Friday, August 10, 2012

Calculators for Ski Design, Cost, Profit/Loss

     Keeping good records during ski building is a must whether it's for your own personal sanity or if you want to run a small business making skis or snowboards.     

     I was getting tired of scratching numbers on a pieces of paper, punching numbers into a calculator, and making notes only to misplace them later, or realize I made an error and having to start all over again.

There were 3 things I found myself constantly jotting down, scribbling on the work bench or on scraps of paper. First, what is it costing me to make a pair of skis? Second, what are the key ski dimensions and what size is the core vs finished ski? Third, if I was to try to make a buck on a pair of skis, what's it costing me and if I charge $X amount what's my profit margin?

It was time to get organized so I created 3 Excel spreadsheets to help me with these tasks. I'm sure there's software such as Quickbooks to do most of this for you. But the spreadsheets are easy to use, maintain, and simple. Best of all they are free. Feel free to copy the spreadsheet and modify to suit your needs. I'm sure I'll be modifying them as time goes by to capture more information.



The Profit/Loss calculator is pretty straight forward. Enter your values into the YELLOW boxes and the remaining boxes are calculated. If the numbers in the 'Estimated Profit After Tax ' are  RED you're losing money. If they are BLACK you're making money. You can make the calculator more sophisticated if you want by adding expenses such as utility expenses for the shop, tool maintenance, taxes, etc.


The Ski Core Calculator is designed for the way I make skis. Some of your default values and calculations may be slightly different. But using the calculator is easy. Enter your numbers  into the YELLOW boxes and the rest of the keys dimensions are calculated for you.  So now when I make a ski core I plug in the final ski dimensions and the calculator tells me the dimensions my ski core should be. I print off the spreadsheet, take it down to my shop, post it on the wall and I have my reference sheet at the ready.

This calculator is designed for 2 skis/boards but can easily be changed add all your skis. Enter all of your skis on the sheet, print it off and you have it ready when ever you need it.

Note: All dimensions are in MM. If your are using SnoCAD-X most of the dimensions can be taken from SnoCAD-X. 

Ski Length - Finished length of the ski
Tip Width - Finished width of the tip
Waist Width - Finished width of the waist
Tail Width - Finished width of the tail
Tip Length - Finished width of the tip
Tail Length - Finished length of the tail
Ski Ctr Set Back- I use 50mm  for set back.  
Running Length - (ski length) -  (tip length) - (tail length)
Ski/Boot Center - This is the length from the tip of the ski to the center. (Running Length/2)+Tip Length
Boot Center (Ski   Center) +50  - (Running Length/2)+Tip Length+50
Toe Mount Area Length - 130mm
Heel Mount Area Length - 230mm
Binding Area (toe mount + heel mount) - The binding area is the thickest part of my wood core. The slope to toward the tip starts in front of the toe and the slope toward the tail starts after the heel mount.
Toe Slope Length - This is the length of the ski from the front of the toe mount to the start of the ski tip.
Tail Slope Length - This is the length of the ski from the end of the heel mount to the start of the tail.


Core w/o sidewalls (dimensions between the edges) - Just as it says, the ski core dimensions minus the sidewalls.
Finished Core Shape dims - This is the ski core with sidewalls. As you can see the dimensions are greater than the true ski dimensions. This allows for trimming to the final dimensions.


    The Material Cost is just that. All the costs of the actual material that goes into making a ski. I have a couple of variables depending on if I'm using a wood veneer top sheet or cotton cloth. I also have on there epoxy vs Poly-Urethane glue.


I hope you find these calculators helpful. Feel free to send questions or comment.




Wednesday, August 1, 2012

R/D Carbon Fiber vs Fiber Glass

8/1/2012

Well, I haven't done much in the way of R/D in the off season until now. You may wonder why ski companies use such exotic materials in their skis. Does it make much difference? What am I really getting and what is it really doing for me other than emptying my bank account. I'll try to demystify some of those questions. Skis are very subjective. A firm ski for one person maybe soft to another. I've skied skis that had great write ups and were supposed to be a very firm "East Coast" skis but in my opinion were too soft for me. Bottom line is you don't know how the ski performs until you're on the snow.

Materials such as carbon fiber, kevlar, titanal (IE it's really an aluminum alloy, no titanium at all! Don't be fooled), some skis do claim to have real titanium. Wood core vs foam core (yuk, foam?? you're kidding me!!). AND what wood core is better than another?

Much of it depends on the type of skiing you do. If you are a back country skier you'll most likely want a lighter/wider ski that can have skins attached to them for climbing. So maybe a foam core is what you want. Weight is a huge concern for back country skiers. For the average East Coast skier you may want a ski design for carve-ability. Maybe you do a lot of glade skiing, that could be different style of ski. And if you're a park rat, that's another entirely different design and ski characteristic.

So back on topic.... The last couple days I made up some test samples of Carbon Fiber (CF) and compared those samples to a set of Fiber Glass (FG) samples I made last year. All test samples measured 3in x 36in.

The materials used for this test were:

                 Uni CF 9.4oz
                 Poplar veneer 1.6mm
                 QCM epoxy (resin EMV049 and hardener ECA032)
                  Ptex base
                  Fiber Glass 20oz
                  Cork .8mm thick

See my detailed write up on skibuilders.com, http://www.skibuilders.com/phpBB2/viewtopic.php?t=3868

Feel free to ask questions. That's it for now!