Hard Tube Bending Tutorial for Open Loop Liquid Cooling

By Steve Burke Published September 29, 2016 at 9:31 am

Liquid cooling has become infinitely more accessible with plug-and-play AIO solutions, but those lack some of the efficacy and all of the aesthetics. Open loop liquid cooling is alive and well in the enthusiast market; it's a niche of a niche, and one that's satisfied by few manufacturers. We had a chance to stop over at Thermaltake's offices while making the City of Industry circuit last week, and used some of that time to film a brief tutorial on hard tube bending.

It felt like filming a cooking show, at times. The format was similar, but it worked well for this process. Open loop liquid cooling is done with either soft tubing or hard tubing, the latter of which must be heated (with a heat gun) to make necessary bends within the system. Soft tubing is more easily manipulated and is as “plug and play” as it gets with an open loop, though “plug and play” isn't really desirable with open loops. Once you're this deep in cooling, best to go all the way.

PETG hard tubing is more leak resistant by nature of the mounting. Hard tubes are less likely to slip off of their mounting barbs with age or transport (fluid between the tube and its mounting point can lubricate the tube, causing a slip and slow leakage). The downside, as with the rest of open loop cooling, is entirely the time requirement and cost increase. Granted, compared to the rest of the loop, hard tubing cost can start to feel negligible.

We might soon be building a wet bench for open loop liquid cooling, as we're starting to receive GPUs with water blocks for testing. Today, we've got a brief hard tube bending tutorial with Thermaltake's Thermal Mike to lead us into our future open loop content. Take a look at that below:

The basics are trivial; you need these items:

Hard tubes of choice. For example, this Pacific kit ($21).
A heat gun capable of getting the tubes into a malleable state. This would work ($30).
Silicone insert to retain the tube's structure when heated. This 3ft option would work. Make sure the diameter matches the tube diameter, though.
Bending kit to assist in making the angles desired. Thermaltake's kit includes a silicone insert and other tools.
Time: About 5 minutes. This becomes more difficult and takes more time as bend complexity increases, but a simple 90-degree bend is quick work.

Workspace Setup

To bend hard tubing, the tube must be made malleable – done with heat – and must also keep the full internal diameter so that flow is not kinked. The entire process takes a few minutes for a simple bend.

Get a glass and fill it with soapy water. You'll want about 10-20% of the glass to be soap – nothing too crazy. Place this off to the side. Next, prepare the heat gun and stand it on its back (if possible) so that it is ready to use hands-free. If you purchased a bending kit, locate the guide with the angle desired. A 90-degree bend or 135-degree bend guide are among the most common. Place this in front of you.

Next, grab the silicone insert and apply soap water to the entire insert. The soap will prevent evaporation of the water while in the tube, which is important for ensuring easy removal once the bend is complete. Insert the silicone into the tube while ensuring it is still retrievable at the end of the process; you'll want to leave at least a quarter-inch of the silicone protruding from the tube.

Making the Bend

Next, turn on the heat gun and hold the tube (with insert) about 1” above the surface of the heat gun, or per the spec of your particular gun. Rotate the tube at a moderate pace while retaining a fixed height offset from the top of the heat gun.

This shouldn't take long, with a decent amount of heat. The tube will feel malleable soon, at which point you should disable the heat gun, place it to the side in a safe fashion (standing up, so that any residual heat on the surface doesn't burn you or nearby elements), and quickly bend the tube in the shape desired. It's ideal to use some sort of guide for this, e.g. a bend kit. Hold for about 20 seconds, then test to see if the tube has hardened.

Once complete, the tube will remain in its new shape permanently and is ready for cuts. You do not have to worry about the bend losing its shape.

That's it. Easy stuff. The rest, of course, is a little more time consuming – but the absolute basics of hard tube bending are easy to get into. It's the more complex bends, like corkscrews and other spirals, that make hard tube bending a skill of greater depth.

Check back soon for the rest of our California tour coverage. We've got Part 1 of our Sean Tracy interview (Technical Director of Star Citizen) going live tomorrow, alongside some MSI laptop coverage.

Editorial: Steve “Lelldorianx” Burke
Video: Andrew “ColossalCake” Coleman

Steve Burke

Steve started GamersNexus back when it was just a cool name, and now it's grown into an expansive website with an overwhelming amount of features. He recalls his first difficult decision with GN's direction: "I didn't know whether or not I wanted 'Gamers' to have a possessive apostrophe -- I mean, grammatically it should, but I didn't like it in the name. It was ugly. I also had people who were typing apostrophes into the address bar - sigh. It made sense to just leave it as 'Gamers.'"

First world problems, Steve. First world problems.