Hi everyone! Just curious if anyone has any experience with glassing schedules for an EPS 2# (30kg/m3) semigun. I will ride the board in waves up to about double overhead or slightly under. The foam blank has a pvc foam stringer.
Was thinking of glassing 6 oz bottom and 6+4 deck, I’m not too worried about dents but more so if this glassing will stop the board from snapping.
Also considering going 4+4 deck and 4+4 bottom?
Also, would these two glass jobs differ a lot flexwise? The board is 6’8" x 18 1/4 x 2 1/4.
I never built a board for Indo, but I did do an EPS semi-gun for a guy to take to Sunset, and did 6+6 deck and 6 bottom. The added strength makes up for the added weight, which is not such a bad thing in boards for bigger surf. In terms of stiffness, I’m pretty sure you’ll have plenty of flex with that foam stringer and still have 6 oz all around. You could certainly go 6+4 on the deck, but that makes the overall structure weaker. I think 4+4 on the bottom is “wasted” strength. Put it on the deck where you’ll need it. I like to take advantage of the reduced weight of the core by adding strength in the layups.
I also did one for a guy here for the biggest days we get (DOH) with the same schedule, and he loves it. My attitude is… added strength = added confidence = more enjoyable sessions.
Thanks for the encouragement. Yeah the shape does have a clean look to it. I copied a board that was custommade for me by Dean Geraghty in Cape town who shapes with the Town and Country license down there. Great board but was snapped by a strong wave in the canaries.
The board has a healthy dose of rocker with a single concave running through the whole board.
I would like to thank all the people writing long interesting threads about doing railbanding. Big thanks especially to Bill Barnfield! Still the trickiest part of the whole shaping process I reckon.
I only have four days to finish the board, but hopefully it will come with me to Bali and the magical islands estwards of Bali…
Next is the spackling… I will try and do this one with epoxy and microballoons to get some more strength than with regular lightweight spackle.
This board is my second EPS shape. Takes a light touch to shape wihtout ripping.
If your going double over head + in Indo…you better pack on the glass. Your projected glassing schedule will never make it off the airplane, let alone the first chuck & crab grab, as a 15 ft face explodes in front of you in 18 inches of water. Reinforce the leash plug too.
In my humble and buckled board opinion: You will need more glass on the bottom of EPS. Single cloth anything won’t cut it. Either do a 6,4. or a 4,4 or something like that. On the deck, do a 6,6 or a 4,4,4. And put a stomp patch under the back foot.
It also depends on what style of cloth you use? 6oz Impact cloth is 40% thinner than regular 6 oz E cloth, and it’s about 15% stronger. It’s not anymore crush resistant, but it sure is more flexible, and dent resistant. Tighter weave means less hotcoat to fill weave, tighter weave stronger glass & less epoxy resin nonsense. But down side mo cloth, mo money.
The difference beween 6,6, top 6 bottom, -and the- 6,6,top 6,4,bottom is about 9-12 oz. to the finished shape. It’s still going to be very light.
My 8’6" that I just finished weighs in at 10.5 lbs with fins and 2-2mm perimeter stringers. Thats a 6,6 top with a 4 oz stomp, 6,4 bottom, with a 4 oz tail patch for the fins. Also a gloss polish finish. It it is very strong, and the weight feels comfortable.
No experience of Indo but in terms of weight I glassed a marko 2lb EPS blank wooden stringer 6’ 9" semigun with 4x4x4 bottom (had some problems and ended up with the extra layer on bottom) and 4x4x4 top. (Normal E glass) Sealed blank with epoxy and q cell. Came out about 6 3/4lb with finplugs. I liked it that weight. Got to use it twice over winter (UK) and had 2 great sessions.
Point Blanks builds a lot of epoxy / eps for travel & Puerto…
Quote:
Mini Guns are glassed with
a layer of 6-oz. E glass, and a layer of 4.7-oz. warp on the deck, with
4-oz. twist deck patch. Bottoms are glassed with a layer of 6-oz. E glass
and a layer of 4.7-oz. warp glass. One triple T-banded western red cedar
stringer.
Guns are glassed with two layers of 6-oz. E glass on the deck and a 4-oz. twist deck patch. Bottoms are glassed with two layers of 6-oz. E glass. One triple T-banded western red cedar stringer in the 7’6", quadruple T-banded stringer in the 8’0".
A more aggressive design than the Rocket Sled, the Mako is meant to be surfed hard off the tail. A bump wing provides drive and a point on the rail to pivot off of, while the overall tail is pulled in for tighter cutbacks and to hold in on steeper, more hollow waves. Increased thickness provides paddling speed for getting into waves and a slight nose flip stops you from burying the nose on late drops or radical turns. The bottom features double concaves for speed and drive fading into a slight tail V for easy rail to rail transitions.6-oz. E + 4.7-oz. warp deck with 4-oz. twist patch. Double 4.7-oz. warp bottom. Triple T-banded 3/16" western red cedar stringer.
6’5" and 6’8" Rocket
Sleds are glassed with two layers of 4.7-oz. warp glass on the deck and
a 4-oz. twist deck patch. Bottoms are glassed with two layers of 4.7-oz.
warp glass. 7’2" and 7’8" Rocket Sleds have a 6-oz. E glass
plus 4.7-oz. warp deck with a 4-oz. twist patch and a double 4.7-oz. warp
bottom. Triple T-banded western red cedar stringer.
PS, their website always talkes about ‘extruded’ EPS, but I’m pretty sure that’s a matter of vague semantic distinction. I believe, like Marko’s, their EPS is blown into moulds, rather than cut from blocks, and that is the ‘extruding’.
At least, when one of mine got a huge fin gouge, I had a good look at some pretty typical bead-foam EPS, not anything like the extruded structure of XPS… FWIW
Benny; pretty sure that the pointblanks boards use a foam similar to the XTR’s…in my understanding it is actually extruded. Don’t know that it makes a big difference though; certainly, XPS is a bit stiffer than EPS of the same density, but that’s not the issue here.
Erik, if you’re looking for resistance to snappage, the one thing that’s REALLY key, that no one here has mentioned yet is laps. Laps, laps, laps. Make’em fat. Make sure they go all the way around and at least 2" onto the surface of the opposite side. That’ll give you the snap resistance. Double laminates will protect you from dings and dents on the deck and bottom panels, but my gut tells me you could put a ton of glass on the panels, but if you chince on the rail laps, it’ll still snap. Look at some tinted guns outta Hawaii and the like (with cutlaps so you can see how big people do’em down there). Kendall posted some photos of his guns a while back…I remember pretty hefty laps. Beauty of this approach is that you get the snap resistance without the weight of glassing the entire panel.
my 2 cents (getting closer and closer to an american 2 cents every day…)
I take issue with GreatWhiteNorth’s opinion on rail laps to reduce the likelihood of snapping a board.
Two things make up the strength of any board. 1: the thickness of the board. 2: the glassing schedule, especially as to placing most of the glass on the thickest part of the board (i.e. deck and bottom). Any cursory understanding of materials mechanics will show you this.
I spoke with Resinhead about this in the last Haleiwa Sways meeting. BTW, I think his glassing recommendation is good.
Next, you have to understand the mechanism of board snaps. I’ve said it again and again: the initial failure DOES NOT result from stresses exceeding the compressive OR the tensile strength of the glass job. The initial failure is shear, between the surface of the foam and the glass job, on the compression side of the board. Once the bond is gone, the glass in compression buckles upward (away from the foam) and you have that characteristic ridge we’ve all seen on boards that are slightly buckled but not broken completely.
What this means to the original poster (and anyone else wanting to get/make/ride boards that don’t snap, is the following:
Thicker boards are stronger, by the square of the thickness change. If you can’t do math, Barbie, a board twice as thick is four times stiffer.
Glassing for strength places the most glass the farthest apart. Thus, glass on the laps does not contribute much.
We all have to find a way to achieve better shear transfer between foam and glass. EPS is particulary weak, and magnifies this problem, especially when spackled/sealed so there is little or no penetration of lam resin into the the shaped blank.
But, however, on the other hand, just suppose… that you believe firmly in flexible surfboards… that you can’t handle a board thicker than 2.5 inches… that you think snapping a board every so often proves you’re a real man surfing real waves… that you can afford to replace such boards every couple days/weeks/months…
Laps are for ding resistance. They help some to transfer shear between bottom and top, like the web of an I-beam, but I place my reliance in snap resistance on deck and bottom glass.
Thanks to all of You for the answers, well I just lammed the bottom with a single 6 oz this evening so can’t really change that… Will try 6+6 on the deck and wider laps on the deck lam.
I used about 600 ml of resin which was plentiful. Could have gotten by on a little less. 600 ml is about 21+ ounces?
Hope my resin doesn’t run out though.
I did not use any filler/spackle at all except for some tiny gouges. To get more strength.
Should I lap both layers onto the bottom ? I’ve got the JC video and the guy who lams a shortboard in the video kind of cuts the first deck layer glass so it doesnt really lap onto the bottom (all that much).
Should I lap both layers onto the bottom? If so I guess I should lap the first one a little less, right?
I have about 25 oz of epoxy and hardener left, Do You think this is enough for 2 layers of 6 oz?
Thanks for all the encouraging advice!
I’ll try and take some pics of the board before I surf it and possibly snap it…touch wood. I’ll try and pick up a couple of spare boards on Bali before heading out to the islands. Will probably go to the island of Sumba again. It’s a nice place…
Board is now finished and in the resource section, It’s my second shape in two pound eps foam. Board came out light…only 5 pounds I put on a 6+6 oz deck and a 6 oz bottom.
Couldnt put on more glass due to lack of resin…hope it stays in one piece for a few waves.
I need advice on which of the redx fins to put on the board. Taking it to Indo tomorrow.
Looks alot like my favorite EPS board (picture enclosed) But your’s hasn’t gone through the buckle cycle yet. Can you count the damage / repairs. Here a hint, there’s at least 4. Glassing schedule 66 top, 6 bottom.
E, Since you’ve been to Sumba before, how did that effect the size of this board. Did you feel you needed more board? I just booked a trip to Nihiwatu and was wondering how many new boards to shape? What glass? semi gun?
I usually ride 6’2" in So Cal. with 4 oz. PS, I just got back from Gothenburg.
Sumba gets quite big, I’ve seen waves around triple overhead a few times. Nihiwatu is very fast with a very steep takeoff, holds big swells as well.
A gun over 7 foot is good to bring if You plan to surf the bigger days. You may or may not get big waves, hard to tell. It’s far to get new boards, so bring spares in case they snap.
