Sacrificial Boards - Custom Snowboards and Longboards

What Makes a good Longboard?

Essentially, grab some wood and put wheels on it. Could work fine, but you'll run into problems. Contoured deck? Well I guess you could carve out the contour from a large block, but that's going to take time and the grain structure probably won't be lined up in the best way and you'll end up breaking it. So what you need is a bunch of thin sheets, glue and a mold.

How thin?
This depends on the contour of the mold, but 1/16th if an inch is typical. If you want dramatic curves you want the plies to be thin enough to form easily.

What glue?
Traditionally wood glue is used. Wood glue technology has grow a lot and you have brands like Titebond and Gorilla Glue that do a great job of holding up to the abuses of your average skater.

How do you make a mold?
This is tough. You can carve or cut your own with some basic tools, skill and patience. If you want accuracy and repeatability, CNC machines are the way to go. These are expensive and require skilled operators as well as 3D design software to create the molds that these machines will cut. A lot of times the easier route is to pay for someone to make these molds for you or just buy existing ones. This is one reason why so many boards from different manufactures have the same shape. Even then, if you choose to have a mold made (which costs money of course), you still need the experienced designer to make them for you. Now imagine you go through all this process and the board you make is good, but not quite as good as it could be. How many times do you want to spend the time and money to make a new mold with these minor changes? At Sacrificial we have our own CNC machines and certified CATIA 3D Design experts, so making new molds and small revisions is never a problem.

Next steps
So after this the boards you made is probably pretty awesome. Besides making anything yourself is a great feeling. But after a time you might notice it's a bit too flexible, or if you made it stiff, then it's probably pretty thick. So you'd like to fix this, so we need to think about the wood.

Wood
Wood is a material science all in its own. Light wood, heavy wood, strong wood... Some is very grainy, some has cool colors, some is porous. On and on. The tradition here is Canadian maple. Why? Cold. The cold Canadian winters cause the trees to grow slower and have tighter growth rings. This makes them strong as well as nice to look at. All our wood laminates are Canadian Maple, but honestly, for the most part so is everyone else’s in the serious board building industry. Bamboo is popular in some areas and other wood surface laminates used for cosmetic appeal but maple is the strong majority.

This is a "must read" on the goods and bads of skateboard wood
Ministry of Wood

http://www.wood-database.com/

This knowledge might get you a little further but to increase the strength, reduce thickness, possibly lose some weight and actually engineer a specific flex pattern you need some advanced composite materials. Currently this is going to be fiberglass, carbon fiber and aramid (Kevlar) fibers. There are more advanced fibers but that takes you into a much higher price range. Some of these we are watching closely and have done some tests on. We may introduce an extreme line later this year but that will probably be in the $300 to $400 range.

Here's a good white paper explaining the various stresses on a composite sandwich panel (Which is what advanced longboards and snowboards are).
Composite Sandwich Core

Fiberglass
Strong tensile strength compared to organic fibers
Low cost compared to carbon and Kevlar
Lower tensile strength than carbon and Kevlar (also more "stretchy")

Carbon Fiber
Very strong tensile strength. Pretty much the state of the art is affordable fibers
Low shear strength (essentially breaks when scratched or hit on the side)
Expensive compared to fiberglass and Kevlar

Aramid Fiber (Kevlar)
Strong tensile strength. Stronger than fiberglass and nearly as strong as carbon fiber
Excellent shear strength
Expensive compared to fiberglass but slightly cheaper than carbon fiber
Certain qualities cause it to absorb or pull in moisture (Super bad for a product used outside)

Benefits of Advanced Composites
Here's a quick reference chart on the Elastic Modulus of some common components

Material	Young's Modulus
Maple	12.62 Gpa
Bamboo	18 Gpa
Fiberglass (E glass)	30-40 Gpa
Aramid (Kevlar)	70-112 Gpa
Carbon Fiber	125-181 Gpa

Right off the bat you can see that none of the organic fibers are as strong as the manufactured fibers. Bamboo might be close to fiberglass (If you call half the strength close), but none are even in the ball park when we look at aramid and carbon fibers.

So Why Wood Anyways?
This probably a time for a huge chart but it really comes down to cost. Not to shake the world, but the primary building material in the future will not be wood. We have materials like graphene, boron, aerogel (and airloy), and various honeycomb hybrids hitting the market and as use of these increases, costs will drop.

Wood was used traditionally because it's, of course, easy to come by. Board builders soon became knowledgeable in the various wood strengths, flexibilities and cost, which brought us to maple and bamboo. As composite materials were added, it was spoke of as being "reinforced" yet the strength of the wood still being considered a factor. In composite engineering we talk a lot about "separation of load bearing surfaces". The more we separate two materials, the stronger the panel becomes. So the material between these plies is there primarily to hold the plies apart. When this core material has a tensile strength five to ten times less than the structural plies, it become almost a null factor is stress calculations.

But...
Compression, weight, durability, ease of repair, mounting hardware (Trucks), vibration dampening are all other factors we need to consider and weight out our best options. Are people going to spend $600 on a board that is just a tiny bit better than a $200 board? Possibly for competition, but not as a majority. So for now, a lot of the higher-tech materials are a bit too hard to come by, so we stay with wood. And let's not forget esthetics. Who doesn't love the look of a fine polished wood grain? Having said that, there are some aerospace materials that we use regularly in different areas that we've been testing for longboard use. Some of this technology being already implemented our ultra high-end snowboards and it's amazing.

Research
So again, check the other sites listed below. MuirSkate has a great tutorial section explaining all the components and what they're for, but so do the others and they might explain things in a better way for you. Another thought is this, if you're just getting started, you're going to make mistakes in things you buy. So research, read the forums (Silverfish Longboarding ), but just get something and go ride. You'll figure out what you like quick enough.

The Sacrificial Board Team