Ski Builders Forum

Hi,

many of you use 2 dovels glued to the base to align the core with the base in the press - definitely a method producing good results!

I want to try it as well, however there are some disadvantages taking a normal dovel:
- You have to cut holes in the fibres below the core
- When using vacuum, if the height of the dovel isn't 100% perfect, you will see it in the end.

So I made my mind up and found a solution so easy you'll love it: Just use thumb tacks!

I love it..
That would have solved the problem of core movement on my last skis!!
On the skis that broke I used an 8mm dowel, and the 8mm hole weakened the core and that is where it broke.. this would solve that problem..
Also it is a pain getting the fibres around the dowel sometimes..
Thanks a ton for sharing this idea.

Just clarifying.. you countersink thumb tack holes in the core to prevent bumps in the base?

I'm a fan of gluing fiberglass straps to the top of the core, then taping the straps to the cassette. I say J skis do that method ina video so it gives me confidence it is a good approach.

PowderCad wrote:Just clarifying.. you countersink thumb tack holes in the core to prevent bumps in the base?

Thats what I do. Pretty easy, I use wood drills and run them counterclockwise. Like this, I prevent the drill really starting to drill... it just countersinks a bit.
Also the hole gets wider at the beginning like this, making it easier to find the hole during layup.

Akiwi wrote:I love it..
That would have solved the problem of core movement on my last skis!!
On the skis that broke I used an 8mm dowel, and the 8mm hole weakened the core and that is where it broke.. this would solve that problem..
Also it is a pain getting the fibres around the dowel sometimes..
Thanks a ton for sharing this idea.

Your post was the reason I started to think about it in the first place :)

Nice idea.
But how do you place the thumb tack on the base? How do you mark its exact position sine the mark will be covered by the tumb tacks baseplate.

I like this method much more than my rather brutal way.

Hi Hannes,

I put the thumb tack in the core, put superglue on its bottom side, put the core exactly where I want it on the base (using tip- and tailspacers as guide) and press down the core -> the thumb tacks stick to the base.

The other advantage of the thumbtack, is that it has a large surface to stick to the base. the dowel method only has a small surface area to glue, and also I found that the superglue would wick up the dowel sticking it to the core.. which made it very difficult to get out of the core without breaking it of the base.
I'll try this method. I started on a new pair of carvers last night.

Have a look at 1/2" carpet tacks, super sharp, flat heads which should bond well despite a smaller head size.

This is dumb. Put the positioning outside the ski core. You dont want a.holes in the core. b.foreign material ie.metal, staples such c.even easier to put it outaide the ski.

Might be dumb, but I am trying it anyway.
I found some roof paper nails that are perfect. (Dachpappenagel)

Montuckys right, core alignment outside your base is the way to go. I've used a roofing nail a few different times and it's hard to keep it from dimpling or pimpling your base. Plus you're putting a hole into your core that's unnecessary. You might not have a dimpling problem much with vacuum pressing but it definitely weakens your core.

Agree that positioning outside the core is better, but:

1) What if you press Cap?

2) If you need extreme positioning precision? For future builds, I am aiming for a normal sidewall which is 2.5 or 3mm thick only (basically humidity protection). If the positioning fails by 1mm its already too much in this case.

I agree with Pmg. for Cap, it is the only way to go.
The hole I drilled is 3mm, and I don't consider that this will make much difference on the strength of the ski.
It is so precise that the core can be positioned with about 0,1 mm accuracy.

Disadvantage of this method.
Yesterday I did a layup, the pins are 3mm wide and 12 mm high. As I put the skis in the vacuum, they both poppped of the pins.. It was a bit fiddly getting them back on. My problem is my core goes right to the tip, so I need a way to hold the cores down onto the bases forcing the tip to curve up.
Next time I will keep the holes tighter.
I thought about pushing the cores onto the pins, and putting a drop of super glue in there... but that could prevent the cores from being pushed further down when the skis are in the press and that wouldn't be ideal.

nrgboards wrote:Montuckys right, core alignment outside your base is the way to go. I've used a roofing nail a few different times and it's hard to keep it from dimpling or pimpling your base. Plus you're putting a hole into your core that's unnecessary. You might not have a dimpling problem much with vacuum pressing but it definitely weakens your core.

You are right.. it dimpels and pimpels the base.
I am surprised at how much