Believe it or not, the glue lines add more stability to the core when compared to a single piece of foam. I showed you the boards Barry Snyder builds - he isn't adding tape or exotic layups to his builds.
You have a 7-3 length and a fat center. Even if you were only using a stringerless blank it wouldn't be that fragile.
With that said, I think you should use 2 layers of 6oz or (better) 3 layers of 4oz on this build in order to get to a good weight. You are building a singlefin, not a thruster. The way you ride those is to go for the big bottom turn, not take off diagonally and double pump on the face. Momentum is your friend, and it takes a certain amount of glide to get that smooth carving style going. An EPS build with a normal glassing schedule will feel more senstive and twitchy by comparison, which is good for actively surfing a thruster cluster. But not so good when you're going for smooth and you're letting that rail line do most of the work for you.
War story. Years ago I did a 7-0 singlefin egg using stringerless 1.5# EPS for the core with a 4#PU insert for the finbox, 4# PU rails and bamboo deck/bottom. I glassed that with a single layer of 4oz under the veneer and a single layer of 4oz over. So that's 2 layers of 4oz + the veneer which will easily have the weight of a 6oz layer. That build ended up being too light for the design. I ended up going back and adding another layer of 4oz top and bottom and THAT combo felt perfect. And it was strong. I passed it around to several people to try and everyone liked it for what it was designed to do.
The point being that too light can be a problem for singlefins if/when you're trying to ride them like a singlefin.
Really great info and insights as usual man, thank you so much. I think I understand what you're saying about wanting more weight on a board that I'm gonna ride as a single fin should be. I'ts counter intuitive for me because I'm a bigger guy (6'1" tall and 220lbs) so I'm always looking for more volume and less weight but what you're saying makes sense to me. I know you reccomend not doing anything fancy with paint/design on this board, but do you think doing some type of simple fabric inlay with a 6+4 fiberglass would make sense to add a bit of weight/strength to the deck? So far I'm really pleased with the work I've done on this board and I do want to make it look good, and also push my build skill limits a bit.
It's your board - you should do you. Nobody is going to hassle you for it. With that said, cloth inlays weren't part of the aesthetic for those boards. They were usually doing paint jobs or an occasional solid resin tint or opaque. If you google "1970s surfboards" you'll get a good look at what these boards looked like in their time.
The main reason we tell new builders to not get carried away with the cosmetics is because it adds another layer of complications to the glassing above and beyond trying to get a clean lamination. But in real life most new glassers end up doing what they want to do anyway. And like I said, it IS your board.
Well, I'm almost at glassing. This board is taking a long time, but significantly less than my first! I'm gonna go put a bit of work in today. filling the voids in those messed up horizontal glue joints at the top. Thinning down the nose and tail a bit. Getting the rails as close as good as I can. Should be ready to glass after today. Plan is to probably paint over the ugly horizontal lines with flat white house paint, and maybe...maaaaybe paint a stylized arrow on the deck.
I have a question about sealing the blank. I don't know anything about sealing, or how or why or if I should do it. If anyone can offer any suggestions on how I should seal the blank, if I should at all, and what to do it with I would really appreciate it. I want the glassing to be as good as it can be on this one.
Following advice on this forum I suppose im gonna go with a heavier glassing on the deck. Was suggested 2 layers of 6 or 3 layers of 4. Would 6+4+4 be too much?
Also also also: Does anyone have a template or exact dimensions for a fins unlimited fin? I bought the single fin box but I don't have access to any single fins to trace the bottom attachment bit, and have no idea what the exact specs of that should be.
Thanks all!! You people are amazing. Here's what it's looking like right now:
Before you do any glassing you will want to do everything you can to get the clean symmetrical shape. One bonus of using slabs to build your blank is that the glue lines are more/less consistent in their spacing, so you can compare where the glue line hits the apex of your rail on each side as one measure of consistency and symmetry.
In your blank the glue lines seem to hit the rail pretty consistently at the nose, but not so much in the tail. That demonstrates the left side near the tail doesn't match the right side. That's very fixable.
Another way to check symmetry is to take measurements on both sides every 3" or so, taking measurements on either side of the center glue line. Use a carpenter's squate or similar to do it - line up with the center glue line and measure the widths on each side at those intervals. I use I metric for those measurements because comparing and adjusting in mm makes it simple. You can run a line of masking tape on one side of the glue line and write your measurements there. If you can get all or your measurements within 1mm or so of each other from left to right then you'll end up with a pretty similar curve on both sides of the board.
All it will take will be a sanding block and some (long) gentle strokes to massage the wider side to match the narrower side. Move slowly because it's easy to go too far. You normally want to do this before you even start turning your rails, but you can also come back afterwards and tweak the rails to match.
Take your time. You're not punching a time clock on this process. It takes as long as it takes. You'll get faster as you gain more experience at it.
Good call dude. Looking at the top photo now I can totally see that the right side is wider/more rounded out than the left. I get excited and just want to move ahead but your advice to slow down is very good for me.
The conventional wisdom on it for us low-volume amateurs it is that you will NEVER regret taking more time on a shape. Just keep working it until it speaks to you.