Beginners Questions

For discussions related to ski/snowboard construction/design methods and techniques.

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Akiwi
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Beginners Questions

Post by Akiwi »

Not sure where the best place is to put all these questions so I will start one thread for all sorts of beginner questions. Maybe others can use this as a general purpose questions thread.

Question 1: Software.
What software is the best to use. I have tried SnoCAD-X, and this looks pretty good, but also seems to be quite limited too. For example I intend to make a rocker / camber ski and snowboard, and I cant see how to do this.

Question 2: Profile table
I have started building my profile table for a Router Bridge system. I intend to make an adjustable table with metal rails (20mm x 5mm steel) and use threaded rods welded onto these with wing-nuts to adjust the height of the rails.
My question is how many adjustible points, and what positions would be best.. anyone else tried this?

Question 3: what is the normal thickness of snowboard and ski cores.
I read everything between 1.5 and 3mm tip and tails. and between 6 and 12mm middle core heights.
I will be starting with a simple laminated Ash core. I will try using a veneer cap construction.
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MontuckyMadman
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Post by MontuckyMadman »

Answer for q1.
Whatever works the best for you.
Answer q2.
Every 10cm?
Answer q3.
Tip spacer is 2mm.
Yes between 6 and 12ish mm.
RYM Experimentals
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Post by RYM Experimentals »

Here's my 3 cents....

Q1; I use SnoCAD as well but not for my camber. I do that by what seems right when I'm setting up my press (I have a adjustable vacuum press so its easy to change to what looks/feels right) ***And I know a compression press is better and Ill get there someday, hopefully when I get a new shop in the next couple years.

Q2; I don't use the router bridge, tried it and found it slow and too inconsistent. I built a jig for my planner that works swell and you can feather the tip/tail by moving your core around a bit. The design is on the forum somewhere but if you cant find it let me know and Ill get a few pictures.

Q3; I generally run 1.5 mm on the tip and tail and 6-7mm in the center.

Happy to answer any other questions as you go. Just remember your likely not going to get it right your first time so don't be too frustrated. Keep building and it gets easier. I think were at about 65 decks now and still learning.
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Akiwi
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Post by Akiwi »

+Thanks for the answers guys.
I know I won't get it right the first time, so yesterday i bought some Pine, in the dimensions I will using to make my Ash cores, so I can do a practice run. I am using the router to start with, and at some stage will get a Planer if I make it that far. But I want to start off with what I have got rather than decking out my workshop with tons of new expensive toys, and then after the first set of skis or board not using them again.

I'll see how far I get tonight.

Another few questions about cores.

1. How long is the thickest part of the ski (Vertically speaking)?
2. from the thickest part, to the tip thinnest part, is it a straight line, or does the thinnest part extend a little along the length of the ski? I realize the tip itsself must be a constant thickness, as tip spacers are flat.
3. how long is the thickest part of a snowboard?
4. I saw on SnoCAD-X that the ski is thickest under the toe and heel of the boot, but gets a little thinner in the middle. Why? Does this help with flex?
5. Same for snowboard?

Sorry if I am asking too many stupid questions.
Last edited by Akiwi on Tue Oct 13, 2015 1:57 am, edited 1 time in total.
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chrismp
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Post by chrismp »

Ryme makes snowboards, so the 6-7mm refer to that. Will be too thin for a regular ski afaik.

As for your follow up questions:

1. depends, there are so many variations to do this. Try to copy something known to be working and see if it works for you as well. You always need to start somewhere. My first boards were really soft based on numbers from this forum, so for the next ones I beefed up the cores a bit.

2. again, no right or wrong way. You can even taper your cores to almost zero and use no tipspacer at all. However, if you want to use regular tipspacer make sure your core ends match the thickness of the spacer.

3. see, answer 1. As a starting point, I usually start thinning the core outside the binding areas on a snowboard.

4. no clue about skis haha. In some snowboards the cores are thinner between the bindings to get a softer flex in that area.

5. see 4.
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Akiwi
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Post by Akiwi »

Hi all. My Profile table is nearly finished, and I am trying to build some fake cores using pine, so I can polish my technique.
I am concerned if I can get a flat surface without a plane..
I might take the bases to the local carpenter or wood seller to get them to make a flat surface for me.

However I watched this video from Community Skis, a custom manufacturer of skis in Mammoth Lakes, CA.
https://www.youtube.com/watch?v=ml5mJhhFJYI

Question 1.
I see they are using Birch ply wood for cores. This would make my life so much easier, and cheaper too.

Why have I never seen this being used anywhere else? Is it worth a try.

Question 2.
Secondly at about 2:20 in the film he is using a jig to cut out the cores. This looks like it would be pretty easy to build using a couple of strips of steel e.g. 20mm x 4mm. I figure this would be pretty easy to simulate in a simple way.
Has anyone else tried this? was it good? bad? ugly.
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chrismp
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Post by chrismp »

The problem with plywood is that it is really hard to get in good quality, especially in Europe. With many plywoods the inner layers are full of knots and even voids sometimes. Unfortunately the European grading System for plywood only considers the quality of the outer layers so you never really know what you get with the inner veneers.

What works though is to use a bunch of veneers on top of each other just like the Line Afterbang. This would even save you the profiling if you chamfer the ends of each layer.

Can't say much about the core jig. Don't think anyone on here has done sth similar, but looks easy enough.
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Akiwi
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Post by Akiwi »

You reckon?. From my experience the plywoods I have used are pretty good. Probably depends on where you get them.
I use Marine quality Birke Multiplex.
OTOH I have never pulled a piece apart to see what exactly is inside. But I have never noticed any gaps or knots.

I guess I will just have to try it & see if it works.
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Hannes
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Post by Hannes »

I used birch multiplex in my first pair of skis. When profiling I saw to or three knots in the inner layers. The ski was a bit on the soft side, so the next pair got ash cores from skibaumarkt with the same profile. The layup was the same as well but the performance was much better.
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chrismp
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Post by chrismp »

This might be due to half the layers being cross grain which does nothing in terms of longitudinal stiffness in a ski, and you don't really need side to side stiffness.

In a proper ski core the grain runs along the length of the ski which helps to stiffen it a bit and probably also make it lighter compared to plywood of the same species.
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Akiwi
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Post by Akiwi »

chrismp wrote:This might be due to half the layers being cross grain which does nothing in terms of longitudinal stiffness in a ski, and you don't really need side to side stiffness.

In a proper ski core the grain runs along the length of the ski which helps to stiffen it a bit and probably also make it lighter compared to plywood of the same species.
Yes, that all makes sense.
especially that every second layer runs horrizontally rather than lengthwise. I guess a bit of carbon could help to even that out.

I'll just have to experiment a bit.
Been working in the cellar welding the rails for my profile table.
Will get them on tomorrow, then have to make the bridge.

As an alternative, I have some Maple veneer used for making skateboards. I guess it would be interesting to glue a few layers of that together.
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skidesmond
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Post by skidesmond »

I wouldn't run out to your big box store and pick up a sheet of birch plywood. It's just not good enough, full of voids and it's not made with exterior glues. Baltic birch or other high grade plywood would work, but IMO it's a trade off. You save a the steps of making the core by using plywood.

I've seen that jig in other videos by other ski makers and it looks reliable, assuming all your tooling is accurate. I've thought about making a jig like that but I'm waiting on another technology that turns your router into a portable quasi-cnc tool.
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MontuckyMadman
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Post by MontuckyMadman »

Thnkinv it might be good to pair som decent baltic burch no void ply with carbon. Damp but poppy and livhtish but not too light and really brittle....
Hannes
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Post by Hannes »

One other thing about the plywood: I didn't trust in its ability to hold the bindingscrews so used inserts. To get them in the right place with the right depth with my basic tools needs a lot of patience and time. So now I prefer spending more money on ash and saving by not using inserts. Makes a better ski with less work for about the same price.

But I am thinking about trying cores from bcomp even though I will need a better profiling rig to work with those.
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Akiwi
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Post by Akiwi »

The bCores look nice, but you will have less wood to hold your screws in than using multiplex. They recommend either using inserts, or adding a binding reinforcement plate as indicated here: http://www.bcomp.ch/files/bcoresd200_pr ... orange.pdf

I am surprised you were worried about your screws pulling out, as birch is a relatively hard wood, and should hold screws well.

I will buy some Ply this weekend and try to make a snowboard core with it. (If I get my profile table finished in time). I should see the internal structure then, and can assess if there are too many knots etc.
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