Compsand #3 and #5

Ed! That's my board skin! I'm certain the e.balsa will perform well - probably better than foam individually...but...foam is so easy...you can shape it and have a board ready the next day and it'll ride well.

An interesting project, to say the least.

I got a call today to arrange delivery of my blanks and other supplies. I a little concerned about hacking in to foam for the first time.

Apparently we’re supposed to get a bunch of Alberta clippers the entire month of December. Might put the lamination stages on hold for a while.

Hack away! More than likely you'll have an outline that will require you to cut a portion of the nose or tail off. On my first board I used that section, before I cut it from the board, and tested all of my tools. Surform, block plane on the stringer, spokeshaven on the stringer, planer and the various sandpapers. You'll gain a quick feel for how quickly the foam and stringer can shape.

Keep us posted on your builds! I'm looking forward to it!

I'm infected! Not only did I receive about 9 pounds of balsa sheeting today, but I ordered some hardwood for inlays, to minimize the wood flooring look:

African Paduka
Cocobolo (really)
Walnut

Walnut is a great look but I doubt it’s a good material for surfboard building. I think it's kind of dense but not as strong as other choices. Ebony would be worse.

There are some great birds eye type of woods that would be great for your next wood order

(Message edited by Bigshow on December 04, 2007)

I looking for the wood I saw that some of them have density in the 50 - 80 pound per cubic foot or was it cubit like the ark? anyway...I was looking for a darker wood to offset the e.balsa and that was stiffer.

Mostly I'm just going to carve up some inset, but I would like to place one plank on the bottom to stiffen up one of the rides.

I've heard of Bird's Eye Maple is that what you're referring too? And...I pretty much at the end of my wood buying phase.

Dennis has built me a frame for a hotbox that I can use to cure, postcure and thermoform with. I purchased 4 - 150 watt bulbs and fixtures, along with some reflective insulating foam. I did a quick test to see if the heat source would be able to generate more than 120 degrees.

After a few minutes I checked my remore thermometer, expecting it to quickly rise. It was 69.5 degrees, which was about 15 degrees in maybe 2 minutes. Good, so I waited to see where it would top out.

10 minutes later it's still at 69.5 degrees, so I figured it flipped a circuit breaker or my wiring blew up. I walk out to look at my test and it all looks good. Then I look at my sensor...all melted and TOO hot to touch.

I think the heat source is good.

so is the sensor fried so to speak? how much did that set you back? bummer!

Don't tell Judy, but I put it in the refrigerator and this morning when I woke up the guage was reading 30 something, so apparently it's still working, albiet slowly

It's just one of those SkyScan Atomic clocks with the moon phase and outdoor temperature, I think they run $20 at Sam's Club.

I really only needed 72 degrees from the lights, so that I can cure the epoxy at room temperature. I think I raised the temperature above 200 degrees!

Best to place the thermocouple separate from the instrumentation.

I didn't place them both in the refrigerator Just the sensor. Although, that reminds me of the time when James was a youngster and fixed himself a bowl of cereal while STILL watching a rather captivating TV show during the evening. The next morning I went to get a cup out of the cabinet for my coffee and found the milk that James had "put away" the night before.

In referring back to the tensile strength discussion I am reminded of the next build. With a compsand you have four distinct surfaces that receive lamination. The exterior, as with all boards but also the inside or interior of each skin that attaches to the EPS core. From the top down they would be:

1) Exterior Deck
2) Interior Deck
3) Interior Hull
4) Exterior Hull

With the way that I am building them, I am afforded the opportunity to not only change the textile in each layer, the thickness of each layer but also the adhesive or resin for each lamination.

I am in the process of designing the next compsand that will have the following build schedule:

1) Exterior Deck Glass 4 oz S Glass
2) Deck Skin 3/32" Balsa
3) Interior Deck Glass 2 oz E Glass
4) EPS 1#
5) Interior Hull Glass 2 oz E Glass
6) Hull Skin 1/16" Balsa
7) Exterior Hull Glass 2 oz S Glass

I want the bottom to be more flexible than the skin and have chosen the skin thickness and glassing schedule to "hopefully" affect this.

Another component, briefly mentioned, is the choice of epoxy for the lamination. I am big fan of Resin Research products, but acquiring anything other than the 2000 resin is typically a special order.

For the build I am planning I am going to use epoxy available at my local TAP Plastics. They carry 3 grades of epoxy and there are 5 separate hardeners. The color or clarity isn't great, the RR is virtually clear, the TAP products are not.

However, I believe that for my purposes the flexural strength (FS) of the TAP Epoxies will fit well with my build.

Without getting into the complexities of the numbers, I'll just say that a HIGHER FLEXURAL STRENGTH number equates to a stiffer cured product.

TAP's Marine Grade Epoxy has a medium hardener and a slow hardener. The FS of the medium is 14,800 and of the slow is 10,500. For compartive purposes, the RR 2000 is 14,800 and the RR 1980, their flexible epoxy, is 13,500.

TAP's General Purpose epoxy has a FS rating of 11,500 and the Super Hard Epoxy is 17,900.

So, I intend to use 4 separate epoxies in this build. The Deck Exterior glass will be laminated with Super Hard (FS = 17,900). The Deck Interior glass will be laminated with Marine Grade using medium hardener (FS = 14,800). The Hull Interior glass will be laminated with General Purpose (FS = 11,500). Finally the Hull Exterior glass will be laminated with Marine Grade using slow hardener (FS = 10,500).

I'm not sure if that will make a difference in the ride, but it demonstrates the ability to fine tune the construction of a board. I would think that creative folks could even segregated it further by laminating a specific section of the textile with a different epoxy (eg super hard on the nose, marine grade with slow through the middle and general purpose on the tail - not that I would suggest that ) This would also be the one area that I am of the opinion that a wet layup is superior to vacuum infusion. The customization of resins to achieve specific characteristics is fairly easy using a wet layup in a bag.

I love teak and zebrano too

Zebrano? I've never heard of that, Petr.

e.Balsa skin laid out and taped up for the bottom of the 4 epoxy board mentioned above (sounds like a 4 cheese & macaroni meal )

The overall skin, take special note of the slippers.

Close up of the tail. The diagonal's in the tail are designed (hopefully) to allow a bit of flex. The under core will have no rocker cut into the foam, then when "pushed" the diagonal will flex and create the tail rocker, as needed and then hopefully twang back when the board is lightened up...at least that's the theory behind it.

Close up of the peak into the nose. The diagonal on the nose is designed to allow a bit of couter-clockwise flex. The Peak or point of the two center sheets extends the grain/strength further up the center of the board, limiting the designed flex to just the inside rail on the nose.

A slightly pulled back pic of the nose.

A rough approximation of what the bottom of tghe board will look like when the skin is trimmed.

That's going to look crazy-cool!

It does look wild doesn't it? Hopefully I will actually be able to discern some performance characteristics from it.

In working with the e.balsa laying out this pattern it was interesting to note the resistance of the wood when changing the orientation of the grain. Attempting to bend the e.balsa perpendicular to the grain showed the most resistance, but a medium "resonance" - the vibration when you "twanged" it.

Bending the sheets with the grain was the easiest, there was almost no resistance offered by the e.balsa and the "resonance" was non existant - it just sort of went "thunk" back into place.

Bending the sheets that were placed at a 45 degree angle to the bending force tending to cause the force to deflect along the grain.

The angle of the diagonal (30, 45, 60 degrees) to the force noticable changed the resistance from each increment.

What I found more interesting was that the resonance - the "twang" of the return was greatest with the diagonal sheets. I'm not sure I understand it, but when I think about the Futures Fins Vector Suspension system...that is also placed at a diagonal to the forces against it. Folks talk about how that is a cumbersome system to avoid the boxes being ripped out, but there is something about the diagonal placement that intrigues me.

Interesting to have more variables to tune in a custom application.

Jeff,
pic too dark to see your slippers. i will try to take some vid. this weekend of me on a xbc 5.4 fish

Hey Salty, did you get out on that fish? The pictures are of Judy holding up the sheet - she has on Clifford (the big red dog) slippers

The skin attached to the bottom of some hotwired 1# EPS

Cool Jeff! Remind me, what are you using to attach the wood to the foam?

Jeff ,
yes i rode on saturday for 3 short runs then the pp throttle cable broke. water was 67' and air was 70' i rode the board with only the center fin and will post the vid tonight.

That is so not fair! Your temps sound like spring.

Matt on this skin attachment I used 2 oz glass. The bottom of the blank is sealed with spackle and then I weighted the rectangular piece of glass. It weighed 2.2 oz. Next I weighed out 1.1 oz of TAP GP resin on the digital scale, and matched the VOLUME of that with hardener. The weight was just over 2.2 oz - something like 2.24 and the volume was just at 2 oz.

Jeff the water at the power plant is 10+ degrees warmer then the water at my place. Last december 24th the water was 69 and air was mid 70's

That's funny. We have a decommissioned Nuke plant close by...Rancho Seco. When it was operational they would cool the reactors using water from this man made lake. The water temp was 70'ish year 'round. As a young man I would sail laser's in the lake...I keep expecting to turn the lights off and see my skin glow green or orange

have you used wnc blanks , at 48 bucks they seem to be a deal ??

Yes I have, they are Mike Walker's of TWP foam supplier. They also have an industrial foam biz, I can't remember the name of it now, but they can supply EPS foam billet. I've used both their blanks and billet foam, good quality and great folks to work with.

Green, orange would be from algae

What color is from radioactivity? I did some fishing up there last year - panfish, I can remember back in the day that fishing was good there all year round. The water seemed to never get cold and I thought I remember reading that the lake never turned over. They didn't allow live bait - probably worried about 120 pound 6 foot minnows as a result of the "warm" water.

i cant load that vid on this mac that i am on , it will be thursday

The skinned blank is cut to the outline, still needs to be sanded in a few places, but this is the basic look...gets rid of the "pergo" look

Back to compsand #5, this is the Firewire knockoff. It has Core-cell A500 skin, balsa rails and eventually will have carbon wrapping the rails (are you reading Johnny?! )

The Core-cell is fairly translucent - in this picture you can see the outline of the blank through the skin.

Bagged and put to bed, hopefully in the morning a skinned board ready for glass and carbon.

The Core-cell is fairly stiff, not quite as stiff as the e.Balsa, but it is consistent through the entire piece, doesn't require any tape up/ assembly and displays significant impact resistance. From a production standpoint, it would make more sense to use Core-cell over e.Balsa as Firewire has done. The reduction in responsiveness I would think is fairly minimal.

OH! and it's not evil.

Out of the bag, ready to trim the deck skin, carbon wrap the rails, exterior lamination and some paint to hide the excess carbon wrap.

Not by best work, but I have the carbon tape wrapped over the rails. It's going to need a decent hotcoat for sanding and art work to cover the uneven lapping.

Are you sure it's not evil?

It's wrapping e.balsa - you know the story.

Out of the bag - warts and all.



I did a lousy job of aligning the tap at te nose on the right side, so I'll need to paint the deck to cover the misalignment after I bag the final lamination. A "crayola" visualization.



The Carbon is a great look but it REALLY stiffened up the balsa perimeter rails, it almost feels like thge carbon alone would make an adequate perimeter rail system.

Looks like a problem similar to mine on the Recycle This II board.

I just had to rush last evening to get the thing in the bag and gave up trying to align the tape...I was planning on painting the deck white like Firewire does, but I'm starting to grow fond of the corecell, so I may just cover the mismatch with a red and black THICK pinline.

jeff - i'm guessing that trying get them to align exactly would be next to impossible.... any ideas how firewire does it? some kind of cutlap before bagging?

I think to tape board with masking tape in needed shape so after bagging resin stick only at unmasked area than after its toasted you simply sand the rest of overflapping carbon.

I allways wondered how people glass thouse swirl resin on bottoms of boards so that swirl colored resin ends exactly on top perfectly around the edge? And resin on top is clear with perfect clean line?

(Message edited by hawaj on December 13, 2007)

This is a good instructional on resin swirls:

http://www.swaylocks.com/forum/gforum.cgi?do=post_view_flat;post=205168;page=2;sb=post_latest_reply;so=ASC;mh =25;guest=16093982

The cut lap with tape you describe works well with a hand lamination, but for me there are two issues. One, as I mentioned in a separate thread, my eyesight is so bad that I wind up hacking into the board. Other folks probably don't have this problem.

The other deals with the vacuum. Things in a vacuum behave very differently. When you use a bag, you don't have the control over the resin flow like you do with a hand lamination and a squeege. Once you pull the vacuum, it forces the resin OUT of the fabric either into the underlying foam or out to the sides. Also under a vacuum it will force epoxy right through the tape So I would have had the same situation, only with some tape laminated under the carbon in this weird shape.

I had to SOAK the carbon to get the epoxy through it. It's not much fun to work with IMO. If you look closely at this picture you'll see where the epoxy was displaced onto the corecell a few INCHJES! That would have laminated any masking tape directly to the deck. Well the popup isn't letting me post the picture but suffice to say that bagging is significantly different than a hand layup.

Let's see if the application will allow me to upload now. YEAH! It inally worked. It's a little hard to see, but if you look closely you can see the sheen radiating in towards the center of the board - that's how far the tape would have been laminated The real issue though is that under a vacuum, the resin is pushed through the tape, it doesn't act like a barrier as in a hand lamination.

Finally figured out how to deal with the balsa rails. One of the struggles I've had was building up the rails. I decide to try them like I did with the d-cell rails. I cut a stack of 1/8" balsa using the rocker outline and then, smeared epoxy all over the sheets and the rail of the foam. Taped it loosely together, slid it into the bag and then pulled the vac. I have built up 1/2" on each side. I plan to do nose and tail blocks with this board, so that made it easier...no significant alingment issues.

Nice work Jeff. I like how you continually solve problems. It’s all about experimentation and process improvement.

You are rigth Jeff I was still in area of handwork and vacu is so different.
What about trying to use some plastic nonsoakable masking tape or rather masking sheet?

Interesting idea. Do you know of anything like that? I wonder if I could coat the masking tape with something - like PVA / mold release agent after laying it down?

Thanks Ed, it's a career attribute - you should see some of the transactions my clients bring to me. I think also the complimentary attribute is not being afraid to fail with this stuff...that probably comes with age where you get to a point that you don't care what others think about you? Pretty soon I'll be walking around in two different colored socks and my glasses taped together after I break them!!! :