When a customer brings a leaking tube fitting to our counter, the fitting itself is rarely the problem. Nine times out of ten, it's how the tube was prepped or how the fitting was made up. Here are the five mistakes we see most, and how to avoid them.
1. A rough or out-of-square cut
A hacksaw cut or a crushed tube end keeps the ferrules from seating evenly. Use a RIDGID tube cutter made for stainless steel, and take light cuts so you don't flatten the tube. Inspect the cutting wheel to make sure it's sharp.
Stainless tubing likes to spin in your hand while you cut. Lock our GRIP-IT TOOL onto the tube first. It holds 1/8", 1/4", 3/8", 1/2", 3/4" and 1" OD tubing steady, so you get a square cut without fighting the tube or scratching your hands.
2. Skipping the deburr
Burrs on the inside and outside of the tube can scratch the ferrule and leave chips in your system. Use a deburring tool on both the ID and OD after every cut, then blow the tube clean.
3. Not bottoming the tube
The tube has to be fully seated against the shoulder inside the fitting body before you tighten. If it isn't, the ferrules grip in the wrong spot and the joint can leak or blow out under pressure. Mark the tube at the nut before you tighten so you can see if it moved.
4. Wrong number of turns
Two-ferrule fittings are made up by turns, not by feel. For most sizes, it's 1-1/4 turns from finger tight. Smaller sizes less than 1/4" it's 3/4 turns from finger tight. Mark the nut at the 6 o'clock position so you can count your turns.
Keep the fitting from turning while you count. Our Fitting Tool holds stainless steel fittings from 1/16" to 1/2" steady, so your turns go on the nut, not the whole fitting.
On larger tube sizes, or in tight spots where you can't get a good swing on the wrench, use a pre-swaging tool. It presets the nut and ferrules onto the tube on the bench, so the final install in place is quick and consistent.
5. Not checking with a gap gauge
A gap inspection gauge tells you in seconds whether the fitting was pulled up enough. If the gauge fits between the nut and the body, it needs more tightening. It's the easiest quality check your crew can do.
Get your crew trained for free
A-Best Industrial Inc. Fittings, Valves, and Tubing offers a free Safety training course for new and existing customers, covering tube fitting installation and tube bending. We also stock the GRIP-IT TOOL, Fitting Tool, RIDGID tube cutters, deburring tools, pre-swaging tools, gap inspection gauges and RIDGID tube benders to do the job right.
Questions? Call us at 310-833-3353 or email sales@abesttube.com.