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Bend Acrylic Pipes Like A Pro

Liquid-cooled PCs are not a new phenomenon. The practice began as so many now-commonplace modding techniques did: Dedicated hobbyists using their ingenuity, garage space, and tools to create their own hardware capable of dramatically improving PC performance. Before long, liquid-cooling became the de facto standard for overclockers everywhere.

Nowadays, adding liquid-cooling to your own system is almost comically easy if you want it to be, but that hasn’t stopped modders from continuing to innovate. More recently, we’ve seen modders make a statement by swapping out traditional tubing, which is pliable and easy to work with, for more rigid plumbing—copper, hard acrylic, etc. In the hands of a skilled craftsman, the results of a hardline liquid-cooling loop can be stunning, as you’ve no doubt seen in the pages of “Mad Reader Mod” once or twice.

Working with rigid tubing properly demands practice, patience, and above all, precision. It requires a different skill set and different tools than traditional tubing. When done right, though, the finished product is as impressive as it is rewarding. As it’s not a technique that’s widely practiced, much less mastered, fitting your rig with a cooling loop of rigid acrylic is something that will turn heads at a LAN party, and may even win you a contest or two.

For this month’s project, we called on a few of our friends in the modding community who have experience in working with rigid tubing. Think of this as your opportunity to get a private lesson on pipe bending from a group of experts who have been modding PCs for years. We’d like to welcome back Richard “Darth Beavis” Surroz, Lee “PcJunkie” Harrington, Ton “TiTON” Khowdee, and Ron L. Christianson. (Surely you will remember the pipes running through Christianson’s Half-Life Black Mesa mod, last month’s Mad Reader Mod winner.) These guys are ready to share their wisdom, so pay attention.

Tools Of The Trade

Unless you already have a well-appointed workshop, there’s a pretty good chance you’ll need to gear up before you can properly work with rigid acrylic tubing. A decent heat gun, which you might already have if you’ve worked with a lot of heat-shrink tubing, is your first must-have. There’s no reason to get carried away here; we’re not trying to reforge Ned Stark’s ancestral sword Ice. A 1,500W gun should do the trick, and if you plan on incorporating rigid acrylic tubing into future mods, we’d recommend investing in a quality unit. You two will have a lot of adventures together, so you might as well buy a gun that will last. Although a few online retailers devoted to PC modding sell heat guns, it’s just as easy to make a trip to your local hardware store and score one there.

Bending acrylic tubing requires two hands, so unless you’ve managed to evolve an extra pair (you lucky transhuman, you), a stand is necessary to hold the heat gun steady while it’s softening up the acrylic tubing. If one is included with the heat gun you buy, so much the better.

And while we’re on the subject of hands, you should grab a pair of heat-resistant gloves for yours. A heat gun’s toasty blast of air is great for making rigid acrylic easily bendable, but it’s not exactly pleasant to hold your hands over for an extended period of time. If you’re working with a long enough section of pipe, you might be able to get away with going gloveless, but heating up smaller pieces of acrylic will surely expose your hands to superheated air. Gloves will also protect your hands from the hot acrylic itself.

The next accessory might not be immediately obvious to amateur benders, but your first attempts could easily become misshapen disasters without it. This miracle tool that will save you from endless embarrassment and humiliation in the face of your fellow modders (OK, really just the material cost of the ruined acrylic) is a piece of silicone tubing that matches the inside diameter of the acrylic tubing. Rigid acrylic bending kits usually include a piece; make sure the insert is at least a little longer that the piece of acrylic tubing, for obvious reasons.

“Using soapy water as a lubricant, the silicone slides inside of the ridged tubing and holds the shape of the ridged tubing, preventing it from flattening out while making your bends,” Christianson explains. Cheap cooking oil is another option for a lubricant, but our experts favored a solution of liquid dish soap and water mostly because the cleanup process is so much simpler.

To be as precise as possible, with clean cuts and perfectly angled bends, you’ll need a little need some help from a couple of other tools. While you’re still learning the tricks of this trade, a set of mandrels will work wonders for making bends at 45-, 90-, and 180-degree angles. We’ll discuss them further once we dive into the process itself, but mandrels acts as a mold of sorts that holds the heated acrylic at a certain angle while it cools and re-hardens.

While we’re shopping for tools to make your hardlining life a little easier, why not get yourself a proper ruler? Sure, you can overestimate a length of pipe and trim it to fit after you’ve bent it, but the trial-and-error method can wind up costing you some excess tubing in the process; depending on your guesstimation skills and the complexity of a given liquid loop, this can add up to a lot of wasted material over the course of a mod. If you really want to be precise, you can buy a specialized ruler that can simulate the angled bends of a particular piece of pipe and indicate the correct length to cut.

You’ll be the one to cut each piece of pipe to fit, and having the right tools can make the process go much more smoothly. Get yourself a decent saw, but be sure the blade has fine teeth. “A coarse saw blade will give you a rough cut, and may shatter the tube,” Khowdee says. “A fine-toothed saw will provide a cleaner cut.”

Even with the right saw blade, you’ll need some help to make clean, professional cuts. A small miter box will let you make perfect perpendicular cuts. Theoretically, any miter box will work if you don’t want to be picky, but this is one instance when it’s not a bad idea to buy a miter box that’s designed for cylinders. After finishing each cut, a handheld plumbing reamer can simplify cleaning and deburring the end of the tube; just buy one that matches the inside and outside diameters of your tubing. Sandpaper can also accomplish this task to an extent, although it’s a little more time-consuming.

If all these tools and guides are making your head spin, or if you’d simply rather swipe your card once and fill up your equipment bag, then score yourself a bending kit that contains all the essentials. Monsoon makes a pair kits that vary based on the pipe diameter you want to use (you can choose between 3/8- x 1/2-inch or 1/2- x 5/8-inch [inside x outside diameter]). These kits are available at online retailers like FrozenCPU and Performance-PCs.

Finally, compression fittings also deserve a mention; although they’re not strictly involved in the bending process, compression fittings made specifically for rigid tubing are a must-buy. You can get away with barbs and clamps for traditional flex tubing, but they’re a major no-no for hardline liquid-cooling.

“With rigid tubing, you can’t apply pressure to the tubing to secure it to the fitting,” Khowdee says. “That is the reason that compression fittings are required for rigid tubing.”

You won’t have to look far to find the right fittings. Again, your friendly online mod supplier has your hookup. For example, PrimoChill Ghost or Revolver fittings or Monsoon’s Chain Gun or Free Center fittings will do the job. Plenty of color choices are available for these fittings, too. Aside from buying compression fittings that are compatible with rigid tubing, feel free to outfit the rest of your loop with your favorite wares; waterblocks, radiators, pumps, and other components are the same for rigid acrylic as they are for flex tubing.

Tube Talk

Feeling a little embarrassed that you’ve arrived so late to the pipe bending party? Don’t be. Tardiness has its advantages, and in this case, you can easily learn what the pros had to learn—ahem—the hard way. You can be a level 90 wizard right out of the gate, and no one will be the wiser.

One such example is the type of tubing that works best for a hardline loop. You hear the term “rigid acrylic” all the time, and we’re guilty of using it, too, but the truth of the matter is that most modders are moving away from using acrylic tubing in their loops. Instead, the material du jour is PETG (polyethylene terephthalate glycol-modified, if you want to impress your organic chemistry professor).

PETG is a thermoplastic, just like acrylic, though the former has found favor among modders for being more durable and less likely to crack or shatter after it’s been bent and re-hardened. We’ve heard too many horror stories, and witnessed one or two ourselves, of liquid-cooling disasters that happened when a mod’s fragile acrylic tubing fractured and broke during transportation. Put simply, if you plan to take your mod to a LAN party or move it frequently, you’re better off with PETG tubing.

“The difference between the two is that acrylic is a little—I should say a lot—more brittle,” says Harrington. “PETG is more forgiving. I can pull against it, and it’s not going to crack.”

Surroz agrees. “PETG tubing is almost shatterproof.” At this juncture, we at CPU recommend that you perform any independent verification of these claims before you actually install your own rigid liquid-cooling setup.

In addition to being able to take more punishment than rigid acrylic tubing, PETG should require less time under the heat gun, according to Khowdee. If you have a lot of pipe to bend, or if you’re still at the bottom of the learning curve and frequently have to reheat and rebend your tubing, those minutes add up.

Until recently, rigid acrylic tubing had one advantage over PETG: visual flair. Acrylic tubing was available in a Skittles-esque spectrum of colors, while PETG was limited to a monochromatic (or perhaps, more appropriately, achromatic) palette: clear. Now, though, popular liquid-cooling manufacturers are catching on. PrimoChill now offers PETG tubing in a variety of colors (red, UV blue, UV pink, etc.), so you can have all of the structural benefits of PETG and match the tubing to your mod’s color scheme, too.

We’re not going to knock clear PETG, though, because plain Jane is still a classy lady. An equally fat rainbow of tinted coolant colors is available, after all. The biggest advantage to buying clear PETG tubing is its price. We’ll let you in on a little secret: PETG is not some magic material invented and developed solely for the benefit of modders, and PETG tubing is used for a variety of purposes. As such, it’s readily available from industrial supply retailers like McMaster-Carr (www.mcmaster.com). Do a little comparison shopping and you’ll likely find PETG tubing available from industrial suppliers for a nice discount. Plus, if you fall in love with hardlining your liquid-cooling loop, find an industrial supply retailer that sells PETG tubing in bulk and save even more. Just make sure to buy tubing that matches the inside and outside diameters of the rest of your liquid-cooling components. (Editor’s note: Further mentions of “rigid tubing” in this article will refer to PETG tubing, as it is the unanimous choice among the modders we spoke to.)

Now that we know what type of tubing to buy, how much should you buy? The answer largely depends on how accurate you are with your measurements. If you prefer a trial-and-error approach, opting to bend first and cut later, then we recommend you follow Christianson’s advice: “Buy twice as much as what you think you’ll need for your project. It takes some patience and practice and wasted material to get the correct bends and master this type of cooling installation.” Even after you have a rigid tubing mod under your belt, it’s a good idea to order a little more than you need. You never know when you’ll make a mistake or decide your mod’s 480mm radiator needs a twin.

Ready, Set . . . Prep

With your toolbox brimming with shiny new toys and a small mountain of tubing at your disposal, it’s time to start bending. Well, almost time.

Anyone who’s built a custom liquid-cooling setup with flex tubing already knows the following: Install all of your other liquid-cooling components before you make your first bend. You’re not some pipe-wasting barbarian who chops up a section of pipe, bends it, and then chops it up even more when it doesn’t fit, are you? Of course not. Flexible tubing lets you cheat this a little, but rigid tubing isn’t forgiving in the slightest. If you have more work to do on your system/mod, a temporary installation is fine as long as you know the components are staying put once everything comes together. Install those waterblocks and mount those radiators; measuring your pipe runs will be much easier in the long run.

At this point, you’ll be able to make decent estimations for how much tubing you’ll need for each run. Don’t get hung up on making the perfect measurement between point A and point B, because it’s not always easy to determine exactly where on a piece of pipe you’ll make a particular bend. As long as you give yourself a few inches on either end of the pipe, you should end up wasting less material.

As for making the actual measurements, every expert we talked to had his own way of doing things. Christianson takes a typical approach, using a tape measure and leaving the pipe sections slightly longer than necessary. (You always want to cut your tubing too long rather than too short.) Khowdee has a piece of flex tubing that he uses to simulate the distance between two points, and Harrington likes to run a strand of baling wire to find out how long each piece of rigid tubing needs to be.

To make the bending process easier, consider mounting your mandrels to a small sheet of plywood or other sturdy board. Monsoon’s mandrel kit, for example, has predrilled holes that let you quickly mount them where they’ll stay put while you bend your tubing.

Next, fill a small container with a solution of water and dish soap, which will act as a lubricant for the silicone insert you’ll slide into each piece of rigid tubing before bending. Optionally, you can also set up a small desk fan to help a heated section of tubing cool faster.

The Bend Is Nigh

Once you feel comfortable with your measurements and you have everything in place, it’s time to grab some tube and get to bending. After you’ve inserted the silicon cylinder into the pipe you want to bend, equip your heat-resistant gloves, because no one likes the smell of fire-roasted hand. Prop up the heat gun on its included stand (or anything that allows for hands-free operation) and turn the gun on. Christianson recommends starting with the heat gun’s lowest setting, if it’s adjustable, especially while you’re still getting the hang of the heat gun, the rigid tubing, and the procedure itself. Got it? OK, time to bend.

With a piece of tubing in hand, hold it over the heat gun’s blast, about four to six inches away from the heat gun. You don’t want to hold the tubing much closer than this, as it will heat too quickly and start bubbling. (Fun fact: To date, a grand total of zero mods with deformed, blistered tubing have been selected as CPU’s Mad Reader Mod.) Don’t stray too far from the heat gun, either, as Surroz explains that heating up the tubing too slowly can be problematic, as well.

Unevenly heating the tubing is just as bad as heating it too quickly. So, as the tubing heats up, continue to rotate it with your fingers so that the surface heats evenly. You should be constantly turning the pipe until it’s ready to bend.

You’ll notice the tubing will begin to flex after a short amount of time under the heat gun’s dragon breath, but resist the urge to remove it from the heat and try to bend it on your mandrel. Keep it under the heat and keep turning it. Ideally, you want the tubing pliable enough that you can bend it with very little effort. Once the tubing flexes under very little pressure (“the consistency of a wet noodle,” according to Surroz), it should be ready to bend.

Next, set the tubing in your mandrel and hold it in place as you wait for it to re-harden. You can simply wait for it to return to room temperature naturally, although Khowdee helps it along with a fan. However, he doesn’t suggest that you shock the tubing by plunging it into a cold water bath, which instantly cools the tubing but might comprise its structural integrity. “Some modders worry that the quick temperature change may crack the tubing,” he says.

Finally, Khowdee recommends starting with your longest runs. If you botch a bend or scorch a portion of pipe, you can salvage the remainder and use it for your loop’s shorter runs.

Cut, Clean, Fit

You’re in the home stretch now. Getting a nice, even bend is arguably the most difficult stage in this process. The last leg of our journey begins with cutting your pipe to fit. If you’ve already premeasured the length of a particular pipe run, you should be able to line up the pipe section to each end of the run to determine where you need to make your cuts. Once you’ve marked the pipe, you’ll get the best cut by slipping the tubing into a specialized miter box that lets you make a perfect perpendicular cut. Break out your fine-toothed saw and start hacking.

Following the cuts, you’ll finish off the section of pipe by cleaning it up, inside and out. Start by sanding each end that you’ve just cut (Christianson uses 150 grit sandpaper). A pipe reamer can help clean up and deburr the inside of the pipe, too. Once you’ve smoothed and deburred the ends of the pipe, run water through it until you’ve washed away any remaining debris, as well as any soapy water leftover from the silicone insert. Obviously, neither is a good a mix for your coolant.

Thankfully, the process of installing rigid tubing is effectively the same as installing flexible tubing. Screw the base of the fitting into the waterblock/radiator/etc., slide the nut over the tube, and tighten them together. Don’t forget your O-rings, and don’t forget to leak-test the loop exactly as you would with traditional tubing. In fact, due to the chance of rigid tubing cracking or shattering, a thorough leak test is even more important.

My Baby’s Got The Bends

There’s no doubting a loop or two of rigid tubing will elevate your mod’s “Wow” factor. If you’re a seasoned modder, you probably already have the necessary tools to do the job in your workshop, and if you don’t, they’re not prohibitively expensive. Really, the three most important things you’ll need are time, patience, and a love of learning curves. If your loop is in need of a new look, give rigid a shot.

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At A Glance

General Information: If you’ve already built a custom liquid-cooling loop and are looking for you next challenge: Replacing your flexible tubing with rigid acrylic or PETG tubing definitely sets the difficulty to Legendary.

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