Took my homemade $109 7’2" out today in about waist high waves and it did okay; got about 10 rides before getting run off by lightning. But I noticed that when I was riding it, the deck seemed “spongy,” almost like I was riding a soft top. Anyone have any reason(s) why it felt like this? Should I add another layer of glass where my feet are? I’ll list the vital statistics, and hopefully someone can tell me why about the spongy deck. By the way, my feet didn’t leave any dents though, and I’m 200 pounds. I purposely made this board thick and wide since it was my first and wanted to make darn sure it would float me. Nose-19" Width-24" Tail-16" Thickness-3" Rocker-Nose-3" Tail-2.5" Blank-Stringerless white EPS from Lowes Glassing-7 oz. on bottom and double 7 oz. on deck Resin-epoxy
The EPS from Lowes is 1# density and you need at least two layers of 7.5 oz. glass on that foam. That is why it’s spongy. 2# density you may get away with less glass. The dents didn’t remain because 1# has good memory. It will cave in time though.
Thanks for the info and advice. I’ll put another layer of glass on it ASAP. One other question-What’s going on when the epoxy resin has one thumbnail size spot where the resin didn’t totally harden, while the rest of the board hardens just fine? Does epoxy resin have to be mixed more thouroughly than polyester? (I try to stir my mixture at least 25 rotations, but it still happens occasionally.)
Yes, epoxy has to be mixed more thoroughly then polyester from what I’ve read. Then again, I’ve read anything from 15 seconds to 5 minutes of stirring for a good mix. Greg knows for sure. regards, Håvard
Keep working on it. You’re doing great, and by the time you finish you’ll have spent the same amount of money as you would have on a polyurethane setup. If it aint broke, don’t fix it.
But you see it is broken. Surfboards need a huge helping of experimentation and innovation. Cheap materials and easy access to them are key drivers of innovation. Rob Olliges
Not to mention that before too long the polyester stuff will go bye bye…
I have never worked with epoxy resin on surfboards. I do how ever work a lot with epoxys in my work. I have found that one of the biggest problems that you run into with epoxys is not mixing enough. My rule for mixing is mix until you get tired of mixing, then give it to someone else to mix until they get tired. That normaly does the trick.
Know a guy that builts boats, he uses a modified drill to mix the epoxy for ~10min. You prepare a batch and when it is ready you start working and mixing the next batch. He does save loads of time with that method (say 10 batches a 5 mins you have saved 50mins!!) If you mix up to 3liters an hour you better use a maschine, when you get tired you get lazy mixing throughoutly. Honestly for home use, building one board, take your time to mix 5 mins and your save. Wet is beautyful A kayak I did. 
Thanks for the comments/advice on epoxy mixing. Marcus, those are really nice looking kayaks, much nicer than that plastic 11-foot kayak I’ve got. (Retail-$600) I’m sure yours are much more…
Infact my boats are ~200€ +100h work [wink] At the moment I am building a squirt kayak (low volume ~130l) in trip building technique. Thats the 3DCAD model. The technique is muc like building a hollow surfboard, you built the hull on stations, the woodstrips are the core material, inside and outside the hull is then glassed. http://fluid.kajakworld.at/fluidworld3/3d/3d.htm 
Mr. Olliges is 100% correct. A reasonable quality $100.00 homemade surfboard for the masses would set surfing free once again. Let`s all just do it!
That reminds me I have got to head over to a local construction site. They should be just about ready to rip the foam out of the poured concrete foundation.
did you guys have any safety problems with the epoxy resin? I heard the fumes could give you a rash or somthing. just let me know what yo did.