Any interest in a build thread?

[Zerps]

Awesome! Cant wait to see what u put together.
Where do you get your blanks? Local or shipped?

[Surfdad]

That's a good question for many folks. I live about 2'ish hours from Santa Cruz so I can sometimes run down there and buy from one of the shapers or Fiberglass Hawaii. BUT most of us have to buy from a shop like Foam EZ or Fiberglass Supply.

The downside to that is the shipping. Can be as much as $100. If I have to order from one of those folks, I'll typically get 3 blanks because the shipping will be the same.

Something I have had good luck with is Craigslist. Folks that have acquired a blank or stopped shaping will unload them for cheap. I've seen them as low as $15. If you get a blank on the cheap and the owner doesn't know what it's made of I'll show you a quick test to determine it quickly.

So that becomes the first thing we need to decide upon. Blanks are made in two basic flavors (there are more like XTR, but they are really rare and esoteric). Those flavors are Expanded Polystyrene or EPS and Polyurethane or PU.

By number of units manufactured, Polyurethane is still the most popular material, but EPS is being touted as the material of choice by many. Personally I feel that PU is the easiest to shape and typically recommend that for folks just starting.

Now I am going to jump ahead and talk about one of the issues with the EPS foam itself. When you laminate EPS you have to use epoxy, whereas PU you can use polyester resin OR epoxy. So PU foam blanks are a little more flexible to use and sometimes are cheaper.

EPS melts when exposed to the styrenes in polyester resin, hence the need for epoxy. Styrenes are also present in spray paint and so guess how we can test the foam?

If you get a blank thru a friend and are unsure what it's made of, cut a tiny piece off and hit it with spray paint. If it melts - it's EPS, if it stay the same, PU! So here are some pictures of that test. The peanut shape is PU and the white is EPS and you'll see it all melted! That's the first post with regard to the type of material of the blank, we'll apply that test to the baknk in the picture. Can you guess what material it's made of?

[Guma]

A quick look at the two sites you put up for blanks, the shortest blank I see is 5'8". Do you special order shorter blanks for wakesurfing or just trim as needed?

[Surfdad]

Thanks for the question, I'm sure folks will find that useful and also thanks for following along.

I just trim as needed. Also those folks carry blanks from a number of manufacturers, so if you tell them what you WANT to achieve: I want a 5 foot board, 20 inches wide, 2 inches thick and with 3 inches of nose rocker they can usually find a kneeboard blank that is closer to your final dimensions, but you're still going to be mowing foam. On the foamez site, they should have PDF files of the various blank manufacturers, which would be more blanks they foamez has on their site. Worth looking into the various sites.

One company I know that manufactures wakesurf shapes or closer to them on a custom order is WNC. It can get a touch pricey, also I will show folks how to make their own blanks out of EPS at some point which can solve the blank availability issue. WNC will cut to your template and save it for reorder, so if you plan to do a bunch they might be the way to go. It's great quality foam and they are pretty good to work with.

[Zerps]

What kind of tools do you use to shape? Sure a planer would be great, but what kind of non power tools could be used?

[Fiveflat]

Wow, I missed this thread!

Thank blank actually came from usblanks.com and they let you come right to the factory and pickup at will call. They are only minutes around the corner from Disneyland

Awesome thread Jeff! Can hardly wait to see it come together!

[TigeTrojan]

Thanks for starting this. I am tuned in and anxiously waiting for more! Very excited at the prospect of making my own board . . . from my own blank.

[Fiveflat]

Is it gonna be like Josh's single fin throwback? Or is it gonna be a big 'ol round nose cruiser?

I'm too excited!

[Surfdad]

@ Zerp and Nick. An electric plane is what we'll use to mow a bunch of foam quickly, but a hand plane will be used to bring the wooden stringer down and a spokeshaven does the same thing up in the curved nose. The rest is sanding blocks and a surfoam. Another handy tool is a long handsaw. Outside of that it's mostly measuring tools. Calipers for thickness, level to make sure we haven't over-done it on one side or another. OH and a pencil.

[Surfdad]

Ok so we need to address one more item on the blank. As fiveflat pointed out, this is a US Blanks, blank and mostly they manufacture polyurethane blanks. They have introduced EPS blanks, but their forte was in PU. Blanks or really all rigid foams come in different densities. An typical PU blank in an ocean surfboard is about 3 pound per cubic foot. Compare that to the 1 pound density I use in most of my composite sandwich boards.

US Blanks gives this gradation:

•BLUE is considered our stock density and is the basis for comparison.
•GREEN, approximately 9% – 10% heavier than BLUE
•CLASSIC, approximately 30% – 32% heavier than BLUE. These blanks will be identified with a brown tipped nose.
•TOW-IN, approximately 205% heavier than BLUE. These blanks will be identified with a black tipped nose.

The blank in the picture has the "brown" paint stripe and so is the "classic" density. That is about 3 pound density. This is a good choice for a noncompetition wakesurf board. The Blue would be a contest level core and the Green something more durable, but lighter than their "average" density CLASSIC option.

The point being that most blank manufacturers offer different density foams, depending upon what you want to achieve and for MOST purposes the 3 pound density or "CLASSIC" in this blank is perfectly fine.

[Surfdad]

Fiveflat, it's your board 'bro! Did you want ot to be a single fin with a huge kookbox or just a cruiser? The rocker is pretty substantial and might lend itself to the single fin. Your call, what'cha want?

[IDBoating]

The point being that most blank manufacturers offer different density foams, depending upon what you want to achieve and for MOST purposes the 3 pound density or "CLASSIC" in this blank is perfectly fine.

I presume that each of us, your students, could choose the blank of our choice and as long as we follow instructions it wouldn't matter if we used different densities of foam?

[Surfdad]

That's a great question WA, thanks for following along and for the question. For the most part that is accurate. There is one area, though, where that doesn't apply and I'll try and remember it when I get further into the build this weekend. This blank is PolyUrethane. The manufacturer molds the blank by pouring in the chemicals, in a liquid state that then expand and turn into this solid foam. That process generates a TON of heat and causes the Polyurethane to form a skin on the outside of the foam that is a diferrent density than the core of the board. Also, Polyurethane tends to be MORE dense on the outside of the blank getting less dense as we go inward.

The higher the density of the blank, the more total area of foam there is to work with and still have a suitably dense foam to work with, as you go lighter, you'll not want to work down to far into the core, or that foam will get very light and possibly not suitable for the pressure from feet.

These blanks are referred to as "close tolerance" meaning there is relatively little shaping that NEEDS to be done before they are ready for applying fiberglass. Lighter density Polyurethane blanks should not be over shaped.

That concern doesn't apply to EPS foam blanks. EPS has a unifrom density throughout.

I'll try and remember to point out the differences between PU and EPS during shaping and laminating.

Thanks again!

[TigeTrojan]

This is great info, thanks again.

I imagine the difference in densities means strength as well. Is a blue density board at risk of breaking just from being banged around on the boat? Or is it just not going to last as long?

Some things get more expensive as they get heavier and some things are the other way around. Which way is it with blanks? (I tried to look that answer up on my own, but couldn't find price info on their site.)

[IDBoating]

That's a great question WA, thanks for following along and for the question.

And thank YOU for doing this! I was reading along in your response, had come up with another question, and then you answered it as I kept reading. You're a great instructor and I'm really looking forward to this project. Thanks again!