some More skis

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More
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some More skis

Post by More »

Kiaora,

I'm from Auckland, NZ, and myself and another couple of mad individuals are embarking on the skibuilding journey.

We've been studying this site for a couple of years now, and it's finally all coming together. Our press is almost complete (just making the second heater mat, control gear, finishing touches sort of stuff), and the actual skis are being CADed up. Materials are in the post from Skilab, and we're hoping to lay up some planks within the next month-ish.

Unfortunately, so far the season sucks - no damn snow! On the other hand, this is giving us a bit of time to work on the press and so on, so progress is fairly rapid at this point.

Anyway, thought I'd just get this ball rolling so that I can post pictures soon. I've been keeping a pretty good photo record, because I cannot thank you chaps enough for laying down such a good trail of breadcrumbs to follow. I'll use up my 5 posts of limbo and then see if we can contribute!

Cheers.
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falls
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Location: Wangaratta, Australia

Post by falls »

Looking forward to seeing some more southern hemisphere building pics!
Don't wait up, I'm off to kill Summer....
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Post by More »

Cheers Falls, and thanks for your detailed journal - it's been incredibly helpful to see the whole process in a similar supply environment to me. I'm insanely jealous of the ease of supply in the states... I guess that'll teach me for living on a strange little island far away from anywhere :)
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Post by More »

Alright, photo dump ahead... Going to get started on our progress so far.

It all starts with the right beer, outside the right scrap yard at the right time.
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Our I-beams weren't in great condition when we got them, but the price was good.
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Much angle grinding with stripping discs ensued.
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We rough cut the beams with a gas axe, and then finished a bit neater with angle grinders.
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Then every night for almost forever was spent drilling holes in the bloody stuff.
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I should have just rented a mag drill and / or got a nice hole saw, stepping through all the bits for our m16 bolts was a bastard. This was definitely a part of the project that wasn't accounted for in the time stakes. I suppose we could have arc welded instead, but I do like the idea of being able to dismantle and hand transport if essential.
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We've used 25x25x1.6 SHS mild steel for the cat track, 6x6m lengths (a little spare). I chopped it 6 at a time against a metal stop I clamped to a pallet to get them all an even length.
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A drop grinder made short work of this job.
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We painted the press frame with a yellow epoxy paint. It was cheaper than vinyl etch primer + a topcoat. I was a little sad to have to paint over the mysterious "one" that someone has very neatly welded periodically along the steel.
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It's too cold in the warehouse at work for epoxy stuff at the moment, so we had to hot box an area to get the paint to cure well.
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James (right) decided that press assembly was woman's work and got his girlfriend on the job.
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Now we couldn't manhandle the stuff without constantly reassembling it, the gantry crane at work became very handy.
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It's also impossible to use it without a shiteating grin on your face.
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More to come shortly....
Last edited by More on Tue Jul 31, 2012 1:53 pm, edited 1 time in total.
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Post by More »

Bladders up next -

Like all things, our bladders were sketched out poorly based on the "that sounds about right" design philosophy.
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We've used the same hose as Falls, 04820558 from BlackwoodsProtector in NZ. link
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I cleaned up some scrap 50x50 angle iron for the clamps, using some leftover stripping discs from the press steel.
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Test fit-
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The clamps were taken off and painted, along with the cattrack suspension rails.
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The bladders had some scrap wood inserted and a spade bit was used to make the input hole.
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(Some resining was happening at the same time - heater mats - hence the respirator)
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This is the washer configuration which has worked well for us:
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These are done up reasonably tight, if they were just left what I'd call "snug" there was a leak detected in one of the plastic washers at 60psi, so they were redone tighter.
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Top to bottom along the bulkhead fitting: Brass nut, soft nitrile rubber washer, steel washer, hard plastic washer (some sort of PE?), bladder, plastic, steel, rubber, and the hex end of the bulkhead union. The bulkhead union is that way around to keep the long tail out of the bladder.
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A doubled offcut of hose went in next to the bladders in the clamps, thanks for the tip Falls.
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The clamps are fixed with M8 bolts - not toooooooo tight but pretty firm.
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Our brass barbs were never used in anger - they were ditched for some sweet push fit Festo gear:
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The bladders are leak free to 80 psi. No silcone or anything. I haven't been brave enough to push them higher... The service pressure rating is 0.9MPa, which is what, 130ish in psi, so we'll probably give them a nudge higher to test once all the moulds and whatnot are in place.

Heater mats are up next...
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More
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Post by More »

We've built two heater mats based on the excellent work laid down in the DIY heater mat thread. Our wire was very thin, we've had to do 4 runs up and down the mat per loop off the bus bars, and we used a 16mm spacing. I have a feeling we've gone about this the hard way, because the wire is actually lightly stiched into the fabric. Each mat is 1050W. They're 0.2 ohms different between them, which I think is pretty damn close! We calculated everything on a unholy blend of paper, whiteboard and spreadsheet-
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Some scrap copper shim was used for bus bars.
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We wire brushed it first to get it nice and clean for soldering later.
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Then it was scored with a knife and flexed to cut.
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The wind points were notched with snips.
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Our cloth that was lying around was a ~400g double bias.
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The ingenious improvised wire spool reduced some tangles, and let two people work at once on the mat.
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we used pins to double back the loops, but stitches every ~15cm along the mat to keep the lines straight. They are indeed very straight. the layup is on coreflute material, which is nice for the pins but becomes important later.
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Shot of the bus bars during soldering. note the fibreglass sleeve jumpers.
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Another shot of the bus bars before resining. We actually did this a bit differently in the second mat, using mini bus bars instead of doubling back a single strand of wire. I was skiing while Jimmy and Krish worked on it (ha, used up some drilling karma) so I wasn't there myself, but I am imformed that it was way easier.
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Testing for the right resistance BEFORE putting resin on it is a good idea.
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We used a spray adhesive to sorta tack the two sheets of glass together before applying resin - which was a next day problem.
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Gently smoothing the fabric together for the glue.
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Our silicone was white, so we put a bit of blue pigment in it for no reason aside from being able to see it wetting out.
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We used 1.5kg of resin per mat. ~1kg was poured on the "top" (as laid up) and squeegied gently into the fabric. it was very thick - this took quite a lot of work to wet through.
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A plastic sheet was draped over the top, and the coreflute under the mat was picked up, and we flipped the whole thing so that we could use rollers on the underside to help wet the resin through.
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We couldn't use rollers on the top side, it was too sticky and thick, it made a mess of things. on the underside however it was great for working that pool of resin through.
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The last 500g of resin was used to make some reinforcing around the bus bars and to thicken the mat on the surface that was now facing up (originally the bottom).
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I need to get my camera back to give you guys some moneyshots of them finished, so that will probably be next week. It's a 4 day cure!

In the meantime, I'm putting castors and levelling feet on the press, tensioning the cat track suspension neatly, and slicing up some aluminium into cassettes for the mats and skis.

Phew, sorry for the marathon posts, but I thought I'd better get started before the problem becomes too big to deal with in one night!

Cheers.
skidesmond
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Post by skidesmond »

Fantastic! Looks like you did all your home work. Great documentation of the build. What's the ETA for the first pair of skis?
twizzstyle
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Location: Kenmore, Wa USA

Post by twizzstyle »

Wow, what a great start! You guys are moving right along, nice work! Taking your time and doing it right now will definitely pay off in the end.

I'm jealous of that gantry crane :)
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MontuckyMadman
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Post by MontuckyMadman »

AWESOME START!!!
Wrong beer.
Image
JK
sammer wrote: I'm still a tang on top guy.
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Post by More »

Des,
Eta is a couple of weeks. Waiting on materials and those last couple of jobs that stretch out, like wiring etc. But I need new skis so I don't want to piss around.

Twizz,
Yeah, there are a lot of perks to building at work. My company sells machinery, so there are lots of usful things around the place.

MM,
The're both the wrong beer! Two of us are avid brewers too, I almost melted when I had to touch the Tui box. However, it's the right beer for the famously atrophied average kiwi's taste buds or lack thereof. Our macro brewers only excell at advertising.

A big thanks to the three of you for the kind words and the help you've dished out to others over the years - you've helped us enormously via proxy.

I'm hoping to bounce some design stuff off your guys before I start making moulds. Cool to do that here, or should I make another post?

Cheers.
twizzstyle
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Post by twizzstyle »

More wrote: I'm hoping to bounce some design stuff off your guys before I start making moulds. Cool to do that here, or should I make another post?
Wherever. There are lots of "should I do this?" threads in the design forum, so you can try to look around in there to get ideas, but everyone is always willing to give their input, good or bad!
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Post by More »

Cheers Twizz. I've actually gone through and read that entire forum, shape should be fine, it's more that I want to get that subjective judgement of "that sounds stiff" or "that sounds medium" with regards to a core thickness profile. Seems that it just takes a bit of experience to get a feel for that. We'll do some CAD and post the details when we can show it visually.
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Post by More »

More photos:

I ripped up some sheets of old ply and chip to serve as spacers to adjust our cavity height on a panel saw:
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We rested the cat track on the spacers and started stringing. We used 4mm shock cord, cheap by the 100m roll. Because I had to buy 100m of it, we ran through every bar in the cat track.
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This was another suprising job. It ended up taking all night to get it threaded (lots of running backwards and forwards across the warehouse carrying slack). The suspension rails are demountable for installing the top moulds, fiddling with bladders etc. We plan to have the top moulds mounted with t-bolts - there is a small gap in the beams for this purpose.
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The press without moulds, also before evening out the cat track tension.
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Cheers.
gozaimaas
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Post by gozaimaas »

Excellent descriptive posts and pictures there mate. Love it.
What goes on in that shop when ski presses arent being manufactured?
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Post by More »

Thanks Goz, the photos are from a few different locations but most of them are taken in the workshop, warehouse, and spindle room of my work; we sell large scale wood processing stuff like cncs, edgebanders, and high speed solid wood processing stuff (some smaller home workshop stuff too, like buzzers, thicknessers, panel saws, blah blah blah). The heater mats were made in Krish's workshop, where he makes longboards from time to time (vacuum pressing). He's the dude in the knitwear :)

some more press details-

Levelling feet + wheels. Will be good if we ever need to move it to where there isn't a gantry crane!
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Cat track tension - we strung the track on stainless braid, and tensioned it like this:
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It's pretty firm.
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Showing how the suspension drops to accept top moulds.
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