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| Home Made Boards (6188 Posts)
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Home Made Boards |
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On 11/2/2004 Aaron W
wrote in from
United States
(24.52.nnn.nnn)
Thanks for all the info!
I have been told (from numerous people) to be very leary of pumps sold on ebay, due to the uncetainty of where they came from.
I plan on making quite a few boards as well as other projects that I would like to work on. I really like the plans that are on joewoodworker.com and think that would suit me best.
Thanks again for the info, and please, if you have any more advice or tips on this topic I would appreciate them greatly.
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On 11/2/2004 Duane
wrote in from
United States
(68.15.nnn.nnn)
You don't really need a very strong pump.
If you plan to build a lot of boards, get a real pump off of eBay. I got very lucky to get a lab-quality pump for $75. Safe, robust and effective. Perserverance pays off but don't buy old junk, and I wouldn't bother buying the cheap diaphragm-style pumps like the little Gast because...
Picking an air conditioner out of the trash will work better. You want a rotary-style compressor, and fridges changed over to pancake style many years ago. Pancake will work but is not as good. Most A/C window units have rotary style, which holds a better vaccum. Rotary has the shape of a beer can, tall and thin. Pancake is squat rounded (oblate spheroid for the techies out there).
We're talking about holding 10 torr here (out of 760 at atmopsheric pressure), so you are pulling over 14 psi vacuum. No need for more.
Pick a bigger GE window unit from the weekly trash haul and you are golden. Make sure the compressor runs. Take the cover off and cut the tubing in and out of the compressor. Use a tubing cutter to avoid getting slag in the tube. Plug it in and one tube will blow and one will suck. Set on "High" Max cold and it will run for hours with no trouble. If it is cold in the room you may have to jump past the thermostat. Use some vacuum grade tubing strapped to the sucking tube and you are set.
The compressor will throw a bit of oil out, so wrap the blowing tube with some loose rags to catch it. Every use, add a little compressor oil into the suck tube, and it will blow the excess out.
The truth is, virtually any vacuum pump will work, but a free one is pretty sweet.
The syringe style like the Roarockit should not be underestimated, a syringe can go way low in pressure, but you must be leak-free in the vacuum bag, or on hand to constantly restore vacuum.
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On 11/1/2004
Bill Boothby
wrote in from
United States
(66.214.nnn.nnn)
I have been watching discussions on vacuum bagging on this forum for a while. Here's my two cents: It's very easy...Check out joewoodworker.com for instruction/info on building a system. Between Ebay and Joewoodworker I was up and running quickly for under $125.00. Most of the decks I press are using layers of 3mm "Baltic Birch" plywood . I'm turning out cambers,concaves S-curves,foam/ply, foam/glass, limited only by my imagination. Have you seen the new "Bahne Banshee"(it was posted on the slalom forum a month or two ago by Jack Smith)? I built the mold and had the first proto in one afternoon. I must confess that I make my living doing cabinetwork,so I know a no brainer when I see one.I have a gang of Jr. High kids turning out some pretty cool slalom decks. I get a tremendous sense of satisfaction out of pulling an exotic plywood shape out of the bag and rendering it into a lively skating platform. Much more so than the "oh my God" kitchens that pay the bills around here. It's really easy, instantly gratifying,HERO status in no time.What could be better?
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On 11/1/2004
Aaron W
wrote in from
United States
(24.52.nnn.nnn)
Hey guys, Im looking for some info on vacuum bagging. Im plannig on making a 11 ply, maple, speedboard with a very mild concave. Since Im bagging it I only need half of a mold to to form my board. How strong of a pump do I need to pull 11 plys of maple to my mold? Again, the concave is going to be very mild, only about a half inch above center.
The reason I am trying the vacuum approach is because I would like to eventually build a board using composites.
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On 11/1/2004
silversurfer
wrote in from
United States
(24.62.nnn.nnn)
Thanks Duane! 3 to 4 lbs. is not bad. But I would like an even lighter deck
if it were feasible without getting super expensive. Of course it needs to be
strong too.
What is the ideal weight for a cruising and push racing deck?
And for a downhill racing board?
Someone on silverfish mentioned that too light of a board would be less stable,
not give as good a ride and be a disadvantage in a downhill racing board.
Do you agree or disagree with that?
But probably not in a flat land racing board, right?
What is the best wood to use?
And what are the best high tech, light weight materials to laminate it to?
At around 3 pounds, I will trust justzoos to build the deck the way he sees fit. It should be great!
But the discussion about light weight materials and decks is facinating.
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On 11/1/2004
ichiban
wrote in from
United States
(68.169.nnn.nnn)
I like the idea of balsa for weight saving properties, but I think it can only be applied to flat-boards. According to this site, balsa is not suitable for steam-bending. Would you guys concur?
http://www.woodbin.com/ref/wood/balsa.htm
The site itself is pretty useful and lists different types of woods with their general characteristics.
http://www.woodbin.com/ref/wood/
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On 11/1/2004 Duane
wrote in from
United States
(68.15.nnn.nnn)
silversurfer, I would estimate that board at 3 pounds, and four if you're not very careful with resin.
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On 11/1/2004 DAve G
wrote in from
United States
(207.69.nnn.nnn)
Tom W,
If it were me..I'd settle for 1 board and place the "thicker" portion a few inches behind the front truck! I know you'll get a board of usefullness rather than 2 that are no use at all!! Cut it extra long and place blocks under it to see where it feels best. Then shape it down to size to utilize the best feel for flex and stiffness
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On 11/1/2004 Tom W.
wrote in from
United Kingdom
(130.246.nnn.nnn)
Simple question :
I have an old wood-core snowboard that I am about to chop up into a couple of slalom decks. However, the snowboard is thicker in the middle than at the ends. If I squeeze two decks out of the snowboard blank, each slalom deck will be a bit thicker at one end than the other.
The question is, should I make the slalom decks thicker at the nose, or at the tail??
Advice appreciated - the bandsaw is spinning in anticipation....
Ride hard, stay safe.
Tom W.
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On 10/31/2004 Yan0
wrote in from
United States
(140.233.nnn.nnn)
As to the superlight boards,
The whole balsa cored board really interests me, but i dont know anything about it. In any case, The board I have in the press right now won't be "superlight", but it will be alot lighter than a simple birch lamination. I took a peice of 5ply, and drew the shape of a board. Then I traced a smaller version of the board inside the bigger one, there is about 5/16" between the outer shape and the inner shape. Then I traced another line from tip to tail about 1/2" wide. Then I traced a bunch of triangles, got out a drill, drilled the corners, and cut it out with a jigsaw. I removed a little under 500g from the board. I am laminating it up with a layer of 3ply on either side. Because I put the epoxy on the 5ply, I also ended up using much less epoxy. I am expecting that it will be slightly more flexable than a 10ply board, so I will probably end up coating it with a layer of carbon or fiberglass.
If this works Out my next project will be reducing the weight of the core, stacking it up so its 10 or 13 ply, and then laminating carbon directly onto the core. Seeing as I dont have a bagging "utility" as of yet, was thinking about coating a peice of 5 ply with packing tape, then sandwhiching the board between two latyers of packing tape coated 5 ply, and pressing the whole deal.
Ohh, and as to packing tape. I just started using it recently. If you have ever laminated a board to the jig, or pressed two boards together and had them stick, I highly reccomend you coat the edges of your jig with packing tape, and coat the edjes of the ply with packing tape. This also helps everythign stay straight in the jig because you can stick the two strips of tape together, and it holds the panels in place.
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On 10/31/2004 toddc
wrote in from
United States
(68.125.nnn.nnn)
good old wood - as in plies - does add a level of dampening. In slalom, you can compare a pocket pistol to a turner or a roe. The turners and roes alway felt very brittle and made my teeth rattle. The layer of maple on the top of the PP smooths every thing out and adds very little weight for this benefit.
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On 10/30/2004 herbn
wrote in from
United States
(152.163.nnn.nnn)
if you're trying to push,or approach upper levels of strength to weight ratio.Ply constructionis gonna come up short.Strength to weight is not the end all criteria for a board though,ply has nice sag,dampening characteristics,ply boards can feel nice and smooth.
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On 10/29/2004 SFKasJ
wrote in from
United States
(68.7.nnn.nnn)
I think it has too much wood and too much CF. The carbon kevlar weave is expensive and won't offer you anything special by having it. You could do one layer of 2ply birch, maple would be better, and then layer on two layers of 6 or 8 oz carbon fiber and it should be plenty stiff and cost a whole lot less.
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On 10/29/2004
silversurfer
wrote in from
United States
(24.62.nnn.nnn)
Ok, as I mentioned before ichiban and I have commisioned justzoos to
build super light and super low speedboard cruisers for us.
I want to thank you all for the comments and suggestions.
In order to keep it reasonable for justzoos to actually build and
still be light this is the composition that he has proposed;
CF/Kevlar weave
birch x 2 ply
single cf
birch x 2 ply
single cf
birch x 2 ply
CF/Kevlar weave
What do you guys think of this?
Will it be strong and light?
Are we on the right track here?
I know that there are even more high tech and space age materials available
but we are trying to keep the cost and complexity to a reasonable level.
Even so we are hoping to create something close to the ultimate speed cruising
longboard.
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On 10/29/2004
frank
wrote in from
United States
(24.153.nnn.nnn)
yan0: Check with heating and air conditioning companies. I use a pump they use for testing air conditioning units. They gave me an old one they dont use anymore. It works great and it was free.
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On 10/28/2004 Yan0
wrote in from
United States
(140.233.nnn.nnn)
On another note,
Svarteld, that press looks sweet, and a hell of alot simpler to get right than the one I cooked up. Here is what I did
I press it with a 3 ton bottle jack, and the weight of my barn. I am working on a press using two or three bottle jacks that lines up the top and bottom of a jig and is self contained, so I dont need to worry about falling my barn everytime I press a board. I am tinking a framework of 6x6 beams or some small I-beam steel... but I need to learn to weld first. Ill try to draw up some stuff and put it on the site.
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On 10/28/2004
Yan0
wrote in from
United States
(140.233.nnn.nnn)
Alot of skis are made that way (honney comb/filler). Both alpine and nordic. I dont know my nordic companies so well, but i know there are some skis with a core of a really light porus wood (like balsa) with a bunch of dado cuts in it, then they take prepreg and laminate around the whole deal. It results in a thick, stiff, and light core. Alpine skis need a bit more strength, and less width, so normally it is just foam wrapped in carbon or glass, but I think it is Voekl that has a few skis with nomex..could be k2. In any case, if the construction can hold up the kind of beatings that skiing puts it through, and still retain its torsional and (longitudinal??) stiffness, it would be great for a longboard.
I dont know exactly what nomex is, so bear with me. I have also seen a honeycomb core mateial made from what appears to be laminated paper. Its a bit like corregated cardboard, but flexable in all directions, and the paper like stuff is STIFF. I ran into it in a ski/snowboard shop. It was cut out like a snowboard, I stood on it, and the walls didnt collapse. As I said, I dont know the name, but that could work out really well too.
On another note, does anyone know where to get ahold of a cheap, reliable lab pump for vaccuum bagging. I started making one from an old refrigerator pump. At this point I am terrified of sending 115A through me while testing it. THere are three little posts to hook up juice to.. No indication as to which is the ground ( I am assuming that if you get the ground right, whether you put the + or - on one pole or another dosent matter, it will just reverse the direction of the pump) Basically, I dont know what in the bloddy hell I am doing, and I would kinda like to live through the experience with out serious damage to my hand, body, or barn. I have checked ebay, and it seems like they have some.. but they get pricy and alot are specialized syringe pumps and the like. I just want something to suck air, and keep on sucking.
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On 10/28/2004
Svarteld
wrote in from
Sweden
(213.64.nnn.nnn)
Thanks :-)
Well, it seems like many high-end "light and strong" constructions are built with carbon fibre prepreg shells, held apart with honeycombs of either aluminium or Nomex. The Swedish fighter Gripen is one, and also Burtons T6 snowboard (using alu), as well as many of Palmers snowboards (using Nomex). Since snowboards need to flex a lot, they use glass fibre, with some addition of carbon strips. To gain in stiffness, I guess you skip the glass and just use prepreg carbon weave, or prepreg one-directional lean carbon fibres, and align them in multiple layers aligned with the biggest loads over the surface. Then vacuum press in heat. But shaping honeycombs will be harder than foam, and edges will probably need reinforcements for impact protection.
Personally, being a beginner in riding speedboards, I don't mind some deck weight since it seems to calm down fast movements. But my damped trucks/boards can't be too heavy, since the dampers add weight, and there's a weight limit for racing - IGSA limits are 5 kg, plus 1 kg "for the allowance in variation of scales". My last one weighs in at 5,6 kg with damper and 92 mm flywheels, so it might pass, but I'm still hoping the next will come close to 5 kg.
Anyone with experience with honeycombs and prepreg carbon in longboards?
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On 10/28/2004 silversurfer
wrote in from
United States
(24.62.nnn.nnn)
Svarteld,
No problem I understand.
I really love your work and would like your input (as well as that of Duane
and herbn) regarding the project that ichiban and I are working with justzoos
on.
If you could check out the the thread I linked a couple of posts below,
and let me know what you think it would be great!
Thanks everyone!
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On 10/28/2004
Svarteld
wrote in from
Sweden
(213.64.nnn.nnn)
Sorry dudes – I'm from Sweden, so splitting a batch with me will be difficult. But balsa sounds interresting as core material, keep posting. Maybe a balsa kingpin would be nice?... Actually, the light wood I'll use for a core reminds of some kind of heavyweight balsa. Anyone planning to replace the balsa with a harder core material around the truck holes?
Since I've been lazy and not building much lately, I'll post some pictures of my press - a pretty simple thing,used with clamps. Instead I've put work into getting all angles as perfect as I could manage. It's responsible for 4 boards so far, in different configurations.
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On 10/28/2004
silversurfer
wrote in from
United States
(24.62.nnn.nnn)
Hmm...
Well maybe you (Duane), me, ichiban, justzoos,herbn, and maybe Svarteld all
split a box?
What is it V-lam balsa?
How much $ is a box and how many longboards will it make?
Does anybody like this idea?
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On 10/28/2004 Duane
wrote in from
United States
(68.15.nnn.nnn)
Yes you can easily mold the balsa core with a one-sided mold. In fact I plan to do just that, using a stack of maple concave blanks as the mold. It is compressible enough to do a fair amount of 3D curvature, probably anything you want skateboard-wise. If you use prepreg, you should heat it up a bit to allow it to stretch or it will wrinkle in 3D curves. It gets tacky when heated so it tends to stay put after that. generally with prepreg you concede a bit on surface appearance, it will never look quite as good as hand-layed air dry with clear epoxy. But it is ungodly light.
Tapered core would be cool but end grain is pretty hard to sand down for thickness evenly, it is made up of blocks glued together and the hardness varies from spot to spot, assuring an uneven sand-out. I suppose a big panel sander used appropriately would work out, but hand belt sanding might not.
I'd just be happy finding a supplier with 24x48 inch sheets, NOT scored, willing to sell less than box quantity. Not an easy proposition, I've found.
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On 10/27/2004 herbn
wrote in from
United States
(64.12.nnn.nnn)
duane,you're talking vertical grain,i guess.so you got the construction.I guess the balsa is flexy enough to vacuum bag onto a single sided mold,is that right? What do you think about tapering the core,for even lighter weight but possibly more importantly, an even flex pattern. Thinner ends by the trucks make for just a bit of small bump complience,but it loads up quick ,doesn't flex to far,keeps things from bouncing to far, with a straight core the board flexs more in the middle, my current board has two full length beams(on either side of the trucks) then there's a beam (carbon wrapped)between the beams ,that reinforcment is about the length of my riding stance. then my trucks are in routed pockets,this increases the flex at the ends of the board just a bit. The main core of my board is just a lowly piece of 1/2 inch birch so so it's nowhere near as light as the balsa core ,i think the birch may dampen a bit more,but i'd love to try feathery balsa core carver one of these days.
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On 10/27/2004 Duane
wrote in from
United States
(68.15.nnn.nnn)
silversurfer, if you want light and plenty strong, use only carbon fiber. Yes, kevlar and glass are tougher but heavier, a properly made carbon board will be essentially unbreakable. Those carbon-shattering wrecks on TV look daunting but those are 200 mph collisions.
For cores foam is lightest but balsa is close and stronger, and you don't have to worry as much about bolt holes crushing with the balsa. But let's assume a light foam.
If you want the lightest you will need to use prepreg carbon and cure the board in an autoclave or vacuum bagged in an oven.
Two layers of 5.6 oz prepreg on each side, 3/8 or 1/2" core. Let's see 9 by 40 inches times 4 at 8.6 oz/yd that's about 9 ounces plus the core, you'd be right at a pound, approximately. It might be too stiff also, speedboard stiff.
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On 10/27/2004 herbn
wrote in from
United States
(152.163.nnn.nnn)
i have no idea what kind of building justzoos is capable of, but thinness shouldn't be all that important,you have drop through trucks so a thick board wouldn't raise you up. I've thought of a really complex build, If you thought up the profile of the low cg design and make a pattern,cut it out of partical board,the pattern for the wood needs to have pins to hold the strips of wood that will be trimmed to that profile,so all the strips of wood in your v lam will have to have a pattern of holes to fit snugly on the shaping pattern.So you'll need a pattern to drill those holes with,all the strips of wood need to start out pretty much exactly the same size. The posibbilities are very cool the core can be thicker in the middle(under your feet)and taper off at the ends.Your board doesn't have alot of drop so the wood strips you sart out with wouldn't need to be too big and a reasonable amount of wood will be turned to dust. Once you have ,let's say 11 bow shaped strips with let's say an 1/8 inch hole every 4-6 inches, you can bolt them together with threaded rod gluing up the v lam,i think some sort of framework might be needed to keep things perfect, once the glue is dry, the threded rods can come out and be replaced with epoxied 1/8 inch carbon rods which makes great cross grain.For skins vacuum bag carbon or s glass, carbon triax is ok but fiberglass triax is to glue thirsty(heavy) regular carbon should be fine,you have extra cross grains anyway. THe cost of having someone else make something like this are probabely ridiculous, i don't think i would even bother ,BUT ,as a personal project ,put in an hour or two every couple of days or once a week ,and thinking things over,over and over again, try not to have setbacks,and eventually you'll have your ultimate board,buying tools for a single project is tough ,but once you got em you find many other uses.I still have to anti up for vacuum bagging equipment ,some day i'll score a good deal on a vacuum pump, there's a joke in the "other uses" phraze.
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