Dope & tape?

Too many leaks back when…. Both gives the best of both worlds.

If some is good, and more is better, then too much must be best.

I've givin' up on the yellow stuff for Megatape on just about everything. Megatape just feels good the way it goes on. Last week, I used Locktite on a Lochinvar indirect tank on the 1-1/2" stainless to copper in and out water supply. I learned my lesson. NO LEAKS. I did use Megatape and the blue dope on the heat exchanger to copper connections which cause me some concern on an earlier job. When everything got fired up, NO LEAKS. I did my happy dance.

Belt and suspenders when you don't want a leak….which is all the time but especially in walls or inaccessible locations. I have done jobs with dope only. Teflon tape makes fitting go on smoother IMHO.

I don't know when Teflon Tape started but I started in 73' and it was in use then.

I can remember a huge job at Amherst College when I started, and we went there for some reason while it was being built.

There was an apprentice sitting in the corner with crates full of black nipples…tons of them. His job was to sit there all day and put Teflon tape on all the nipples…. think I would have quit if I was him.

Tape was available when I started in 1980, but it was thin. Easy to snap off when you’re done winding, but you had to wrap it 10 times to get enough material on the threads. I found a place back east that offered a thicker mil tape and ordered it by the case.

My head hurts :)

What did you do yesterday?

We talked about pipe dope all night.

Maybe we should talk about a Hartford Loop or a Drop Header or something.

Still far, far better than sitting watching reality tv….

At least that's my honest opinion.

Viessmann's Lambda Pro combustion system anyone?

It uses an ionization probe to monitor flue gases, allowing the boiler to auto-calibrate for gas type, quality, and altitude, ensuring high efficiency (up to 98%) and low emissions without manual adjustments.

How come others don't use it?

baxi does, calls it GA "gas adaptive"

you will also see it as a spec option for some commercial units, common engineering term now is "O2 trim" I think the lochinvar name is "hellcat" (an option for Crest boilers), aerco offers "aertrim" for their Benchmark boilers. I'm not positive they all function on the exact same principles as lambda pro, which itself has gone through changes. (just looked up aerco, they are directly monitoring o2 with a sensor, so similar results but a much more expensive way to get there imo)

the current lambda pro+ (plus!) also uses a mass flow air sensor in its calculations in addition to the ionization current.

as to why most don't utilize this? cost primarily. but also they aren't nearly as in control of their supply chain as a company like Viessmann has been. seems silly but the more complicated your burner control, the tighter tolerances you need for components. That adds cost sure, but its also just really hard to do.

I am very much a fan of lambda pro but I am also confident I could steel-man an argument against it if called upon

@JohnGoad

There is no requirement to use yellow "gas Teflon tape" on gas or anything else. Regular Teflon is allowed.

On fuel oil piping no Teflon tape is allowed which is a stupid requirement IMHO.

I have always been happy with regular Teflon tape. I don't care for 'Blue Monster" and never tried the yellow tape.

Dont tell that to my local gas monopoly… they will explain as you redo your work they are the local jurisdiction having authority, and you will obey!! They dont allow mega press yet!

TO teach is one thing to learn is another, to practice perfectly requires perfect practice. All connections require education to do it right. The hardest teacher is experience but it is the truest. But experience can be wrong. Just because it looks simple, or won't leak right away doesn't mean it won't fail. The tragedy of many failures prove that.

Anything ,wiring, welding, carpentry, piping all fail because it is done poorly. And the ways are many. Pipes are not all the same, threads, torque, materials, even what the pipe is used for makes a difference. water v chemicals, pressure, temperature, low or high. Torque applied. All thread dopes are not equal, but all dopes who use them are. The correct choice is just that choosing all the right things required to make it leak free.

Too loose, too tight. The variables in any pipe joint require not just the skill in application, but the knowledge of what is approved and proven works. If it is wrong in any way, it can leak. It's a skilled job because it requires skill. Pipe compounds have restrictions and permissions in can degrade over time. Ambient temperature changes between build and use can make it leak. Even if all that is correct, you still have material defects, and then the skill of the person, who even if they know what to use, may not know the how.

It is why training in the trades is a lifelong school of instruction as things always change! and who knows, Even manufactures, teachers can be wrong. Imagine if the advice you learned was wrong, incomplete, or it will not work in all situations. The classic sign of a novice is they have yet much to learn. And we can learn a lot from heating help.com

I wonder how connections are tested. In the seventies the first plastic pipe was approved for DHW. I could make nylon compression ring connections fail quite quickly with fast shut-off.

@HomerJSmith, that one gas fitting you did, I fixed it for you. 😉

When I first started using the blue monster tape, I was tightening fittings as I always would with the white stuff. After cracking a few fittings and valves using the blue, I read the directions on the label that was still intact. Three raps from now on and no cracked fittings. I never needed written directions for tape until then. I was treating the blue as if it were the white stuff. Go figure.

I can't imagine either way working, there's too many variables.

You need to feel the connection and what it's doing.

I mostly agree, but I've also seen a lot of guys threading pipe with a machine and stopping at random points making the threads either too shallow or too deep.

How exactly do straight threads make unions uncessary?

I greatly prefer tapered threads that really, if done correctly do not rely on gaskets or sealant. The straight threads I've used like BSPP still need to be fully tight, you can't just load the threads up and stop wherever you want.

@ChrisJ

Your right. How tight it feels is important.

I used to dislike guys who made the fittings on with the pipe machine for that reason. I only did that if I was in a real hurry and when working on something where it was unlikely to cause an issue like an oil tank vent line or a condensate tank vent or overflow etc.

When I was threading with dies, I was unfamiliar with the first thing I would do is take a piece of pipe and make a mark 6" from the end then thread it dope it and put a fitting on it and measure how far it made in and go from there. In a tight spot 1/8-1/4" is a big deal. Out in the open its not.