mb2778
Junior Member
Hi everyone, I'm new to the forum, but after searching through hundreds of older posts and finding answers to half the questions I had, I figured you guys seemed like the people to go to with a variety of questions I have regarding a new kayak project....
So, I'm in the process of building a 16' sea kayak that's meant to be nimble and light (ideally, under 40 lbs). The kayak design has been completed and CAD drawings are in the works. Once these CAD drawings are finished, the hull plug will be machined with a CNC router specifically designed to cut surfboard foam. I expect little trouble in the plug and subsequent female mold construction process, but have some questions about the process after this point.
I would like to vacuum infuse the boat (using West 107 epoxy, likely with 206 hardener) with an eye towards removing as much unnecessary weight as possible while maintaining stiffness and durability. To this end, I've been considering various lamination schedules but have yet to settle on anything. Short of testing each possibility, I'm not sure how to go about calculating the lamination needs, so I've pretty much guessed as to a lay up that should be relatively strong, stiff, and light.
I'm thinking I will start with a surface coat of epoxy mixed with graphite powder to provide some UV and abrasion resistance. I'm not exactly sure as to how I'll apply this considering the vacuum infusion. One possibility would be to coat the mold with the epoxy/graphite and allow this to gel before continuing with vacuum infusion under the normal process (i.e. lay up the various layers on the gelled epoxy). The other possibility would be to apply the surface coat after the boat is pulled from the mold, but I'd like to avoid this if at all possible so as to limit the number of hours spend sanding. The final possibility would be to allow the coat to dry significantly in the mold, thus providing a tack-free surface on which to lay the lamination, but I'm concerned about the bonding between the surface coat and subsequent layers if I do this. Are any of these methods preferable, or should I scrap this idea completely and go with a different surface coat? Ideally, I'd like the carbon cloth to be visible through the surface coat.
After the surface coat, I'd lay down a light layer of carbon cloth. I'm not exactly sure which cloth I should chose for this purpose, but I'm thinking either a 2x2 twill or two layers of unidirectional laid down either running at 0/90 degrees (i.e. bow to stern and port to starboard) or 45/45 (i.e. starboard bow to port stern, port bow to starboard stern). Can you recommend a particular cloth style/weight/or method for laying down the carbon? The goal is obviously to maximize stiffness in both directions.
Following the carbon, I'd like to layup a layer of Kevlar so as to provide some puncture resistance. Once again, I'm unsure what variety of cloth would be best for this application.
After the Kevlar, I would likely lay down some sort of core that would double as my infusion media. I'm drawn to Soric, but was wondering if this is the right choice (over infusionmat, divinycell, etc.) for core/infusion media. Once again, the goal is to minimize weight and maximize stiffness. My plan is to lay a core down in the entire boat, but I'm thinking it may be better in terms of weight to limit core use to structural reinforcements. If I do this, where would be the best places to reinforce? I'm thinking the entire cockpit area should receive a core and that a longitudinal stringer of core material should be run down the middle to add extra stiffness. I'm also thinking small strips of coring up the sheer would work well as stiffening ribs. I'm completely lost as to whether or not I'm going totally overkill in my construction or not. If I chose to use the coring in select areas, how do I promote good resin flow over those areas that do not have a core? Do I also add a flow medium over the entire hull after laying down the peel ply?
Would it be lighter to instead use a thin layer of fiberglass as the center of the sandwich?
Also, would it be better to selectively use carbon tape and no core to help stiffen the boat?
After the core material, I'd lay down one more layer of carbon (to take full advantage of the stiffening provided by separating the skins) or possibly Kevlar. Should I prefer one over the other for this inside skin? Lastly, I'd consider putting a very very thin fiberglass (S or S2) cloth on the inside to provide for easy sanding/abrasion resistance. Is this recommended and if so what style/weight glass should I use?
For the deck, I'm thinking one layer of Carbon on the outside followed by a layer of Kevlar and some reinforcements along the center, either in the form of a core strip or some carbon or kevlar tape down the middle. In the area immediately in front of the cockpit and around hatches, I'd add a layer of Soric followed by another very thin sheet of Kevlar to prevent buckling or oilcanning under the loads of a rescue.
I cannot thank you guys enough for your help! Hopefully after this project i'll be able to contribute some valuable know-how around here.
So, I'm in the process of building a 16' sea kayak that's meant to be nimble and light (ideally, under 40 lbs). The kayak design has been completed and CAD drawings are in the works. Once these CAD drawings are finished, the hull plug will be machined with a CNC router specifically designed to cut surfboard foam. I expect little trouble in the plug and subsequent female mold construction process, but have some questions about the process after this point.
I would like to vacuum infuse the boat (using West 107 epoxy, likely with 206 hardener) with an eye towards removing as much unnecessary weight as possible while maintaining stiffness and durability. To this end, I've been considering various lamination schedules but have yet to settle on anything. Short of testing each possibility, I'm not sure how to go about calculating the lamination needs, so I've pretty much guessed as to a lay up that should be relatively strong, stiff, and light.
I'm thinking I will start with a surface coat of epoxy mixed with graphite powder to provide some UV and abrasion resistance. I'm not exactly sure as to how I'll apply this considering the vacuum infusion. One possibility would be to coat the mold with the epoxy/graphite and allow this to gel before continuing with vacuum infusion under the normal process (i.e. lay up the various layers on the gelled epoxy). The other possibility would be to apply the surface coat after the boat is pulled from the mold, but I'd like to avoid this if at all possible so as to limit the number of hours spend sanding. The final possibility would be to allow the coat to dry significantly in the mold, thus providing a tack-free surface on which to lay the lamination, but I'm concerned about the bonding between the surface coat and subsequent layers if I do this. Are any of these methods preferable, or should I scrap this idea completely and go with a different surface coat? Ideally, I'd like the carbon cloth to be visible through the surface coat.
After the surface coat, I'd lay down a light layer of carbon cloth. I'm not exactly sure which cloth I should chose for this purpose, but I'm thinking either a 2x2 twill or two layers of unidirectional laid down either running at 0/90 degrees (i.e. bow to stern and port to starboard) or 45/45 (i.e. starboard bow to port stern, port bow to starboard stern). Can you recommend a particular cloth style/weight/or method for laying down the carbon? The goal is obviously to maximize stiffness in both directions.
Following the carbon, I'd like to layup a layer of Kevlar so as to provide some puncture resistance. Once again, I'm unsure what variety of cloth would be best for this application.
After the Kevlar, I would likely lay down some sort of core that would double as my infusion media. I'm drawn to Soric, but was wondering if this is the right choice (over infusionmat, divinycell, etc.) for core/infusion media. Once again, the goal is to minimize weight and maximize stiffness. My plan is to lay a core down in the entire boat, but I'm thinking it may be better in terms of weight to limit core use to structural reinforcements. If I do this, where would be the best places to reinforce? I'm thinking the entire cockpit area should receive a core and that a longitudinal stringer of core material should be run down the middle to add extra stiffness. I'm also thinking small strips of coring up the sheer would work well as stiffening ribs. I'm completely lost as to whether or not I'm going totally overkill in my construction or not. If I chose to use the coring in select areas, how do I promote good resin flow over those areas that do not have a core? Do I also add a flow medium over the entire hull after laying down the peel ply?
Would it be lighter to instead use a thin layer of fiberglass as the center of the sandwich?
Also, would it be better to selectively use carbon tape and no core to help stiffen the boat?
After the core material, I'd lay down one more layer of carbon (to take full advantage of the stiffening provided by separating the skins) or possibly Kevlar. Should I prefer one over the other for this inside skin? Lastly, I'd consider putting a very very thin fiberglass (S or S2) cloth on the inside to provide for easy sanding/abrasion resistance. Is this recommended and if so what style/weight glass should I use?
For the deck, I'm thinking one layer of Carbon on the outside followed by a layer of Kevlar and some reinforcements along the center, either in the form of a core strip or some carbon or kevlar tape down the middle. In the area immediately in front of the cockpit and around hatches, I'd add a layer of Soric followed by another very thin sheet of Kevlar to prevent buckling or oilcanning under the loads of a rescue.
I cannot thank you guys enough for your help! Hopefully after this project i'll be able to contribute some valuable know-how around here.
