my press

[Brazen]

thanks to all of you for your ideas, i still have some questions.
maybe a mixture of all your suggestions may help. looking forward to the results that may occur

Also, shorten your cattrack, the pieces on the ends of the tip-block are actually pulling it up in the tip radius. That's my 2 cents. And, nice press!!

you mean the track-parts that are overhanging? why pulling it up, the cable is balanced without any tension..!?


Ahhh, what I meant was that unless you are making toboggans, I believe there's too much track in the radius area...I would try coming up a little lower with the track at both ends...I would also use wire nuts to set the track to length rather than adding to the tip-block height with a 20mm square channel on the right end. That's just me though.

[Richuk]

Something like this: http://shop.toastabags.com/. Placed between the hardboard and the cassette:



Are you using heat?

[Brazen]

I had run into the same problem with my press and solved it by shortening the top mold ends...if you look at yours, there's less of a gap for the hose to expand into right in the area you're having the problem.

I agree with this and I would reduce the gap between the upper and lower mould. This will give you a greater surface area under press from the hose and not the track.

I agree, the hose has inflated almost entirely in the camber section...close the center gap, pull in the ends. Done deal. At least, that's what I would do...pain in the ass, right?

[sir.orange]

Something like this: http://shop.toastabags.com/. Placed between the hardboard and the cassette:

Are you using heat?

im not using heat (constant low budget)... i use resin to be tempered, but my workshop is pretty cold, not warm enough for the pre cure, so im thinking about covering the entire press with an insulated box. electricity is for free in my workshop thats the good one about it.

... I would reduce the gap between the upper and lower mould. This will give you a greater surface area under press from the hose and not the track.

I agree, the hose has inflated almost entirely in the camber section...close the center gap, pull in the ends. Done deal. At least, that's what I would do...pain in the ass, right?

sounds like a solution, but right...pain in the ass, that unhandy block.

[sir.orange]

what is the alias of the skevik guys in this forum here?

i just viewed their great layup video on vimeo: http://www.vimeo.com/6523899
check out 3:42min. i m wondering if these wooden blocks in the tip/tail area of the press are to increase presure in these areas!?

i m still having the problem that i dont get enough presure there (even at 80psi) i ve shortened my mould ends and reduced the gap betwenn top and bottom mould

[MontuckyMadman]

With a narrow press opening or a smaller top mold, the part of the bladder that extends past the mold inflates and pushes on the press and wants to straighten the tip section and reduce pressure there, IMO. Yes add some blocks or allow the bladder to expand without pressing on the top part of the press.
Hydraulic rams in the tip and tail work well also.

[redbull]

i just viewed their great layup video on vimeo:
check out 3:42min. i m wondering if these wooden blocks in the tip/tail area of the press are to increase presure in these areas!?

Yes we use these blocks to increase the force in the tip/tail area. We have been pressing at 50psi. It works fairly good, but we still do get a bit more epoxy under the base than other areas. I actually just looked at pneumatic rams the other day, going to upgrade to those this year.

I don't agree it takes high pressure to force a radius - sorry DBS. You just need to take a minute to look at what areas of the press pressurise first and put a slip layer in. I was using teflon coated baking sheets, worked like a charm.

I'm on the same page as Richuk. For my setup, the tip and center (waist) of the molds get pressurized first. Drawing a straight line from waist to tip, the length is shorter than following the mold; therefore, the cassette needs to slip.

The rams should fix this nicely. Pressurize them first, to get the cassette contoured to the mold. Pressurize the bladder. Then I'm going to experiment with depressurizing the rams and just allow the bladder to hold uniform pressure. Don't want any force/stress concentrations from the rams to the skis. Make sense?

P.S. Is it just me or is this site running slower than before. It almost gets frustrating. Was trying to reply earlier but couldn't log in...

[sir.orange]

i had only a single piece top-mould, i divided it now into two equal pieces and hang it up on skateboard wheels. the top-mould is now easy to adjust, the gap between the two pieces is filled mdf scrap.





chipboards are fillings between press frame and top-mould. there s a gap of something like 18mm remaining because i didn t work too proper. the mould including the fillings gets lifted with inflating the hoses. "dry" tests worked fine.
i didn t press skis with this set-up yet, but i think it should work so far. what do you think?
the radius-pressure-problem is solved with wooden boards in those sections. a pneumatic rams set-up would be around 450€, too much for now, wood works fine...skis will follow soon

[rockaukum]

reduce the gap above the top mold with shims. This will make the cavity smaller and you should get better pressing results. As I understand it, you do not want to allow the hose to get round while inflating. If it gets round (because of the gap being large) it will not fill the void in the tip transition area.
ra