How to Make Carbon Fibre Sheet - 3 Alternative Methods 

+Easy Composites Ltd Hey do you guys sell the little leak check valve?

Yes we do; we call it a 'Leak Flow Indicator'; you'll find it in our Vacuum Equipment category.

Easy Composites Ltd can you make karbon 0.8 mm???

Dear Sir , It was really pretty informative,We would like to venture in to manufacturing of carbon fibre. Would it be ok if we get in touch with you directly to enlighten us with you advice and suggestions. Regards Amiya Tripathy tripathy.amiya@gmail.com

Could you please demonstrate the strength of a single layer of ~100, ~160 and ~250 g/m^2 twill weave?

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@William Jeremias instablaster =)

@Van Anthony Thanks so much for your reply. I found the site through google and im waiting for the hacking stuff now. Takes quite some time so I will reply here later with my results.

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@William Jeremias glad I could help xD

+Andy McKee Thanks for the feedback Andy and thanks for your custom. We have some more videos coming very soon, within a few weeks!

Here are some good video too: ru-vid.com/show-UCXmPnjpQUpoPm7b_6oSdQ1g

A tip for you my friend (with the sincerest intent). Nobody needs a university or even high school education to make composites, but what will definitely erase any positive illusion of such "paper" education is using SMS shorthand, which stopped making sense when smart phones were invented.

Thanks Sean, be sure to check out our other composites tutorials too then, lots more to learn about :)

Thanks Rob, appreciate your feedback 👍

+WhirlybirdFlyer You're very welcome; we love making these videos and inspiring people to get involved - "March of the Makers" and all that. UAV/drones is a very interesting area for advanced composites so it's likely we'll be producing some videos on this subject in the not-too-distant future.

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.

Glad you enjoyed :)

Most Glass manufacturers and distributors should be able to supply you sheet glass in various sizes. You can use standard float glass as long as you are careful with it to avoid breakage.

Glad you enjoyed!

Demoulding while only part cured will almost certainly ruin the surface of the part and depending how far cured, it may well flex and fold.

Thank you very much!

Answering your queries in reverse, a scratched surface is not ideal as any imperfections will end up on the finished part; additionally, its much hard to release coat a mould surface with such issues so there is a risk that the piece will bond to the tool. MDF isn't a great option as surface porosity makes release agent application a problem but a sealed surface such as Melamine faced chipboard (as used for kitchen carcasses) or hard plastics should be fine with an appropriate release agent.

Wet lay tends to be the weakest due to the high resin content and inconsistency in layups. I've seen resin infusion and prepreg used high performance applications such as race car monocoques, but prepreg is the most consistent you can get with carbon and you'll get highest fiber to resin ratio and that'll result in the highest strength/ stiffness to weight ratio. That's why prepreg is used in fighter jets, formula 1 cars, etc

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. We do not recommend waxs as they tend to wipe off too easily.

Glad you enjoyed the video :)

We're more specialists in composites. We do have adhesives suitable for metal to metal bonding (both methacrylates and epoxies can be used) but I don't think this would be high on our priority list for tutorials. If you look on our website, you will see that the technical datasheets for the Permabond adhesives and the VuduGlu VM100 both include information (and peel/lap shear strength) for the adhesives used on different substrates (including different metals) so you should be able to find the information you're after there.

The sheet would need the temperature tolerance to work properly. It should be stiff enough.

Our stock sheets have some mechanical data on the product listing.

Hi Andrew, no, lack of air exposure would not slow down the cure. Once the resin and hardener are mixed they will cure, no matter what. Many processes we cover, including the resin infusion shown in the video, are 'closed mould' which means there's no face open to the air. For what you're planning, polyester resin will tend to be a bit faster than you'd want. Use a low reactivity catalyst or at least a low percentage of catalyst. Other than that, you should be fine.

@@easycompositestv Hi Guys, thanks for the reply. I did think about this after reading your reply and it makes sense now. I've been prototyping with your foam and made a small panel sandwich of 3mm foam in between 2 single twill plys using polyester resin and wow it's stiff. This has given me the confidence to continue my project using less carbon than originally planned.

+Glenn Laney Hi Glenn, using wet-lay it can be very difficult, if not impossible, to get a perfect finish using wet-lay. This is something that we've tried to be honest about in this video. With the right resin and a good laminating technique you can get pretty close but even making a single sided sheet, without vacuum, you are likely to struggle to achieve perfection.

One side glass is available, maybe you don't have a good control of resin content or temperature.

Hi Tonyo, yes, this should work just fine. Hand layup is rarely a *perfect* surface finish, as we tried to show in this video, but it can be very good if done correctly. Alternatively, you could buy a sheet of our ready made carbon fibre veneer, which is perfect, and then bond it to your plywood.

It is certainly an idea we shall bear in mind when we consider subjects for future videos.

You're welcome Ricky.

You wouldn't use a gelcoat for a prepreg but you could certainly use one for the hand layup and infusion processes.

So I assume you're asking about the cure of the 'prepreg' sheet. The temperature and the length of time will depend on the prepreg you're using. The prepreg we used in this video has been updated since we made the tutorial, it would now be our XPREG XC110 prepreg which has a final cure temperature of 120°C. You can find out lots more about the cure cycle for XPREG XC110 on the datasheet for the prepreg, here: www.easycomposites.co.uk/#!/prepreg/component-prepregs/xpreg-xc110-prepreg-carbon-fibre-22-twill-210g.html

Thank you

Hi C S, We recommend 6-7 coats on a clean, uncoated surface.

You could mould and make a cylinder by pretty much all 3 processes in the video once you have a mould. Rigidity is down to number of layers and orientation of the fibres.

@@easycompositestvthanks. I just started amateur rocketry, so I am considering carbon fibre for the large body and substructure

You can use the technique in the video for smaller sheets to achieve the same finish we did.

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.

Hi Chris, yes, we're planning to do an explainer video on composites sandwich panels and cored construction in the not-too-distant future so stay tuned.

There would be negligible differences between the two options; weight-wise, they should be much the same; the only difference in strength is likely to be as a result of the orientation of fibres but if all fibres were oriented at 0 & 90degrees, then the strength would be much the same as well.

@@easycompositestv grateful for your reply... you guys are amazing 👏

Hi Luke, yes, this is a fine plan. Uses folded metal as moulds works great. Laminating starter kit would be the perfect set of materials. The only thing I’d suggest would be to get a small bottle of EasyLease CR1 as your release agent. Although the laminating kit includes PVA release agent, this really won’t apply well onto aluminium and so would probably cause release problems. EasyLease would work perfectly on aluminium. You can even use two folded sheets and use them to sandwich your laminate in the middle, clamp the sheets together and you can get a smooth finish on both sides.

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.

Given enough pressure you could probably get a perfect finish in this way, yes but you really do need a lot of pressure.

Yes, but it will never be possible to have a perfect pinhole free cosmetic finish. Only resin infusion will give a perfect finish, but only on one side.

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.

Thank you very much! Great video and products you have, plus a very good way of explaining what's going on with those materials. Best regards!

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.

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.

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.

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.

I use glass for some things, thicker metal for others... I took the steel to a friend at the machine shop and had it lvld x2 those sandwich together well and i like how it holds and releases heat slowly for ramp downs

Mobile nambar kya he

Oven curing is only necessary when the resin cure profile requires it. Many resins are designed to cure at room temperature.

Would be very wasteful in most cases.

@@easycompositestv If you do it properly, you waste alittle but not too much. And if you get a clean piece of plastic, you can lay it on top of the last layer of Carbon and squeegee the resin out to make a super smooth finish. Did it with fiberglass a few days ago.

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.

Alright, thanks a lot for the info, I will give it a shot

In practice it is hard to get the air out and get a good finish that way.

@@easycompositestv Ah ok thanks for reply! 👍

We use a heated platten press with glass both sides Marc.

@@easycompositestv Many thanks!

The choice mainly comes down to what equipment you have, the size of the thing that you're making and the surface finish quality that you want to achieve. The idea of this video is to show the different methods and what results they will achieve and also how practical (time consuming) each of them is. We hoped this would then equip you with the information you need to determine the best method for your project.

Many use a pretty typical epoxy with relatively thin laminates to maintain flexibility.

+Leo Curious The trick to eliminating print through is to make sure your laminate is 100% cured before you release it and also to run your infusions a little resin rich (so slightly more than the optimum 60/40 fibre/resin ratio. Also, if you do use heat to cure, always make sure you release the sheet when it's cold.

A kevlar composite panel would be laid up in exactly the same way. The only difference is you need Kevlar Shears to cut the fabric.

The issue is likely to be your UD; when stacked up, the filaments of carbon interlock and don't allow resin to flow through; you would normally ned to use UD in single plies between layers of woven or Biax materials so as to allow the resin to flow through and around the fibres.

Time and temperature. Follow the cure time and temperature for the resin you are using.

+davidgruty Hi David, it depends on whether you can get the right spec sheet for your application. It would be unusual to find unidirectional sheet for example, or to find a specific hybrid fabric that you're after (carbon/kevlar or spread-tow etc.) so making your own sheet can be very useful if you need something that's available already.

+Easy Composites Ltd thanks for the answer

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!

The raw material is carbon fibre strands which are bundled into tows then used to weave the fabric cloth which you see in the videos.

For the scale of the sheets in this video, there would be no practical benefit. Potentially on large sheets you may initially save some time on wet lay sheets but it is not essential. Large 2m by 1m sheets can, with an experienced laminator, wet out a layer and spread the resin within a couple of minutes with a brush or roller so there is little time to be saved.

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

Dont have access to prepreg or a hot press though :( What kind of interlaminar flow media can you suggest please? because my required size is around 2 to 2.5mm and a lot of flow media in the market are very very thick. Any flow media that compresses inside the laminate?

That's easy for us, more details please visit www.xccarbonfiber.com for answer.

It really depends, there are lots of different areas of a bike frame, some with 10+ plies of 300gsm UD and other areas with only 3 or 4 plies. Have a look at our video on how to make a carbon fibre bike frame, that should tell you most of what you want to know : )