I built my own press - no vacuum pump or compressor needed!!

[twizzstyle]

I still think its wasted effort. you're better off doing vacuum, this is nothing more than a clamp press with a cushion in the middle. The water does nothing.

[summitskier]

hmmm

[Skammy]

Neat idea and it's nice to see something different from always heading towards the standard steel press with firehose..
but I do kind of see where twizzstyle is coming from..

[Richuk]

Interesting alternative ... http://www.jasondejong.ca/Archery/Lamin ... Tools.html

[Steevner]

I think it's an awesome idea. Very simplistic. I'd be willing to sacrifice some pressure to save 1000+lbs and $1000+ of steel sitting in my garage. I think a lot of people on here equate higher pressure = better skis. But not necessarily, imo. Maybe you'll squeeze out a few more grams of epoxy, but for a garage builder I can't justify spending that much for a tinkering project.

Also, for the water heating, if you were feeling really magyver/cowboy/engineer about it, you could calculate the pressure in the hose and figure out what the boiling temp of water is at that level. As well, you could use supersaturated salt-water to increase the boiling point. Then you could have a (slightly) safer press. Still incredibly sketchy/dangerous, but you've minimized some risks!

[gladegp]

Ok so how much pressure could a construction like this create? Supersimplistic approach.

Normal pressure for a ski press is maybe 60 Psi = 413 kPa

Area of the ski press is 200cmx40cm or 78.7"x15.7" =8000cm2=1240 sq. in

Weight held by the rods is about 33747kg or 74400lbs

Divide that on 16 steel rods equals 2109kg 4650lbs/rod

How much do you think a rod can hold? 500kg or 1000lbs (would equal to 15psi)? More?

[fa]

it depends on the rod's cross section area
nominal strength for common steel is 1400kg/cm^2 (elastic deformation)
so in reality, i d guess quite more before a rod fails

anyway, i think you ve missed something in your calculation above
to find the total needed load, you should consider just the SKI's surface area.
the size of the PRESS is irrelevant to the pressure applied on the ski (given that the ski is smaller than the press)

[gladegp]

it depends on the rod's cross section area
nominal strength for common steel is 1400kg/cm^2 (elastic deformation)
so in reality, i d guess quite more before a rod fails

anyway, i think you ve missed something in your calculation above
to find the total needed load, you should consider just the SKI's surface area.
the size of the PRESS is irrelevant to the pressure applied on the ski (given that the ski is smaller than the press)

Ok yes I think I missed a bit in the calculation as well I think I would have gotten an F in math class...

Ok so a much smaller area then would give higher pressure using the same amount of force (smaller force for the same amount of pressure). So maybe this kind of press could give quite high pressure. Seems like a good idea.
Maybe it's the threads or the holes in the wooden beams which would fail first

[fa]

the 1.4ton/cm^2 in my previous post is quite conservative

http://www.roymech.co.uk/Useful_Tables/ ... rength.htm

a 4.6 grade steel rod, the 2nd lowest graded steel, in M12 has a tensile strength of 2,4tons (still some safety margin left, but you d probably wont need to push it more)
higher graded steel (5.6, 8.8 etc) goes way more than that

axial tensile forces are in general cheap to handle. steel is getting heavy when stability issues are involved (buckling ie), and/or when the profiles should resist bending moments