Cattrack concerns (square pegs, round hole)

mattman · Post by **mattman** » Thu Mar 08, 2012 8:43 pm

Ok, so if we are thinking of switching from a vacuum setup to a setup with a cattrack. My concern is that if you fit 1" square tubes along the curve of our tips/tails, you end up with a .014" gap along the middle of each tube as well as an 1/8" gap between tubes...this is exactly what you would expect when fitting squares inside a circle. I am assuming that the aluminum top cassette is suppose to evenly distribute this pressure, fixing the cattrack's shortcomings. Is this correct? How well does it do this on tips? Has anyone found that certain sheet metal gauges are too thin that the cassette starts to bend like the cattrack, not the ski? We like to run at lower pressures, so we would like to choose a gauge that will fix the cattrack's problems, but not be overly thick. What are peoples' experiences with cattracks and the "square pegs round hole" problem?

falls · Post by **falls** » Thu Mar 08, 2012 11:51 pm

you are right, but it seems to work. I use 1.6mm thick aluminium sheet for my top cassette sheet then heat blanket then a sheet of 3mm masonite (hardboard). I have 20mm square aluminium tubes for my cat track, not 1 inch square (25mm). I think the smaller the better around the tip curve.

vinman · Post by **vinman** » Fri Mar 09, 2012 4:08 am

I have a wooden hockey stick cat track, with bigger gaps than that. I use 3/16 hardboard and a thin 1/8 rubber mat under my cat track. This plus rhe silicone blankets and aluminum top skin seem to smooth out the majority of any waves in the top sheet. I do get some waves but they are minimal and almost unnoticeable. I'm going to add a bit more rubber under the track to see if it Smooths things out even more.

freeglider · Post by **freeglider** » Thu Mar 15, 2012 12:55 pm

I doubt rubber will smooth things out. It will just deform, but not distribute the pressure.

I'm thinking of building a press and have been thinking about the cattrack problem as well. This idea of using square tubes doesn't play with me. It has worked apparently for many people though. But why bother with a pneumatic press if you distribute the pressure through (somehow) shaped metal?

Maybe if I could somehow "trap" the hose to the volume above the board (maybe a bit over it) with a metal sheet or something, I could get even pressure through the whole width without a cattrack.

twizzstyle · Post by **twizzstyle** » Thu Mar 15, 2012 1:56 pm

freeglider wrote:This idea of using square tubes doesn't play with me. It has worked apparently for many people though.

Including all of the largest ski/snowboard manufacturers in the world

It works, and it works good. This isn't an old debate.

Sure, if you have a sheet of metal thick enough that it won't conform laterally from the firehose, that will work. But that is going to be a VERY thick, VERY expensive, piece of metal, which will have to be pre-bent for every mold (length/camber/tip shape) that you have. The beauty of a cattrack is that it works with any (2D) mold you can dream up!

twizzstyle · Post by **twizzstyle** » Thu Mar 15, 2012 1:57 pm

freeglider wrote:why bother with a pneumatic press if you distribute the pressure through (somehow) shaped metal?

Have a better way to evenly distribute 50,000lb of force safely?

vinman · Post by **vinman** » Thu Mar 15, 2012 3:11 pm

I can tell you that the rubber and the hardboard absolutely help to smooth things out. My rubber mat is no thicker than 1/8 inch and is lined with a nylon fabric...no deformation. It provides a compression layer to help even out any inconsistencies caused by my ghetto hockey stick cat track.

I know because I can compare skis made with and without....definitely less waves with the compression layer.

freeglider · Post by **freeglider** » Fri Mar 16, 2012 2:42 am

twizzstyle wrote:Have a better way to evenly distribute 50,000lb of force safely?

All right, but this idea of even distribution fails if you press a curve with squares. My board's top is perfectly curved, so how do you achieve that with square aluminium cattrack?

I was thinking (maybe I'm dreaming too much here) of using a plate, which would be torsionally strong and longitudinally flexible. Maybe some kind of material? Or something like Elan's Waveflex used in their Speedwave, Waveflex and Amphibio skis.

I can't yet post a link so go to google, type elanskis and find them if you're interested. In the "Technology" section you have "torsion" and in the "Products" section you have "Waveflex" and "Amphibio Waveflex".

The idea is for the waves not to allow bending in the direction in which they run, but to allow the plate to bend in the longitudinal direction because of thinner portions between the waves.
but i don't really know how the hose would press such a waved plate and if there would be enough (or any) effect on pressure distribution.

Vinman, sorry, my bad. I didn't notice it was a rubber MAT. Because just a layer of rubber surely wouldn't help

twizzstyle · Post by **twizzstyle** » Fri Mar 16, 2012 6:43 am

freeglider wrote: I was thinking (maybe I'm dreaming too much here) of using a plate, which would be torsionally strong and longitudinally flexible.

I think you mean laterally, not torsionally. Such a thing exists. It's called a cattrack, made with square tubes

You've just got to have some trust here - with a sufficiently thick cassette material (or something like a rubber mat) you get zero waviness with a cattrack made with square tubes. The ski/snowboard tip radii aren't as tight as you might think.

mattman · Post by **mattman** » Sun Mar 18, 2012 5:26 am

Ok, I am certainly not doubting or trying to reinvent-the-cattrack. I just want to know what smooth-things-out-layers people are using with positive results.

Vinman: So with the aluminum cassette, 3/16 of hardboard, and no rubber, the hardboard and cassette were still segmenting?!! Could high pressing pressure be a factor? Is the rubber between the cattrack and the hardboard?

Twizzstyle: What layers are you using? I always just assumed that most people simply went: cattrack, heat blanket, aluminum and that the aluminum was just thick enough to not yield and segment.

doughboyshredder · Post by **doughboyshredder** » Sun Mar 18, 2012 10:25 am

My cat track is made of 1/2" x 1" steel. The gap between sections on the radiused section is so miniscule that it does not translate through the aluminum sheet, heat blanket, aluminum sheet, and aluminum cassette.

.8mm aluminum sheets and cassette

vinman · Post by **vinman** » Sun Mar 18, 2012 11:46 am

Segmenting...not not really. It is more that my drilling was done by hand and the hockey stick track sections are not perfectly flush.

The rubber mat goes under the track, hardboard under that, heater blanket the aluminum sheet.

mattman · Post by **mattman** » Sun Mar 18, 2012 1:00 pm

Doughboy: so you have cattrack, .8mm alum, blanket, .8mm alum, .8mm alum?

twizzstyle · Post by **twizzstyle** » Mon Mar 19, 2012 7:03 am

I just have cattrack (3/4" square aluminum), heat blanket, and a single layer of aluminum (I can't remember the thickness, but 0.8mm seems about right)

Ski Builders Forum

Ski Builders Forum

Cattrack concerns (square pegs, round hole)

Cattrack concerns (square pegs, round hole)