Rail Channels

General Discussion
1

The new design for my yearly two boards is shaping up. they’ll be 10’ EPS, full Carbon (2x 4.8oz top, 1x4.8oz bottom) with (Harbor)nose rails and rail channels instead of a stringer.

I used nose rails on my first board that I made last year and like them. I’ve read (here) about rail channels used instead of a stringer. I’ve come up with two channel designs.

(refer to Cross Sec. drawing, hope they turned out OK)

a. Is the type of channel that I imagined Greg L. described (here on SL). Use a dowel with sand paper wraped and rub on foam till 3/8" deep. Glass such that top groove can be felt.

b. After shaping and before glassing cut ‘V’ in foam, lift out ‘V’ and glass leaving 1" lap onto deck. Put ‘V’ foam back in and glass all of deck.

Both types of channels would be parabolic (?) following the rail line as in Deck drawing (red lines).

I’m looking for feedback from ALL of you experienced/knowledgable shapers/designers/thinkers!

Thanks (in advance!)

Les

2

Woops! Where are the drawings? I’ll try again here…

3

Sorry, the cross section drawing was too small. Here… this should be visable.

Les

4

See attached, (sorry, I’m in the way, I’ve been meaning to take pics of just the board, but laziness intervenes, never do today what you can put off till tomorrow…some photo guy took these and put em up on the web…)

I put those in with a 1 inch diameter dowel, 2 inches long, ends well rounded off to avoid catching the foam, with 80 grit glued to it… taped a line around the rails first, then started running the dowel smoothly just to the inside of the tape line until I had a groove going. I then removed the tape and took them down to an acceptable depth (i think around 3/8 inch, just before the sides became vertical). As in most shaping steps, long, smooth strokes give the best result. I then took a screen and went over the rims of the channels so that they were rounded as well–remember, sharp edges are harder to glass, sand, etc. and may not be as strong in this application. The V idea would probably be harder to glass as well, and cutting the EPS with a razor will be problematic, because of tearing.

Glassing went as Greg says in the archives, just forget about them till everything else is done, then gently run a thumb down the channel, pressing the glass down into it, and squeezing excess resin out onto the rail, where it can be collected with the squeegee or run off the edge. This step also will tighten your laminate up an extra notch, which is nice. keep the power sander away from the edges, because of burn through, just sand by hand, with sandpaper wrapped around a finger or thumb.

They are really neat, I find that they give a pretty good handhold when duck diving/getting up.

wells

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Hey,

I used rail channels on my eps no stringer deal as well. Did them as wells did his(G.Loehr…) and they came out fine. One thing though ,I thought I read here that on boards longer than around say 6’-7’ that you NEED the stringer for support/structure. That boards longer than that would tend to snap easily? Maybe the carbon would provide the support needed? Someone with more experience will chime in…Wells have you built them longer than in the pics(no stringer…)?? Curious…peace and waves…

Sean W.

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good point,

No, that’s my only one, and it’s only 6’2"…

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Rail Channels in the shaped blank … See attached photo

8

Damn hotcoat, that thing looks remarkably similar to my little fishy. You can’t tell from the pics, but my channels taper off as they approach the tail as well…I brought mine together on the nose, though. Cute board…

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The channels look pretty neat. But just a thought - what effect would be achieved if they were on the bottom? How would that affect the boards performance, particularly on a longboard?

10

Another Pic of my new fish before glassing . It does have a stringer and will be glassed in Greg Lohers epoxy . eps blank the builder “artist” I think also uses Syntech . A special cloth that also adds strength.Gonna be real light and Strong … He made this 6’6" for me . I’m 200lbs and 49 yrs old and like all my boards a little bigger . Can’t wait to try it … maybe soon with the tropical outlook here in Florida

11

I’m in the process of getting my materials act together to shape a 5’5" Lis Fish and using a pair of 2" thick eps planks for the core … spoke a few times with Greg Loehr about stringering versus rail channels and he said “why not use a sandwich stringer?” - a 6" width of 6oz cloth sandwiched down the center, between the planks, all bedded down with RR epoxy … I can even coax in a bit of rocker during the setup. Greg sez this’ll be every bit as strong as a stringer or rail channels. This sounds very appealing to me - I’m gonna try it.

Personally, though I know they work extremely well, I just don’t think I like the aesthetic look of rail channels. YMMV.

12

Wells…thanks for the how-to and Sean…Rail only for short boards? Damn!

OK, I’ve read that the wood stringers don’t work that good they are just left overs from days long gone. The board breaks from the rail, the fibers of the wood stringers are not lined up to create strength…

So what about a carbon fiber ‘I’ beam stringer? Cut the blank down the middle, wet out two layers of CF, place in foam and have 1" hang out (deck and bottom side) to lay flat. The CF ‘I’ beam would be connected (much better!) to the deck and bottom when glassed. And, to address the breakage from the rail, use rail channels also.

Les

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Hotcoat, Is that a Steve Forestall(sp) ? Looks very similar to the ones I have seen by him,nice board. The “I” beam seems as if it would work,though I like the idea above from G.Loehr. 6" carbon strip between the cores.

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Below image is what Sean (Oceans23) wanted to post (above) …

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Wells, looks like some good stuff there!

Can you tell me a bit about your foam you use- specifically density and bead size?

Thanks!

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Did you mean me, or hotcoat? His is the one in the shaping bay…mine’s the blue one at the top of the thread…

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You, Wells. thanks

If hotcoat would like to add his info, it would be appreciated too.

18

I was afraid you’d say that…

That, friends and neighbors, is extruded dow blueboard, Styrofoam brand rigid insulation foam. That’s right, the dreaded “dead horse” of surfboard foams. After reading all the invective about how it delams, I went ahead and got some anyway. Hell, at $30 per blank, how could you lose? I took some steps to counteract the delam issue, and figured that since I live in san francisco, and it won’t get too hot, I stood a chance of pulling it off.

First of all, that stuff is dynamite. It shapes similar to clark foam, it tears a little, but a gentle touch remedies that. It’s strong, resilient, and light. I grooved the surface with razorblades and squeegeed epoxy in there hard, which in my peel tests seemed to stick the glass down real well, even tearing out big hunks of foam when I peeled them up. When the thing was finished, I loved it. light, stiff but springy, and bombproof. I even stood on the upturned bottom and jumped up and down so that the rocker was being mashed flat on the ground. Not a scratch, no pressure dings, and it sprang right back into shape.

Well, the jury has been out the whole summer, and I surfed that thing really hard. I even put a ding in the tail, and left it open for a week, laughing at the fact that the foam didn’t take in one bit. It was dry 30 minutes after I washed it out to repair it.

Now, the jury hasn’t given me a verdict yet, but none of them will look me in the eye.

I started to notice a soft area in the tail, on the deck, right where my back foot goes. Ah, normal crushing, I thought. Well, the soft area spread, and now if I flex the board really hard, it wrinkles up a bit, almost all the way across the board. Delam. Rats.

So I’m gonna have to reccomend against using the foam. It wasn’t a total loss, I got a good summer out of it and that board is still magic (it’s my third backyard board, I’m quite proud of it in spite of the Achilles’ heel) and I’m sure I will be able to keep it alive for quite a while, but it won’t last forever (sigh). The good news is I can always shape another just like it…anyone know of an EDRO foam distributor in the bay area?

Wells

19

Wells, thanks for the info (and for sticking out your neck concerning the dreaded foam!). Sounds like you are an experimenting soul, and good on ya for that!

Which DOW product was that? The blue XPS board that one would find in a Home Depot or Lowes, or was it the “Surfboard” board (which is not carried/stocked and would have to be a special order)?

I have been having problems finding a suitable source for EPS in my neck of the woods. I went so far as to put an order together and was about to give my CC# to the company when I was told “oh yeah, this has to go to a commercial address” (when I was assured that they would deliver to a home address when I initiated contact with them). So now I have to figure out what exactly constitutes a commercial address (since this is personal use, I was to avoid having it shipped to my place of work… perhaps they will deliver to my friend’s surf shop… but in the end, what the hell is the difference, really?

For those reasons, I was thinking of just trying to get some over-the-counter foam somewhere and having at it, knowing full well my board would prob not last that long (considering my lack of experience shaping, I figured it would not be a big loss anyway). Something I thought might help cure the bonding/delam issue was by painting the surface of a shaped (and roughed up) board with an epoxy paint… I figured maybe the flowing liquid would seep into the nooks and crannies better than trying to work thicker epoxy into them during the lam-up. I’ve used an “epoxy” spray-paint for other projects that seems like it would work for such an experiment as long as the propellant did not interact with the foam.

20

Hackeysaky,

http://www.dow.com/styrofoam/

and click on “what is styrofoam”

also,

http://dowbp-us-commercial.buildscape.com/items/?type=products

Click on STYROFOAM square-edge. It’s about 2 lbs per cu. ft. and has compressive strength of 25 PSI.

Also, archive it at swaylocks. There’s plenty, and what it all boils down to is that nothing really sticks that well. Apparently it’s copolymerized with 10% polyethylene, to which nothing will stick. The only way to join PE to itself or something else is by melting it, and even that doesn’t work that well. Don’t believe me? Try gluing the milky clear tupperware you have in your kitchen with ANY glue you have. if it’s PE, I guarantee nothing will stick.

Also, since it’s closed cell foam and doesn’t take in water, it doesn’t take in epoxy either. You could let really slow curing epoxy sit there for 12 hours, and it won’t go one bit deeper. With clark foam, as you laminate, the resin soaks in just a little, going down into the foam and creating a physical bond that has more surface area than just the very skin. Same for the cheater coat over EPS (i think…) What I tried was to force that by slitting the foam and forcing the epoxy down into the cells I had ruptured with the exacto. It worked pretty well, too, but there’s another reason the foam won’t work. (also gave it kind of a pinstriped oxford look too hee hee)

Since the cells are closed, and tight, pressure can’t migrate through the foam. so what happens is you get some inevitable crushing, the cells pop, the air in them forms in a cavity, then heating/cooling or repeated foot contact causes it to exert pressure. since (as we just discussed) the weak point is the foam/epoxy junction, the bubble pushes out under the skin. Delam. Clark foam and EPS don’t have this problem, in part because pressure can dissipate through the foam.

The other thing I found out is that guys have been trying this for thirty years. I would imagine that every sticky product under the sun has been tried, and if anything had worked, I’m sure we’d know about it, and many more would be using the stuff.

Again, I wouldn’t reccomend it, and the beaded white stuff can usually be had OTC at the same places that sell the blue stuff, but if you must, and you get some, mail me back and I’ll do my best to share what I learned (you have to sign an affidavit that says you wont come cryin’ to me though, grin). I got mine from an insulation distributor in Oakland that was listed in the yellow pages under Dow Styrofoam Wholesalers.

Good luck, wells