Hi guys,

Hi,

Helmets are a funny one to give advice on, it's pretty important that they work! so to start I will say that you must test whatever you build and be happy that it meets or exceeds the performance required for what it is intended to do. - fortunately in you case the shell construction should be fairly easy to build to be safer than the 'standard' keeper helmet.

To keep weight within range you will want the shell to be no thicker than 2.5mm in the most part. - if you build it thicker of course it will be stronger but you will start to get pretty heavy! your main thing to consider is the fibre choice, for impact you are really looking at kevlar or diolen, the carbon will give you stiffness but can fracture more easily. You can select the outer layer for cosmetic reasons it will only amount to less than 10% of your total laminate thickness so choose whatever you like the look of! The inner layer would be best made from a heavy kevlar (like 300g) this will help stop any fractured laminate puncturing through.

So for arguments sake we shall say that we have a 200g 2/2 twill carbon on the outer skin and the 300g kevlar on the inner skin we have built up approximately 0.6mm of total thickness not leaving us with 1.4mm still available I'd look to go for a combination of carbon and kevlar here to take advantage of both the strength and stiffness maybe 2 x 450g carbon alternating with 2 x 175g kevlar would be a good place to start, so the schedule looks like this: 200g 2/2 carbon, 175g Kevlar, 450g 2/2 carbon, 175g Kevlar, 450g 2/2 carbon, 300g kevlar.

With regard to resin you are looking for something with a high mechanical performance the EL2 resin would be ideal for a high demand application such as this.

I can't stress enough the requirement for destructive testing, and a controlled manufacturing process (such as infusion), remember someone's trusting there life to your composites skills!

Paul Statham
Easy Composites / Carbon Mods - Technical

thanks a lot Paul for the information...

There are some small changes

Last time I took the weight of the helmet with the foam and so on still inthe helmet...

when the helmet is fully stripped the weight is only 347gram for the helmet and 125gram for the backhead protection

   

the mould is ready now and worked out nicely.

about your set-up of layers... does that makes changes now that you know the original weight of the helmet is less now?

I see you wouldn't use any fiberglass in the lay-up, do you have any reason why I shouldnt use it?

I ordered you sample package a while ago and I see a material with a mix of Carbon fiber and Kevlar woven together... would that make any changes to use that?

Hope I'm not asking to much questions

Ps, I'm filming the whole process of the mouldmaking and will also do the process of infusion en lay-up so at the end I will show you the entire proces in a youtube video

Kind regards Matthieu Libeert

Matthieu Libeert
Founder MAT2 Composites X Sports
website: www.mat2composites.com

Hi Matthieu,

It's nice to see your progress. Answers to your questions as follows:

about your set-up of layers... does that makes changes now that you know the original weight of the helmet is less now?

Basing your layup on the original layup (or material thickness) the helmet is a good starting point so if you've now established that the original used less material then you could adjust your own laminate accordingly. Like Paul said, these are starting points and testing will be neccessary to determine what's right in practice.

I see you wouldn't use any fiberglass in the lay-up, do you have any reason why I shouldnt use it?

Fibreglass is a fiarly low-tech reinforcement and if you're trying to make a strong, light composite you therefore wouldn't generally include glass in there. Carbon is stiffer than glass, kevlar is tougher; this means other than cost savings there is not much reason to use glass.

I ordered you sample package a while ago and I see a material with a mix of Carbon fiber and Kevlar woven together... would that make any changes to use that?

No, I think carbon/kevlar hybrid would make a good reinforcement for your helmet.

Ps, I'm filming the whole process of the mouldmaking and will also do the process of infusion en lay-up so at the end I will show you the entire proces in a youtube video Wink

Can't wait to see it!

All the best, Matt

Matt Statham
Easy Composites / Carbon Mods - Technical Sales

Hi guys, 

hi guys,

it's been a while but I have been quit busy for school and so on...

So I have all my materials... I have a 1m² Carbon fiber 2/2 twill 3k 195g

                                                       1m² Black Diolen 2/2 twill 200g

                                                       1m² Kevlar 2/2 twill 300g

                                                       1m² Carbon fiber 2/2 twill 12k 450g

                                                       IN2 Epoxy infusion resin 1kg SLOW

                                                       Clear Epoxy gelcoat 1.2kg

the mould has been sanded and pollished so the part is ready for infusion.

I would like some advice of you guys for the lay-up and where I should realy take care of... (I've doing some infusion and similar projects but this helmet looks quit a difficult shape)

this is how i guess i will do it:

1. mouldrelease the mould

2. apply the gelcoat

3. after a few hours the gelcoat will get tacky?! (it's the first time I work with the Easycomposites gelcoat)

4. apply one layer of Carbon 200g

5. apply one layer of Black diolen

6. apply one layer 300g Kevlar

7. apply one layer 450g Carbon

Some more questions and remarks 

-Will this be strong enough?! (must be quit stiff) the problem is I only have 1m² of each material and the pattern of the helmet is around 50cm-60cm (egg chaped)

-I will have some leftovers that I will use to reinforce on the important spots.

-I have some pvc core material 2mm I could use, would it be good to add this?!

-I also have the backplate of the helmet (small part attached on the back of the head) that I will do with wet-laminating and vacubag... can I use Infusin Epoxy for this?!

-Whats the best Allignment of degrees between the layer?

I hope some of you could answer my questions

Kind Regards Matthieu Libeert

Matthieu Libeert
Founder MAT2 Composites X Sports
website: www.mat2composites.com

new update on the helmet the backplate is ready 

Hi, Mat.

Too bad you had issues with the gelcoat.

I hope we'll soon see the complete helmet

 



 


    A $1000 electronic device will always protect a 10 cents fuse

will be up for next week I guess...

Hi Matthieu,

Nice project, there is nothing wrong with easycomposites gel coat, for sure may in your case you need let it cure the gel coat first before looking next step for wet lay up process. in the easycomposites video tutorial, matt perform how to use the compatible gel coat.

Regard

Leon