epoxy laps...

Hey guys… If doing a carbon deck/color bottom with a clear deck lam overlapping to bottom, should the overlaps be cut or freelapped??? I tried searching but couldn’t hook up on anything.

John, I understand the “carbon deck/color bottom” okay, but what’s a “clear deck lam overlapping to bottom”? Are you laminating a glass layer over the carbon deck layer? No color on the deck carbon will leave you with a black deck. Very hot, no? I’ve never used carbon before. Maybe somebody who has can jump in and say whether to cover glass with carbon, or vise versa. I’d definitely take the carbon to the lap edge and laminate the glass and carbon together for strength. Where will the color edge be? If you’re covering the carbon edge with bottom color, you could cut or freelap the carbon edge. Your choice, as far as looks go. I would probably try a reverse lap, laminating the deck first. I’d tape and cut the carbon lap edge at the flat-to-rail roll transition, then fill and sand the edge. I’ve pressed a smoothed glass edge into the foam. I like the way it keeps full strength to the lap edge.

Noodle - Thanks for the response. I was thinking of a tint bottom and rail with a cut lap. Considering the carbon deck within the cutlap (trimming it for a clean edge right at the rail overlap from the bottom) followed by a clear lam over the carbon and overlapping to the bottom. Wasn’t sure if a freelap from the deck using epoxy resin would be completely transparent on the bottom… maybe requiring a cutlap? Using Silane glass so I’m thinking a freelap would be OK.

John, I would cutlap the bottom glass first. I would treat the deck carbon just like I treat fabric inlays. I’d make an exact pattern out of tissue paper, laid on the board. I’d pin the tissue to the carbon and cut the carbon with rotary shears on a cutting board. That will make a clean edge. I’d place the cut carbon in place, and tack-tape it to the tint edge. I’d lay the top glass on and cut it. Lay the glass edges back, remove the tape, lay the edges back down, and resin it up. If you’re careful not to apply too much squeegee pressure, the carbon won’t move. The cut edge should help keep the carbon in place. Squeegee from the deck center to the ends. This way you’ll have a monolithic bond between the carbon and top glass… lots stronger. Good luck, Noodle

John, Thats a pretty unbalanced sandwich you are making. Let us know if you have any rocker changes or twisting problems once glassed. Sluggo

You may be right and I’m willing to listen to your argument. One problem I’ve been working on for some time is caved in decks. I’m convinced it’s not “overshaping”… check virtually any used board and you’ll see what I mean. My solution so far has been to beef up the glassing schedule on the decks with a hefty weight tax. If I can get a stronger deck and save some weight, I’m willing to try. As far as “unbalanced sandwich” - I don’t have the crushing problem on the bottom so why add extra weight there? Not sure I see the connection with carbon cloth and twist or rocker distortion.

I took my new 7’4" carbon fiber/balsa hollow out today for the first time…Noticable difference #1 - This beauty is stiff, not ride wise, but easily the strongest board I’ve ever had…No qustion about it…And my lightest hollow to date - 13#… The CF difference is so dramatic that riding is believing…I’m seriously questioning the flex theories that have been around for years… This board was so fast off of HARD mid-face turns that it blew my mind…No wasted energy in flexing and rebounding… And the life span of a board that doesn’t break down due to repeated flexing will be a lot longer…I think it’ll ride like a new board years from now… John… Do yourself a favor and use CF on your board, just figure out a way to keep it cool…Paint…???..Wood…??? Paul

Paul - I actually like the look and it doesn’t get that hot around here… definitely not like Florida or SoCal. I plan to keep it topside down unless it’s in the water. By the way - I finally got a listen to “Let’s Talk Surfing.” Great interview with you and Dale!

Oh Yeah…CF is more frayable than fiberglass…Heep it in mind if you’re considering it as a deck patch…I’d do a cut lap…

Twist is usually not an issue with epoxy because there isn’t the shrinkage that you have with polyester. This also reduces innerlaminate tension which is one of the things that reduces fatique, which will make Pauls board last for many years longer. Carbon also doesn’t fatique nearly as fast or as much in the end as glass. S-glass will fatigue 80% over it’s lifespan as opposed to 40% for carbon.

Holland isn’t very hot, but I had overheating problems with carbon. My advice, don’t make a black board, even with a little sun shine it wil become way to hot, wax would melt, or there might be some serious delaminating problems. Peter Rijk

Greg, I when I was talking about unbalanced I was talking about carbon on one side and fiberglass on the other. Even with epoxy, an unbalanced composite will create some strange distortions. Sluggo

Perhaps from use but not when the board is being produced. I’ve made over 20,000 polyester boards and I’ve seen twist and warped rockers from laminating, especially in summer. But not with epoxy.

Greg, In making composite parts, it is real important to have a balanced laminate (Im not talking about surfoards), otherwise you will encounter all sorts of twisting and cuping problems. This is not a resin issue I am talking about, but a fiber issue. However with your standard surfboards with a core that is several inches thick, and such a thin laminate of e-glass, one layer of glass on the bottom and 2 layers on the deck, the unbalanced laminate probably doesn’t cause much distortion. However if you laminate one side with carbon and one side in e-glass, I am curious if their is any movement. Sluggo

In the past it has taken multiple layers of glass on the deck to keep from caving in - a real bugaboo in my opinion. In my opinion a board should NOT self destruct under your feet in normal use. I’ve generally stuck with single layer bottoms. I have encountered twist but I thought it was mainly from the stringer torqueing after the board was shaped - before it was glassed. Would a single carbon layer plus one glass layer be as unbalanced as three glass layers?

Don’t know, Im just curious. Ive seen carbon prepreg panels with 1/2"honeycomb cores were they accidently did the same amount of carbon uni in three layers, and three different directions were they did the uni layers in the wrong sequence and the panel cupped. The uni carbon was very light weight. It’s easier to draw a picture of this, but oh well. I know we are talking about woven carbon and glass and not uni’s, but I am curious. Sluggo

A lot of that depends on the service temperature, the curing temperature(s), and the support of the part during cure. Your right about unbalanced laminations causing warping in parts other than surfboards. Again the shrinkage of polyester is an issue at about 8% whereas epoxies generally are less than 3%.