Hello, I am interested in purchasing the kits to build a skid plate outof carbon fiber for my moto...sure, it probably costs less to buy one from amanufacturer but, I thought it would be a good project to learn how to make itmyself...I am just not sure how many layers of carbon fiber or kevlar I wouldneed to use. Any suggestions, would be appreciated. Please remember, the bottomof a motorcycle (offroad) will take some hits on rocks or dirt. Also, thefinish, do I just apply a clear coat of paint? (Great tutorials and website!!)Tank you!! Miguel

Hi Miguel,

Thanks for your enquiry.

You don't mention whether or not you have got a mould available for this project (or even an original part to use as the starting point) but I'll assume that you've got the shape that you want to make carbon/kevlar but no mould. If this is the case my suggestion would be as follows:

If the size of the part you want to make is less than about 30cm x 30cm then our Epoxy Mould Making Starter Kit would be perfect for making the mould itself. If it's larger than that then we either have our Large Epoxy Mould Making Starter Kit (which contains enough material for just under 1sqm of mould) or you could even take a look at our Uni-Mould system (if you want to make lots of moulds for other parts on your bike).

Once you've made your mould then you'll need the resin, reinforcement and tools to do the laminating itself. For a skid-plate on an offroad bike you'll certainly need a decent thickness of material to give you the impact protection and strength that you want. I would expect something like 5mm of kevlar reinforcement would be about right. Kevlar would certainly be the better choice material over carbon fibre but if you want to include some carbon/kevlar hybrid then this can be used in just the same way.

I would strongly suggest making the very bottom layer (or bottom 2-3 layers) of reinforcement out of pure Kevlar - since this will be subjected to frequent impacts, kevlar will hold up a LOT better than carbon.

Our 300g Kevlar works out at about 0.4mm per layer (in a finished laminate) which means that to make a 5mm thick plate you'll need about 11 layers of the kevlar.

I would suggest our EL-2 Epoxy Laminating Resin as the resin you use for this part. It wets out Kevlar beautifully, cures quickly and cures very strong. You'll need about the same weight in resin as you have in cloth so if you buy 3m of 300g kevlar (900g of kevlar) then you'd want 1kg of resin. Allow a little extra for the pot/brush etc.

Also, thefinish, do I just apply a clear coat of paint?

My suggestion would be just to leave it as it is (after trimming it). If it's going to get bashed by rocks then there's no point in painting it, only to have the paint chip off!

I hope this helps, Matt


Matt Statham
Easy Composites / Carbon Mods - Technical Sales

Matt,

Ireally appreciate your information and suggestions, they're very helpful. Justa few more questions (sorry). Does kevlar have the same weight savingscharacteristics as carbon fiber? Also, if I wanted to make the "look"of the skid plate or outer layers to be out of carbon fiber but, reinforcedwith kevlar, would I use the same epoxy laminating resin and how many layers ofeach material would you recommend (11?)?

Bythe way, I will be ordering the small mould making kit as I dont have a moldyet, only the bike. How would you suggest transferring the bends and shape ofthe bottom of the bike without some of the irregularities of the partsunderneath the bike?

Thankyou very much!!

Ican't wait to begin...

Miguel

Hi Miguel,

Answers as follows...

Justa few more questions (sorry). Does kevlar have the same weight savingscharacteristics as carbon fiber?

Kevlar is a stronger reinforcement than glass and so a kevlar reinforced part will be stiffer for the same weight than a GRP part. It's not quite a 'stiff' as carbon fibre (which has the highest tensile strength of all those materials) but it does offer a much better abrasion and impact resistance. It's also a low density material which means that for a given thickness of laminate it will result in a light part.

if I wanted to make the "look"of the skid plate or outer layers to be out of carbon fiber but, reinforcedwith kevlar, would I use the same epoxy laminating resin and how many layers ofeach material would you recommend (11?)?

Yes, the resin would stay the same. If you want the outer layers to be carbon fibre then this is no problem, just make the first and last layers carbon (or carbon/kevlar). To do this, just substitute the first and last (meaning 9 layers of Kevlar, 2 layers of carbon (each side)). It does depend of course on what thickness you want the laminate to be - I only guessed that 5mm would be appropriate.

How would you suggest transferring the bends and shape ofthe bottom of the bike without some of the irregularities of the partsunderneath the bike?

I would suggest using something like some a thick sheet of sheetwax smoothed and pressed into place on the underside of the bike to create a nice regular contour on which you could base the sump guard/skid plate. Here's a link to the sheet wax on our site. I would think that a 2mm sheet would be good, 5mm would be another option.

All the best, Matt


Matt Statham
Easy Composites / Carbon Mods - Technical Sales

Sheet wax! So this stuff if flexible enough for me to shape to somethign but strong enough to make a mold from?



If Brute Force Isn''''t working your not using enough...

Depends what you mean by 'make a mould'... You can make a mould by taking the mould from the wax, but you can't really use the wax as a mould to make a part, unless it was a total one-off because the wax normally gets destroyed when it's released from.

It's really pliable, you can easily get it to follow the contour of something like a wing mirror in one piece.

The most common application for it is to make a mould for a 'shell' to cover something; going back to the wing mirror for instance, if you wanted to have a mould to make a cover that goes over the existing mirror, the mould must be bigger than the original part so that the inside of the cover is not smaller than the original component. Applying say 1mm sheet wax over this part before making the mould will make the mould that little bit bigger to allow for the thickness of 1mm for the carbon part.   

The sheet wax does not leave a perfectly finished mould, it would be usable but a small amount of sanding and polishing will be needed if you want a great flat gloss, for this reason I would always recomend a double gel-coat so there's no risk of 'breaking through' the the mould backing.

Paul Statham
Easy Composites / Carbon Mods - Technical

I see it's more of a spacer than anything for making a casing or cover for something.

The wax simulates the thickness of your carbon shell, then you can make you "Mould" and have the clearance you need to fit over your casted part.



If Brute Force Isn''''t working your not using enough...

Yeah that about sums it up!

It's also great for making bariers around a part for the flanges on a mould.

Paul Statham
Easy Composites / Carbon Mods - Technical