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Wrapping wood in carbon fibre. Answered


After cutting my own wooden lacrosse shaft using the tutorial on Instructables, it snapped within half an hour of use. Now I know this was because the grain was pretty poor and it was not a strong wood, but someone suggested that I wrap a shaft in carbon fiber so that it is slightly stronger, limits horizontal movement and reduces denting.

I just have a few questions about trying this;

Would this carbon fiber be appropriate for the project. http://compositeenvisions.com/raw-fabric-cloth-2/carbon-fiber-97/carbon-fiber-fabric-plain-weave-3k-5-7oz-tape-605.html if not where should I look?

The biggest problem I see is somehow packing the carbon tight around the shaft so there are no bubbles and it is consistently straight all the way down the shaft, there is a vacuum packing basics tutorial on instructables but I'm not sure if you could use that for a lacrosse shaft. Instead of making my own bag as per tutorial would just a plain bag (http://compositeenvisions.com/vacuum-infusion-equipment-71/nylon-vacuum-bagging-film-500.html) be fine then clamp off the unneeded extra, although are those bags re usable? Because I don't want to have to pay $5 USD every time I would like to wrap something. I saw something called bleeder cloth as well, would this be needed to stop excess resin sticking to the shaft?

When it comes to the carbon, I know someone who sails a lot and has some experience with carbon fiber but none with vacuum packing who said I should lay it up like the image attached to decrease horizontal movement while allowing vertical flex. Would this have the desired affect as if this is successful I plan to make a ton more for a high school team I help coach. I've attached a image to give you some idea of what I'm talking about.

Then for the actual laying of the carbon itself, a shaft is not a flat surface so you can't just pour it on like the Youtube video's I've found. I'm not sure how to pull this off.

Then afterwards, is there a simple way to test the properties of the shaft; specifically flex and impact strength. Because even if I don't end up wrapping the shafts I still need to test the wood to compare it to alloy.

Sorry about the small essay, but I would really like to give this a good shot. Because shipping shafts from the states is quite expensive, being able to make my own and then put graphics on them would be amazing.



5 years ago

Any carbon fiber mesh you get will be fine.

As for applying the carbon fiber and resin... First wrap the shaft with the fiber and cut it to size. You will want more that 1 layer and you will want to try to offset the weave on each layer for more strength. Cut each piece so the ends meet with no overlap. With everything pre cut you can start layering the resin and carbon. Use a paint brush to apply a thick coating of resin to the shaft. Wrap a single layer of carbon around the shaft. Use a rubber roller to ensure you get as much of the access resin and air bubbles out from the layer. Apply another heavy layer of resin and the next layer of carbon and role that out Keep going for all your layers making sure the seams of each layer are at different points so they don't overlap creating a weak point.

Now if you did a really good job of rolling the access resin and air out you don't need to vacuum it. But for best results you can get some heavy plastic and heavy duty double sided tape from the hardware store and create your own bag. Then use a good strong shop vac to hold it under pressure till the resin cures. Don't forget to use a release agent on the bag before wrapping your piece.

In testing the strength of the material you will need a force gauge. Laboratories will place the material in question under a hydrolic press attached to a force gauge which will show how much force it took to break the shaft. Other methods have the shaft between to stable points. The force gauge is hung from the middle of the shaft and weights are added to the gauge till the shaft breaks. It all depends on what kind of force gauge you have available to you and how you plan on applying the breaking force to the material. Specifically what forces are you having to measure. Downward force on a shaft laying horizontally will be different then downward force applied to the material when it's vertical.

But why go through all that hassle and expense when that kind of data is freely available online or through testing laboratories like UL who do this kind of testing all the time and have data sheets on the various materials you want to know about.


Reply 5 years ago

Thanks heaps for that, it was quite detailed and should help a lot in the process. I had a look for the wood data on UL and couldn't find anything (assuming http://www.ul.com/global/eng/pages/ is the correct site).

The other thing I forgot to ask about is which epoxy would be suitable for this project considering it's wood, a epoxy based timber sealant (http://www.epoxyglue.com/timber-sealer.html), or a laminate (http://www.epoxyglue.com/laminating.html).


Reply 5 years ago

You don't base the resin choice of the material your covering. You base it off what the carbon fiber needs. The carbon fiber isn't so much bonding to the pole as it is creating a shell around it. You want to use an Epoxy Resin. It should finish clear.