Crimp vs Compression: Which Hose Fitting is Best for Your Needs?

[araanandv2]

Hi,

Please explain ..

What is Crimp amd compression crimp hose fittings?
What are the advantages and disadvantages of flare and flareless fitting?When to go for flare and flareless fittings?

Thanks
Ana

 

[Danger]

Hi.
I wasn't aware of a difference between 'crimp' and 'compression crimp', other than possibly the materials involved. My experience is limited to having had a couple of custom hoses made up at the local shop. The pressure rating might depend upon how the crimp is created.
Flares act as their own gaskets, so it's easier to seal a high-pressure joint with flared couplers (as evidenced by brake-line fittings). I can't see any disadvantage to using flares, other than the couple of seconds that it takes to create one. You'd have to be pretty desperate for that to dissuade you. The advantage to them over a regular fitting is that line pressure actually helps them to seal by forcing them into the receiver tighter. That isolates the joint itself from the pressure that might otherwise back out between the tube and the collar.

 

[FredGarvin]

A compression fitting uses a ferrule that bites into the tube. The one big advantage is that there is no special end treatment required to prepare the tube. The installation is a permanent one because once the nut is locked down and the compression fitting sinched in, the ferrule will need to be cut off the tube. The installation is pretty easy to do, but a lot of people don't know the proper methodology. I personally have had leak issues using them in outdoor situations. Swagelok fittings are a very widely used brand of compression fittings and valves. Many places insist on using these fittings.

Personally, I prefer 37 degree flared fittings. I have had better luck with them in leak prevention, especially over long time periods and systems that fluctuate its pressure over wide range. The fittings are a bit less expensive as well. They do require a flaring tool and a bit of talent to make a burr free flare. Some tubing does not flare very well too. Therefore you need to know some special tricks to make them work well (like putting some oil on the flaring tool).

 

[Danger]

Thanks for the clarification, Fred. I've used compression fittings (on my engine oil gauge, for instance), but didn't know what they were called.