Leakage in my pipes, how to densify/seal?

Question

I've never built with pipes before so maybe I'd need some general advice regarding leakage. On a specific note, I've built a system (see picture) where it leaks practically everywhere. I've sealed it with NASTRO P.T.F.E tape on some places where it seems to work. I've screwed the pipe parts very hard so it shouldn't leak but it does.. a lot. It seems unreasonable that I need to use NASTRO tape everywhere. How do professionals do it? My bathrooom pipes doesn't have any tape, what are they doing differently?

Edit (25th of march):

Answer 1

Hold the tape in your left hand – to avoid running it the wrong way and having it unravel as you start threading.

If you can bottom-out four adapters into each other, they're likely all the right thread type, you just didn't use enough tape. IME, warping it three times is sufficient. On fittings that don't like to cooperate, you may need substantially more to make the seal.

When applying the tape, you should only stretch it with enough pressure to let it sink into the threads. If you pull any harder, you'll cheat the depth of the wrap. Finish it by seating it well with your thumb or rolling it in your palm.

---

I see in the picture only a pair of pliers and no crescent wrench or pipe wrench. I'd have said that was your problem, except that you somehow managed to bottom-out those fittings, so my vote is they're just loosey-goosey. Note, with enough tape on them to seal and without the proper wrench, you might never get it airtight.

I don't bother to pressure test a fitting that BOs, I already know it's going to leak. I just take it apart and:

Use more tape.

When you pipe-fit, you're looking for the tension to become progressively stronger (to the unexplainable point that has ever been expressed to me as, "that's good"; it only comes via experience), if it all of a sudden stops, you're likely in trouble.

(source)

Imagine standing to the left of the photo. Hold the pipe in your right hand and the tape in your left, and it's basically impossible to do it the wrong way. It is recommended, as shown above, not to cover the first two threads but I do anyway. Having built up a good wrap at the rear threads, I'd finish it off with a warp or two around the starter threads, so that it looks like this:

(source)

Answer 2

You should be using fittings that are applicable to the application, and should not be mixing and matching thread types. If you need to go from a fitting with tapered threads, to a fitting with straight threads. Then you should use an appropriate adapter.

I'm not sure why you're anti-PTFE tape. It's cheap, easy to use, and works well. PTFE tape is not specifically designed to seal threads, even though that's how it's commonly thought of. In fact, PTFE tape reduces the friction in the threaded joint. This allows you to get the joint tighter, which lets the fittings seat together properly. This is especially effective with tapered threads, though can also help seat straight thread fittings as long as it's not over applied. When working with straight threads, you'll find that paste dopes work better than tape dopes.

If you're looking to design a system that can be disassembled, and reassembled often. Then you're going to want to use fittings that don't rely on the threads to make the seal. The fittings may be held in place by threads, but the seal itself should be independent of the threads. If the seal is dependent on washers and/or O-rings, you'll want to be careful ow much you tighten it down. Crushing and/or deforming the washer/O-ring, can actually cause leaks.

Answer 3

Sorry for my original answer Lennart. I was thinking the red thing was an upside down compressed air tank & this was all pneumatics, though I did see your plumbing reference initially.

That's a lot of fittings & looking at it a 4th time, you look fine on matched fittings. However they do look thread bottomed, meaning you're out of threads for anymore tightening.

That would be the reason for leaks & you really shouldn't need tape much of anywhere. The "plumbing secret" is rubber type stuff. You need a lot of Washers &/or O-rings to make this work, at just hand-tight, without a single drip.

You'll have to get a box of "Assorted Washers &/or O-rings" at the store since none seem to have come with any of the fittings. Measure the receiving cup for sizes you'll be after. Washers for wide cup shoulders (if any) & O-rings for very narrow cup shoulders.

I don't know what you're doing & of course I know you don't know what you're doing, but the brass item & the 1 or 2 fittings on either side don't seem necessary. I thought it was a ball valve, but I can't make out a handle anywhere.