Summer skibuilding 2014

[pavelbozak]

Hi, I just realized to put some images from my second season of skibuilding. There is such a hot weather, that I can t go out to profile my next cores :D and continue with working. This year I have finished 5 pairs and I would like to add maybe five or six more pairs :)

I am a student and don´t have some CNC machines, or other expensive equipement. I just use my father´s "workshop" and try to improvize as much as possible, but that doesn t mean I don t want to built my ski with high precision :) aka router is very powerfull helper when building skis....

Let´s try to upload some photos:


my skipress.... designed for 6 bar pressure (I use the pressure of 5 bars). In fact, this is the first thing, I d like to built new. It doesn t mean it is not good, but it seams to be quite anoying to put skis with the whole form into it from frontside... I spend so much time with core fixation to pretect it from shifting. And I d also make some better heating. My aim is temperature about 50 °C, so now my heating is a kind of sauna around the press :D. Looks horrible, but it works for now....


Layup with the whole bottom form (it is very heavy and 2 persons re needed to get it into the press)


Cores I use are made from high qualite ash wood. My experience is that it is not easy to built soft skis :D But In fact I am happy with that...


Core density detail...

Last year I used bangkirai for sidewalls but this year I decided to try black locust (it is quite cheap in here to get it). But bangkirai for sidewalls seems to be perfect (after 31 days of skiing on my moms skis, absolutely no defects). The only problem is price of the bangkirai wood...


Attached sidewalls (Black locust)


one funny picture... I overroutered one core so I decided to try how flexible is it... almost impossible to break it and this core was not from the best wood I have :)

for cutting bases and cores into shapes I use classicaly halftemplates. It takes me about 1,5 - 2 hours to make it smooth and nice but then I don t need CNC... with that method is possible to reach quite good results and make exatly shapes which you need...



That one is for my "pro model" - 195 BM skis with 45 m turning radius :)

Here is my ski family:

one pair is missing.,, I use wooden topsheets. I love wood look and my opinion is that if u use solid veneer it is much better than some nylon for ski properties... Today I tried to make some woodburnings into my skis, so I will post some photos next time...

[Smiley]

Hi,

Where are you finding black locust? I live in Switzerland and am having a difficult time finding anything other than beech, pine and paulownia.

Thanks,

J

[MadRussian]

nice work

BTW you press can be easily modified to insert cassette normally

[gav wa]

nice work

BTW you press can be easily modified to insert cassette normally

Was just thinking the same thing. My original press was designed similar to yours and I very quickly realized it was a pain to use. You just need to add some decent supports at the ends and a couple of very sturdy beams along the top and bottom.

[pavelbozak]

Hi,

Where are you finding black locust? I live in Switzerland and am having a difficult time finding anything other than beech, pine and paulownia.

Thanks,

J

Hey, it is not easy to find black locust wood in quality, that u need for sidewalls. But here in Czech republic it is possible and quite cheap, but u have to go and check plenty of wood in several warehouses... I ve checked two palettes of wood to find 5 nice pieces.... First problem is that this wood contains quite a lot knots and the second one is that it twists as hell... I ve never seen such a twisty wood...

BTW I ve found severel exclusive pieces of black locust and decided to make one skis from those pieces...BM 195 cm long skis for my brother. Just connected with some biaxial fiber glass 0-90 and biaxial carbon fiber +- 45 and the resul is very nice stiff flex and no possible torsion twist... Little dissadvantage is weight - 2,7 kg per ski (195: 140 - 119 - 128).

The other way how to get black locust is to cut some trees :D ... here in CZE there is too much black locusts. This tree is not originally grew in here and is taken like "knapweed". But this method is quite slow and complicated, you have to cut it, dry it, sort it....

For u from SUI could be difficuilt to come here for some black locust, but I remember that guy who sold me this wood, told me he had plenty of black locust from Austria...

I would recommed u bangkirai wood for sidewalls. I ve tested it and this wood rips in durability... No problem with bonding like other tropical woods. It is possible to get in format like 25 mm X 145 mm X 2(4,6 ...) m. It is basicaly sold for outdoor floors.

For ski core I use ash, quite heavy in contrary to mixed cores (poplar/ash act...) But I say ash is the best wood for making skis, which are aimed for downhill/performance skiing. I bought 3 sheets of siberian cedar, it was just a random situation, cause I met guy in my neighbourhood who is a distributor of that wood, so I decided to try it for "superlight" core. We will see how good that wood is in connection with plenty of carbon stringers :). Its density is similiar to poplar, flexion is almost the same but the pressure durability and ability to hold screws is much better.

[pavelbozak]

just finished few burnings, ready to be varnished with special 2 component PU yacht coat (7 layers recommended)

[pavelbozak]

nice work

BTW you press can be easily modified to insert cassette normally

thanks, I think it will be easier to built new one and keep this one as a second option. I have some extra firehoses in deposit and I hope I ll get some cheap iron in the near future.

The best about this press is the fact that it is light, strong and "mobile" and you can easily dissamble and put it into deposit... Now I have a place where I can have my press permanently.

I am now wondering about heating. My aim is temperature about 50 degrees and keeping my skis in press for whole day (or 16 hours). My present heating is something like improvized heatbox around the press, such a small sauna. I can easily reach temperatures between 40 - 50 °C. I was thinking about heat-blanket but my abilities with elektricity are really not the best and there is also not possible to buy such a silicon mixture to built it. So I d like to design my press in dimensios that I can easily close an isolated area around the press and switch on some usual radiotars and ventilate hot air in the closed area with ventilator.... Maybe a bit crazy sollution, but I hope it will work :)

[MontuckyMadman]

these people can make you a custom heat blanket, I dont know what trade restrictions you have with china but they make a good product.
http://alirubber.en.alibaba.com/

[MadRussian]

I am now wondering about heating. My aim is temperature about 50 degrees and keeping my skis in press for whole day (or 16 hours). My present heating is something like improvized heatbox around the press, such a small sauna. I can easily reach temperatures between 40 - 50 °C. I was thinking about heat-blanket but my abilities with elektricity are really not the best and there is also not possible to buy such a silicon mixture to built it. So I d like to design my press in dimensios that I can easily close an isolated area around the press and switch on some usual radiotars and ventilate hot air in the closed area with ventilator.... Maybe a bit crazy sollution, but I hope it will work

silicone blankets is not difficult to make. Don't have to be an electrician or rocket scientist. It took me longer to figure out blanket design then actually making it. Also you will need controller if you don't want to build one from PID and SSR you can buy line voltage temperature controller (look up my Journal).
As far silicone you don't have to use two parts silicone like everybody using. My blankets built from silicone in tubes. It take about five tubes pair blanket. imo impregnating 3x fiberglass with silicon is overkill and not necessary.
Anyway good luck in whatever way you choose to go

[gav wa]

http://www.ebay.com.au/itm/Keenovo-Sili ... RTM1714243

These are an option, but damn expensive. I'm sure you could find cheaper. Or read the thread on home made heat blankets and try making a simple small one to see how you go. Everything you need to know is right there and it's actually a lot easier than it first seems.

Plenty of silicone rubber can be found on ebay
http://www.ebay.com.au/itm/Liquid-Silic ... 460db3788e

[pavelbozak]

Thank u all guys for your advices! I tried to write to the alibabarubber (upper link) and their response was very fast... I think for me is enough to have top heating so I would take only one blanket - 180 USD with icluded shipping, it seems to be very cheap and for me then building my own blanket would not be wealthy... Is it possible only 135 USD per blanket in demensions 200 x 35 cm???

btw that similiar blanket out of germany costs 300 EUR (like 400 USD)

[pavelbozak]

just removed from ski press and brushed into right shape (not finished sidewalls yet)

191 cm, shark tips, 140 - 108 - 120, R 23, solid tip rocker, cca 2200g (but quite nice stiff flex)

construction is okulen base + ash/cedar wood core + carbon biax + fiberglass biax (+- 45°) + oak veneer

I will add some polyurethane coat


















I am not decided about finishing wood design, maybe some pyrography or design aka surfboard stripes [/img]

[MadRussian]

BTW I ve found severel exclusive pieces of black locust and decided to make one skis from those pieces...BM 195 cm long skis for my brother. Just connected with some biaxial fiber glass 0-90 and biaxial carbon fiber +- 45 and the resul is very nice stiff flex and no possible torsion twist... Little dissadvantage is weight - 2,7 kg per ski (195: 140 - 119 - 128).

The other way how to get black locust is to cut some trees

2.7 is not bad for skis that size.
Did you get a chance to try skis build with black Locust/black Locust sidewall?
you only one recently mentioning to using black Locust. I'm trying to get some feedback. Inthe future I going to use it for sidewall maybe even in core construction mix this popular but I have no idea what to expect

[pavelbozak]

Hi, i have already tried sidewalls from bangkirai wood. Durability is amazing and also the look. Someone says that wooden sidewalls increase the amount of vibration in skis but i dont think so...

this summer i decided to go with black locust sidewalls. BL is very hard but in the same time flexible wood. It was used also for building bows. It is not necessary to ipregnate or varnish it. The only problem i can see now is that the BL wood twists as hell, so it is not the easiest to work with it.

i will tell during winter. I have also tried siberian cedar instead of ash. It is light and the flex is very similiar to harder ash....

[MadRussian]

from your descriptions it sound BL should be good choice of wood for skis.If BL good to make bows, should be good to make skis.
I compared BL with hard Maple
http://www.wood-database.com/lumber-ide ... ard-maple/
http://www.wood-database.com/lumber-ide ... ck-locust/

BL slightly heavier and substantially harder.

. The only problem i can see now is that the BL wood twists as hell, so it is not the easiest to work with it.

What you mean? Twists while driving? Twists after cutting?