Ski Builders Forum

pmg wrote:Hi,

5-6cm for powder might do, I think on hard pack it will suck. What I would do: Depending on your shoe size you can adjust the position of your foot via the demo bindings by ~5cm. So I would put the binding in a way that you can have a normal stance at the center of the sidecut and up to 5cm backwards.

Regarding Inserts: I use Rampamuffen Typ C to do exactly what you want. Its a bit more work than normal mounting, but once its done its great. Also you dont have to care about the type of wood under the binding.
Have a look here:
http://www.skibuilders.com/phpBB2/viewtopic.php?t=4793

Thanks for the tip with the Rampamuffen. I got those and put them in. They were a pain to get in, and some were pushed open at the top a bit.
I found the best way to get them in was to put them in upside down with the split at the bottom of the ski, and to screw them in by inserting the screw. I did it that way on the second ski after bending a couple of the inserts when putting them in. They are long enough that I am not worried about the screws not holding.

What size drill bit do you use for the inserts? I used a 6 or 6.5. Maybe I should have gone bigger.

I got the Marker Griffon Schizo bindings which can be moved 6cm front and back.

If I have a aluminium/metal mould for twin tip ski lenght 180 cm, can I make a shorter ski with traditional tail tip if I make a separate tail part and glue it to mould. Use hot glue so that it could be removed? Yes Im using vacuum. Just to have plastic on top side?

What could be core thickness for touring ski 85 mm in middle, lenght 175 cm; ash and birch as core material? Thanks if someone replay.

heke wrote:If I have a aluminium/metal mould for twin tip ski lenght 180 cm, can I make a shorter ski with traditional tail tip if I make a separate tail part and glue it to mould. Use hot glue so that it could be removed? Yes Im using vacuum. Just to have plastic on top side?

What could be core thickness for touring ski 85 mm in middle, lenght 175 cm; ash and birch as core material? Thanks if someone replay.

I think that depends on if you have an extra layer of something over your Aluminium / metal mould.
It is important to have a very smooth transition between the two parts, so if you filled the transition with somethng, and then have an extra layer of something between the mould and your ski, then it should be OK.

I have a sheet of clear polycarbonate which is about 1mm thick on top of my mould. I have a printout of my skis or snowboard under that so I can position things perfectly. this should help hide any bumps.

That said, I think that it would be difficult to get a smooth transition between the ski base and new tail portion... though it is probably not that important there.

For core thickness, as Ash and Birch are relatively stiff, I would think 2 mm whould be fine for tip / tail.
In the middle I am not so sure. I went for 11 mm on my skis which are 94 wide and they seem OK, though stiff in the middle.

I make Cap construction with vacuum. On the first pair I just insert tip spacer as big piece and cut away parts after laminating. Would it be stupid idea to cut the tip spacer on final dimension before laminating as core is. I think this would give better result and the veneer would bend as in side wall.

I hope my bad English explains my idea?

What ever I will try😊

heke wrote:I make Cap construction with vacuum. On the first pair I just insert tip spacer as big piece and cut away parts after laminating. Would it be stupid idea to cut the tip spacer on final dimension before laminating as core is. I think this would give better result and the veneer would bend as in side wall.

I hope my bad English explains my idea?

What ever I will try😊

It would work.
Of course if you do this then you don't need to use a tip spacer. You could just extend your core to include the tip.

As I understand it, one of the main reasons for using a tip spacer is as a substitute for sidewall material. and with cap construction you don't need this.

Akiwi wrote:It would work.
Of course if you do this then you don't need to use a tip spacer. You could just extend your core to include the tip.

As I understand it, one of the main reasons for using a tip spacer is as a substitute for sidewall material. and with cap construction you don't need this.

Hi,
according to my understanding vacuum don't have enought power to bend the wood core to tip /tail? This plastic bend easily. Yes the plastic must be much more dureable compare to veneer.

Vacuum should easily bend your wood cores.
Unless you prebend your cores they will not lay flat in your mold and make your layup and alignment more difficult.
They will also add some internal stress, trying to straighten out inside your ski.
This is one reason why people use tip spacer.

sam

sammer wrote:Vacuum should easily bend your wood cores.
Unless you prebend your cores they will not lay flat in your mold and make your layup and alignment more difficult.
They will also add some internal stress, trying to straighten out inside your ski.
This is one reason why people use tip spacer.

sam

thanks I was also thinking that the bending will increase some stress to wood. In traditional wood ski manufacturing they bend the tip by using hot water or steam as you surely know. Some day i will try this as I want to build full wood skies

I switched to wood tip spacers some times ago and have no problems. No bending of any kind cassette going in the press flat.... not sure if vacuum press would produce same results.

I use an interlock style tip with a 2 mm thick wood center surrounded by 25mm plastic tip spacer. I have no issues with flat bases or with mold conformity as long as the plastic and the wood are the same thickness. Also no issues with maintaining tip rise with this style of tip.

vinman wrote:I use an interlock style tip with a 2 mm thick wood center surrounded by 25mm plastic tip spacer. I have no issues with flat bases or with mold conformity as long as the plastic and the wood are the same thickness. Also no issues with maintaining tip rise with this style of tip.

Do you use vacuum?

I need to make a test with some shorter wood piece in vacuum.

I have seen in some films that also GF is use as tip spacer. How tick is one 170 g glass when it is laminated?

If I make a ski woth only GF 760 gtriax on top so that woof shows trough, will this give good surface if I use this https://www.skibaumarkt.de/produkt/lochfolie/ on top.

I mean does it requested some twilling or other thin GF on top?

http://www.blizzard-ski.com/products/zero-g-78/

Surface like this, with out finger joints

heke wrote:If I make a ski woth only GF 760 gtriax on top so that woof shows trough, will this give good surface if I use this https://www.skibaumarkt.de/produkt/lochfolie/ on top.

I mean does it requested some twilling or other thin GF on top?

http://www.blizzard-ski.com/products/zero-g-78/

Surface like this, with out finger joints

I think if you have 760g Triax on the top and pottom of a wood core, this should be fine.
I normally use Peel Ply under my perforated foil.. however this makes a rough surface that needs to be sanded before painting.
I think it would work.. however you could also put a thin layer of fiberglass cloth on top like this for a nicer finish.
http://shop.hp-textiles.com/shop/Versta ... -P80E.html

More stupid questions. I have use Cap construction. Is it really so that it gives lower torsion compare to sandwich? For me a box takes more torsion than two layers..

I have Atomic skies with cap and fisher skies with sandwich..all are race skies atomic are with highest torsion.

The first pair seems to work well and torsion with cap construction is ok.

My opinion is that a cap constuction would be torsionally stiffer than a sandwich construction board. As you say, the diagonal fibres are completely enclosig the core.
Also I would think that the layers of fiberglass and resin would be better at transferring preassure to the edges, than a softer sidewall construction.

Though I have not scientifically tested it.