Kublai ski press with new lowering top mold assembly

[bigKam]

Hi Everybody!

First, happy Thanksgiving holiday!

I made a modification to my ski press (named Kublai) that I'd like to share. You might find it useful. I did not do an exhaustive search through this forum to see if anybody else has done this exact design, so I apologize if this is a repeat.

Anyway, I think the illustrations and pictures say it all. At the bottom of this thread there's a link to the video that shows this thing in action. The modification was cheap ($40).

I built the I-beam style, fix cavity ski press named Kublai back in 2007. The original post can be found here: http://www.skibuilders.com/phpBB2/viewtopic.php?t=668

It was a nice design, and the cattrack helps to distribute the pressure. I've pressed many many skis with success. However, the cavity being of fixed height was sometimes a pain. For one, I had to 'squeeze' the cassette into the cavity. Sometimes it would go in easy; other times I had to fight the cassette, and occasionally I would get shifting of parts, etc. Also, adjusting and cleaning the heater and the bottom mold under limited space was tricky at times.

I dreamed of having a top mold assembly that would raise and lower, like some of the clam-shell press designs out there. This way, I could layup then gently close the shell and press.

Over the past few months I thought about building an entirely new press with hinged top beams and using a hydraulic ramp or similar to open and close the press. I started working on the design on pen and paper, but finally thought it was silly to waste the press I already had. So instead, here's what I came up with:



As you can see, the top mold, cattrack, and fire hose now float are not connected to the top beam anymore, but instead the whole assembly (I call it the top mold assembly) is connected to two supports and a beam (made of 4x4 wood). The beam is then supported (balanced) by a cheap bottle jack (Harbor freight $20). I fabricated a small metal clamp that connects the jack to the beam to avoid any slip. The jack itself is fixed to a wooden base to keep it from tipping over, but the base isn't connected to the top beam either. This way I can slide the whole top mold assembly and the jack side to side if I need to make fine adjustments. Notice that the two vertical supports (made of 2x4's) passes through the gap that separates the two top I-beams. I drew dotted lines to indicate that the vertical supports are hidden behind the I-beam. Luckily, I left just enough space for the 2x4's to fit through to connect to the top mold.

As shown above, the bottle jack is raised and thus the top mold is raised well above the bottom mold and cassette. So now I can slide in the bottom mold and cassette!!! Also, I can change out the tip/tail molds with ease.

Show here is a sequence shot of how it all works:


After the bottom mold is slid underneath the top mold assembly, the jack is lowered, and voila, the top mold gently lowers onto the cassette!!! The space between the top beam and the top of the top mold is filled with solid blocks made from scrap 2x4s.

So, I've tested this new modification and it works beautifully. I can raise and lower the top mold so I can slide in the bottom mold. I designed the bottom mold to sit on a tray that I can slide into the press.

I hope this modification is useful to some of you. Please look at the video near the bottom of this page as it shows the press in action:

http://www.skilab.com/projects/rondonnier/

Cheers,
Kam

[MontuckyMadman]

pretty damn sweet thanks for the details.

[skidesmond]

Very clever way to raise and lower the top mold. I can relate w/ the frustration of getting the cassette into the press.

happy Thanksgiving!

[rockaukum]

Kam,
Nice work. I have a press that the whole top portion raises and lowers with bottle jacks. One thing I would like to change is having the bottom raise and lower into place because my with my design the bottle jacks are between the two lengths of fire hose. Other than that this is the way to go. Much improved for loading the cassettes!
open

closed

[richie]

yup this summer I am rebuilding my Ibeam press to includehinged end andrams, I have all the pneumatics so just need to get the steel turned in lathe and welded onto the existing short end beams to turn it into a hinge and joint, plus get some big pins cut. This will make life a lot easier for me, and avoid the exact same issues. will post pics of mods when done. cheers

[feldybikes]

Tangentially OT: that video was rad. I like the contrast of the CNC router, then the mixer that looks like it came from Goodwill for the epoxy. Same with the pro base grinder and the old iron. Only use the good stuff where you need to -- I like it!

[MontuckyMadman]

Its a shame you have a cnc and still put holes in your cores for alignment purposes.
Perhaps if you helped share more about your purposes and techniques and read more of the posts on here you would learn some better ways to do that.

[holmtech]

Kam,

I'm just getting started and am in the process of bolting together a new press very much like Kublai and I'm debating doing something like you're showing here. I've got four 7.5' W12x26 beams that I'm bolting together with a 1" gap (I figure I could do something like you have but with 3/4" boards running between the beams.

I was wondering what's the distance you have between your top and bottom beams? From your old post you were 13" originally? Did you change that for this? Would you have changed the 13" had you to do it over again but weren't making this mod?

Thanks! This resource you guys have built is amazing!

Mark

[bigKam]

@ MontuckyMadman -- yes, yes, I know I know...that CNC is nice and precise. I tune it like I tune my bike every few weeks and wax the o-rings on the sealed bearings.

I wish I had more time in the day to dig thoroughly through this form.....

Anyway, I haven't found a good way to line things up other than poking holes everywhere. Alignment is key. Any thoughts? I'm happy to listen. Now that I'm doing the cap skis, core alignment is even more critical. I have to be within +/-0.5 mm now....yikes!

@holmtech -- yes, still at 13", but I'd separate it enough to fit a 2x4, so 1.5" gap is good. Besides, you are going to want a nice and wide platform to work on.

I wouldn't change much if I did it again. The 13" gap is sufficient, even if you do the mod and it will provide some cushion in case you need it. Better to have a little more throat than too little.

Good luck!

[Richuk]

Have you considered a vac approach for the topsheets on Kam. It's an extra process, granted, but it gives you greater design flexibility within cassette.

It will definitely add to the number of options for holding the core in place.

[bigKam]

@Richuk -- Yes, I've vacuum pressed skis before, but I don't understand what you mean and how it would solve the issue of alignment with the core and the topsheet. Can you explain? Thanks!

[Richuk]

I'm assuming, perhaps wrongly, that including the topsheet when pressing, limits the option to orientate/hold the core in place. You don't want to mark the topsheet un-necessarily.

You could consider pressing without the topsheet - just include a layer of peel ply. Remove the peel ply once you are happy with the result and then vac the topsheet in place - it gives you the level of mechanical bond you require, if you don't do this straight away. I've lost the link to the clip of the France company that does this.

Otherwise, you might find something like this tricky: viewtopic.php?t=2459&postdays=0&postorder=asc&start=30

Depending on the thickness of you cassette, you could locate around a hex socket bolt. This might provide you with the option to drill out the head and use it as a locating point for the pin located within the top half of the cassette.

[MontuckyMadman]

OK so you will have to tel me more about damping.
Im not sold on kevlar but ...


So its a semi cap, tip and tail are cut like a standard sandwich?
Use extended tip and tail with alignment pins and trim off with flash, ala 333 skis style.
So you get rid off those lame holes in the middle of the core maybe.

Depends if you are able to use a flat cassette. Might be tricky as they are not very tall.
Those one guys used a small AL pointed nipple in their one vimeo vid to hold the core in place. Pretty nice kinda like I am describing but it then become permanent.

We us the dowel system and super glue to the AL cassette for each ski prior to pressing takes just a few minutes.

hope this makes sense cause I have no idea what rich is saying. sorry just me.

[Richuk]

MM, I'm suggesting that the dowel used in your process won't work for Kam and should be replaced with a hex socket bolt.

I've posted a pdf about kevlar in the past - think its part of an Alex13 thread. It's serves a dual function - mechanical and vibration dampening properties.

Search about the web for further details. This is something I came across this morning, helpful graphic: http://www.vectranfiber.com/BrochurePro ... mping.aspx