Capricorn XS Premium Extra Low Friction PTFE Bowden Tubing

High Lubricity Additives make XS Series tubing the lowest friction Bowden tubing on the market. These are not a coating, but are inside the PTFE. Less friction means more responsiveness, less retraction, more accurate prints, less slippage, wear, and tear on the extruder, and less clogging when printing chunky filaments such as some woodfills or ironfills.

Lower retraction means time saved every time the extruder retracts. Over the course of a print, a few milliseconds here and a few there add up to a lot of time saved.

1.9mm ± 0.05mm Inner Diameter A tighter inner diameter tolerance than traditional tubing reduces the "wiggle room," or buckling, inside the tube, allowing you to print flexible filaments even on the longest Bowden systems.

High Temperature Resistance - The high-temperature additive improves the thermal properties of the PTFE, allowing it to print at higher temperatures for longer duty cycles. XS tubing will operate at even higher temperatures than TL serie. 

Technical Specifications

PTFE, or Polytetrafluoroethylene, is a synthetic polymer commonly used as a coating for non-stick pots and pans. It is the slipperiest substance known to man, and is said to be the only surface to which a gecko cannot stick. Although Bowden tubes can be made from several different polymers, PTFE is generally considered the best because of its high melting point and low coefficient of friction.

1.75mm Bowden tubing, because of its small diameter, is made with an expensive paste extrusion process. Very precise equipment is needed to obtain a consistent shape and internal diameter. Additives such as colorant are difficult, because the PTFE doesn't readily want to mix with anything. Plain white PTFE is the cheapest and most common.

Capricorn tubing is manufactured using the most sophisticated equipment currently available. It always comes out perfectly round, and the diameter stays as consistent as possible.

TL Bowden Tubing is made from pure virgin Japanese PTFE resin. This resin is not only translucent, it is also slightly softer and more flexible than average PTFE.

TL tubing features a 2.0mm nominal inner diameter. This makes it well suited for printing larger or uneven diameter filaments such as wood and metal flake filaments. Higher end wood filaments especially have a tendency to be "chunky," containing large bits of real wood.

XS Bowden Tubing is also made from the highest quality pure virgin Japanese PTFE, and formed using the paste extrusion process. However, Capricorn have added a "Secret Sauce" which lowers the coefficient of friction. This additive also makes the tubing dark and opaque.

XS tubing has a nominal internal diameter of 1.9mm. This smaller diameter makes it ideal for printing flexible filaments, because there is no room for the filament to bind up inside the tube. The low friction coefficient allows any filament to glide through the tube with ease.

Technical parameters

	Competitor's Opaque White Tubing	Competitor's Translucent White Tubing	Capricorn Premium TL Series	Capricorn Premium XS Series
Additives	None	None	Blue Color	Blue Color and Secret High Lubricity Additive Mixture
Best For Chunky Filaments	No	No	Yes	Yes
Best For Flexible Filaments	No	No	No	Yes
Can See Through	No	Yes	Yes	No
Pulling Friction *	1.0	0.9	0.8	0.8
Color	White	White, Clear, or Translucent	Blue, Translucent	Dark Blue
Density (kg/m3)	2100-2200	2100-2200	2100 +/-100	2300 +/-100
Hardness	50-70	50-70	55	60-65
Inner Diameter (mm)	Typically 2.0 to 2.1	Typically 2.0 to 2.1	2.05 +/- 0.05	1.90 +/- 0.05
Linear Thermal Expansion at 250 °C	No data	No data	3.4-3.6%	2.2-3.3%
Material	Cheapest PTFE, FEP, or Other Polymers	Better PTFE, PFA, or Other Polymers	Highest Quality Pure Virgin PTFE	Highest Quality Pure Virgin PTFE
Melting Point (°C) **	Variable, as low as 220	Variable, as low as 220	around 300	up to 340
Outer Diameter (mm)	Typically 3.9 to 4.1	Typically 3.9 to 4.1	3.95 +/- 0.05	3.95 +/- 0.05
Roundness (ϵ)	Variable	Variable	< 0.1	< 0.1
Stiffness ***	High	High	Medium	Medium High
Thermal Conductivity (W/m-k)	No data	No data	0.25	0.25
Wear Rate (gm/s)	No data	No data	0.01	0.01
Young's Modulus (GPa) ****	Variable	Variable	0.5	0.53

* Pulling Friction is calculated as the average force required to pull 1.2 meters of 1.75mm PLA filament through 1 meter of tubing at a constant speed, relative to 1 meter of cheap white reference tubing. Note that although we observed the friction of the TL series to be about the same or even slightly lower than XS series, it also has a larger internal diameter.

** Temperatures were approximated by heating samples of all tubing simultaneously, observing how quickly each one began to deform. Printer failures may happen at significantly lower temperatures

*** Other Bowden tubes may vary significantly in stiffness, depending on the material from which they're made. Tubing generally tends to be more flexible than most, with the TL being more flexible than XS, partly because of the difference in additives, and partly because the XS has a greater cross-sectional area (XSA) due to the smaller internal diameter.

**** Young's Modulus (YM) is the measure of elasticity of the material. XS Series additives give the PTFE a slightly greater YM than the TL Series.

Safety precautions

PTFE is a flouropolymer, which exists in a state of matter known as a "glass." This means it does not "melt," like an ice cube, but rather slowly gets softer and softer as it gets warmer. Eventually it will either become a liquid, or catch fire.

Between room temperature and catching fire, all polymers emit tiny amounts of harmful gasses, known as "off-gassing." The hotter they get, the more they will emit. See Chart*

Because PTFE tends to have better temperature resistance (meaning it stays firmer at higher temperatures before significant deformation) than lower quality PTFE tubes, a number of users have reported success using it "inside the hot end."

This is not something you should do willy-nilly. Just because it works, doesn't mean there aren't precautions to be taken. If you use PTFE, or any polymer for that matter, inside the hot end or anywhere excessive temperatures may be experienced, you will potentially create harmful off-gassing. Not only that, but the polymer you are extruding may be creating harmful gasses as well.

We strongly recommend running your 3D printer in a well ventilated area, away from children and pets.

In a classroom environment, we encourage printing with PLA, and staying away from higher temperature materials, whether you use Bowden tubing or not.

Always have adult supervision when operating a 3D printer.

Keep razor-sharp Bowden tubing cutters out of reach of children.

Safety printing temperatures

Temp (Deg C)	Will it work?	Is it Safe?
170	Yes	Yes. This temperature is perfectly safe for printing PLA.
180	Yes	Yes. All good.
190	Yes	Yes. This is the within the optimal range for printing with PLA and even some ABS.
200	Yes	Yes.This temperature is perfectly safe for printing PLA.
210	Yes	Mostly. There is evidence that even at 202, PTFE can be harmful to pet birds
225	Yes	Yes.This is the ideal temperature range for most ABS. When printing ABS, the most danger comes from off-gassing and nanoparticles of the ABS itsself.
250	Yes	Yes.You should be fine printing slightly higher temp materials lsuch as PETG in this range. (As long as there are no pet birds in the house.)
260	Yes	We do not recommend printing with TL tubing above this range. XS Series tubing has additives that will allow it to print at higher temperatures without deforming, but safety is still a concern due to PTFE offgassing.
270	Yes	Mostly. 270 is approximately the highest temperature at which we have had sustained successful printing over many hours/days/months with no issues.
275	Yes	Maybe. At this temperature, PTFE off-gassing has been known to kill pet birds because their cardiovascular system is much more efficient at absorbing toxins than ours. Printing high temperature materials should be done by experienced professionals only. It is still relatively safe to humans and other pets, but it is best to err on the side of caution and always print in a well ventilated area.
280	Maybe	Maybe. At the 280-290 range, the tubing is likely to eventually deform during long prints.
300	Tube lifespan will be shortened	Maybe. This is entering the danger zone. Printing at these temps should only be attempted in a well ventilated area. PTFE may start to soften and fail physically after some time. Also, the filament you are printing with may be creating off-gassing as well. We recommend using XS series tubing only above this point, and running the printer in a well-ventilated area.
340	Tube lifespan will be very short	NO. At this temperature range, the PTFE will deform physically and may cause clogging. We know some people have had success at these temps but we can't promise it will work for any given set up. Printing at these temps should only be attempted in a well ventilated area.
400+	No	NO. At this temperature range, off-gassing dangerous to humans will be created by both the filament and the PTFE tube, and the life of the tube will certainly be diminished. The authors of this paper performed their tests at 460 C We do not recommend printing in this temperature range.