is Too much Preasure Possible

[Bloefeld]

Ok... Well, if you position the tape anywhere over/under the ski itself and it is in the press or vacuum it will leave an indentation on the ski. Believe or not I placed making tape on the bottom of a ski, pressed at 45-50 psi and it left an impression on the base, ever so small but noticeable. Just be careful where the heating element goes. The AL should heat ok.

It's ok if your press is crazy expensive Seriously though, looking forward to seeing your designs, etc.

As for posting a PDF file.... When I wanted to post an Excel spreadsheet I had to convert it to a jpg file and then I was able to post it to photobucket.com and then able to link it to a post in SB.

Hi Again,

Thanks for the method to post my PDF's. That saved me a bunch of screwing around!

I doubt that 1 inch wide tape say 1/16 inch thick is going to deflect the 1/2 inch aluminium that it is on top of. But if that is a concern one could router out the space for the tape in the aluminium. Just get a high rpm router and a good guide and a carbide bit say 1/4 inch wide and set it as deep as necessary to accommodate the heating tape. Mill the top of the plate so the bottom of it stays smooth. Then no problems for sure!

I never use coolant when milling aluminium but it is a good idea to stop fairly often to blow away the chips. You can go pretty fast too. On my mill (I so miss my mill) I would run at 10,000 rpm and 200 inches per minute travel. It could easily have milled at twice that speed, but the mill only went that fast.

Cheers,

Bloefeld.

[skidesmond]

Oh, I was unclear that the Al is 1/2in thick. S/b good to go.

[sammer]

Tape will leave an impression on your base using vacuum as well.

I think the 1/2 inch aluminum would work but would probably cost more in the long run as every different ski would need new plates.
Plus the bending to shape you'd need a good sized slip roll.
Probably cheaper and more effective to just fork out the dough and buy some silicone blankets.

But that's just me I'm cheap!

sam

[Bloefeld]

Tape will leave an impression on your base using vacuum as well.

I think the 1/2 inch aluminum would work but would probably cost more in the long run as every different ski would need new plates.
Plus the bending to shape you'd need a good sized slip roll.
Probably cheaper and more effective to just fork out the dough and buy some silicone blankets.

But that's just me I'm cheap!

sam

Hi Sam,

If I understand the state-of-the-art in Skibuilders forum ski presses, there is a wood form that determines the actual shape of ski. My idea would be to attach the aluminium on top of this (perhaps use slotted holes in the aluminium to give it some play). The pressure would deform the aluminium and conform to the shape of the wooden pressure plate that is usually used.

In thinking about this a bit more, I would use segments of the tape in say five zones on the aluminium. This way you would be able to control the heat for the tips, tales, midsection, and connecting sections.

Way overkill, but what great epoxy cure you would end up with. I've used zone heat for some parts that were wildly different in thickness and it solved a host of problems.

I may be over-thinking this all just a tad.

Cheers,

Bloefeld

PS Went to Nakiska for half a day yesterday. When I got there it was beautiful sunshine. By the time I got my ticket and junk sorted out, cloud had blown in and made the light diabolical. But there was actually some sort of snow-like material underfoot. This blew away when big winds came and left the hill with patches of identically coloured snow and glare ice. I am really starting to dislike how that place keeps trying to kill me. :-)

[Richuk]

I'm just doing a bit of reading - I'd like to write something intelligent, but it seems all the good spots are taken : )

[chrismp]

why go through all that trouble with heat tape and not build a blanket yourself? it's cheap and not that hard.

[Bloefeld]

why go through all that trouble with heat tape and not build a blanket yourself? it's cheap and not that hard.

I was under the impression that heating blankets were too expensive and that a lot of builders were only heating one side of the ski, or not heating the ski at all.

So, I suggested an alternative that would not be that expensive and would give what I believe to be a good result.

Now you tell us that it is cheap and easy to build a heating system for presses. Please tell us more, or point us to some links that will help.

I am no glutton for punishment and I'm pretty lazy to boot, so if you can save us some time and money, do tell.

Cheers,

Bloefeld

[MontuckyMadman]

read this.
http://www.skibuilders.com/phpBB2/viewtopic.php?t=2690
Make them 220 and your controllers also.

[Bloefeld]

read this.
http://www.skibuilders.com/phpBB2/viewtopic.php?t=2690
Make them 220 and your controllers also.

MontuckyMadman,

Thank you so much for the link. It does seem pretty straight forward and a lot cheaper than buying the stuff.

So here is an idea. I build my press and use the idea of two aluminium pressure plates. I heat the plates with resistance wire of appropriate diameter and length in the 3 to 5 zones I had in mind. I insulate them with fiberglass, and pot them in my aluminium plate with high-temp silicone as used in the thread.

Then I control them with PLC's and a cheap desktop computer. With thermo-couples inserted into the centre of my fiber matrix and ramp up each section of each zone on each side until I get to my optimal cure temperature and then start the ramp down. It would even be possible to control the ramp-down by running water through fluoro-carbon tubes that would also be inserted into the aluminium. This could all be easily automated so that once you start up your system, you could walk away and forget it (unless you burn your shop down).

Am I mental or what?

Thanks again for your help.

Cheers,

Bloefeld

[sammer]

The pressure would deform the aluminium and conform to the shape of the wooden pressure plate that is usually used.

In thinking about this a bit more, I would use segments of the tape in say five zones on the aluminium. This way you would be able to control the heat for the tips, tales, midsection, and connecting sections.

I don't think the aluminum would maintain the shape of your mold, generally you have to over bend.
You might also have an issue with bridging if your tip/tail radius is too tight.
I could be wrong so give it a try

My point was that 1/2" thick aluminum is expensive, especially if your building a variety of skis you'll need new sheets for every variation.

Being able to control heat in different parts of your ski could have some potential, though it would also require a pretty substantial cash outlay.
Numerous PID's SSR's and thermo couples put this out or the realm of the average home builder.

As your post suggested using the 1" heat tape as an inexpensive heat alternative you're suddenly approaching more than unaffordable.

I'm curious to see what you do end up building and how much you're going the spend to achieve it.

Just sayin'


sam

[MontuckyMadman]

essentially what you are describing is about the way the $100K Austrian made presses work.
The nice thing about a multi zone heat is you can for instance ramp the temp in the forebody and tip of the ski on the top only to give a nice gradual rocker profile to a long radius pow ski without having to retool, giving you more options and camber profiles from one mold.
You could also make an entirely reverse camber ski from a flat mold as well.

[Bloefeld]

essentially what you are describing is about the way the $100K Austrian made presses work.
The nice thing about a multi zone heat is you can for instance ramp the temp in the forebody and tip of the ski on the top only to give a nice gradual rocker profile to a long radius pow ski without having to retool, giving you more options and camber profiles from one mold.
You could also make an entirely reverse camber ski from a flat mold as well.

Great, then I'm on the right track.

One of the things I have done is design and build plants for the products I have created. In doing this, I have build loads of jigs, fixtures, and automated processes from temperature control, materials handling automation, glass cutting systems, to 5 axis robots. I used products like ITEM

http://www.item24.com/en/

I have found that these systems were a lot cheaper to build than using welded and machined steel. With ITEM you can make a design error and easily fix it. So you get to keep whacking away at something until it is perfect. Then it is easy to use cheaper materials.

I will likely use ITEM to build my press. It will be more expensive for me, but I know I will want to keep modifying it for some time to come.

I will build the system for around $5.000. A lot of money for me to invest until I look at the price tag of a pair of off the shelf skis. Maybe I can sell a few pairs to defray the costs to some degree. :-)

The thermo couple set-up is only needed until the process is perfected, then they will no longer be needed, I will have enough information to control the process by using PLC's to control the heating and cooling cycles.

While I will never build a press as you describe, I think I can build a press that will let me build 4 to 8 pairs per day. If something commercial comes of this, the investment in the press and other automation will pay for itself fast. If not, I will still have a pretty cool gizmo around.

Cheers,

Bloefeld

[MontuckyMadman]

If you are looking to spend 5k on anything made of extruded al material make it a a nice cnc machine for making molds and cores and templates for rapid prototyping.
Maybe you already have access to a cnc machine with high repeatability?
The press and pressing is pretty basic, the heat control is important. Being able to measure your results and make effective and accurate repeatable changes for a specific outcome is the tough part.
That's my opinion.

[twizzstyle]

I skipped a lot of that after I read 1" wide heat tape and 1/2" thick aluminum. 1/2" thick?! Holy smokes! Good luck bending that! How much would a 1/2" thick aluminum plate cost? I'm going to guess $150-$200? And you'll need two. A silicone heat blanket of proper size is around $200, far cheaper option I bet.

[Richuk]

Yeah - what is Black Diamond thinking!