epoxy vs PU dimensions

General Discussion
1

hi, im new to swaylocks, and am exited to have access to such a great source of knowledge. ive been searching the forums for some time now and have had trouble finding the answer to this question, im going to be making my first board and im going to try to replicate my firewire shortboard, i want to make a PU board for my first shape, PU construction seems to be a little more straight forward than epoxy, i was wondering, do i have to change the dimensions on the PU board in order for it to ride the same as my firewire did? im 17 and am a auto collision tech so i have alot of expreience with sand paper and shaping, im thinking that making surfboards mite come pretty natrally to me (hopefully). im 6’4" 160 lbs (tall stick) and my firewire is 6’6 x 19 3/4 x 2 1/2.

Thanks!

2

Hello, IMHO no you don’t need to make any dimensional changes when making a PU or epoxy, however no matter what you do they won’t ride exactly the same! even if you got the shape identical it will feel a little different due to the composite firewire having more weight in the shell and less in the core. yes I think auto-panel skill would be very useful for getting a good finish on surfboards! btw surfboard design is very subjective and I’ve seen a number of posts from builders who do think that thickness changes should be made. But I base my experiences on riding tuflites and self built compsands. The tuflites were designed by famous shapers who didn’t seem to make dimensional changes and they went great.

3

I’m not really qualified to answer your query , but welcome to Swaylocks !

4

i have been told that you can go an 8th inch thinner on eps over Pu. so for your PU board you could add 1/8th+.

but im still a green noob. its just my 2 cents

5

those firewires are pretty thin and pack some buoyancy in them.

I’m sure someone who owns/rides a firewire could chime in on their impression of float.

my gut reaction is as the previous gentleman said…add some more volume to the PU board.

6

Around me, the old rule of thumb was take an 1/8 inch off the thickness for EPS. However, I think that rule came not from bouyancy differences between the two materials (there is none!) but due to differences in flex. The old epoxies were a lot stiffer, and making the board thinner gave it a more PU-like flexiness.

Today, I don’t change anything because of the availability of better materials.

7

Being 17 years old you should be able to paddle a bloody fence paling! And 160lbs is what, about 80kgs?

Don’t go any thicker than 2 1/2 especially with the other dimensions you’ve got. because for a young guy thats a lot of surfboard.

Of couse you ability will dictate your dimensions as well.But if you go any thicker and you surf a lot you’ll be shaping a new narrower thinner board very soon.

Good luck

Daren

8

thanks for all the info, ive decided to go with 6’4 X 19" x 2 3/8" (down sizeing a bit) i got a 6’6 ice9 blank and am going to start shaping right now! ill post some pics or somthin when its all done and glassed.

9

Hi wesman,I’m fairly new to shaping as well.I’ve made 1 poly board and am finishing up 1 eps/epoxy.My opinion is the eps/epoxy was cleaner and easier to do.You have alot more time to get the glassing right also with epoxy.I think with a good eps blank(1.5# to 2#) you may enjoy the shaping a bit more vs a poly.You could even go with a WMD blank from segway composites,you’d get to work a little with eps and poly foam to see which one you prefer to work with,you’ll have to use epoxy to glass it though.Epoxy=longer working time and no respirator while glassing,easier clean up.