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| Home Made Boards (6188 Posts)
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Home Made Boards |
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duane
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On 12/20/2004 tom in toronto
wrote in from
Canada
(64.228.nnn.nnn)
Yeah, the board i just made is marine/CF(uni) w epoxy/marine. What kind of wood exactly I don't know. Should have snapped it by now but the CF is really tough! But I've been told glass is better for pumping, and has a more forgiving feel. If it's like the mountainboard, that'll be sweet. The mountainboard is an MBS Core 16. Real springy, even at my 210lbs. I think a sandwich of birch and glass w a CF rebar ought to be pretty snappy. Agree or Disagree?
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wood on the outside
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On 12/20/2004 duane
wrote in from
United States
(165.121.nnn.nnn)
I think the best surface layer is the real thin birch aircraft ply,3 layers in less than 1/8", although I suppose a single veneer could work.
for snap try the 12" wide unidirectional carbon, not too expensive
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greg
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On 12/20/2004 tom in toronto
wrote in from
Canada
(64.228.nnn.nnn)
Greg,
I wasn't used to the flex, so I didn't trust it right away, but it's been holding up remakably well. It goes fast, takes turns fast, slaloms down hills like crazy...if you aren't riding a flex board, GET ONE! I don't know how it compares to any commercially available flexdecks, but it feels a lot like my mountainboard, but way more responsive. Its a great all-round design, and the responsiveness has enabled me to learn and improve dramatically...an organic, fluid, high-performance feel. Specs as follows:
36" L 8.5" W 27.5" WB 3/4" camber, No concave, Flat when standing, bows down maybe 1/2 or 3/4? in a hard turn, and feels soooo smoooooooooooooooth.
Having said that, the next one's glass/BB/glass w a CF rebar thru the truckmounts, 34" x 8.25 w a 25" WB. Cheers!
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Tom, your carbon flex board?
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On 12/20/2004
Greg Olsen
wrote in from
Canada
(206.172.nnn.nnn)
Tom,
Tell me how your carbon flex board feels and works. How much does it flex when just standing on it and during a full deep carve what sense you you get of it flexing? Thanks.
Greg
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duane
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On 12/20/2004 tom in toronto
wrote in from
Canada
(142.20.nnn.nnn)
duane,
thanks for that. I like the sound of that melamine sheet. But your last entries gave me an idea: veneer, glass, 5-ply birch core, glass, veneer ? What do you think? I really like the natural wood look and I'm looking for quite a lot of snappy flex. I'm trying for a replica of the GS/City Bomber by Insect (if it goes well). Any functional drawbacks w this layup?
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melamine surface
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On 12/20/2004 Duane
wrote in from
United States
(68.15.nnn.nnn)
here's a link to that melamine shelf material. I like to use these as a surface for wetting out the fabric as well. The resin doesn't stick very well so you can pull the wetted cloth right off. use black for glass so you can see when it is fully wetted out. the price and size are right, too
http://www.lowes.com/lkn?action=productDetail&productId=108040-977-7004240869
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finishes and top sheets
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On 12/20/2004 Duane
wrote in from
United States
(68.15.nnn.nnn)
It doesn't really matter if you use high density pe or low density, neither will stick. The low density is just more flexible and less likely to wrinkle, you can pull it taut.
Most commercial boards are made with a topsheet, which, just like it sounds, is a layer of film that goes on last (and first, if there is one on both sides) that has a nice pre-finished surface, and often the graphics pre-printed as well. The best way to do the graphics is to pre-print on the back side, so it shows through the clear areas. It is damn difficult to get the actual lamination resin to take on a perfect appearance, and a topsheet makes all this irrelevant. The topsheets are treated to bond well to the resin, and often are embossed with a fine semi-gloss pattern. That helps hide minute flaws.
Some boards use other techniques, I think the Pistols are particularly clever to use a layer of wood on the "bottom" (top when in use, bottom of lamination), then the laminates in the middle, then a graphics topsheet that ends up on the bottom. This way, both outside layers are pre-finished and opaque, so small bubbles, pinholes and other small flaws don't show, and the boards look great.
Many of the topsheets are polyester, further treated to bond well. They have been used for decades for skis, and then later, snowboards.
Another way to get a semi-gloss is to lay the board up on a mold with a matte finish, the white melamine laminated shelf stock they sell at Home Depot works very well, it can be bent for camber. I used that for my last board. It should be waxed 3 times with carnuba. The board popped right off, and the resin dribbles around the edge came right off, so I can use the shelf again as good as new.
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P.S.
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On 12/20/2004 tom in toronto
wrote in from
Canada
(142.20.nnn.nnn)
By the way, if I get a really smooth surface on the glass laminates top and bottom, should I sand them lightly or leave them glossy? Is there a strength/flexibility advantage either way? I ask because I notice the commercial boards all appear to have a mat finish, but it surely doesn't come out of the press like that, does it? If my assumption on that is correct, I'm curious why they would dull the finish purposely if it's not necessary.
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PE sheeting
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On 12/20/2004 tom in toronto
wrote in from
Canada
(142.20.nnn.nnn)
So, you say low density PE is better no-stick than high density? I have both, but the low only in a 1mm sheet, probably fine for a simple sandwich lay-up?
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PE for bagging
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On 12/20/2004 Duane
wrote in from
United States
(68.15.nnn.nnn)
polyethylene is the stuff you want for bagging, but low density polyethyene is preferred, it is more flexible and more clear than high density. It doesn't stick because of LOW surface energy.
I see quite a few people having trouble with wrinkles. There are a coule ways around this. First is using the right gage of film, I like something around 2 mils (thousandths of an inch), for reference a T-sak from the market is 0.7 mil, too thin, and the "heavy-duty" rolled film at the hardware store is usually 4 mil, too thick. PE film will shrink when hit with heat, so you can lightly heat it with a hair dryer after tacking it down and the wirnkles will shrink right out.
I like another technique better. I fix a frame around the laminate that sticks up an inch or so proud of the table (mold). The bagging film is sealed outside of the perimeter of the frame. I hook the vacuum hose up to a hole in the table, and inside the frame but outside the laminate there is rolled dry fiberglass cloth for breather. When you turn on the vacuum, the film is drawn tight across the frame, but above the laminate, then down onto the laminate, center first, without a single wrinkle. The nice thing is that this tends to squeegee the resin to the edges a bit as well.
A film around 2 mil is strong enough not to burst, but stretches well. A little heat (but not too much) helps if you need to smooth it a bit.
I adapted this technique from vacuum forming of plastics, where the plastic sheet is attached to a frame, then drawn into the mold with vacuum. With the vacuum forming technique, the frame is a clamp frame with a super-soft silicone rubber bottom seal, you just place it down onto the vacuum table and it seals itself. I have been meaning to make such a frame for mounting the sealing film, re-usable and no tacky tape mess.
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alu/carbon
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On 12/20/2004
Svarteld
wrote in from
Sweden
(213.64.nnn.nnn)
Folks, thanks for all the thoughts about galvanic corrosion.
I'll try to build a support for the rear foot on the duck tail, when in air tuck, shaped to fit the shoe. I'll mount it with the same holes drilled for the rear truck, so I can experiment with different shapes without drilling lots of holes, or making a new deck. Think I'll also add some kind of support for the rear foot when foot braking and maybe toe-dip-braking. Here's a rough idea of it:
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nothing sticks to polyethylene
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On 12/19/2004
Greg Olsen
wrote in from
Canada
(206.172.nnn.nnn)
Tom,
Polyethylene sheeting is a great no-stick solution. Nothing sticks to it. Every bag or dish you get in that material is essentially one big cross-linked molecule so there are no sites for chemical bonding (I think that is the explanation..also something about high surface energy???). The bag I used for my attempt at vacuum bagging was a heavy polyethylene. I am thinking about buying one of thoe hand pumped vacuum bagging kits from another fellow Canadian..can't remember the name... I would protect the system from getting wrecked by putting the work to be pressed into another poly bag in the mesh-lined bag that he provides. The mesh layer which is closest to the work in his system allows the air an evacuation path back to the pump. Any resin oozing out of a lamination would wreck the mesh. I really think I will get one of those systems.
Greg
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herbn you nailed it
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On 12/19/2004
Greg Olsen
wrote in from
Canada
(206.172.nnn.nnn)
It is a high tech heavyweight as you describe! I couldn't say what the resin/cloth ratio is but likely is is high. It barely flexes at all and I weigh 215lbs(today). So I have the look right but I need to use a proper vaccum bagging technique with the excess resin being soaked up with a disposable absorber or just not use random mat when I hand layup. It soaks up A LOT of resin. I knew that but I was trying this for the first time on a budget. Epoxy resin would have given me a higher strength to weight ratio as well. I will take what I know and transfer it to an epoxy and carbon fibre version. Maybe in the spring. But I would like to use hand layup techniques.. and avoid vacuum bagging altogether. I don't want the equipment investment.
Again NOT having seen a decent high tech commercial board I do not know how they flex. And if people stand over the ends of the boards just inside the trucks how much does a racing board need to flex? The racing pumping i have seen is more of a twisting motion than the unweighting pumping I have done to date for fun on my super flexy LY Allstar for instance. I guess the farther toward the middle of the deck the front foot is the more the flex is invoked. Is there a measure one could use to get the flex right? lbs per inch of compression? Thanks guys.
Greg
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P.S.
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On 12/19/2004 tom in toronto
wrote in from
Canada
(64.228.nnn.nnn)
I forgot to mention... I have access to lots of plastic sheeting... high density polyethylene and polypropylene. Would that work as no-stick? Can I just spray some silicone on any old plastic or is there a danger of the resins reacting w silicone?
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to herbN
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On 12/19/2004 tom in toronto
wrote in from
Canada
(64.228.nnn.nnn)
Hello, herbN
Just wanted to ask you about the no-stick you mentioned a week or two ago re: fiberglass laminations. What is a good no-stick sheet to use in the glass/birch/glass pressing process?
Also, I'm wondering if the birch veneer sold in a 12" x 99" roll at the lumber shop is suitable for boards (it's 100% natural wood - no adhesive)? Would a board of 10 plies (all glued with the grains running nose-to-tail) flex less and twist more than 2 pcs of regular 5-ply? If so, will using tri-ax glass negate any twisting? I'm thinking it would, but just curious about the quality of these veneers on a big roll. If they work, it could make for some interesting lay-ups.
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gregs board
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On 12/19/2004 herbn
wrote in from
United States
(205.188.nnn.nnn)
i guess i needed a bit more of a discription to comment also the first pics,on my monitor looked pretty flat, like the patterns were sort of a painted on graffic. Now i see,and you discribe a board that has a lot extra resin,how's the weight, did you manage to make a high tech heavy weight,i've done this as well. You got the overall look correct,and if you went to a proper vacuum bagging operation,right from skin one, you'd have a fantastic board. It may be ok as is,how is the weight? and is it flexy for it's/your weight?
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Thanks continued...
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On 12/19/2004
Greg Olsen
wrote in from
Canada
(206.172.nnn.nnn)
So I wrapped the core with a layer of basic cloth, one side cut to the same size as the core, the other side wrapped around the edge and sealed on the other side. This was using the basic reading on Swaylock about surfboard building. I had trouble getting the glass which wrapped around to the underside to stick. I had to constantly brush the flaps of glass down until the resin really started thickening up and setting. I ended up with a blank covered with on layer of glass and it did not look great. I carved wheel wells out with a drum/spindle sander and laid a couple more layers of glass on. The sidewalls seemed impossible to deal with and the resin was eating the foam in the wheel wells slightly. It was going to be a long haul at this rate to get something I liked. So I sanded it smooth and decided to try a homemade vacuum bagging solution. I laid up 3 layers of cloth and mat on each side of the core. They were rectangles larger than the core and I painted resin around the perimeter of core for about 2 inches out and pressed the top glass down to join with the bottom. The core with glass envelope looked like a big lozenge sealed in a bag. I put the whole wet mess in a large plastic bag (actually an Industrial Dust collection system bag on a flat table and connected the vacuum from the dust collector o the bag, sealed the connection with duct tape and hit the switch. The bag immediately sucked down over the board, all wrinkled but flat. There was too much resin and it no where to go. A proper vacuum bagging system has a porous non-stick membrane which touches the wet resin. The excess resin gets squeezed out through the porosity of this layer into a disposable absorbent layer and the whole thing compresses with a nice strong low resin to fabric ratio. Mine though, compressed with the excess resin bulging up in waves of wrinkles. But what it did was give a nice big flat surface, larger than the core on the bottom side and the look of an ICK on the bottom (core under a deck look). The excess hard flanges around the perimeter of the core were strong and thick enough to act as an upper deck so I shaped the deck by hand with a belt sander to the shape in the pictures in this post. It was so ugly, and I was so fed up I just painted it red and black and put some trucks on to try it. As shown in these pictures it flexed quite a bit...too much. After a week or so I got up the energy to sand the whole thing flat with a belt sander and hand sand all of the transition areas along the edge of the core on the bottom. The stripes in the graphics are the result of sanding out the high resin wrinkles until they were almost flat and clear leaving the low areas painted. Then I wrapped the newer layers over. I added several more layers of glass and fabric and mat (random) and sanded between each layer.
I hand sanded nice radii on the edges of the thin upper deck and sealed them with resin put on with a small brush. Eventually it came out looking almost as in the first pictures I posted. I did a couple of thick Hot Coats (over-activated resin) and sanded it very smooth with 80-150-320. Then I built dams up around the whole perimeter with duct tape and poured a thin pool of thinned out (styrene thinner in resin) gloss coat and finally sanded the whole thing with some 400-600-1000 wet sanding paper. Then I did some misting of red car paint and clear coat from a can on the bottom.
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Thanks.
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On 12/19/2004
Greg Olsen
wrote in from
Canada
(206.172.nnn.nnn)
Well thanks guys! As you can see I am a TOTAL suck for attention...and praise. My wife constantly says" Oh GROW UP!!" Didn't get enough as a kid I guess or....too much and got addicted to it. Either way Seasons Greetings to all!! I really lucked out building this one as it turned out to be a series of happy accidents and a lot of sanding and filling. Tom, I wish I had gone the route of laminating some BB (Baltic Birch) with glass. I have a Land Yachtz All star made from that (glass on the outside of BB) but it is too soft for any real speed, great for slower and flatland pumping though. How does it work using the glass as a bonding layer in the interior? I will try one of those next. I am sure you spent much more $$ than I did as I used only cheap polyester resin and cloth from Crappy Tire (Canadian Tire for you who don't know our pet name of a Canadian chain-store). It actually probably has way too much resin in it as a percentage of cloth/mat. But I had fun doing it.
It also doesn't flex much at all so I am having to learn how to skate a basically rigid board. New kinda' pump required. Are the top slalom boards out there on the market quite rigid?
To start I cut out a piece of 1/2" foam core board, basically hobby board but a higher tech version from Alcan that was lying around work. But the hobby boards would have worked. The foam core does NOTHING structurally. It serves only to hold the skins of the top and bottom apart a certain distance from each other (theoretically more distance the stronger: Modulus of Elasticity I think is the term involved here). The result is a skinned torsion box stronger than the sum of the parts, much like a lightweight interior door for your house is strong and rigid and light. The way I have connected the top and bottom layers copies ICK (ICK was the first to do it this way I think) with a strong beveled sidewall you get a stronger board (torsion box) yet. And I think that look is also the result of making the composite lay-up simpler. Really not knowing what I am talking about but looking back through skate deck history Turner wrapped a core much like a small surfboard would be made. But Ick (I think) perhaps came up with the idea of smaller core than the upper portion of the deck. So anyway I was reading about vacuum bag molding and hand lay ups etc on Swaylock a surfboard building forum and trying figure out how to make this thing. I am always experimenting with fabrication techniques but in the background I am always trying to see how hand-made processes are scaled up to manufacturing volumes (I am an Industrial Designer so it’s my job to know stuff like that).
continued on next post......
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carbon, glass, greg's slalom
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On 12/19/2004 tom in toronto
wrote in from
Canada
(64.228.nnn.nnn)
Greg...yes we were stunned into an awed silence. That looks like a good lamination, and a lot of work. I researched at the boat-repair shop and found it a bit out of my price-range to build a foam-core, especially before I've got my technique wired. I weigh about 210 and I'm looking to build my second flex-deck now. The first is marine-ply (whatever that means...I didn't trust the feel of it at first but its holding up nicely) with carbon and epoxy btw the wood layers. Next one will be a glass sandwich w baltic birch and epoxy, and I think I'll include a carbon beam through the truck-mounts. Maybe I should ask you some details about foam-core. How do you treat the edges?
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greg's board
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On 12/19/2004
joseph
wrote in from
Australia
(211.30.nnn.nnn)
i liked it. nothing else to say except that it's a pretty cool looking slalom board. how did you build it?
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carbon
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On 12/18/2004 Roboto PDX
wrote in from
United States
(24.20.nnn.nnn)
Thanks MSK I did not want to look up how to spell "galvanic". But you hit it. carbon will loose it's strength if exposed to a conductive surface for any prolonged time. As someone pointed out carbon fiber has very strong tensile strength but very weak sheer strength.
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Aluminum And Carbon
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On 12/18/2004
msk
wrote in from
United States
(68.190.nnn.nnn)
"that may be done in vary strict aircraft engineering circle to isplate the aluminum from harsh direct stresses from the carbon."
The main reason for using a layer of glass is to prevent galvanic corrosion. Putting carbon and aluminum in direct contact creates an electrical current. Most carbon bike frames in the late 80s/early 90s were made with carbon tubes glued to aluminum lugs, and joint failures were common. Trek, along with a few other companies, started putting a layer of glass in the joint, which drastically reduced the failure rate. If there isn't some sort of insulating layer between the materials, the joint will often fail within a few years. Even more important on aircraft...
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Stunned silence!
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On 12/17/2004
Greg Olsen
wrote in from
Canada
(206.172.nnn.nnn)
Hey you dudes! Did I stun ya into silence with my awesome board or do ya hate it?! ;) Come on welcome me to the fold. Friendly friendly how abouts? Or is there a secret password? ;) Anyone tried a foamcore wrapped glass deck before. I would like to make the next one softer but I am not sure if this kind of deck is supposed to flex or not(mine doesn't). Anyone used that Vinyl-Ester resin. It is supposed to flex. Iw was just trying to do it on the cheap for the first one. Anyone here a Mechanical Engineer?
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that reminds me
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On 12/16/2004 herbn
wrote in from
United States
(152.163.nnn.nnn)
that may be done in vary strict aircraft engineering circle to isplate the aluminum from harsh direct stresses from the carbon. It sounds familiar, an engineering guy i knew mmentioned it once. kevlar interwoven in a carbon part can also hold it together if the carbon fails.
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alum and carbon
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On 12/16/2004
robotoPDX
wrote in from
United States
(24.20.nnn.nnn)
a very thin layer of fiberglass between your carbon fiber and aluminium would remove any risk. This is used often for points where aluminium touches carbon fiber.
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