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VIDEO TUTORIAL

How to Make Carbon Fibre Sheet - 3 Alternative Methods - Video Tutorial

The aim of the tutorial is to show the ease with which high quality carbon fibre sheet can be made for both cosmetic and structural applications and to help guide your choice on manufacturing technique and material selection in order to produce a commercial quality sheet that matches your exact requirements.

Even if you don't plan to or need to make your own carbon fibre sheet, this guide should give you a better understanding of how carbon fibre sheets can be made and how factors such as fibre orientation and production method can significantly influence their behaviour and performance.

The three different manufacturing methods we'll be looking at to make our sheets are a simple hand lay-up process using dry carbon fibre fabric hand laminated using epoxy resin, resin infusion where we'll be using a vacuum process to infuse epoxy resin through dry carbon reinforcement and finally oven cured prepreg where we’ll use uncured prepreg carbon fibre, vacuum bagged and cured under vacuum in an oven.

Below you will find a brief description of the materials and process used in each of the practical segments of the video when making carbon fibre sheet. All examples are laid up onto conventional glass sheets which have been prepared with Easy-Lease Chemical Release Agent.

TUTORIAL BREAKDOWN

1. Hand lay-up

Two different hand-layup carbon fibre sheets are produced, one using 6 layers of 100g unidirectional carbon fibre and one using alternating layers of 210g 2/2 twill carbon fibre and 300g +/- 45° biaxial carbon fibre.

EL2 epoxy resin is wetted into the reinforcement using a laminating brush and then a layer of peel-ply is applied to the back of the sheet to allow excess resin to be squeezed from the laminate and also leave a bond-able textured finish.

2. Resin infusion

Two different laminates are used in the resin infusion demonstration, one using the same alternating layers of 200g 2/2 twill carbon fibre and 300g +/- 45° biaxial carbon fibre that are used in the hand-layup demonstration and the other using 6 layers of 650g carbon fibre. The sheets are infused using IN2 epoxy infusion resin.

The reinforcement is covered with a layer of peel-ply which is cut over-size to create a resin break before a layer of infusion mesh is positioned directly over the reinforcement. Resin infusion spiral and resin infusion connectors are put in place before vacuum bagging tape and VB160 vacuum bagging film are used to complete the vacuum bagging stack. Vacuum is supplied by our EC.4 compact composites vacuum pump with a resin infusion catch-pot in place to eliminate the risk of resin being drawn into the vacuum pump.

3. Oven-cured prepreg layup

A single laminate sample is prepared using a layer of our old Easy-Preg out-of-autoclave surfacing prepreg top and bottom with three layers of our old 430g Vari-Preg prepreg (two of them cut on the 45° bias) making up the thickness.

These pre-pregs have been superceeded by our XPREG range of carbon fibre pre-pregs.

The layers of prepreg are consolidated using a plastic finned laminating roller before being covered in a layer of R210 unperforated FEP release film. A layer of breather cloth is positioned over the laminate and into some clear space to the side of the sheet onto which a through-bag connector is positioned (our connector is fitted with quick release vacuum couplings). The sheet is envelope bagged using VB160 vacuum bagging film and sealed with vacuum bag sealant tape.

The vacuum bagged prepreg sample is then loaded into our soon-to-be-release OV301 curing oven to cure under full vacuum for several hours.

DISCUSSION (27)

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

Adven Ture27/11/2021

How about sheets requiring both two sides being the same high glossy finish?

Easy Composites› Matt

Making double A sided sheets is very difficult. We're one of very few companies that offer a double-A sided carbon fibre sheet but to make them we have specially adapted pneumatic heated platen presses which press prepreg carbon fibre between sheets of toughened glass. Other than sticking two single-sided sheets back-to-back, I'm not aware of any way to reliably make a double-A side carbon fibre sheet without this very specialist (and quite expensive) equipment.

Yaseen Mulla

Which one is having high stiffness and high strength?

Easy Composites› Matt

The stiffness and the strength of a carbon fibre sheet is most influenced by the reinforcement, then to a much lesser extent by the resin matrix and then to a lesser extent again by the lamination method. Given identical reinforcement (the carbon fibre) there would be no real measurable difference between the resin infused sheet and the prepreg sheet. The hand-laminated sheet would perform slightly less well on stiffness and strength owing to a lower fibre fraction (i.e. higher resin content) and some minor internal voiding.

JOAO FRIATAS

Have you done any testing with triaxial carbon fiber?

Easy Composites› Matt

Yes, certainly. You don't really need to 'test' a triax, or any other fibre orientation, you know what you'll get. In each direction that you have the fibre aligned you will be adding stiffness in that direction, but at the loss of stiffness in other directions. A triaxial fibre orientation (usually -45/0/+45) will give you 1/3 of the maximum achievable stiffness down the length (the 0 direction) and most of the remaining stiffness will be focused around torsional stiffness whilst making some off-axis contribution in the 0 and 90. There's a little more to it than that but that's the basics!

Gary Shehab

Can epoxy resin be sprayed instead of brushing resin?

Easy Composites› Matt

I can't think of many situations where spraying a laminating resin would be appropriate. For starters, the hand laminating process uses the brush action to help wet out the carbon fibres. Spraying resin directly onto dry carbon is likely to result in the resin just sitting on the surface of the fibre and not wetting it out properly.

Javid Shahmoradov

What type of glass sheet do you use, and what thickness?

Easy Composites› Matt

We use 6mm toughened laminated glass for our infused sheets. For pre-preg sheet you need a non-laminated glass.

Mike South

Can these same principles be used to make flax fibre sheets?

Easy Composites› Matt

Yes you can use these principles in this way to make sheet using natural fibres such as Flax.

Inacio Horta

Is there any problem using infusion resin for hand laminating?

Easy Composites› Matt

It's not a big problem. The main disadvantage to an infusion resin vs a laminating resin for hand laminating is that the very low viscosity of the infusion resin causes it to 'drain' down out of the reinforcement when trying to laminate on steep sides or vertical surfaces, causing the resin to pool/puddle at the bottom. For flat surfaces this isn't a problem and you might actually find that infusion resin makes a better resin for hand laminating in this situation.

刘亚星

Is this the same strength carbon fiber that would be used on a supercar?

Easy Composites› Matt

It's essentially the same carbon fibre as that used in some supercars. They tend to use prepreg or resin infusion processes (or derivatives of these processes) but, yes, this is in essence the same thing.

carbon xc

The finished sheets seem quite elastic, is there a standard tensile test?

Easy Composites› Matt

That's probably just the appearance these sheets give at the relatively thin thicknesses we made them. Carbon is - of course - a very high modulus material; however, when the sheet is only very thin and you bend it, you're only asking the fibres on the top and bottom to extend by tiny fractions of a percent which even carbon will do. There are lots of standard tests for composite materials - at Easy Composites we have a fully equipped state-of-the-art test lab where we can conduct pretty much any ISO/ASTM tests (tensile modulus, tensile strength, shear, peel, 3 point bend etc.). We plan to start producing some videos using the equipment in the lab quite soon so you would probably find these interesting. For what it's worth, you would see almost no difference in tensile modulus or tensile strength between any of the sheets made in this video because these two properties are determined almost entirely by the mechanical properties of the fibre. Since the dry fabrics and our prepregs are made out of the same spec fibre they would perform almost exactly the same on tensile tests. The biggest factor of all would be the fibre orientation whereby UD would far outperform woven or +/- 45'C bias orientation simply due to the fact that the fibres are all running in the direction that the test is being performed in.

Anil Kumar V J

an we make composite laminate in the combination of Carbon and Glass fabrics?

Easy Composites› Matt

For wet lay up or resin infusion, you would use the same epoxy resin. For pre-preg sheet manufacture, the biggest issue is going to be finding a source of pre-preg glass fibre as it is not very common.

brian boddecker

How thick is it possible to make carbon fibre sheets using the infusion method?

Easy Composites› Matt

In theory you could make sheets very thick - 10mm plus - however the difficulty comes in ensuring the resin is able to infuse throughout the whole fabric stack which can depend on a lot of factors such as flow media placement, how loose or tight the fabric weave is, viscosity etc. You also need to ensure the resin is slow curing enough to give time for the infusion to fully wet out the fibre before it starts to gel/cure.

GREGOR OSSAS

I want to build a carbon plate 400x400mm @ 4mm thickness, what materials would I need?

Easy Composites› Matt

Entirely depends on the method you intend to use and preference of cloth types. Our fabrics have the thickness listed in the fabric specification so you can use this easily to work out how many layers you may want. We would recommend using the thicker 450gsm and 650gsm cloths for some of the inner layers as it is a great value way to build thickness with less actual layers and also at a proportionately cheaper price. The finer details of the lay up is down to your preference and needs, for example, like in the video you may wish to add some carbon Biaxial cloth to improve torsional stiffness.

Jarko Konnenen

What would be best way to make a sheet with both sides similar perfect mirror finish ?

Easy Composites› Matt

You can do this with prepreg in one cure by sandwiching the prepreg between two sheets of glass, providing you use a suitable OOA (out of autoclave) prepreg, like our EasyPreg. An alternative method would be to make two single sided sheets, finished with peel-ply, and then bond them back to back.

Rami Rouhana

Is the prepreg sample as strong as the vacuum infused sample if the mesh layers are the same ?

Easy Composites› Matt

Yes, the mechanical properties of prepreg and resin infused sheet are virtually the same, if the reinforcement is the same. They will both have about a 60/40 fibre fraction and similar (low) void content.

Trump

How about wet layup with pressure during curing. For example, glass on both sides clamped together?

Easy Composites› Matt

You Could in theory vacuum bag a wet laid up sheet or clamp two sheets together. However care needs to be taken to ensure the force is even across the sheet and with vacuum bagging you need to ensure the right level of vacuum is used.

SURE D

Would 4-6mm UD infused sheet make a good print bed for a 3D printer? Temperatures between 40-120 C°?.

Easy Composites› Matt

The service temperature of 120°C is the main issue here; it would be possible to make a carbon fibre sheet with a 120°C service temperature but many resins would not be suitable. From our range, our XC130 UD prepreg cured at 140°C would give you a reliable service temperature of 120°C, the other systems (infusion resin and laminating resin) would not have the temperature range.

Chris Athanasopoulos

Say you want to make a 4mm thick carbon fibre sheet, can u use the hand lay technique instead of the resin infusion?

Easy Composites› Matt

Both techniques can be used for thicker sheets. With hand/wet lay, you will just need to take extra care not to put too much resin on each layer of fabric so that your sheet is not too resin rich.

MurphysLaw996

Is it possible to use vacuum bagging and get both faces finished? Or what method should we use to get both faces finished?

Easy Composites› Matt

Some people have had success this way although it is easy to get air trapped. Presses can also be used to achieve a similar effect, especially with pre-preg carbon fibres.

Phong Nyugen

I wonder if you can get more resin out with a thin layer of porous hard silicone rubber so it would dip in between the weaves?

Easy Composites› Matt

Potentially yes, subject to a bit of experimentation. However if the silicone dips into the weave pattern, the finished sheet would not be perfectly smooth.

Marc Cretten

What is your process to get both sides of the surface the same (smooth with gloss or matt)? Run two panels of glass in a vacuum?

Easy Composites› Matt

Almost. For a smooth double sided carbon fibre sheet we use a heated platen press with glass sheet both sides.

mirceaandreighinea

where do we place the simple wet lay vacuum bagging, what thickness to expect? is it the same with resin infusion vacuum bagging?

Easy Composites› Matt

Ultimately it depends on the level of vacuum used (wet lay vacuum bagging is only at partial vacuum), however the difference will only be slight.

Sushant Mhatugade

I want to make composite leaf spring from carbon fiber. Which method i have to use? Which type of carbon fiber is best choice for it?

Easy Composites› Matt

A leaf spring, if it could be made , would likely use mostly Uni-directional fibres for most of its construction. Resin infusion might be a nice neat method to make multiple leaves at once as you could lay up a larger sheet then cut and slice it to suit.

SAMUEL SANJEEV

Hey guys, how would you achieve a carbon fiber sheet of 2mm thickness with double sided gloss finish between two glass laminates through resin infusion?

Easy Composites› Matt

Double sided sheets can be very hard to produce with infusion. You would need an internal flow medium to allow the resin to flow. Typically a lot of double sided carbon sheet is made using pre-preg carbon fibre cured in a press to achieve the high gloss finish on both sides. The other way to do it would be to resin infuse two 1mm sheets (which would be gloss A-side on one side) and then bond them together, back-to-back.

josiah hoffman

What I'm wondering is how much of a weigh difference there is, provided that they all have the same reinforcement layup? How much heavier is the hand layup vs resin infusion vs prepreg?

Easy Composites› Matt

There's really not great deal in it. Resin infusion and prepreg will result in a fibre : resin ratio of 60:40, wet lay can be as good as 50:50 but is often more like 40:60. So, a 20% higher resin ratio (or lower fibre ratio) in the wet-lay sheet.

Lenmour Bell

I have a question about the infusion lay up. I realized you used a vacuum pump with a some kind of vacuum canister; how important is this, because when u did the pre preg lay up you didn't use the canister again?

Easy Composites› Matt

The 'vacuum canister' is a Resin Infusion Catch-Pot. These are used for resin infusion but not needed for prepreg because the purpose of the catch pot is to prevent excess liquid resin from being accidentally drawn into the vacuum pump (which would ruin it). With resin infusion, this is a risk because you have a supply of liquid resin feeding resin into the project which can find its way to the vacuum line and into the pump. With prepreg, there is a fixed, measured amount of resin in the laminate already and no surplus resin to accidentally get drawn into the pump.

Lucie Mulumba

I'd like to make 2mm thick panels using 0.3mm carbon fiber cloth and wet lay process. How many layers would you estimate I would need? Also, would squeezing the layers between two pieces of glass work in a similar way to vacuum pressing?

Easy Composites› Matt

If your layers are 0.3mm thick then you need 7 layers to get over 2mm in thickness. Depending on how well consolidated your layers are, you may find that 6 layers achieves the desired thickness, albeit the sheet will be more resin rich. two pieces of glass will help but you are unlikely to achieve as good a finish as doing it under vacuum.

Johanes Green

Trying to follow this tutorial I've had problems with the laminate sticking to the glass and also had problems cleaning the glass. I used LG 285 and HG 285. What do you recommend for cleaning the glass and what to use on the glass so that the composite won't stick to it?

Easy Composites› Matt

You will need to ensure you have a good application of release agent to ensure the resin does not stick to the glass. We recommend a Chemical Release Agent such as our EasyLease Chemical Release Agent which works very well on glass. You didn't mention which process you used for the laminating but certainly avoid waxes if you're using a high temperature process, such as resin infusion but generally speaking wax is not suitable for use on glass because it's actually difficult to get it to stay on the glass, this might well explain your problem. Use Easy Lease and you should be fine. For cleaning the glass (especially to remove old traces of release agent), Acetone or our Mould Cleaner would be best.