Pow 4 all, please

[Mutombo]

Hi guys! I´m posting some pictures of our progress with the mold.
We have almost finished it. It consist on a mix between clamp and neumatic press. We don´t have air compressor so we decided to blow air into de hose, close the air valves and then apply pressure by clamping the two molds with the bladder inside to do a uniform pressure.
Here are the pictures until today 24/04/2006
1. Drawing the line to saw the wood

2. Sawing it

3. Sanding the mold

4. Cutting the tubes to clamp the mold

5. Painting them

6. Drawing the holes

7. Drilling the holes

8. Glueing the mold

9. Because of the bad quality of the saw the different strips didn´t make a flat surface so we dediced to put a slim metal sheet (1mm thick) but we had a lot of problems to bend it (even with the torch) but finally we got it

10. Cutting the sheet


And this is all at this moment, I´ll post you some more pictures when we continue with the process!

[Skivolkl]

Great pictures, I can't wait to see some more. You might want to sand down your mold so the pieces fit together as close as possible be for you attach the metal to the top of the mold. My first mold had some small imperfections that I thought would be covered up with sheet metal like the method you guys are using and the imperfections could be seen as high and low spots in the base. I also used vaccuum pressing so there was not a lot of preassure on the skis in the mold. The high spots can be removed with a base grind, but the low spots are there for good. Even with a few low spots (1-2mm) in each ski they still worked pretty well. I am looking forward to the pictures of your hybrid pneumatic/clamp press, it sounds like a good idea.

[windsurfer]

nice idea with that combination pneumatic/clamp.
Sounds easy to build. I only built a clamp press. But yours seams to be better!
I am looking forward how it works!

[Mutombo]

We almost finished our press, we only have to cut the slender sticks.
We have tested it and it seems to work, first of all we blow a little bit of air into the hose and then tighten the nuts, then blow air again and tighten again to get the final pressure. We blow air with a simple feet pump, the bike valve seems to withstand that pressure well.

We´ve left 24 h with the pressure and there are no air leaks.

The only problem I´ve seen is the plait it makes in tip and tail section due to shape. I don´t know if it will affect causing different pressure in this point.

Soon more

[hose-man]

Looking good! It's cool to see everyone's different approaches to the same problem. You look like you have another suitable solution here.

[Idris]

With a foot pump you can put in as much pressure as a compressor. Or at least enough pressure to destroy a mold. So beware. But also you might want to try inflating a bit once you have put your mold together.

[Mutombo]

Yes Idris, yoy are right, we pump enough air inside the blade thar everything started to sound like a submarine in deep water. But everything held in its position.

Yesterday we pressed our first ski. And the result was not good. As I posted in other topics we lost our patience and try to hurry as possible (this is because I have some friends that are going in two weeks to the french Alps to a glacier and I wanted they tested this first pair in order to make the second better).
We made some mistakes as gluing the edges before bending them: fatal error, the second one was the top mold had less radious as the bottom mold so the bladder didn´t press uniformly in the arc so the wood core didn´t glue with the base, maybe this was because the tip and tail section was about 4 mm (the good was very soft so we decided to to tip and tail wider than usual) so it was hard to bend.
The third mistake was we designed a ski too long for the press so the tip and tail were too high and most important thing was that when pressing everything moved and we didn´t see it so the ski has a very high tail different to the small tip height ( with this ski you go better switch in deep powder than usual riding haha)
And the final mistake was trying to use HDPE as topsheet. This material without any treatment does not glue with the eposy wo we lost our topsheet.
I wanted to call this ski " Garbage in garage" because of the topsheet material (black rubbish bags). Now looking at the result I think this is the best name for this ski, because it´s a sloppy ski made in a garage hahaha.
Although all of this I´m very happy of being able to press our first ski.
Tomorrow I´ll saw you some pictures of the process...

[G-man]

Great attitude Mutombo... so important to keep it fun. I've been surprised how well a ski still works, even after suffering from a number of pretty big mistakes. I've seen some factory skis that I'd call garbage, also. I'm looking forward to your pictures and a report on the second ski when it's pressed.

G-man

[Mutombo]

Thx G-man we have worked a lot to develop this proyect and we are not going to throw it away. We know that if we still do ot havinf fun we´ll be able to make a good pair.
Probably this first ski will last few runs (if it´s able to do it haha) but we are thinkg about making the second ski different to the first one to learn more about ski building in order to do our second pair better.
Well let´s see some pictures of the proccess:
This is gluing the wood strips, it´s samba good, a fairly soft wood that comes from africa, we decided to use this material because they only had pine and samba wood near our lab. Pine was very hard and heavy, and didn´t have enough flexibility to do a ski (or it seemed to me).

After this we had to brush the steel edges to remove rust from them:

Brushing them

look at the difference between brushed edges and the ones with rust

For this first ski we used 1,3 mm edges with a 0.9 mm base (thx davide!!)
We had to hurry so we didn´t spent to much time making a edge bender hahaa

This was the first mistake, it´s neccesary to be patient on this step, with a torch and the adecuate tool.

So, I started gluing the edge to the base and then trying to bend them in the tip and tail section... big mistake. After some sloppy work trying to solve the situation we started profiling the wood core:

We used a planer and two wood rails to give the core the adecuate shape
This was simple but not very precise.

As you can see, we manage to do as simple as we can, not too much proffesional but it works, with a little bit more patient I think we´ll do it well.

[Mutombo]

Some more pictures:
We had to prebend the wood core, we profiled with this dimensions: 4 mmin tip and tail and 14 in the center core, I think this is too much so we had some problems to bend it, now I think it´s better to make the core narrower and use more fiberglass to reach the adecuate rigidity.
Prebending the core with hot water:

And this is during lay up. In this picture you can see that the base is too long for this press (we´ll have to do the next one shorter)

We used biaxial fiberglas in this first ski. First 150 gr/m² in the bottom layer and over this 300 gr/m² under the wood core and over it 300 gr/m² with the fibers rotated 45º from the previous ones.

The top layer didn´t work well in tip and tail zone it´s close to unglue because of the tension...
And this is the topsheet...

It didn´t glue with the epoxy so after pressing the ski we removed it.
The ski is in the press:

Look at this, because of the different radious between the top and bottom mold the bladder didn´t press the uniformly so tip and tail were not well pressed.

Next pictures will show you the final proccess

[collin]

Some more pictures: ...

Boo Geocities. It looks like you exceeded your Geocities bandwidth quota. If it keeps happening you could try posting your pics on flickr. Maybe they'll be up later and I can get my vaicarious diy ski fix...

Edit: Cool pics. It's great to see some body trying to keep everything as simple as possible to see if it still works.

[Buuk]

@Mutombo: If you want to I can also host your pictures.
Just let me know!

[Mutombo]

Ey thx Buuk, next time I´ll try to host the pictures in another hosting to solve this problem, thx anyway.
We finally built our second ski and tried to solve all the problems we had in the first one. We allmost get it but we commited two important mistakes (specially one). The fisrt one is that the ski moved into the press again when adjusting the blade and started pressing. Due to this, the ski has a very high tip and low tail, the other one has high tail and low tip so we decided to turn around it. One ski will have inverted sidecut but I think it can work to know something about how it runs.
The second one was that the resin flew over the base. In the first one we used tape to avoid this problem but we found another one: the tape glued so much that was almost imposible to remove, now the base is so sticky I don´t now if it will slide a little bit...
In the second one we used painters tape which has less glue so we solve this problem but find another one, the resin flew between the edge and the base...
My main concern is how can I fix the ski so they cannot move when pressing. I´ve seen a solution can be use nails in the waist but a prebend is needed in this case and we cannot do it because our bottom mold has a metal sheet and we cannot nail anything on it. Any advice???
And here is a picture of the skis:

Now I have to fix the bindings and test them in our local snowdome (while the snow comes...)
Next one we´ll be better!

[davide]

To fix the skis you can use magnets, or double side tape. You can also put some wood spacers on the mould, and they will keep the ski in position.

You can use sand paper and/or a scraper to clean the base.

[littleKam]

i actually really like the look of those skis. they remind of a shiny wood floor. cool use of the hand-held planer!

snowdome?