Best air line thread sealant or PTFE?

[JOEPRO]

Starting upgrades on my domestic garage air lines this evening



The biggest change is standard to PVL XF fittings everywhere.

I am using PTFE, haven't tested it yet but the ones I have installed so far don't feel too great / tight. I re wrapped some with even more PTFE.

Is there another product for this which works better? Like a Loctite paste sealer or somfink?

 

[JOEPRO]

Maybe a product like this is better than PTFE?

 

[mike 109444]

There is a thicker ptfe tape used for gas piping. Toolstation it's yellow

 

[Ross365]

Not all PTFE tape is the same. There's the cheap stuff, which is probably a co-polymer, usually OK on water, then there's the good stuff which I think is pure PTFE which is good with gas to very high pressure. Unfortunately, there's no marking that distinguish them, just the price and the feel of them. For the good stuff I'd probably go to RS components, unless you have an account with Swagelok or similar.

 

[indy4x]

Screwfix liquid PTFE, used it on all my compressor fittings including the PCL XF on the air line and air tools

 

[Turbo]

When I installed my air lines I used ptfe tape & had quite a few leaks. I redid it all using loctite 572 & had no leaks since. In fact I rarely use ptfe tape at all, its 572 for most thread sealing.

If you look out on ebay you can get 572 cheap, especially if its near its use by date. Ignore that date, its perfectly fine for domestic use. I'm still using a tube that's 5 years past its date!

 

[JOEPRO]

When I installed my air lines I used ptfe tape & had quite a few leaks. I redid it all using loctite 572 & had no leaks since. In fact I rarely use ptfe tape at all, its 572 for most thread sealing.

If you look out on ebay you can get 572 cheap, especially if its near its use by date. Ignore that date, its perfectly fine for domestic use. I'm still using a tube that's 5 years past its date!

Thanks I ordered a tube of Loctite 572 there and awaiting some PCL hoses and fittings to arrive. Then I'll upgrade all my compressors had just done one but realise from using it yesterday I'll need all to match up in both garages ideally

 

[Turbo]

For a while I'd been messing around with both standard pcl & XF fittings in my workshop. When I installed the airlines I switched everything over to the XF/euro fittings. They flow more air than the std ones so you have more torque from your rattle gun plus most air tools now come with the XF fittings already fitted.

 

[Ross365]

I've never had problems with leaks when using high quality tape, including the rig I built which had water at ~2200psig.

With the liquid sealants, how well do they keep after they've been opened? A lot of comparable products seem to start going off as soon as opened and you go back to them only to find they've gone solid.

 

[tigdlo]

I've not yet had problems with the cheapest PTFE from toolstation or screwfix as long as I don't mix parallel and tapered threads.

 

[Morrisman]

Starting upgrades on my domestic garage air lines this evening


The biggest change is standard to PVL XF fittings everywhere.

I am using PTFE, haven't tested it yet but the ones I have installed so far don't feel too great / tight. I re wrapped some with even more PTFE.

Is there another product for this which works better? Like a Loctite paste sealer or somfink?

If they're tapered threads they should get tight at some stage, if they don't then maybe they're mismatched, NPT versus BSP? Or just chinesium.

Theoretically they should seal without tape, but we know that's never going to happen.

 

[Ross365]

I've not yet had problems with the cheapest PTFE from toolstation or screwfix as long as I don't mix parallel and tapered threads.

Yep, it will do generally, and mixing thread types should be a no-no anyway. I usually have a couple of rolls of cheap tape and a couple of rolls of good stuff in stock; you can certainly feel the difference.

I buy all kinds of stuff from the far east, and don't often find myself disappointed. That said, if there's one area where that stuff is sometimes a bit troublesome it seems to be on anything with threads on. I see it with electronic kit; the electronics will be great, but the threaded connectors (like the small SMA screw-on connectors) can be pretty poor.

 

[mtt.tr]

Tape or loctite string.

Now I just use ptfe liquid sealent. Really good stuff

 

[mike os]

generally i use locktite 577 these days......

 

[Blue Chips]

Depending on the threads, I usually use either Loctite 567 or Loctite 577. Never had a leak. Not inexpensive stuff, but a little goes a long ways. 567 is great for stainless pipe, which I use on our water systems here, due to the rather acidic ground water.

https://www.gracoroberts.com/home/wp-content/uploads/2016/09/LOCTITE-567-and-577.pdf

 

[Turbo]

With the liquid sealants, how well do they keep after they've been opened? A lot of comparable products seem to start going off as soon as opened and you go back to them only to find they've gone solid.

I'm still using a tube of loctite 572 I opened 6 years ago!

 

[Arclikeharrypotter]

Loctite 577, or 545.

 

[timgunn1962]

Screwfix sell a couple of Flomasta thread sealants. A blue "liquid ptfe" and a "pipe thread seal". Both work very well. I use the liquid ptfe for just about every threaded pneumatic joint I make. It is easy to dismantle compared to the "pipe thread seal", which is an anaerobic sealant.

I used to use Loctite 577 when work were paying. When I'd run out and needed something quick and cheap for a job at home, the Flomasta liquid ptfe seemed to fit the bill. It worked just as well as the 577 for that job and I've been using it ever since.

I use the Flomasta "pipe thread seal" where I used to use Loctite 542, primarily on high-pressure hydraulic fittings, but occasionally on pneumatic stuff where I want to ensure that the thread sealed with liquid ptfe comes undone more easily.

 

[PhillipM]

I've just been looking for something very similar to that Tim - I need to seal a massive thread (M120) against water ingress but any of the threadlockers or sealers seem to be far too strong (it's only a hand tight nut/ring and the only way to help remove it bar fingers is a couple of 3mm pin holes).
Wonder if that liquid pfte is a lot softer/easier to undo.

edit: although their breakaway torque figures seem pretty high, hmm.

 

[timgunn1962]

At a 60mm radius and over 300mm of circumference, I'd be wary of using any sort of setting sealant.

We've resorted to snotting up plastic gland conduit threads with silicone grease and that's been pretty effective against the British weather. I don't know how well it would work with a constant head of water though, if you have one to contend with.

We've also resorted to Low-Modulus Silicone sealant as a threadseal with mixed materials (metal/plastic). Good old Copaslip seems to work remarkably well on metal-metal threads