6'6" Nugget/Lazor Zap inspired compsand build

General Discussion
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Thought I’d share my somewhat unorthodox and chaotic build methods. Living in a remote part of Costa Rica ensures that I can never get the proper materials for the job, which means I have to get creative.

The Balsa - Last June we cut down 5 balsa trees that were starting to block our solar panels. They were about 6 years old. I took the trunks to a mill about 20 miles away and had them squared up. The locals thought I was a crazy gringo spending good money milling useless balsa. After about 2 hours of milling (the wood was too soft for their blades and kept getting gummed up), I ended up with about 8 sticks of 4"x8"x11’. I think it cost me $30.

The Foam - 1 lbs EPS I had to drive about 3 hours away to a building materials supplier for 4x8 sheets of 3".

Vac System - I converted an old DC tire pump with the help of  these instructions.

http://www.instructables.com/id/convert-a-tire-inflator-type-air-compressor-into-a/

Honestly, I didn’t think it would work. It does and well.

I made the bag from vinyl using contact cement to seal it, then added a valve from an inner tube, a couple of 0-rings and clamps.

The Build - I output a version of the profile with a 1/4" taken off the top to allow for the 1/8" skins, then make a template with 1/4" plywood.

I rip 3) 10 1/2"  x  7’ blocks of foam then transfer the profile to them. Since I’ll need a rocker table I carefully cut the bottom line and leave about 1/2" of material. I do this 6 times and now have the material for the rocker table.

I trim the rest of the foam and now have the material for the board.

I glue it all together and clamp it.

The next step is preparing the balsa for the skins. I use the table saw and cut 1/4" strips from a 6" block. Since the stock is too thick for the table saw, I make two passes, top and bottom, then finish it off on the band saw. When I have all my pieces I run them through the planer until they’re 1/8". I straighten then on the table saw.

I have a few pieces of some old balsa that has a lot of red in it, so I’m using two strips of that in the skin for a double stringer effect. I tape the pieces together tight, then glue them.

Next steps, cut and shape the board, trim the skins, then bag it.

I know I’m getting into tricky territory with this board, particularly in the complex bottom (loaded dome) contours and such, so any advice on getting it right would be much appreciated. I’m a novice builder and would love some input from the many experienced out there.

 

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Looks Good Tio, 

 I don't have any advice just encouragment.  By The way what part of Costa Rica do you live?

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hi, interesting build you are doing there , i made my first rocker bed about 6 years ago the same way as you have done , i used a piece of 4mm ply over the top of the bed just to keeo it all extra smooth , just make sure all the corners have no sharp edges to puncture the bag , you only need about 0.4- 0.7 bar to vac on the deck skin

i have been thinking of making a nugget as well in the compsand method and what i was thinking of doing which is a bit of a reverse of what i normally do ,

normally i used weights to press the foam onto the bottom skin ,build up the rails ,shape rails and then vac on the deck skin , this way is fine for flat or concave bottoms , i use vacuum if i press the bottom skin over double concave ,

to do a dome bottom i thought of attaching the rails first onto the foam , you would probabally need to make a profile of the rail curve and rocker ,glue up the rails to this profile jig and then glue the curved and rockered rail peices to the foam

shape up the deck of the foam to blend into the rails and then vac on the deck , the bottom needs to be flat at this stage but the rocker will be locked in , you can then glue in a piece of extra eps to the depth of the domes you require ,blend it all in and then vacuum your bottom skin on the bottom , the rocker should all hold in place because the deck skin is holding it all together , 

or use largerpieces of balsa for the rails ,say 1/2 inch deeper all round, this could then be cut back after the deck is vacced on to give a 1/2 inch protrusion of foam lower than the rails , the domes can be shaped into this foam ,then blended in and the bottom skin vacced on, pete

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whats up tio. I like your methods, cool build. I camped out at matapalo a couple times, eight and ten years ago…wild and beautiful part of the country, although there were a couple more houses on the beach than there were the first time i went, i bet its still pretty wild compared to other places that look like they been ridden hard. Im jealous of you to be living there. I checked the instructables link, so that works alright? Last summer i found a tire inflator to one day modify, maybe i’ll finally see about setting it up. Its a coleman 12v dc inflator, but it has a cig lighter attachment for power. Do you think if i chopped that off and twisted on the end of an xtension cord would be ok? Is it necessary to run it through a battery charger or can i just plug it in an outlet? I see where the air intake is. But there is also a separate thing besides the inflator tube that is threaded with a tiny rod in it, maybe i just leave that alone? Electricity and mechanics is a mystery to me. If you have any tips, thanks. Besides waves, are there still parrots and monkeys and giant rodents in yer neighborhood…

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Nice,I’d love to score some balsa in those lengths.I would shape the blank all the way,rails,bottom contours,get it all good the way you want it.Glass it,single layer top and bottom of whatever your using.Template your balsa skins and cut them out to fit your board,the deck skin will be wider because of the way it wraps the dome of the deck,dont go too wide on your skins because they will split at the edges if they wrap too far onto the rails.Once the glassed foam is cured brush some resin onto the skins,attach them to the board and tape into place and bag it.You can lay it on the rocker table to keep the rocker in check,but I would only put the skinned board in the bag.The reason for preglassing is you now have protected your work with a hard shell in case you are pulling too much vacuum,your foam will not get crushed.It will also allow the skins to be pulled into your shaped bottom contours and your board will maintain its rocker.Once it cures,pull it out of the bag and remark the outline but remove the foam rails and then some,glue on some 1/4" balsa strips that are cut to your rocker profile,you may get away with 3/8" thick.Build your rails out to the desired thickness then shape them and clean up the rest of your board.Glass and finish the board.I’m not sure what density your foam is,if it is 1pound or less you may want to install a vent,and you may also want to add some balsa blocks where your fins are going to be,even with glassons the foam will break down eventually from the stress of the fins,and the tail will delam.The inserts should go all the way to the deckskin too.Good luck and have fun,we like pictures!

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Got hit with the SPAM filter and couldn’t post until now.

Thanks for the wisdom, guys. I’ll keep posting as I progress the build.

 

Dpicton, don’t plug that thing into the wall outlet, you’ll fry it. You need to get a AC to DC convertor box. That’s what I did for my Tire pump. 

Artz, I live at Cabo Matapalo on the Osa Peninsula.

 

 

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Hey Jesus… thanks for the advice. I asure you, it is much appreciated.  I wouldn’t have glassed before bagging, but I can see how that its key. Cheers!

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I know how much everyone loves pictures, so I was diligent in taking lots… too bad my memory disc got corrupted somewhere between my shop and my home… lost them all. In any case, took a few shots today of where I’m at.

 

I cut out the outline/plan-shape, then flattened the bottom and cleaned up the deck. I then marked 1 1/2" in from the outline to allow for the rails and removed it.

I put marks on the blank where the board thickness should be at 1 1/2" in from the rails. I measured from the bottom.

I shaped the bottom, putting a slight V in the tail, slight concave in the middle with a very soft and rounded bevel from the rails that gets a bit harder as it makes it way to the nose. Not sure what one would call that, but I’m at the stage where I’m still perfectly happy to play around with some basic concepts.  I’m pleased with the way it looks. In any case, I’ll learn something when I get it wet.

 

I’ll be taking Jesus’ advice (hard to resist a pun here) and will be glassing the blank before I skin it. I made marks for the foam inserts, but then wasn’t sure if I should glass the board before I add the foam or after. Anyone got any thoughts on this?

I template the skins and cut them out on the bandsaw.

 

Next steps, glass the foam, add inserts and then bag it.

 

 

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Cool,looks good.You should add the inserts before you glass the blank,what are you using for inserts?

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I was planning to use some PU foam scraps I have lying around.

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I made a compsand nugget a couple of years ago, full loaded dome bottom. I bagged and skinned the deck  the bottom in one shot. To get away from a rocker bed you can make temp rails from mdf/masonite and attach them to the blank to hold the rocker, then remove them when finished and attach the balsa rails. The dome came out fine. just don’t do too much curve, its so subtle its hardly there for the most part. 

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Hey Burnsie, thanks for the post. Yeah, I’m thinking I have a bit too much dome on the bottom. Going to take your advice and smooth it out even more. I don’t suppose you have a shot of the bottom of that Nugget you made.

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After a long drive to Panama and a long ride back I’m eager to go again.

I did as Jesus said and glassed the board before bagging. Great tip. The balsa held the bottom shape perfectly when I put it in the bag and no need for rocker table, though I did have it under the bag for support. Sorry no pics.

I’m using locally supplied epoxy, which I’ve been using for the past year or so. What can I say? It works… thats about it. I have 0 experience with other epoxies, so I guess the bar is pretty low. In any case, I used the laminating resin only for the inside, since it is a little yellow, plus its hard enough in about 2 hours.

I put the foam and balsa sheets into the bag coated with resin, turn on the little DC tire inflator and wait for the bag to be empty. Just before it is, I make sure the bag is evenly spread out, then I walk away.

2 Hours later I return to the pump and turn it off. Pull the board out and it all looks fine.

Next day I sand the edges to be flush with the foam, which has a layer of glass protecting it from the sandpaper (love this perk).

I clean up the deck and bottom of the board.

On to the rails. I believe I am basically using the same method of building out the rails as Paul Jensen does. 1/2" x 1/4" strips of balsa and cork, attached by contact cement. I like to start with a line of cork all the way around. Normally I would coat the sides of the EPS with some epoxy so the cement doesn’t melt into the foam, but since I have the glass layer around the board already (did I mention I love this) no need for that.

The only cork I have been able to find down here comes in sheets, so I have to cut the strips. I roll the cork up and use my bandsaw to slice off 1/2 pieces… unroll and you have a strip.

Yes, I’m ashamed of the clutter in my shop.

I attach two strips of cork top and bottom, then the other side.

 

 

I sand it down to begin the rail shape.

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I take a strip of balsa and attach it to the top, then another to the bottom.

Here’s where it gets repetitive.

 

Anyway, I put one row of balsa on and then sand it further into the rail shape.I know, it looks like the world’s biggest sanding block, but its just the perspective.

 

 

 

So far I’m pretty happy with it, but I realized today that I realy don’t have a clear view of the rails in my mind. I’ll go pretty much 50/50, transitioning the domed bottom smoothly into the rail. Not so clear on the tail. I’ve got a Takayama with 50/50 rails and it pretty much holds that straight through to the tail. I’ve put a bit of a ‘V’ in the tail, so that would probably be fine. Any thoughts on this? Sure wish I had a Nugget to take a look at.

 

More tomorrow.