Clamp Press Building Question

[ireynolds]

There seem to be some of the finer details missing from the how to of building a clamp press. I don't have the resources to go for the fancy pneumatic press so i'm going simple. I have a design drawn up with all measurements necessary but would rather do it right the first time and not waste any of what little money i have. Any advice or guides or how to's on building a clamp press. I'm also wondering more specifically, is sheet metal required on all surfaces that will be touching the ski in the press or are there other materials that the apoxy will not bond to. Any info would be awesome. Thanks all

[Idris]

Don't. Use a vacuum press instead. Lots of us here have built durable skis successfully using a vacuum setup. A clamp press will be a engineering nightmare to get right. And will be insufficient if built wrong. An alternative is Plywood's fabric pneumatic press , a work of genius!

[ireynolds]

If i build the clamp press first...most importantly the base...will i be able to use the same mold to make a vacuum press. A little trial and error never hurt and I have an idea i wanted to try. As this is a first attempt at ever building skis i want to do it as economically as possible till i have a better idea

[Motherhucker]

I began to build a clamp press. But the precision that is necessary to get a clamp press to work is much higher.
Vacuum presses are much easier to get to work. And it is easy to change size for different skis or boards.

[knightsofnii]

you will need some type of pressure equalizer. That's the main purpose the airbag serves in most pneumatic press designs. Though I've worked with clamp style presses that were also pneumatic where the airbag simply pushed up the bottom mold to the top. Anyway you need something inbetween the clamps to distribute the pressure or else you will have voids everywhere, unless you're a god and have an arsenal of cnc equipment to make it exact.

But you can cheat by using a layer of cardboard or foam to distribute things evenly, I've seen this work quite well.

[hugocacola]

thats like kngth said

i had seen a press with hidraulic and it need very precise molds and nice rubber. but the best is spending money in a nice press, fire hose and cattrack, poor people spend money twice...

[knightsofnii]

hugo's right, its a dilemna any way you look at it.

you can easily spend half of the price for a good pneumatic press while trying to build a vacuum or clamp style thing, only to find out you dont like it. Though some have had a lot of success with the simpler methods and have built better stuff than I can with what I have.

pneumatic presses, and vacuum tables, are both tried and proven designs, some industry still use clamp style, even bottle jack clamp style. But the best way to do it is with a layer of cardboard, foam, rubber, between the top of the snowboard and the top plate, to equalize any pressure gaps. For skateboards I think they use cork somehow.

[Nick's Sticks]

I remember hearing about something about using sandbags for a press. I can't imagine getting anything close to the pressure of a pneumatic press but the sand would help distribute pressure over the entire surface (maybe). Not to mention that unless you own a quarry or live on a sandy beach your house would look like you were preparing for a flood. Than again... depending on where you live it might kill two birds with one stone.

[knightsofnii]

sandbagging only work if you possibly built a huge frame with a huge bag over top and filled the entire thing with sand

using seperate bags, no matter how you do it you will have gaps, and piling shit on top of them doesnt increase or distribute much of anything

maybe build your board up, build that top box, fill it with concrete, let both cure.
then you hae a top mold that you could MAYBE use a few more times

you could also build the top mold and put some type of foam layer between, or cardboard, but make sure you use one piece that is full length, no gaps.

you coullllld, also use a million steel bars LIKE a cat track, over a steel/alu sheet, and bolt each one down individually. just make sure you have medium or slow cure for that one. only trouble is if you put the bars in tension on the ends like that, they will bend up in the middle of the board and you'll still have pressure equalization problems.

if you want cheap, vac bag it

[Nick's Sticks]

I agree. Vacuum bagging is the way to go. If you want to build a pneumatic press later you could try and reuse your bottom mold, as long as it is built to withstand the pressure.

[twizzstyle]

I'll give my little bit of advice here.

A few years ago I tried making a clamp press. At the time I thought it was awesome, I only pressed two skis, and they were completely unskiable, but I was still very proud.

Looking back, I can't believe I would have built something like that. In order to get even pressure, you have to have a perfectly shaped top mold, which just isn't feasible unless it is CNC machined.

Vacuum bagging is great, I do lots of vacuum bagging stuff making carbon fiber parts, but that is all stuff done into complicated female molds (recently made a carbon fiber mandolin). The problem is, with vacuum bagging skis, that is the equivalent of a firehose press, where you are pressing at ~14psi (atmospheric pressure). With a pneumatic (firehose) press you can press at MUCH higher pressure.

We just finished our new press frame a few weeks ago, and pressed our first ski this past weekend, and it turned out near perfect.

If you have the space, it is definately worth the extra time and money to build a nice pneumatic press.