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Carbon/Kevlar, Carbon Fiber and Glass on the Petrel Interior


You don't need to see more sanding, but that is what needs to happen before glassing the inside so I kept the sanding footage to a minimum in this video. Next I added a fillet in the chine. The Petrel has a hard chine aft of the cockpit, while it doesn't need a fillet adding one will strengthen the corner and make it easier to lay in the fabric. Zip-lock bag makes a good piping tool to squeeze a controlled bead of thickened epoxy into the chine. The epoxy is regular epoxy with wood flour added to the point of peanut butter thickness. This bead of "dookie schmutz" is pressed into the corner with a plastic picnic spoon. I then scrape the excess schmutz off with a plastic squeegee.

I found a Carbon/Kevlar Hybrid cloth with pure carbon in the warp and pure Kevlar in the weft. This means that the carbon runs down the length of the roll and the Kevlar runs across the roll. A strip planked boat really needs most of its reinforcement across its width and the carbon provides the most reinforcement. The Kevlar serves mostly to hold the boat together if it receives an impact that breaks the carbon and it will still do this when it is running lengthwise.

This logic means that I roll the cloth across the boat and cover the inside in several pieces. In an open canoe I might not like the resulting overlapping areas, but in a closed kayak it won't be very visible. One benefit is rolling it out this way is much more efficient with the cloth than going down the length of the boat in one piece where you need to cut off big, long pieces off either side.

I laid the cloth right in on top of the wet fillet. I could have let it dry but then I would have had to sand the fillet smooth. Laying it in wet requires a little care that I don't press the cloth too hard into the soft fillet and make a mess of it, but the results are good.

The Carbon/Kevlar cloth absorbs more resin than fiberglass and is thus a little heavier. I keep spreading the resin around, allowing it to soak in slowly and then squeegee out the excess. The cloth absorbs slowly relative to the glass, so you need to be sure it is completely saturated before you quit.

I have the shop heat turned up high (85° F - 30° C) to lower the viscosity of the resin, but this also makes the resin thicken up quicker so I don't wait to wet out the whole boat before squeegeeing, I wetout a section then squeegee each. I'll come back later and double check for dry spots and add resin and resqueegee as needed. You will notice that the cloth does not change color much with the resin, but it should be dark and barely glossy when fully saturated.

The deck gets a section of carbon fiber around the cockpit and then glass on the ends. The carbon is wet out in the same way as the hybrid cloth but due to the complex shape of the cockpit area it takes some care to get the fabric to comform. Dabbing the cloth with the brush instead of stroking the surface helps prevent it from getting too distorted.

Notice how much faster the glass wets out. A quick swipe with squeegee to push some resin over the surface and the job is almost done.

Squeegeeing into the grunge cup will pull the cloth tight and on the inner surface of the boat, this can cause it to lift off the surface particularly in sharp interior corners and chines. This causes "bridging" where a bubble forms under the fabric.

The natural inclination is to use your squeegee to press the cloth back into the chine, either that or you will want to load up your brush with resin and paint more resin into the bubble. These obvious solutions rarely work. Since the squeeging pulled the cloth out of the corner you need to feed cloth back into it. You will notice that I press the brush into the fabric above the offending bubble. This slides cloth down from the free edge and fills in the corner with cloth where enough resin that is already waiting. A couple more swipes with the squeegee removes any remaining excess and further sets the cloth tight against the wood.