Homemade Blank and all

After reading through several of the threads I got inspired to finally take on a full surf SUP build to include the blank (sorry its a SUP but I only surf them). This is a total science project for me like a super sized surfboard and one that I am willing to see through even if it crumbles to pieces. The Board- 8’9" x 30.75" x 4.15" at about 135Ltrs. 5 fin FCS II with FCS handle. Me- 6’2" at 210Lbs.
I was able to get 2" wide ultra light (like .5Lb) EPS sheet foam for this build. Its total junk… but its all i could find here in Japan. I laid the board design up in AKU like I usually do and printed off my rocker template and out line. I used the rocker template to cut a LOT of ribs out and used gorilla glue to glue it all up. Seemed pretty good except that I have a ton of air gaps from the glue not filling in all of the way. That leads to my first question… How bad will this effect the board after glassing? The board will have two vents, one in the handle and one stand alone vent either down by the tail or up toward the nose. Will it still gas off too much and separate the lamination?
So far I have built the blank and shaped the board (took forever with the light foam). I installed higher density blocks for the fin plugs. I have applied my first carbon rail. Pretty stoked and nothing unusual at this point other than the wicked soft foam.
So now I get into the real questions for the group.
Should I spackle the deck and bottom before lamination? I heard good and bad both ways so i need some input.
Next- I have access to 2.5mm ply that is pretty good stuff. Is it worth putting a piece on the deck? I also have a 5ft piece of carbon cloth coming in the mail. I was contemplating sandwiching the carbon and the wood. Is that a worth while idea or should I go with just carbon on the deck with two layers of 6oz over it? Im keen to try the wood especially on the ultra light foam. But don’t want to turn the thing into a tank and it not add any value to the finished product. Thoughts? I have a small amount of vector netting left as well but didn’t plan on using it for this one build. Bottom will have 6/4 schedule with a carbon strip full length.
I will be putting on the other carbon rail and cleaning up the foam inserts and /installing the plugs. More to come! Super stoked. looking forward to hearing folks thoughts!

Wow! I get annoyed having to glue in one stringer, let alone 15-16 ribs.
I would not add Vectornet unless it is early enough in the lam process that it gets buried in cloth and resin.
Big talk on SUP layups here : https://www.standupzone.com/forum/index.php/topic,27149.0.html

if it’s really 0,5 lb foam you must make a sandwich skin, only thick skin will résist buckling, such light foam can’t stabilize compressed skin and fight against dents. spackle with resin/micro slurry, far stronger than drywall spackle. on 1,2lb i use 2x6 bottom and i ll not go less but i don’t like the sponge feeling of too thin skin on eps like most of the super light eps/epoxy boards on the market (carbon warp, future flex, etc).

I think I am following you. Can shift to a slurry mix instead of sparkle. I don’t have any fancy vacuum gear to work with. All outdoor and very simple build techniques. I do have plenty of 6oz glass to use. I am already committed to carbon rails and can put a 3" carbon strip full length down the bottom. My main concern is the deck. I will be getting a large piece of carbon material 5ft long for the deck where my feet go. Just not sure of that will be enough with 6oz on the deck or if I should go with the wood on the deck.

without vacuum bag it will be hard to well glue wood. what you can do to had thickness to your lam is to laminate fiberglass with a resin slurry (epoxy/micro) then you spread over fresh lam more dry micro and pull off all micro that was not glue then lay another layer of glass and lam again. first layer and last layer have to be laminate with resin only and between layers with resin slurry and dry micro spread. do a carbon deck patch as first layer over foam then one layer 6oz glass only epoxy, spread dry micro over, lam an other 6oz with slurry, spread dry micro, lam an other layer with resin only let dry. if it’s not stiff enough do a carbon patch cover by pad.

If you can do wood on the deck, that would be the best. That ply will be strong, but I don’t know about weight. I can only get a 1/8" mahogany door skin ply here and it made the board heavy.
You might be able to get away with a thickened epoxy sealer then 3 layers of glass

Lamet, great idea. I never thought about that extensive of a lamination process but part of it might be necessary for the deck.
Shark- Yeah man I know the wood would make it crazy strong but your right… the weight is a major concern.
Right now I have finished the other carbon rail, installed the fin plugs and run my carbon strip down the bottom center. Next up will be lamination the bottom with two layers of 6oz. After that I have made the foam inserts for the handle and leash plugs to be installed. My carbon deck patch hasn’t arrived yet so that gives me some time before the deck is ready for lamination. And yes… I realize my rail carbon and bottom of the board look disgusting! Ha ha. I have no time for prettying it up when it will all be covered up with color in the end. Thank you for the continued input. Im all ears as I move ahead. Thoughts ideas feedback are welcome. At the end of the day its all for fun!

Got all of the plugs/handle in. Installed the carbon deck… had just enough to cover the entire deck of the board. Figured, why not?! My handle install was garbage job but got it done and cleaned up. Did the whole thing by hand since I didn’t have a proper jig… lame. Don’t have pics yet but I did the bottom lam as per previous discussion. Took resin and mixed cabosil into it. Painted the bottom of the board and then rolled the cloth onto it. Poured a bit more resin into it and let it be. I will sand the edges and then do the full lap bottom around to the top carbon. Few more steps to go on this one. This is the first full carbon deck I have ever done… not as easy as I figured.

So you’re saying do each layer separately using slurry to increase the distance between cloth layers because strength increases as a cube of skin thickness?

You can always go for a closed cell deck patch to protect the deck (well, hide the indentations, actually). Added weight countered by added float.

yes it’s an old tech use for windsurf and many other industrial builds. there is some variation, some with dry micro in fiber before lam, like sphertex, other with foaming resin or with projection of dry micro over wet resin. except dings, surfboards skin break because of buckling forces, every thing that increase flexural stiffness reinforced skin, each time you double thickness you x8 stiffness.

UPDATE- Red Board/ Lemat
After I glossed the carbon down to the deck I used Lemat’s idea on both sides of the board. On the bottom I mixed a slurry and did one layer at a time (2 layers total on the bottom). This made a huge difference! On the deck I mixed a slurry and covered the carbon weave before I put down the first layer of glass. I rolled the 6oz over the slurry and glassed it down with regular epoxy. Wow what a difference in the board! It is SO solid right now. Im totally stoked on how this is coming out. Great suggestion Lemat!! I am learning at the cyclic rate and stoked on this build. I have one more layer of 6oz for the top and then its on to color hotcoating over the black lam. I am going to go with a solid yellow and work on the burn through style. May look crap but its my vision and Im seeing this one through to the bitter end. Ha ha.
PS- It rained on the board last night after lamination, argh!! Ha ha. Luckily the resin was just past tacky and I was able to quickly scoop it up and get it into my small storage shed. I will follow up on how and if this has an affect. Seeing as how I plan to put another layer right over it I don’t see it being an issue but fairly stressful at that particular moment!

So checked the board this evening to see if the rain actually messed up the lamination… uh yeah. Bummed. That surface should be all black! Instead it has a white frosted look to it where the rain sat on it before I got it put away and dried off… fail on my part. Anyone have thoughts? As it sits it doesn’t seem to be terrible, but I have never seen it this bad even having worked outside all of these years. I planned to do the final layer right over it and simply seal it all up. Sound like a plan or is this something I need to investigate further? Again… rain onto semi cured epoxy… wow did not expect this result.

It can be one kind of blush. Take water with soap and clean the board with à scotch brit, rinse then dry.

Yes… that white stuff should come off without too much trouble. It’s definitely a good idea to remove it even if you will be adding color over it. It may affect the bond of the next layer. Otherwise - looking good!

I’ve made a ton of progress on the home made SUP. I got all of the lamination done and used a yellow to hot coat. The yellow didn’t make much of a difference with the black… oh well. Sanding went well. The board weight definitely shot up! I decided to color the final sealer coat as well to try and get the board more yellow. Seems to have worked. I definitely put the handle to far back. Hopefully the fins and pad will balance it out. The Cup/plug installs went ok. I had to dig a bit to get one of the fin plugs exposed but it worked out. I think this thing might actually work! Still have the bottom to sealer coat and its down to finish sanding.

Looking good Clint. Did the white stuff from the rain sand off easily?
Did you go straight yellow or a couple parts white and then some yellow?
I leave handles to the end, finding the balance point with fin-pad-leash. I don’t make enough (of anything) to know where they go ahead of time.


So the white stuff did NOT come off the board when I tried to clean it with soap and water. I ended up having to skuff the surface before finishing up the last lamination layer. I was both very surprised and bummed at my mess. Needles to say its all long gone now, but lesson learned. I did add some white to the final pigment with the yellow. It helped.
Yup, I should have waited on the handle!! So lame. Oh well. Hope the leash and fins and pads offset it a bit. Stoked to give it a go soon.

Bottom sealer coat done. Unfortunately, I have rushed this project in multiple stages along the way trying to hustle through the build. It has taken me about 45 hours to build this board from .5Lb EPS sheet foam to a completed board with carbon deck and rails, handle, front vent, dual leash plugs and five fin FCS II fin plugs. I got a second set of hands for the carbon rails and bottom lamination, rest by myself. She isn’t pretty just yet but very solid. I have some sanding to do but Im very close to hitting the water. I will post final weight once complete.

And of course… There is always a bug in the mix! Ha ha.

Finished the board and got her in the water. Final weight and dims- 22.8Lbs for an 8’10" x 30.9" x 4.2" 136Ltrs.
I am happy with how it came out but doubtful I will build another blank like this by hand. I ended up with about 45 hours in this build!! INSANE. Enjoyed the process though. I got an extremely cheap deck pad and threw it on so I could get in the water. I need to replace the tail portion with a pad that has a kicker. The bottom of this board is basically a Vee/ sipiral vee throughout. Not crazy deep but enough to get through chop and keep me stable on this board. Surfed well in choppy conditions and I was kinda surprised by how fast it is. Ended up putting a set of XL FCS II Performers in as a thruster set… perfect!
I have learned more on this build than I have on almost any other board I’ve made. Thanks to those that provided input and the motivation to even try this! Im so stoked that the board works and didn’t end up weighing 100Lbs!
Whats next? I have one more board to finish for a friend here in Japan and then its time to close down the shack and head back to the states!! Yew. Im pumped…my surfboard build price is about to be cut in HALF!! Thanks again guys.