Thanks in large part to Gary at SidewinderComputers.com, I am able to bring you this review of 18 different types of water cooling tubing. Gary provided me with a couple of feet of most of the tubing in this review from his rather extensive collection available online. I also procured a few different types myself that Sidewinder does not carry such as Primoflex and Masterkleer.
The 18 different types of tubing reviewed include a variety of thick and thin-wall 1/2" tubing, a selection of 7/16" tubing and some 3/8" tubing. The tubing reviewed is pictured below (with larger tubing on the left and smaller on the right).
My review is broken down into four general sections as follows:
- General Description
- Bend Radius & Resistance to Kinking
- Barb Compatibility
The basic brands of tubing evaluated here include:
- Tygon R-3603: Clear laboratory grade tubing available in a wide range of sizes
- Tygon R-3400: Black UV resistant tubing available in a few sizes
- Tygon R-1000: Clear soft vinyl tubing
- Duralene PVC: A less expensive clear PVC tubing
- Primoflex: Available in UV reactive colors (blue, red, green, and clear) - soft and flexible
- MasterKleer: Inexpensive, ubiquitous, clear 7/16" ID 5/8" OD tubing
Note that Tygon, Duralene, and even MasterKleer are made by Saint Gobain Performance Plastics.
Where to buy: All of the Tygon/Duralene products are available from Sidewinder. MasterKleer is available from almost any water cooling shop and as far as I've seen, Primoflex is only available from Performance PC's.
The following picture shows the 1/2" tubing selection reviewed here. Note how the tacky silicone like texture of the Primoflex is a dust magnet. The colors of the cut cross-sections are indicative of the overal tint of the tubing.... that is, the Primoflex has an almost purple hue, while the R-1000 has a yellow tint and the Duralene has a very slight blue tint.
The next picture shows the 1/2" thin-wall tubing and 7/16" tubing selection. Again note the color of the cut cross-sections which are exagerating the tint of the tubing.
The next picture shows the small bore 3/8" tubing selection. Note the relative thick walls of the Primoflex in this picture compared to the others.
McMaster has a great description of Durometer hardness and an excellent picture...
Durometer is the international standard for measuring the hardness of rubber,
plastic, and most nonmetallic materials. The hardness of a material is its
resistance to surface penetration. Harder materials have more wear resistance,
but they are also less flexible.
The tubing in this review can be ranked as follows from hardest to softest:
- Tygon R-3400: Rated durometer of 64
- Duralene: Rated durometer of 55 but this is definitely wrong... more like 60
- MasterKleer: Very close to Duralene... estimate it to be 60
- Tygon R-3603: Rated durometer of 55
- Primoflex: Estimate it to be about 45
- Tygon R-1000: Rated durometer of 40
Here's a picture showing the effect that durometer has on kink resistance or allowing the tubing to maintain it's tubular shape in relatively tight bends. In this photo, all three types of tubing have the same dimensions (ID and wall thickness) but dramatically different durometer ratings. As you can see with this tight radius, the high durometer R-3400 is able to maintain its shape without kinking while the lesser durometer tubing cannot.
Durometer is something to pay attention to when choosing the right tubing for your application. In some cases, you can use thinner wall tubing with a higher durometer to maintain the same kink-resistance as a thicker softer tubing. However, a very stiff composition such as the R-3400 will place a lot more tube torque on your blocks than softer tubing.
In this analysis, I used pieces of red heat-shrink to demonstrate the clarity and/or tint of the tubing. Pay attention to any change in hue of the red heat-shrink and the clarity of the letters on the heat-shrink wall.
In the following picture, you can see the difference in the major brands of tubing in the 1/2" thick-wall category. Note how the Primoflex clear is not really clear. It's actually very opaque and has a slight purple/blue tint. The Duralene is very clear but has a slight blue tint that turns the heat-shrink color slightly pink. Both brands of Tygon are similarly clear but the R-1000 does have a slightly yellow hue.
In the next picture, you can see the difference in clarity in the medium sized tubing. Note that MasterKleer is aptly named as it is the most clear in my observation. It has absolutely no tint and is very transparent. However, as many people know, MasterKleer does not stay clear very long... after 6 months in a loop consisting of a 10:1 distilled:Pentosin coolant mixture, the Masterkleer is anything but clear (second picture below). The others are similar to their larger versions above.
MasterKleer after 6 months in a loop:
The smaller tubing samples all exhibit the same clarity attributes of their bigger counterparts...
Bend Radius and Resistance to Kinking
Most tubing in this review has a bend radius in the 1.5" to 2" range, which of course translates into bend diameter of about 3-4". Perhaps coincidentally, this also corresponds to the distance between barbs on NB/SB blocks on a typical Intel motherboard. Since the point at which a tube starts to kink is a very subjective measure, I decided to take another more objective approach and allow you to judge for yourself. The collection of photos below were all taken in an identical way and then combined in Photoshop for easy comparison.
The testing simply shows how well the various tube samples hold their shape when subjected to barb distances of either 4 or 3 inches. The test jig is rather simple as shown in the photo below... An MCW-30 with an appropriate barb is clamped to the bench with the barb centered over the 1" mark on the ruler. I then adjusted the tube to the 4 or 5 inch mark on the ruler as shown and took a photo of the tube's shape so you can gauge how it behaves with a 3 or 4 inch barb-to-barb distance respectively.
Using these photos and knowing the barb-to-barb distance you have to work with, you can easily assess whether your desired tubing will hold its shape sufficiently to your satisfaction or not.
The first photo below shows how the various thick-wall 1/2" tubing performed with a 4-inch bend. Note how all the samples don't show any signs of kinking.
The next photo shows how the various thick-wall 1/2" tubing performed with a 3-inch bend (likely exceeding their rated minimum bend radius). All the samples are showing some signs of flattening but are still usable except for the R-1000 which has almost fully kinked due to it's very soft durometer.
The next photo shows how the various thin-wall 1/2" tubing performed with a 4-inch bend. Note that the extra 1/32" wall thickness on the R-3603 in the top pic allows it to maintain it's shape while it's slightly thinner wall counterpart just below is fully kinked. This illustrates the importance of wall thickness in bend radius.
None of these samples could avoid kinking with a 3-inch bend so that photo is ommited.
The next photo shows how the various 7/16" tubing performed with a 4-inch bend. The R-3603 with 1/8" wall (top) has a slight kink while the Masterkleer with similar wall but higher durometer is not showing any deformation at all just like the thicker walled R-3603. The thin-wall R-3400 is starting to noticably flatten at the apex. At any rate, all of the tubing in this situation could be used without much restriction.
The next photo shows how the various 7/16" tubing hold up under a tighter 3-inch bend. Now the 3/8" ID and 5/8" OD Tygon and Masterkleer samples are both showing signs of flattening at the apex while the thicker wall R-3603 holds its shape nicely. The thin-wall R-3400 has collapsed comletely at this bend radius.
The last photo shows how the various 3/8" tubing holds up under a 3-inch bend. Here, the Primoflex is looking very good while the others are noticably flattening at the apex. In fact, it should be noted that the low durometer of the Primoflex also allows it to easily manage bends in multiple planes.
Overall, the best tubing for kink resistance is one which has the thickest walls in proportion to it's diameter with the highest durometer being a second consideration. Thus the Tygon R-3603 7/16" ID with 11/16" OD (1/8" wall thickness) provides the best kink resistance of the tubing suitable for 1/2" barbs. For 3/8" tubing, the Primoflex 3/8" ID - 5/8" OD (1/8" wall) is by far the best choice for kink resistance on tight bends.
As most folks know, 7/16" tubing fits snugly enough over 1/2" barbs that it forms a water-tight seal without the need for clamps. The picture below illustrates the difference in how snugly 1/2" and 7/16" tubing fit over a typical 1/2" barb.
For those people considering compression barbs, such as those made by Koolance (which I am very partial to) you should note that you can only use thin-wall 1/2" tubing with their 1/2" compression fittings. You can also use 7/16" ID - 5/8" OD but it fits so snugly it will be frustrating and possibly damaging to get tightened or untightened. I really recommend 1/16" wall thickness tubing with Koolance 1/2" compression fittings which really limits your tube routing to large bends.
The 3/8" Koolance compression fittings are compatible with all 3/8" ID - 1/2" OD tubing.