Use Ferrules and Fittings That Match the Material of the Tubing
by Luke Wurban, on Mon, Sep 30, 2019 @ 11:09 AM
Swagelok's informational video describes how to select which materials to use for ferrules and fittings to match your tubing
Review our video to be guided through how to properly choose the fittings, ferrules, and tubing materials to match your applications.
Matching materials means the parts won't end up fighting each other
Tubing comes in a variety of materials, but so do Swagelok tube fittings. So how do you know which material of fittings and ferrules to choose with your tubing? Generally we suggest that you use like materials with like materials. So if you have stainless steel tubing, use stainless steel ferrules and fittings. On plastic tubing, use plastic ferrules and fittings.
On copper tubing we suggest using brass ferrules and fittings. Since brass is an alloy of copper and zinc, you are still using like materials.
The reason for matching materials is simple: You want the ferrules to be stronger than the tubing so that the ferrules can swage onto the tubing and lock into place. If the ferrules are made of softer material than the tubing, you won't get that swaging action. Brass, for instance, is softer than stainless steel. So brass ferrules won't give you the full swaging action on stainless steel tubing.
But sometimes you don't want the swaging action of the ferrules. Suppose you are using a thermocouple or some other sensor probe. You want to insert the probe into the fluid line, but you don't want to lock it into place because you'll need to remove the probe. Or suppose you are using glass tubing, and you are worried that hard metal ferrules will fracture the glass.
In those cases you might want to use plastic ferrules. Perhaps you'll want a front ferrule made of Teflon because it's the most chemically compatible material. For the back you might want nylon. It's a little harder than Teflon, so it will help deform the front ferrule. You'll still get a good seal when you tighten them down, but you won't get the full swaging action.
We've produced a short video that shows you what we are talking about. Your applications might be unique, so if you still have any questions or concerns please call Edmonton Valve & Fitting at 780-437-0640 or send a note through our contact page. We would be happy to help you find the right materials to ensure your fluid systems are installed correctly.