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VIDEO TUTORIAL

USED IN THIS PROJECT

Although not necessarily an exhaustive list, the following tools and materials, supplied by Easy Composites, were used in this project.

The quantity shown below is the approximate amount used in the project rounded up to the nearest available kit size or quantity.

TOOLS & EQUIPMENT
OV301 Precision Composites Curing Oven Thumbnail
OV301OV301 Precision Composites Curing Oven£1914.00 /each

Total £0.00
MATERIALS & CONSUMABLES
Easy-Lease Chemical Release Agent 100ml Thumbnail
ELRA-01Easy-Lease Chemical Release Agent 100ml£6.80 /pack

Composites High Shrink Tape (25mm) 10m Roll Thumbnail
CST-25-10Composites High Shrink Tape (25mm) 10m Roll£4.32 /roll

XC130 300g Unidirectional Prepreg Carbon Fibre (300mm) 2m Roll Thumbnail
XC130-C2412UD-300(300)-2XC130 300g Unidirectional Prepreg Carbon Fibre (300mm) 2m Roll£28.20 /roll

XC110 210g 2x2 Twill 3k Prepreg Carbon Fibre (1250mm) 1m Roll Thumbnail
XC110-C331T2-210(1250)-1XC110 210g 2x2 Twill 3k Prepreg Carbon Fibre (1250mm) 1m Roll£63.92 /roll

Total £0.00

VIDEO TUTORIAL

How to Make a Roll Wrapped Carbon Fibre Tube

In this tutorial you can learn how to use a metal mandrel, prepreg carbon fibre and shrink tape to produce a bespoke carbon fibre tube using the roll wrapping process.

The roll wrapping process is used by composite manufacturers to produce high strength carbon fibre tubes, either with a basic unfinished appearance or with a cosmetic finished appearance. Indeed, Easy Composites carry one of the largest range of roll wrapped carbon fibre tubes available to buy online. Sometimes however, the need arises for a carbon fibre tube of very specific dimensions, fibre type/orientation or appearance.

Providing the tube you wish to make has parallel sides or a continuous taper then it is possible to use the roll wrapping process to make your own bespoke carbon fibre tube without the need for any specialist machinery beyond a metal mandrel of the right size and an oven large enough to cure the tube in.

If, instead, you need to make a carbon fibre tube that is not straight, such as handlebars or a more complex tubular frame structure such as a suspension wishbone or bike frame then take a look at our tutorial on making a carbon fibre tube using a split-mould.

Explained below are the materials and processes used in the tutorial.


TUTORIAL BREAKDOWN

Metal mandrel

1. Metal mandrel

The roll wrapping process involves wrapping prepreg carbon fibre around a metal mandrel and so the starting point is to have a metal mandrel of the correct diameter for the size tube that you want to create. Because the carbon fibre will be wrapped around the outside of the mandrel, the mandrel itself needs to have an outside diameter that matches the inside diameter of the carbon fibre tube you will use it to make. The outside diameter of your carbon fibre tube will be determined by the amount of reinforcement (the number of layers) you wrap around the mandrel.

In the video we use an aluminium mandrel because the high coefficient of thermal expansion (CTE) of aluminium makes it well-suited to the roll wrapping process. Steel or other metals can be used but metals with higher CTE will make the process easier.

If you want to produce a tapered carbon fibre tube then you will most likely need to use a lathe to turn down a solid aluminium rod to create a tapered mandrel.

Once you have a correctly sized mandrel, ensure it is completely clean and as smooth as possible to aid with extraction. The mandrel should then be thoroughly prepared with a high temperature chemical release agent, such as Easy-Lease.

Prepreg carbon fibre

2. Prepreg carbon fibre

Although in theory it may be possible to use alternative types of reinforcements, such as a dry fabric wetted out with an epoxy resin, in practice only prepreg carbon fibre offers the precision and ease of handling required for the roll wrapping process.

In the tutorial we use a layer of XPREG® XC110 210g woven prepreg on the inside of the tube, followed by several layers of XC130 300g unidirectional prepreg, finished with a final layer of the XC110 210g woven prepreg again on the outside of the tube. Because the woven prepreg has fibres oriented in the 0° axis (down the length of the tube) and in the 90° axis (around the circumference of the tube) these layers add what is known as hoop strength to the tube, making the tube less vulnerable to crush or burst forces and splintering. The bulk of the reinforcement, in the 0° axis, gives the tube its longitudinal stiffness.

By altering the layup to include more or less woven layers or by changing or alternating the orientation of the unidirectional plies allows the performance of the tube to be precisely optimised for its specific use. For example, a tube for a prop-shaft will encounter primarily torsional forces and so the unidirectional fibre can be aligned off-axis, at 45° for example, specifically to handle these forces.

Composites shrink tape

3. Composites shrink tape

Once the prepreg carbon fibre reinforcement has been wrapped around the mandrel as tightly as possible, the reinforcement is then tightly wrapped with a composites shrink tape to provide further consolidation.

When applying the shrink tape it is important to ensure there is lots of overlap. Each wrap of the tape advances only a few millimetres down the tube. Although time consuming to do by hand, having lots of overlap in this way will provide much more consolidation pressure when the tape contracts during the cure.

Oven cure

4. Oven cure

Besides the mandrel, having an oven to cure the tube in is likely to be the main limiting factor when considering the roll wrapping process outside of a full production environment. However, unlike other prepreg processes, the roll wrapping process does not require precise temperature control or the multi-step 'ramp and soak' cure cycles often needed. Nor does the process require an active vacuum line into the oven. Therefore, the only requirements for an oven to cure a roll wrapped tubes are basic temperature control and sufficient size to fit the tube in. Depending on the size of the tube you want to make, anything from a domestic oven to a powder-coating oven could be used.

In the video tutorial, we're using our OV301 precision composites curing oven. The XPREG XC110 prepreg is loaded into the oven at 120°C, flat temperature, and allowed to cure for 1hr 30mins.


DISCUSSION (28)

Please share any questions or comments you may have about this video tutorial.


Josh
How does the process differ for square and rectangular tubing?
Easy CompositesMatt
The problem with anything other than a round mandrel (so square, rectangular, hexagonal etc.) is that you get exaggerated pressure from the shrink tape on the outside corners of the shape and consequently reduced pressure on the flat faces. That's not to say that non-round shapes can't be made using a roll-wrapping technique but there are some compromises.

Shane Johnson
What liquids and gases can and can't be used internally, i.e if used as a water fuel or gas pipe? Also what pressures and temperatures it could work too?
Easy CompositesMatt
Pressures would be determined by the layup of the tube. To design a tube to take very high pressure you would actually want the majority of the carbon fibre in the 'hoop' direction, not longitudinally; giving you a layup more similar to a filament wound composite pressure vessel. In terms of temperature, that's determined by the resin system in the prepreg and the cure temperature. In this case we used the XPREG XC110 which has a maximum service temperature of 110°C. For transport or containment of liquids it would be a very good idea to coat the inside of the tube using a sealer. This can be done by pouring sealer inside and then rolling it around. A product like GTS75 from Caswell Europe is designed as a composite 'tank sealer' and will provide good fuel resistance.

pbkayakyer
So that's how fishing pole blanks are made?
Easy CompositesMatt
Actually, a lot of them are made using a pultrusion process because they use 100% UD carbon running down their length. This makes them incredibly strong and light in the longitudinal bend direction but very vulnerable to crushing/splintering.

CampoDrone
Would this exact process do for sailing masts?
Easy CompositesMatt
In principal although masts can be tapered or different profile shapes. Sometimes they're made using the roll wrapped process and sometimes they're made using a split mould process (see our other video).

TechGuy
Could this be done with resin and vacuum infusion ?
Easy CompositesMatt
Well, theoretically yes but practically it would be a very awkward form to be trying to set up for a resin infusion. You'd probably be better off wet-laying and then shrink wrapping if you didn't want to use prepreg. The high temp cure is still an integral part of the process (for the expansion of the mandrel and contraction of the tape) but that could still be used for a wet lay or infused part.

ToyCorp
Could this technique be used for prop shafts and driveshafts?
Easy CompositesMatt
Carbon fibre prop shafts and driveshafts do exist and a lot of them are made using the roll wrapped technique. Generally, for prop shafts you need fibre alignment on the bias (angled) so that the tube has maximum torsional strength.

Laurent Karout
Could a tube like this be used as a rear axle on racing go-karts?
Easy CompositesMatt
Well, in theory you could but there's a lot about a carbon fibre tube that doesn't really make it the best choice for an application like a rear axle.

James Ford
Great video! Would it be possible to make a sliding fit with two tubes?
Easy CompositesMatt
As long as you are careful in designing the right thickness of your lay up then you can making sliding fit tubes. Quite often carbon tubes are made this way for extending poles for window cleaning, flag poles, fishing gear etc . Remember to allow a small gap for manufacturing tolerance and so the tubes have a small gap to allow smooth and easy sliding.

Spaceman Systems
Wouldn't it be better to just buy a ready made tube, rather than make one?
Easy CompositesMatt
Yes, certainly; if you can buy the tube you need that that's going to be quicker, easier and cheaper. And hey, we'd be happy to sell you that tube :). The purpose of this video is to explain the process and also show how it could be used to produce your own tube if it just wasn't possible to get one at the dimensions or fibre configuration that you need.

Chris Athanasopoulos
Could you make a carbon tube with a wet lay or infused process instead of prepreg?
Easy CompositesMatt
You could certainly wet lay in a very similar way to the repair done here and also similarly to a tube repair as seen in our Fishing Pole Repair Video. Infusion would be much harder in a practical sense for smaller tube sizes, although for bigger sizes it may work using a tubular bagging film and extra care to ensure the resin is evenly distributed all around the tube.

Captain Awesome
Would not a 'sock tube' weave be a safer bet? It would of course need vacuum infusion.
Easy CompositesMatt
Safer in what sense? - The main issue with a woven sleeve is that the fibre orientation is predominantly at +/- 45 degrees. At the very least it will be considerably 'off axis' meaning that you don't have fibre alignment in the direction you need it in (i.e. running lengthways down the tube). For tubes where you do want lots of torsional stiffness then a carbon sleeve would be an option although, to be honest, you would probably switch to a filament winding process in that case.

Armando Mal
Can you use the shrink wrap for carbon fiber skinning parts to remove excessive epoxy?
Easy CompositesMatt
Yes, in theory. The issue really would be whether the thing you're wrapping is something that you could actually wrap tape around? If you were skinning something tubular, like a frame, then it would work.

Joshus Szeto
Can these tubes handle constant temperatures of 100°C (e.g. automotive radiator piping)?
Easy CompositesMatt
Hi Joshua, good question. So, because this tube was cured at 120°C the basic principle is that they would be OK for a service temperature of anything less than that (let's say 100°C to be on the safe-side). However, a couple of things would worry me about your application. One is the anti-freeze and the other is the continuous exposure to hot water. Although in the short term neither of these would be a huge problem, I think for permanent exposure to this environment a carbon fibre tube wouldn't really be suitable.

Adan Syahdan
Can I make carbon fiber tube from sheets of carbon Kevlar? Not carbon prepreg like in the video..??
Easy CompositesMatt
Hi Adan, yes, you could make a Kevlar composite tube using prepreg Kevlar reinforcement in just the same way as we've done using carbon prepreg. You might not find it as easy to track down prepreg Kevlar reinforcement though, it is less common. We don't stock it as standard but we do make for bespoke orders.

TomE1248
Do you pre heat the oven to get the aluminium tube to expand quicker before the epoxy starts to cure?
Easy CompositesMatt
Hi Tom, good questions. The oven was already at temperature and yes, this helps to ensure that the aluminium expands before the epoxy cures. As for using a solid mandrel, yes, same principle. It definitely is possible to use a solid mandrel but - if you have one - a tube will warm up quicker and so would tend to be better for this process.

Preston Edmonds
How much internal psi can the tube withstand? Can be used for turbo or supercharger tubing? Say a 3 or 4 inch tube?
Easy CompositesMatt
This was just a mock-up part so we don't have any data for it. There would be no problem at all though making a tube that could take almost any pressure you needed, it's simply a case of increasing the wall thickness (layers of carbon). Hydraulic testing would be a good and safe way to check for the pressure rating of the component.

Brad Maas
Slight overlap, would that be 5mm or 10mm? For additional strength could more layers help? Rotational strength? You make it look easy. Thanx
Easy CompositesMatt
The overlap is only necessary to hold the fabrics together during the rolling process, so in this case the overlap was actually very small at around 3mm.

Troy Dield
This is great stuff. But where is the resin? When was the resin added? Is the resin already impregnated into the carbon fiber sheet? Thanks in advance.
Easy CompositesMatt
Hi Troy, yes, we're using prepreg carbon fibre which has the resin already in it. See this introduction video: https://www.youtube.com/watch?v=HfrFaKDsJxc to understand more about prepreg

Miller Chassis
Great video as usual guys. I'm interested in using a tapered mandrel to do a similar thing. Once the part is cured what kind of service temperature can it handle?
Easy CompositesMatt
As a basic rule for prepregs (and you can always consult the datasheet to confirm the details for a specific material) the service temperature is likely to be just slightly lower than the cure temperature. In this case we cured at 120°C so a 110°C service temperature could be expected. As it happens, 110°C is the service temperature for this prepreg following a 120°C cure.

Adam Craig
Can you use a wax shape, for example the S-bend at the start of the video. Wrap the wax block up and then melt it out later, like how lost wax casting molds are formed?
Easy CompositesMatt
Hi Adam... sort of. The material that we're using to make the tube in this video is prepreg carbon fibre which must be heated to a relatively high temperature in order to cure. If we were to use a wax mandrel, together with prepreg carbon fibre, then we're likely to melt the wax before the prepreg cures. Also, if you're following this basic roll wrapping process, including wrapping the mandrel and reinforcement with the shrink tape then when the tape contracts at temperature it would put too much pressure on a soft wax (especially at temperature) and squash it. Therefore, if you're using prepregs and want to use a sacrificial mandrel then you normally need to be looking at water-soluble cores that can be washed out. These materials are quite high-tech, usually you would either need a split mould to cast the water-soluble mandrel or you would need to CNC machine it from a solid block of the material.

Airwolf357
I plan to build a J3 kitten ultralight aircraft. Some manufacturers use carbon tubes to create the airframe structure to lighten and strengthen it. How can this be accomplished?
Easy CompositesMatt
Thank you for the comments and post. Whilst I understand that there are very few restrictions on the materials and approvals for ultra-light aviation, it would still be very important to be totally confident with your materials and processes for applications as critical as an airframe. Having said that, I have no doubt that some manufacturers can safely and successfully incorporate carbon fibre tubes into their airframes increase strength (or stiffness) and reduce weight. Usually it's the joins that are the most difficult part when using composite tubing. We'll certainly keep this in mind and see if there are some videos we can produce to cover this topic.

awils334
Can you do this any other way without using pre preg carbon and baking? Like a wet lay up with room temp curing epoxy? Would love to know, wouldn't be as strong but that doesn't matter
Easy CompositesMatt
It would probably be possible to do the process using wet-lay. The reason I say probably is because this process - as you hopefully understand from the video - relies on the expansion and contraction of the mandrel as the temperature changes. That's how it's possible to get the carbon part off the mandrel. With wet layup and a parallel mandrel your only option for contracting the mandrel (and removing the carbon tube) would be to freeze it. However, with freezing you'll only be dropping the temperature by 40°C (from 20° to minus 20°) whereas with an oven we're increasing by 100°C (from 20 to 120°C). However, another option would be wet lay and then oven cure.

Payback118
How does the wall thickness remain the same? Surely there's a section of the wall which should be slightly thicker/thinner? Concentricity cannot be the same throughout the wall thickness?
Easy CompositesMatt
Yes, that's right, we've got 'good' consistency in the wall thickness but it's never going to be perfect. The more accurate the cutting dimensions, the closer you can get.

Simao Pedro Bras Silva
I am working on a project where there is a contact abrasion on the floor, at speed. Does carbon fibre have the same or more abrasion resistance than steel? Would Kevlar be a better choice?
Easy CompositesMatt
Hi Simao, it's very rare that carbon fibre, or indeed any composite material, makes a good wear face/bearing surface. You would normally combine the advantages of the carbon tube (stronger, lighter, stiffer) with a material that would make a good friction/wear/bearing surface, like plastics or metal. If you do need a composite material to have improved abrasion resistance then yes, it would definitively be better to use Kevlar rather than glass or carbon.

Alfaduk
Would love to see a video of how to attach metal to the CF tubes to help build frames or frame reinforcements, like a strut tower brace. An ultimate video would be how to create a CF antiroll bar, like the Porsche 911 GT2 RS uses .............
Easy CompositesMatt
OK, thanks for the comments. We do plan to do a video on fittings and fasteners for making carbon fibre assemblies, we could cover some of the things you're talking about in that.

holeyrivet
Will the resin hold up to some chemicals? Say if I wanted to use these for coolant pipes in a car? Also if I can suggest a topic for your next video, a motorcycle fuel tank? I’ve been want to do one for years but I really find any info on the subject. Thanks
Easy CompositesMatt
Epoxy had pretty good chemical tolerance and also a tube that's been cured at 120°C should have an operating temperature that's up to the 100°C you'd need for a cooling system. HOWEVER - continuous exposure to antifreeze and boiling water is not really what a carbon fibre tube like this is designed for and so I wouldn't recommend it. As for the motorcycle tank, yes, we'll definitely be making this video in the future. The trick is to use a tank sealer to protect the composite laminate from the fuel. Make sure you're subscribed to find out when we make this video!

AJ Hartman Aero
Nice video as always. When I did some tubes for my car I wrapped some extra tows around the ends to make beads, kinda like your step to pull it off if necessary. This way there's much less chance of a coupler popping off. My application was for car intake tubes that see boost pressure.
Easy CompositesMatt
Yep, nice tip and nice way to get a small, neat step on the end of your tubes. Totally makes sense.

R4M_InternetExplorer_EXE
There's any process like "Lost PLA" (used in greensand mold making) where you wrap the part you want and after it has cured, you apply heat or a chemical process to melt or dissolve the inner mold? This would massively help at creating very complex parts and never seen it done on carbon fiber
Easy CompositesMatt
Yes, there are a few 'lost' core process that can be used with carbon fibre, including low melting point alloys (like Wood's metal) and soluble core materials. We definitely hope to do some tutorials using one or more of these processes in the future.

LEAVE A COMMENT OR QUESTION

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USED IN THIS PROJECT

Although not necessarily an exhaustive list, the following tools and materials, supplied by Easy Composites, were used in this project.

The quantity shown below is the approximate amount used in the project rounded up to the nearest available kit size or quantity.

TOOLS & EQUIPMENT
OV301 Precision Composites Curing Oven Thumbnail
OV301OV301 Precision Composites Curing Oven£1914.00 /each

Total £0.00
MATERIALS & CONSUMABLES
Easy-Lease Chemical Release Agent 100ml Thumbnail
ELRA-01Easy-Lease Chemical Release Agent 100ml£6.80 /pack

Composites High Shrink Tape (25mm) 10m Roll Thumbnail
CST-25-10Composites High Shrink Tape (25mm) 10m Roll£4.32 /roll

XC130 300g Unidirectional Prepreg Carbon Fibre (300mm) 2m Roll Thumbnail
XC130-C2412UD-300(300)-2XC130 300g Unidirectional Prepreg Carbon Fibre (300mm) 2m Roll£28.20 /roll

XC110 210g 2x2 Twill 3k Prepreg Carbon Fibre (1250mm) 1m Roll Thumbnail
XC110-C331T2-210(1250)-1XC110 210g 2x2 Twill 3k Prepreg Carbon Fibre (1250mm) 1m Roll£63.92 /roll

Total £0.00

DISCUSSION (28)

Please share any questions or comments you may have about this video tutorial.


Josh
How does the process differ for square and rectangular tubing?
Easy CompositesMatt
The problem with anything other than a round mandrel (so square, rectangular, hexagonal etc.) is that you get exaggerated pressure from the shrink tape on the outside corners of the shape and consequently reduced pressure on the flat faces. That's not to say that non-round shapes can't be made using a roll-wrapping technique but there are some compromises.

Shane Johnson
What liquids and gases can and can't be used internally, i.e if used as a water fuel or gas pipe? Also what pressures and temperatures it could work too?
Easy CompositesMatt
Pressures would be determined by the layup of the tube. To design a tube to take very high pressure you would actually want the majority of the carbon fibre in the 'hoop' direction, not longitudinally; giving you a layup more similar to a filament wound composite pressure vessel. In terms of temperature, that's determined by the resin system in the prepreg and the cure temperature. In this case we used the XPREG XC110 which has a maximum service temperature of 110°C. For transport or containment of liquids it would be a very good idea to coat the inside of the tube using a sealer. This can be done by pouring sealer inside and then rolling it around. A product like GTS75 from Caswell Europe is designed as a composite 'tank sealer' and will provide good fuel resistance.

pbkayakyer
So that's how fishing pole blanks are made?
Easy CompositesMatt
Actually, a lot of them are made using a pultrusion process because they use 100% UD carbon running down their length. This makes them incredibly strong and light in the longitudinal bend direction but very vulnerable to crushing/splintering.

CampoDrone
Would this exact process do for sailing masts?
Easy CompositesMatt
In principal although masts can be tapered or different profile shapes. Sometimes they're made using the roll wrapped process and sometimes they're made using a split mould process (see our other video).

TechGuy
Could this be done with resin and vacuum infusion ?
Easy CompositesMatt
Well, theoretically yes but practically it would be a very awkward form to be trying to set up for a resin infusion. You'd probably be better off wet-laying and then shrink wrapping if you didn't want to use prepreg. The high temp cure is still an integral part of the process (for the expansion of the mandrel and contraction of the tape) but that could still be used for a wet lay or infused part.

ToyCorp
Could this technique be used for prop shafts and driveshafts?
Easy CompositesMatt
Carbon fibre prop shafts and driveshafts do exist and a lot of them are made using the roll wrapped technique. Generally, for prop shafts you need fibre alignment on the bias (angled) so that the tube has maximum torsional strength.

Laurent Karout
Could a tube like this be used as a rear axle on racing go-karts?
Easy CompositesMatt
Well, in theory you could but there's a lot about a carbon fibre tube that doesn't really make it the best choice for an application like a rear axle.

James Ford
Great video! Would it be possible to make a sliding fit with two tubes?
Easy CompositesMatt
As long as you are careful in designing the right thickness of your lay up then you can making sliding fit tubes. Quite often carbon tubes are made this way for extending poles for window cleaning, flag poles, fishing gear etc . Remember to allow a small gap for manufacturing tolerance and so the tubes have a small gap to allow smooth and easy sliding.

Spaceman Systems
Wouldn't it be better to just buy a ready made tube, rather than make one?
Easy CompositesMatt
Yes, certainly; if you can buy the tube you need that that's going to be quicker, easier and cheaper. And hey, we'd be happy to sell you that tube :). The purpose of this video is to explain the process and also show how it could be used to produce your own tube if it just wasn't possible to get one at the dimensions or fibre configuration that you need.

Chris Athanasopoulos
Could you make a carbon tube with a wet lay or infused process instead of prepreg?
Easy CompositesMatt
You could certainly wet lay in a very similar way to the repair done here and also similarly to a tube repair as seen in our Fishing Pole Repair Video. Infusion would be much harder in a practical sense for smaller tube sizes, although for bigger sizes it may work using a tubular bagging film and extra care to ensure the resin is evenly distributed all around the tube.

Captain Awesome
Would not a 'sock tube' weave be a safer bet? It would of course need vacuum infusion.
Easy CompositesMatt
Safer in what sense? - The main issue with a woven sleeve is that the fibre orientation is predominantly at +/- 45 degrees. At the very least it will be considerably 'off axis' meaning that you don't have fibre alignment in the direction you need it in (i.e. running lengthways down the tube). For tubes where you do want lots of torsional stiffness then a carbon sleeve would be an option although, to be honest, you would probably switch to a filament winding process in that case.

Armando Mal
Can you use the shrink wrap for carbon fiber skinning parts to remove excessive epoxy?
Easy CompositesMatt
Yes, in theory. The issue really would be whether the thing you're wrapping is something that you could actually wrap tape around? If you were skinning something tubular, like a frame, then it would work.

Joshus Szeto
Can these tubes handle constant temperatures of 100°C (e.g. automotive radiator piping)?
Easy CompositesMatt
Hi Joshua, good question. So, because this tube was cured at 120°C the basic principle is that they would be OK for a service temperature of anything less than that (let's say 100°C to be on the safe-side). However, a couple of things would worry me about your application. One is the anti-freeze and the other is the continuous exposure to hot water. Although in the short term neither of these would be a huge problem, I think for permanent exposure to this environment a carbon fibre tube wouldn't really be suitable.

Adan Syahdan
Can I make carbon fiber tube from sheets of carbon Kevlar? Not carbon prepreg like in the video..??
Easy CompositesMatt
Hi Adan, yes, you could make a Kevlar composite tube using prepreg Kevlar reinforcement in just the same way as we've done using carbon prepreg. You might not find it as easy to track down prepreg Kevlar reinforcement though, it is less common. We don't stock it as standard but we do make for bespoke orders.

TomE1248
Do you pre heat the oven to get the aluminium tube to expand quicker before the epoxy starts to cure?
Easy CompositesMatt
Hi Tom, good questions. The oven was already at temperature and yes, this helps to ensure that the aluminium expands before the epoxy cures. As for using a solid mandrel, yes, same principle. It definitely is possible to use a solid mandrel but - if you have one - a tube will warm up quicker and so would tend to be better for this process.

Preston Edmonds
How much internal psi can the tube withstand? Can be used for turbo or supercharger tubing? Say a 3 or 4 inch tube?
Easy CompositesMatt
This was just a mock-up part so we don't have any data for it. There would be no problem at all though making a tube that could take almost any pressure you needed, it's simply a case of increasing the wall thickness (layers of carbon). Hydraulic testing would be a good and safe way to check for the pressure rating of the component.

Brad Maas
Slight overlap, would that be 5mm or 10mm? For additional strength could more layers help? Rotational strength? You make it look easy. Thanx
Easy CompositesMatt
The overlap is only necessary to hold the fabrics together during the rolling process, so in this case the overlap was actually very small at around 3mm.

Troy Dield
This is great stuff. But where is the resin? When was the resin added? Is the resin already impregnated into the carbon fiber sheet? Thanks in advance.
Easy CompositesMatt
Hi Troy, yes, we're using prepreg carbon fibre which has the resin already in it. See this introduction video: https://www.youtube.com/watch?v=HfrFaKDsJxc to understand more about prepreg

Miller Chassis
Great video as usual guys. I'm interested in using a tapered mandrel to do a similar thing. Once the part is cured what kind of service temperature can it handle?
Easy CompositesMatt
As a basic rule for prepregs (and you can always consult the datasheet to confirm the details for a specific material) the service temperature is likely to be just slightly lower than the cure temperature. In this case we cured at 120°C so a 110°C service temperature could be expected. As it happens, 110°C is the service temperature for this prepreg following a 120°C cure.

Adam Craig
Can you use a wax shape, for example the S-bend at the start of the video. Wrap the wax block up and then melt it out later, like how lost wax casting molds are formed?
Easy CompositesMatt
Hi Adam... sort of. The material that we're using to make the tube in this video is prepreg carbon fibre which must be heated to a relatively high temperature in order to cure. If we were to use a wax mandrel, together with prepreg carbon fibre, then we're likely to melt the wax before the prepreg cures. Also, if you're following this basic roll wrapping process, including wrapping the mandrel and reinforcement with the shrink tape then when the tape contracts at temperature it would put too much pressure on a soft wax (especially at temperature) and squash it. Therefore, if you're using prepregs and want to use a sacrificial mandrel then you normally need to be looking at water-soluble cores that can be washed out. These materials are quite high-tech, usually you would either need a split mould to cast the water-soluble mandrel or you would need to CNC machine it from a solid block of the material.

Airwolf357
I plan to build a J3 kitten ultralight aircraft. Some manufacturers use carbon tubes to create the airframe structure to lighten and strengthen it. How can this be accomplished?
Easy CompositesMatt
Thank you for the comments and post. Whilst I understand that there are very few restrictions on the materials and approvals for ultra-light aviation, it would still be very important to be totally confident with your materials and processes for applications as critical as an airframe. Having said that, I have no doubt that some manufacturers can safely and successfully incorporate carbon fibre tubes into their airframes increase strength (or stiffness) and reduce weight. Usually it's the joins that are the most difficult part when using composite tubing. We'll certainly keep this in mind and see if there are some videos we can produce to cover this topic.

awils334
Can you do this any other way without using pre preg carbon and baking? Like a wet lay up with room temp curing epoxy? Would love to know, wouldn't be as strong but that doesn't matter
Easy CompositesMatt
It would probably be possible to do the process using wet-lay. The reason I say probably is because this process - as you hopefully understand from the video - relies on the expansion and contraction of the mandrel as the temperature changes. That's how it's possible to get the carbon part off the mandrel. With wet layup and a parallel mandrel your only option for contracting the mandrel (and removing the carbon tube) would be to freeze it. However, with freezing you'll only be dropping the temperature by 40°C (from 20° to minus 20°) whereas with an oven we're increasing by 100°C (from 20 to 120°C). However, another option would be wet lay and then oven cure.

Payback118
How does the wall thickness remain the same? Surely there's a section of the wall which should be slightly thicker/thinner? Concentricity cannot be the same throughout the wall thickness?
Easy CompositesMatt
Yes, that's right, we've got 'good' consistency in the wall thickness but it's never going to be perfect. The more accurate the cutting dimensions, the closer you can get.

Simao Pedro Bras Silva
I am working on a project where there is a contact abrasion on the floor, at speed. Does carbon fibre have the same or more abrasion resistance than steel? Would Kevlar be a better choice?
Easy CompositesMatt
Hi Simao, it's very rare that carbon fibre, or indeed any composite material, makes a good wear face/bearing surface. You would normally combine the advantages of the carbon tube (stronger, lighter, stiffer) with a material that would make a good friction/wear/bearing surface, like plastics or metal. If you do need a composite material to have improved abrasion resistance then yes, it would definitively be better to use Kevlar rather than glass or carbon.

Alfaduk
Would love to see a video of how to attach metal to the CF tubes to help build frames or frame reinforcements, like a strut tower brace. An ultimate video would be how to create a CF antiroll bar, like the Porsche 911 GT2 RS uses .............
Easy CompositesMatt
OK, thanks for the comments. We do plan to do a video on fittings and fasteners for making carbon fibre assemblies, we could cover some of the things you're talking about in that.

holeyrivet
Will the resin hold up to some chemicals? Say if I wanted to use these for coolant pipes in a car? Also if I can suggest a topic for your next video, a motorcycle fuel tank? I’ve been want to do one for years but I really find any info on the subject. Thanks
Easy CompositesMatt
Epoxy had pretty good chemical tolerance and also a tube that's been cured at 120°C should have an operating temperature that's up to the 100°C you'd need for a cooling system. HOWEVER - continuous exposure to antifreeze and boiling water is not really what a carbon fibre tube like this is designed for and so I wouldn't recommend it. As for the motorcycle tank, yes, we'll definitely be making this video in the future. The trick is to use a tank sealer to protect the composite laminate from the fuel. Make sure you're subscribed to find out when we make this video!

AJ Hartman Aero
Nice video as always. When I did some tubes for my car I wrapped some extra tows around the ends to make beads, kinda like your step to pull it off if necessary. This way there's much less chance of a coupler popping off. My application was for car intake tubes that see boost pressure.
Easy CompositesMatt
Yep, nice tip and nice way to get a small, neat step on the end of your tubes. Totally makes sense.

R4M_InternetExplorer_EXE
There's any process like "Lost PLA" (used in greensand mold making) where you wrap the part you want and after it has cured, you apply heat or a chemical process to melt or dissolve the inner mold? This would massively help at creating very complex parts and never seen it done on carbon fiber
Easy CompositesMatt
Yes, there are a few 'lost' core process that can be used with carbon fibre, including low melting point alloys (like Wood's metal) and soluble core materials. We definitely hope to do some tutorials using one or more of these processes in the future.

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