How to Use Soft Tubing
The issue with soft tubing is less to do with the process of fitting it, and more to do with identifying how to run a length of it. It’s all to do with bend tolerances. The shorter the length, and the tighter the bend you want, the more likely you are to kink it. If it kinks, coolant can’t flow around the loop, temperatures skyrocket, pressure can build up, and it can damage the components within the loop. This is why it’s useful to plan the loop out beforehand, and even include a few 90-degree extension fittings here and there. A clean soft-tube build typically requires quite a few angled fittings.
That aside, how do you actually do it? First, attach your soft-tubing compression fittings to the two components you want to connect. Then remove the compression caps from both fittings, revealing the barb underneath. Now take your coil of soft tubing, and run a length of it between the two fittings. Make sure you measure from the bottom of the barbs when you do this. Next, cut off slightly more tubing than you think you need. You can always shorten a length of soft tubing later.
Now you’re going to take the compression cap and slide it along the tube, making sure it’s in the correct orientation to secure itself back on to the fitting. Next, take a pair of needle-nose pliers, insert them into the end of the tube, and then carefully stretch out the bottom of the tubing in both directions. Now you can wiggle that stretched part of the tube on to the barb and past the lip of the fitting. Finally, secure the compression cap back on to the fitting, and repeat the process at the other end.