Ski Builders Forum

Let us know how it works out Kelvin. I am very intrigued

We were able to test out the heated press and it is AWESOME! We were able to press 2 pairs in a few hours. Each pair took 40 mins. Pictures and writeup are coming soon.

kelvin

yes, the heated press was a success! i'll have some photos to share at the end of the day. must work now...

Great. Glad to hear it went well.

Its amazing how you just need to talk to the right people. The guys I talked to about the heat blanket were nice but did not think it would work. I was also working on putting the blanket in the top part of the mold as well, which probably was the main problem.

So, did the blanket you use extend the full length of the ski? i.e. up the tip and tail curves? Sorry....I'll wait for the full report.

I'm axious to know how this worked. I was starting to move on to a more expensive solution of having electric heating elements built into a sheet of aluminum. Basicly a heated platen design.

Glad you were able to make it work!

-jordan

Awesome BigKam! Can't wait to hear the particulars...

for now, drool over the intro photo.. . http://www.skibuilders.com/

Kelvin did a fantastic job building and designing the heated addition to our press. it works like a charm, and it only takes about 40-minutes for a pair of skis to cure. i personally think that heat is the way to go!

Kelvin is in the process of writing up an article about the heated press. we'll post it soon along with comments about our two new pairs of skis: Daddy's Little Girl and Kaffeine.

couple questions about pressing..... I'm getting ready to make the base contour of the mold portion of the press. I plan on using MDF. I will alternate camber pieces with tip/tail radius pieces. I read (somewhere on here) that with this layout there is some wavy-ness in the ski base that has to be tuned out. I still need to purchase the sheeting for the base & top release layers. What are you using as your release layers and is is effective in minimising this wavy effect? I'm getting ready to order the last few things I need from Durasurf & I need to know if you're using any plasics in the over/under layering of the press. I remember that someone was using 1/8" MDF layers to smooth the wavy-ness but with marginal success.

Thanks as always.

PS- I've checked the site a dozen times this evening waiting for the details on the new skis & hot press

hose-man wrote:couple questions about pressing..... I'm getting ready to make the base contour of the mold portion of the press. I plan on using MDF. I will alternate camber pieces with tip/tail radius pieces. I read (somewhere on here) that with this layout there is some wavy-ness in the ski base that has to be tuned out. I still need to purchase the sheeting for the base & top release layers. What are you using as your release layers and is is effective in minimising this wavy effect? I'm getting ready to order the last few things I need from Durasurf & I need to know if you're using any plasics in the over/under layering of the press. I remember that someone was using 1/8" MDF layers to smooth the wavy-ness but with marginal success.

Thanks as always.

PS- I've checked the site a dozen times this evening waiting for the details on the new skis & hot press

hose-man: one of the causes for the wavy-ness is our mold design. to minimize cost and make the building process easier, we decided to space the ribs as shown in http://www.skibuilders.com/howto/equip/mold01.jpg. notice how there's a gap between each rib. the width of the gap is the thickness of an MDF rib. we covered the mold with a couple sheets of 1/8 - 1/4" hardboard. we thought it would be enough to provide for a smooth surface, but during pressing the pressurized hose can exert quite a bit of force, therefore causing the ski's base to be wavy. in our skis we noticed that the wave pattern matched the rib-spacing pattern in our mold, which suggested that our rib design was a potential cause. so, one way to avoid such wavy-ness is to make the base mold solid, i.e., do not space the ribs as we have done. doing that will cost a lot of $$ and time, obviously. but that avenue is probably not necessary. for example, in our heated press Kelvin added a sheet of aluminum (i think 1/16") on top of the two layers of hardboard and heater element. the alumium made the mold surface more resistance to "bending" over the gaps in the mold. so, if you can make the mold surface "stiffer", then you can probably avoid the wavy-ness effect. and interestingly, we didn't notice any wavy-ness with the two new skis we pressed using Kelvin's modification. the only thing we noticed was the base was slightly concave. this most likely is caused by the edges, because we did not recess the core material to account for the fact that the edges stick up above the base material. anyway, both the concave and wavy-ness isn't much of a problem as long as it's not severe. they can be removed by grinding..

be patient, we'll have photos soon !

I indend to use the same alternating rib assembly for my press base in order to allow me to vary the length of the ski. I suppose that the heat cure might also hasten the curing process enough that the ski doesn't have time to deform into the spaces between the ribs. Since my cure will be heated as well, I may not need to even worry about this.

Has anyone else got a way to vary the length of the ski press base without the gaps of the alternating tip/tail and camber ribs?

hose-man: one of the causes for the wavy-ness is our mold design. to minimize cost and make the building process easier, we decided to space the ribs as shown in http://www.skibuilders.com/howto/equip/mold01.jpg. notice how there's a gap between each rib. the width of the gap is the thickness of an MDF rib. we covered the mold with a couple sheets of 1/8 - 1/4" hardboard. we thought it would be enough to provide for a smooth surface, but during pressing the pressurized hose can exert quite a bit of force, therefore causing the ski's base to be wavy.

BTW the above link to image is a dead-end

What are you currently using as a release layer above the topsheet to keep excess epoxy from gluing the ski to the press. Below the ski I 'm guessing would just be the painter's plastic to contain the glue.

oops, remove the "." from the end of the link. anyway, it's the second photo on this page: http://www.skibuilders.com/howto/equip/mold.shtml

for release paper, Dan Graf suggested for the heated press to use baking sheets. you know, the wax-like paper that you use to cover a tray to keep cookies and what not from sticking during the baking process. i forget the brand name, but Kelvin knows and i'm sure he'll chime in at some point. i'm on the east coast right now and it's 3 hours earlier than Seattle. Kelvin is probably still in bed dreaming about skis....

Does the camber in the mold still have to be exagerated in the heated press? I remember reading that previously you were loosing about 10mm of camber.
Thanks,
Ben

Ben wrote:Does the camber in the mold still have to be exagerated in the heated press? I remember reading that previously you were loosing about 10mm of camber.
Thanks,
Ben

NO!! in fact, we didn't notice much relaxation. our mold has 28mm of camber, and previous to using heat, we experienced significant loss in camber. but the heated press seems to produce skis with camber that matches the camber in the mold. for example, the two pairs of skis we just made using the heated press has like 25mm of camber! it's ridiculous. anyway, we'll show some photos and talk more about this.

We are using parchment paper (from the baking section) as the release. It works great and doesn't melt like plastic would. (thanks dan for that tip)

The aluminum sheet seemed to have taken care of the waviness. It is a little (<.5mm) concave, but is less than it was before the aluminum addition. On the 'daddie's', I put a rabbet in the cores to allow for edge tabs. It seems flatter, but I can't really tell for sure until I clean up the skis and pass them through our belt sander.

I was quite surprised that the camber didn't relax. We'll have to modify our mold to fix that. They are like springboards now.

Kelvin

Has anyone else got a way to vary the length of the ski press base without the gaps of the alternating tip/tail and camber ribs?

My mold actually is able to adjust length and I don't use ribs. I am set up to press one ski at a time. For the ends, I just cut several pieces out of 2x4's, (similar to the MDF ones the Kams use) and used straight brackets to mount them to the mold. My "mold" for my first pair of skis consisted of a 1x8 piece of utility grade lumber. It didn't have any camber, but I wanted to make it as simple as possible for my first round. The ends didn't really see a lot of force pushing them back because the bladder continues past them and pretty much pins them in place.

I also have a mold made of several 2x4's that I cut to shape and glued together. I haven't tried using this mold yet, but I think it should work pretty well with the end pieces screwed to it.

Greg. do you end up with a kink, ledge or flat spot where the tip block terminates?