Attention backyard builders...I need help

I'd like to build a surfboard and need help. My idea is to make a smaller version of my Hyperlite 5'6" broadcast. I know I could buy the shorter version of the broadcast, but I would like to get the satisfaction out of doing it myself. Here are some requirements. It must fit into a standard wakeboard rack just like my store bought broadcast. It must be cheap, cheap, cheap! I have the time, but am a little short on funds. Here are my questions:

1. Can I build this out of the insulation foam that is used for residential home building and keep it within the thickness of my store bought board?
2. Stringer--Is the stringer just routed into the top or bottom of the board or does it go all the way thru with each half of the board glued to either side of the stringer?
3. Anything wrong with me using old wakeboard fins for this board? I want something shorter and more maneuverable than my store bought board so that I can do spins and such.
4. How much do you think this board will cost to build? Can you provide a cost breakdown?
Thanks for your input
Steve

Cool project! I'll attempt to answer your questions.

1. Can I build this out of the insulation foam.

It's possible, but the white insulation foam isn't the best, it typically contains reground material. The pink or blue insulation is XPS foam
and is known for delamination. There are folks that swear by it and folks that swear AT it.

For your purposes, you'll want a minimum of 2 pcf foam.

2. Stringer--Is the stringer just routed into

It goes all the way through. Matt S showed a good build where he used the factory cut edges of his foam to glue up to his stringer. Cut your foam in half, glue to the string with gorilla glue or epoxy. Common stringer material is basswood, but you can also use the luan door skin
from Home Depot. Any cheap plywood would work also.

3. Anything wrong with me using old wakeboard fins for this board?

I can't even begin to list the issues with using those, but...they are cheap. Single best thing you can do for your board is install decent fins, UNLESS you are thinking skimmer, in which case, that's the design they use, single trailer. You'll want to reinforce that area for the thru-bolts.


4. How much do you think this board will cost to build?

Foam 20
Stringer 8
Epoxy 45
Fiberglass 20
Supplies 20

What is that, $113? If you scavanged material, you can build it for under $100, I'm sure.

Hope that helps, and keep us posted if you decided to build!

thanks Jeff,
I was hoping you would respond. Follow up questions.
1. minimum of 2pcf foam. Is that 2pounds per cubic foot?
2. stringer thickness should be what?
3. With the stringer and 2pcf foam, can I build this and keep it skinny so that it will fit in my wb rack?

i wish i could build mine that cheap

Brewkettle, you could, but I'm suggesting functional materials rather than "top-of-the-line" materials. You aren't striving for the lowest cost.

Glad to help, Steve.

1. Is that 2pounds per cubic foot?

Yes, indeedy.

2. stringer thickness should be what?

If I were undertaking this build, trying to keep the board thin, I would go with a hefty 1/4" plywood, even if I had to make it out of several glued up layers of door skin.

3. With the stringer and 2pcf foam, can I build this and keep it skinny so that it will fit in my wb rack?

I do believe so, you'll most likely need to beef up the laminate schedule. Many of the high end skimmers are less than 1" thick. They contain no stringer material, instead substituting a higher density foam and 3 layers of fiberglass top and bottom. A surf industry standard glassing schedule is double 6 oz top, single 6 oz bottom. If you went with 3 layers of 6 oz top and bottom, you should have a sturdy board.

ok Jeff,
The local home depot has a foam insulation board made by owens corning called Foamular 150. It's an extruded polystyrene insulation board that comes in 1, 1 1/2, and 2 inch thicknesses. I cannot find the PCF rating of which you speak in any of the technical literature. I'm thinking this is the foam I need since I'm not going to be using the professional stuff.

As far as doing this as a process, my first step is going to be taking my store bought broadcast and making a smaller pattern to use to cut out my foam. I'll be making a pattern of the top/bottom and a profile pattern correct?

Next I plan to make my stringer and get its profile shaped properly before slicing the foam in half and then gluing the stringer in place. Good so far? Also, as far as resizing this thing, the store bought shorter broadcast board is 4'9" as opposed to my longer 5'6" board. Would you recommend that I build my homemade board somewhere around the 4'9" or would you go even smaller. I am 5'9" and weigh about 180. Again, I'd like a samller board that I can do spins on. Also, the boards are of similar width. Woudl you maintain the width between the longer and shorter board or would you keep the smaller one proportional?

Next question, is it possible to make an entire wakesurf board from materials found only at Home Depot? Including fins, traction, etc?




I know they don't have fins and traction pads there, but could McGyver (surfdad) do it?

NNNNOOOOOOOOOOOOOOOO!!!!!!!!! Just say no to XPS. We need a foam intervention! I'll feel guilty if I don't warn you about the XPS. It's co-polymorized with polyethelene, which NOTHING sticks to. The standard process is to strip the slick surface off with 60 grit sandpaper before you go to laminate it. IF it delam's, I will SO be point a finger and saying: "I told you so!" maybe even (nah, nah, nah, nah, nahhhhhh)

The pink is no doubt rated 25 PSI, which translates to about 1.8 pcf. That's pretty close, but I wouldn't scrimp on the stringer or lamination schedule.

For your size and weight, I wouldn't go any shorter than 4'6". I'm concerned about the fin choice, so I'd probably stick with your original 4'9" or maybe a 4'8". If you don't take the rails in a bit, it might look funny. It won't affect the ride, but I'd keep the width to around 18.5 to 20.0 inches. Lay it out on paper and look at it. If it looks weird, like it's too fat, reduce the width. I know, not very scientific, but honestly it always seems to work for me.

I don't know if you need a profile pattern so much. I would be careful of the rocker as you'll be shortening this board significantly and the reduction in rocker, may have you pearling frequently. I think I would adjust the nose rocker UP a bit and then just freehand that on the blank. Was I speaking English? As you reduce the length of the board, most likely taking it off the nose, that will reduce the nose rocker if you simply match it to the longer board.

So far so good, with the exception of the use of the dreaded XPSSSSSSSSSSS.

Hey dtw, yeah it can be done. You can get that bathtub stick down EVA for the traction. The flowers would be the best! My Home Depot carries crappy Epoxy and I think it's a 9 oz fiberglass - super heavy duty, but also kind of crappy. My local HD also carries both the XPS and EPS foam, and a Luan door skin for the stringer.

I would think the biggest challenge is locating the fiberglass, a slow enough epoxy and then the fins. Otherwise, it's a trip to TAP or a local plastics store for the fiberglass and epoxy.

Someone did an XPS build last year, but I can't find the thread now. I did have this picture of the stringer glue up, it might be a good resource if you can still find that thread.

I like flowers....

Nice clamps Jeff!

ok jeff, if xps is that bad, what alternative can be found locally (that is, not ordering a specialty board foam) that would be better than the construction foam and still remain cheap

Don't'cha just love tie downs, Chris?!

EPS - EXPANDED not extruded. It's the white beaded foam, most likely in the same Home Depot. Most of us call that white beaded foam styrofoam, when, in fact, the Dow Blue XPS is actually trade named Styrofoam. What you want to use is the white beaded EPS. If your local HD doesn't have it, an insulation contractor locally most likely will. Super cheap also, no doubt less than the pink XPS.

jeff, how thick of a block do you think I'll need for this. the local lowe's has it but 3/4 is the maximum thickness. still trying to lcoate an insulation supplier that might have a better selection

If you bend in your rocker, you can get away with two 1/2 thick pieces. Mix up so slow epoxy, slather it on one side of both pieces, and then onto the stringer. Lay it down on something solid like your garage floor. Prop up the nose JUST ON THE FOAM, so that it matches your the rocker in your stringer and then place some weight on the foam so that the nose bends to your rocker and jury rig some clamps to hold everything in place. Tie downs, heavy weights, whatever works. I'd probably use a foaming PU glue (gorilla glue) to attach the stringer to the EPS, just because it will fill in any irregularities.

Otherwise, just measure your nose rocker, add the deck thickness at the nose and that's how thick of a billet you'll need. For example: If you want 1.5" of nose rocker and the nose to be a healthy 1/2" thick, you'd look for a 2" thick piece of EPS (1.5 + .5 = 2). Hey I can still add! Depending upon your tail rocker you can actually reduce that number, but I find it easier to have a bit of extra foam to work with.

Jeff, so the XPS blue is no good, but the XPS pink might work?

Hey Joe, no...I'm sorry if I wasn't clear. Both the pink and blue are the same formulation, it's just that blue is made by Dow and Pink by Corning.

Greg Loehr is the purveyor of Resin Research epoxy, he also was a Dow distributor back in the day. This is what Mr. Loehr has to say about XPS and it's generally accepted by the industry:

"Another question in this tread was about Shulers foam being used by Patagonia and others. This is an extruded polystyrene (XPS). I was the Dow distributor for a similar product about 12 years ago. The problem we had then, and the problem that continues to plague it today, is delamination. This is caused by the fact that a significant amount of blowing agent is trapped in the cells during production. Blowing agent expands under heat. That's what makes it work. 95% of the blowing agent in EPS foam is lost during the pre-expansion process. 95% of what's left is lost in the molding or press cycle. With urethane the chemicals are being changed during the polymerization process and you end up with only CO2 left in the cells. But with XPS the cells are left filled with blowing agent gases. When these cells are damaged, and the gas released is then heated, a delamination or bubble forms under the glass. Also these foams are copolymerized with polyethylene which NOTHING sticks to. This makes the problem even worse. This problem has existed with XPS since Bob Simmons first used it in the 50's. Also the new Solomon blank is based on an XPS foam so don't go holding your breath on that one either. While it's true that these foams are superior as far as being water tight, today I'll go with EDRO EPS"

So the issue for us behind the boat is that heel dents, release the blowing agent and when you are in the boat, the temperature is HOT - causing the expansion of those blowing agents and subsequent delamination.

This should be "Surfdads' backyard builders tutorial" sticky...

Thanks dimitri. How have you been? I haven't "seen" you around in awhile.

I wonder if we should adopt some practice where if someone is doing a build, or showing a ballast install if we should start it with something like "RESOURCE: " that would make a search easier.



(Message edited by surfdad on February 05, 2009)

Great idea Jeff! But you always have great ideas, like tie-downs for clamps

Thank you Chris, that's very kind of you.

Seriously Jeff, you could start 90% of your posts with "RESOURCE"

thanks for sharing all your ideas...the only thing missing is the smell of resin while reading your posts

Good thread. I agree with Jeff -- The blue XPS is not desirable. But you CAN do it. Just shape your board (the foam shapes really nicely). Then as Jeff said - scratch the whole thing down with 60 grit (or even better 40 or 36 grit). You want all those deep scratches to provide a bond between the foam and the resin.

On the pic Jeff posted above, the better way would have been to cut the foam in half and flip the edges -- gluing up the outside (factory edge) to the stringer. But also, you'd want to scratch up that inside edge of the foam that is being glued to the stringer with probably 60 grit a bit.

Here's another pic of a glue up with EPS foam.
Funny thing is it seems totally McGyver'ed... but that is very similar to the way some of the "big boys" do it.