the threaded part. 25 grooves were then filed in the thread of the pipe and the same number in the coupling, all parallel with the pipe and 2/3 the depth of the thread. When all this deliberate mutilation was finished the threads were cleaned thoroughly and coated with cement. The joint was then screwed up so that the lengthwise grooves did not come up opposite one another. The outer ends were then plugged and tested to 425 psi of air without leaking. The same was found after a 1,000 psi hydraulic test. The amount of defect in the pipe was at least 100 times greater than pipe rejected by fitters. This showed the amount of ignorance about defects in threaded pipe that exists." We are talking about a involute circle. Remember everyone! Friction is the death of a proper joint. (Heat) Hence, pipe dope. If you use pipe dope as a lubricant and not a sealant, you'll not go wrong. Plumber for 42 years
Yep. Pipe dope/teflon is not to fill voids in the threads. It's to reduce friction, and that allows the fittings to be screwed up further with the same amount of effort. The threads deform easier so the male and female conform better.
I have the habit of taping and doping the threads when I pipe, just because I have found leaks on doped only threads through the years. I haven't seen the cut away of a connection till now.
Awesome cutaway! One question - how tight is tight enough? I ran into one video that said hand tighten and then 1-2 revolutions using wrench. Did that seen reasonable? How tight is too tight? Thank you!
I have always done by "when you think its tight enough, give it another solid pull" method. I know, not scientific. But really, there is no "too tight". Certainly, if the threads disappear into the fitting, that is too tight. The 1 to 2 revolutions is not tight enough. GFM
@@grayfurnaceman Great info about how tight to make galvanized NPT. Do you tighten as much for brass NPT? I think the "1-2 turns after hand tight" rule is for plastic NPT by the way.
I'm not sure what you're using these threads for cause they fail on me repeatedly. Maybe cause of what I'm doing. I'm using these pipes to cook phosphate salts at 1100C to distill white phosphorus. No matter what, when the pipes get hot... the vaporous phosphorus leaks right out. And I can't use a permanent seal cause I need to remove, clean, reload the "furnace" for testing. Do you have any suggestion in the world as to what I should use? I haven't tried pipe dope cause I thought it was for permanent seals but I'll try if you think it'll work?
+Robert Cece The temp is too high for pipe dope. You are limited to either welding the connections or using very high temp brazing compound, such as sil phos. Hope this helps. GFM
You're a threat cutaway shows full thread engagement which is very important to prevent leaks many times the threading dies are not set correctly and do not give you full thread engagement
I agree with you on the Teflon tape. I was a Navy Diver, and all the instructions I was acquainted with while working on dive systems stated that Teflon tape is not a sealant; it is a lubricant. Granted it does have sealing properites, though that is not it's designed purpose.
Watch this video at 1.5 speed and its much better. Great and informative man thanks
Hi Grayfurnaceman, I'm just writing to say "THANK YOU" for all of your awesome videos. I appreciate your efforts as I have learned a lot...thanks for sharing.
You're one of the best teachers I have ever had!
The cut away was a great visualization
Thanks for the support.
GFM
Whoa....you like to use the internet to learn about random stuff, too?
I agree. It is much easier for me to understand something if I actually see it than if someone just talks about it, and I know a lot of people who are the same way.
*Great close-ups. You the man, Grayfurnaceman!*
Nice to see the cutaway and close-up photos. good video
Nice close up shots. I prefer the blue dope over the yellow though they both work good. Thanks for sharing.
Another Great Video !
Although I knew you would do a Great Job of breaking it down, I'm always amazed at the extent of your Detailed Information for small and seemingly simple issues.
Please keep these coming, although I rarely comment, I always Like, & Look forward to Each of Your Videos! Thanks For Sharing your Great Info !!
Nice video on the cut away! I usually use pipe dope for sure on gas line but usually use Teflon tape for water have had pretty good results? But I'm not a plumber or pipe fitter or anything just for repairs I still have galvanized pipe in my house and soon going to pex for my water supply! Most of the galvanized is as old as the house of course except for a few new repairs I had to do. But a small repair seems to become a little bigger one with new pipes to old one's. In most cases any way.
Always wondered about this subject. Super great video and explanation. In 1972 I bought a pipe cutter; pipe threading kit, and a can of pipe dope that has an applicator brush in the cap. I still use all 3---but not very often. Have done a lot of gas pipe over the 40 years with no issues--including installing a furnace in 1972. The dope is a blackish gooey stuff which loses moisture over time. The can states to add alcohol to revive it. Once dry on a joint, this stuff is like cement. It also now stinks in the can. I have pondered the thought of pitching it out, but always end up keeping it on the shelf. To keep it going, I put its container inside another to seal and save it. It's like a petroleum based substance. All pipe I see these days is marked "Made in China."
DOLRED Its dead. Replace it.
GFM
grayfurnaceman
Oh shucks, I am so sentimental and this stuff is nearly as old as me...since age 21. PS---comment on seeing Made in China pipe---yeah, I usually buy such stuff at the box stores. ..
How about a video on how to clock a pipe fitting. How much is too tight? 90% of the time I work with pipe fittings it's almost more than 3/4 of a turn away from where I want it and I have to really crank on it get it back to the spot I want.
Nicely done. Thx👍
In addition to a sealant the dope also acts as a lubricant to cut down on friction which allows you to tighten the joint with less effort to get that thread to thread interference fit.
***** Absolutely agree on that.
GFM
great detailed picture thanks a lot...:)
There is thread called CS hydril that makes up with no dope and is a gas tight seal.We used it in the oil feild but its too expensive and NPT works just as well in most cases.
It is very practical and make me understand the problem.
Thanks for the support
GFM
My grandpa was a plumber back in the 20s and they used paint for pipe dope. That's how Teflon tape was invented.
Could be.
GFM
The threads on brake bleeder screws are also tapered, which is a real pain when you break one off. Some calipers are really expensive and it's a shame to have to replace one just for that.
*Hold on there, spelunkerdbuddy. Are you **_sure_** brake bleeder threads are tapered? Of course the tip is tapered to seal off the brake pressure, but I do believe the threads aren't tapered.*
Next time I go to the shop, I'll have another look.
Speaking of iron pipe fittings stay away from the garbage quality fittings made in China.
I was piping for compressed air in my shop and a few of the elbows cracked right down the casting seam when tightened (they weren't overtightened either) and they expect these to be used on propane or natural gas? Scary stuff. I use Ward made in USA fittings now.
Great explanation! Just curious why you don't like Teflon tape. Have you seen a lot of failures with it or something? I haven't used pipe dope very much because when I need to fix plumbing or gas pipes I usually need it fixed quickly, so my go to for years has been Teflon tape. I have never seen it leak when it is correctly wrapped and the connection is tight, although it can be a pain to use.
I have had multiple failures that are fixed by pipe dope.
GFM
@@grayfurnaceman Interesting, thanks for explaining. My biggest problem with Teflon tape is that it is a pain to use, especially in tight spaces.
"Crane experiments on defects in threads. A piece of eight-inch pipe was threaded for a distance of 2 and 1/4 inches. The pipe was then put into a lathe and mutilated. In the threaded part, three grooves were turned,each 3/16th of an inch wide and to the bottom of the thread. The tops of the remaining threads with the exception of the one at the end of the pipe were turned off, giving them a flat surface 1/32" wide. Next, at 3 points on the circumference of the tapered threads, flat spots were filed,1" long and 2" wide, extending 1" on the threaded part. 25 grooves were then filed in the thread of the pipe and the same number in the coupling, all parallel with the pipe and 2/3 the depth of the thread. When all this deliberate mutilation was finished the threads were cleaned thoroughly and coated with cement. The joint was then screwed up so that the lengthwise grooves did not come up opposite one another. The outer ends were then plugged and tested to 425 psi of air without leaking. The same was found after a 1,000 psi hydraulic test. The amount of defect in the pipe was at least 100 times greater than pipe rejected by fitters. This showed the amount of ignorance about defects in threaded pipe that exists." We are talking about a involute circle. Remember everyone! Friction is the death of a proper joint. (Heat) Hence, pipe dope. If you use pipe dope as a lubricant and not a sealant, you'll not go wrong. Plumber for 42 years
Yep. Pipe dope/teflon is not to fill voids in the threads. It's to reduce friction, and that allows the fittings to be screwed up further with the same amount of effort. The threads deform easier so the male and female conform better.
I have the habit of taping and doping the threads when I pipe, just because I have found leaks on doped only threads through the years. I haven't seen the cut away of a connection till now.
***** Can't argue with that.
GFM
I do that as well. Especially when I'm tying into old work.
Awesome cutaway!
One question - how tight is tight enough? I ran into one video that said hand tighten and then 1-2 revolutions using wrench. Did that seen reasonable? How tight is too tight? Thank you!
I have always done by "when you think its tight enough, give it another solid pull" method. I know, not scientific. But really, there is no "too tight". Certainly, if the threads disappear into the fitting, that is too tight. The 1 to 2 revolutions is not tight enough.
GFM
@@grayfurnaceman Great info about how tight to make galvanized NPT. Do you tighten as much for brass NPT? I think the "1-2 turns after hand tight" rule is for plastic NPT by the way.
@@DellAnderson It is pretty much the same
GFM
@@grayfurnaceman Thanks!
this vid is awesome..really cleared many doubts
Thanks for the support.
GFM
I'm not sure what you're using these threads for cause they fail on me repeatedly. Maybe cause of what I'm doing. I'm using these pipes to cook phosphate salts at 1100C to distill white phosphorus. No matter what, when the pipes get hot... the vaporous phosphorus leaks right out. And I can't use a permanent seal cause I need to remove, clean, reload the "furnace" for testing. Do you have any suggestion in the world as to what I should use? I haven't tried pipe dope cause I thought it was for permanent seals but I'll try if you think it'll work?
+Robert Cece The temp is too high for pipe dope. You are limited to either welding the connections or using very high temp brazing compound, such as sil phos. Hope this helps.
GFM
I see your point, thank you...
This guy got the serious zoom in on display...
You're a threat cutaway shows full thread engagement which is very important to prevent leaks many times the threading dies are not set correctly and do not give you full thread engagement
Gary Smith The Rigid dies seem to be worst for this. Had lots of trouble with them.
GFM