Balsa core carbon fiber powder board

[carlito]

So, board cured. Then post cured at 145 f for 3 hours. cool down and start pulling off layers. Here's the peel ply coming off:


Here is a shot of spotting the inserts by laying the template back onto the press. Do this now. Again, don't ask about the alternatives. not as pretty!:


Here is a shot of me cutting off the sidewall dam at the edge contact. The board is now off the press.


Shot of releasing the sidewall dam from the sidewall with a high tech pair of cam-lock pliers. Note glue residue and sawdust and anything else sticking to the glue (spray contact, not epoxy) residue. Grrr. I used to try to clean this up with solvents, but the easiest thing, by far is to suck it up and just sand it off when you do a base grind. The solvents in the water solution break up the glue residue quickly. If you want to clean up residue, this is the best thing i've found yet. Just get some water additive for the base grinder from the shop guys and water it down. apply to base and scrape with a drywall/putty knife. Toluene is better but I would like to avoid cancer if i can.


Crap photo with cheap digital camera of sidewall/edge with dam removed. It's basically finished. Just sand and varnish with finish coat. Ill try to get a better photo later


Board cut out and ready to flow coat:




So for this board, after this i put on two coats of epoxy, sanded and sprayed on a layer of clear coat. Base grind and sharpen and wax and rode the thing. Tracked down a bit of real powder in the trees and the thing is great. Waiting for a storm, and gotta get some soft bindings/boots.

[Richuk]

The board is so light it hovers above the bench

Great journal entries.

[tufty]

Made. Of. Awesome.

[twizzstyle]

I might have missed it, but how much does the board weigh compared to a more traditional layup? Looks great.

You mentioned Boeing Surplus - unfortunately the store itself closed down about 5 years ago, and now they only have online auctions (works just like ebay). (I work for Boeing)

You also made a comment about posting too many details or being boring - many people on here are engineers, and those that aren't are engineers at heart. The more information the better! nice work on the board!

[skidesmond]

Yes, details are always good along with pics. Keep up the good work.

[carlito]

Thanks for the info on Boeing Surplus, disappointed as I am. I have moved to Golden bc from Whistler 6 years ago now. Haven't been down the I-5 since.

The weight of the board is pretty similar to standard layup. I end up using 12 + 9 oz/sq yd per facing. Thats 21 oz/sq yd total, compared to 22 oz triax and typical resin/fibre ratios and it's basically a wash. There is a bit of weight savings in the balsa. I haven't weighed things in forever, but it seems light for such a large board. 172 long, 25.6 waist, big nose.

I never used carbon as a weight savings tool. I was drawn to the stuff because it doesn't seem to go soft like glass does. You can also get much better stiffness at the same weight as glass. I just started using the 12 oz biax for torsional stiffness and am very impressed with the way things ride. Especially in the skis. It is very difficult to get high torsional stiffness without increasing lengthwise stiffness without going to these exotics. You can't really do it with core thickness. I think the biggest reason high performance carving skis are getting so short is that they can't make em stiff enough torsionally if they are long and skinny unless they are stiff overall. "Team" gs race skis can afford to be stiff so they are a bit of an exception, but sold to the public stuff is getting pretty short. This is all completely irrelevant to the park riders who probably don't want torsionally stiff boards

Is it worth the cost? I don't know. I like the pop, the snap, the power of the carbon. The longevity is great, but you have to be pretty happy with what you build, you'll have it a long time. Build something you don't like and it'll be an albatross around your neck for a long while. That or suck it up and try again.

Sometimes I think about a cheaper hobby, like crack cocaine or polo.

Later, Carlito

[fa]

carlito, great work!
can you please clarify the following:
how you prevent wood dam from sticking to the board?
there is a groove on the dams for the edge, does that mean that a part (or the hole) top side of the edge is left exposed (no fg -resin there)?
waiting to see it finished
thanks

[carlito]

Sidewall dams

The dams are made of wood. They have a .5 mm deep by 2 mm tall groove, or kerf cut into a corner. They are then profiled to match the core of the board or skis + 3 mm. They are then mold released do they dont stick to the sidewalls. I am currently using a wax and am somewhat concerned about transfer. Will soon find some other way to release them. Have made them of UHMW but they grew and bulged between the screws and did not work. The groove fits the edge and holds the edge down to the press and against the side of the p-tex.

This does mean that .5mm of edge is proud, or protudes from the sidewall. people always ask about this, usually with an eye to durability/strength. Never had a problem. Remember, this leaves three quarters of the edge supported (1.5 mm), and it is supported by a very well bonded, strong, FRC sidewall, that has a "C" shaped cross section. This can be compared to a pretty weak/brittle poorly bonded (really unbondable) chunk of plastic, or perhaps a more ductile, better bonded, rubber or ureathane chunk which does not really transfer shear loads from the edge to the top facing. Caps put a FRP over the edge, but also a long, bondline with no real surface area to speak of. They break open if you look at a rock, and try to fix it. Of the "standard" options i think the best is to use wood (bamboo seems good) sidewalls and seal them up well. What I am doing is, i think, a good compromise. It is strong and durable and the sidewalls come off the press nearly done. Downside is the fiddly manufacture of throw-away dams, and required time of assembly/sealing of the press surface. Compromise compromise....

Well, its puking snow and minus 10 celsius. Got new boots for the powder board yesterday. Takin care of the 2 year old and shovellin' today. Grrr.

Thanks for the questions! Carlito

[Richuk]

Is polypropylene more stable? Epoxy won't bond

[twizzstyle]

Sometimes I think about a cheaper hobby, like crack cocaine or polo.

Ha! Don't we all!

[Brazen]

Yeah, some days it would be cheaper just to buy a case of beer, lock yourself in the bathroom with it and flush 1 dollar bills by the handfuls down the toilet. You get to keep the ones that float back up and who knows...the upstairs neighbor might flush a 100 down.