My internship at PMGear

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Idris
Posts: 381
Joined: Wed Jun 29, 2005 3:34 pm
Location: Chamonix, France
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My internship at PMGear

Post by Idris »

My internship at PMGear – Helping out some buddies.

Why PM Gear is making their own skis
First a little history –. The Bro Model ski, as some of you may know, was designed through a consensus of opinion by online ski freaks who frequent the Powder Magazine and Teton Gravity Research online message boards. The ski’s side cut was relatively easy to determine. But the core profile took numerous attempts and prototype test trips to Mt. Hood to develop and nail the desired dimensions. After two winters of two crappy subcontractors failing to deliver as promised and proving themselves quite useless in terms of quality and delivery, it was time for a little DIY. With some leftover materials from unmade skis from the last subcontractor, an old pneumatic ski press and lots of determination, it was time for PM Gear to undertake production of its own skis.

My first week was a whirlwind introduction into not just making skis but making new models from scratch. The 188 and 179 (99mm underfoot) already existed. But the 179 Fat (115 underfoot) and 192 Fat (also 115 underfoot) did not previously exist. We knocked out fifteen pair of previous models in addition to new prototypes in an exhausting run of prepping and pressing and were then off to Mt. Hood to test.

That we were testing was common knowledge on the internet. We had people fly in from the mid west and east coast. Folks drove down from Canada. Just to try our new boards. A really great but nerve wracking time. We had never skied anything we had made before.

The skis themselves worked out great. There were a few issues of course. But these were traced to Resin, temp, and material issues not design or basic construction issues.

Me skiing a 179 fat and a 192 fat at the same time!

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The 179’s being flight tested

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The way the Bro models are made is none to different to the way Kam, Kam and Kelvin describe. But here goes anyway.

The core is white Aspen, laminated and shaped by a woodworking ace in Washington who happened to work for K2 prior to being made unemployed as they moved their production overseas. The same place cuts and profiles the sidewalls.

The Bases are also cut in the PNW by CNC drawknife rather than router or die cut. The graphics printing for the top sheets hail from the Northwest. Edges are from Ohio – Nice pre bent ones (eventually).

First part of the process is sidewalls on cores. Hot glue is they way it’s done. A bit at a time, from the center out not from one end – Alignment is easier this way. Binding retention patches of ‘Dore – Tech’ are stapled in place.

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The cores are now routed to give the edges a place to sit and avoid a concave base.

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The sidewall then gets flame treated with a blowtorch to aid the fiberglass and resin adhering to it.

Bases get edges

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They are clamped and Cyanoacrylate (super glue) in place. This is a job that I started to hate very quickly but actually got quite good at. Until we got pre-bent edges. This did mean bending edges from scratch.

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But even the pre-bent ones aren’t perfect and have to be tweaked and trimmed to fit.

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Tip and tail spacers have to be fame treated before pressing. Fiberglass has to be cut to size and VDS rubber strips.

For the existing models, the 188 and 179 we had cassette type molds left over from the previous year. For the new one (179 fat and 192 fat) Rob (above) created some from scratch.

To stop stuff sticking the mold its top plate, the press upper and lower surfaces are coated in mold release wax.

In a perfect world the Base with edges would just drop into the mold and sit there. More often than not a clamp here or there may be needed to keep things in place. I tougher cases I superglued them into the mold – my problems were all caused by warped base materials – thanks crown plastics ;(

Everything set out and ready to go. Set the timer for 22 min

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2 for mixing, 20 pot life for layup. Measure the epoxy, mix with kebab stick in a recycled Starbucks water cup – yes we went to Starbucks a lot – there are 3 in less than 2 miles!

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Epoxy on the base, making sure to get some between all the edge tangs. I ended up doing most of my spreading by hand not brush or plastic/metal scraper preferred by others. Trying not to get too much on the mold outside the base, it’s going to get covered anyway, but the less the better.

VDS covered in resin by rubbing it into the resin on the base, then putting over the edges. Fiberglass sheet, or two (depending on which ski stiffness I’m making). With resin to wet out of course.

Core goes on next. Aligned sideways by the mold. Lengthwise by eye to check alignment marks. Clamp in place with spring clips, tip/tail spacers at the same time as the core. More resin, plenty in the tip and tail area. More glass for the upper layer followed by the top sheet.

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This is aligned by marks on the center and on the ends. A top plate for the mold –just flat aluminum. Recheck alignment and clamp in place.

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Time for the press. The mold is aligned by a keyway. But you still have to look to see if its square. A bit of pressure before taking the clamps off. Add 20 min to the timer and wind up the pressure.

Our press I think was originally at some distant point in history a snowboard press. It doesn’t have a cat track but there are plenty of non original parts from the last decade or so. And it’s wide, over a foot. The camber block top and bottom are one ski wide though. The lower one is adjusted for length by screw threads and taking out blocks. The upper half is adjusted by removing block sections. But it’s the backing to the firehose so it doesn’t need to be fine tunable .It’s heated by heat pads which sit under aluminum sheets to protect them – controlled by a digital controller. The actuator is a firehose the same as many homebuilt presses. It’s retained along with the upper heat pad by bedsprings to the upper camber block. The big advantage of this press over others I’ve seen is it opens up like a clam shell. Giving you room to wing your ski into the press, not feeding into a narrow gap.
The I beams it’s made from are massive. These are faced by a 1inch plate on both the upper and lower halves. But it still bows a little when you are pressing at 95psi!

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It’s a temperamental old thing. Here we are by flashlight and Car headlamp in the middle of a Reno blackout trying to figure out why our heat pad wiring was miss behaving before the power went out.

When pressing a lot o resin seeps out of the mold. Yes we could have used less resin when laying up. But if we did so, it would take longer and there is more chance of not getting enough resin inside the ski

The skis come out piping hot with quite a bit of flashing (excess material overlap). Most of the time the ski separates from the mold easily enough. Some times you have to resort to prying it out.

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They go on a cooling rack overnight to give the resin a chance to properly harden.

Next up is rough trimming by band saw. Then rough sanding with a nasty rotary sander.

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This is a particularly unpleasant beast to work with. Lots of noise, vibes and dust.
The finish sand is done on a wet sander that is in fact on old base grinder.

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The bases are cleaned up and flattened on another belt grinder. The boot center mark is measured and marked by hand.

Since I left they have moved out of the double wide and into a real industrial space. Enough to have all the machines indoors, store materials and still have room to breath.. The rotary sander has been replaced by a vertical wet sander. Many other minor things have been upgraded.

7 weeks in Reno I learned a lot. No myths were really dispelled. Because of this site and others and the fact ski building is hard graft not ‘rocket science’. I did learn that more than ever that preparation is everything and there are a thousand and one ways to screw up a perfectly good ski.

Even if you do everything right. Then temperature, resin, the time of day or the ‘price of fish’ (undeterminable variable) can screw things up. This isn’t engineering or science it’s art!

I got this gig because I’ve know Splat for many years before the idea of PMGear. And I thought (and was right I hope) that it is a venture investing my time into (as a ski bum with many K$ of student loans I don’t have any money to invest).
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burny
Posts: 50
Joined: Wed Jun 07, 2006 12:25 am
Location: Bavaria

Post by burny »

cool, thanks a lot for sharing !!

G-man
Posts: 600
Joined: Sat Mar 25, 2006 3:58 pm
Location: northern sierra nevada

Post by G-man »

Idris,

Very nice post. I'm sure it took a lot of time to put together. You did such a good job... why, I don't even have any questions! Great perspectives on the 'art' of ski building and all of the many things that can go wrong.

I'll make only one comment regarding the pictures... I sure suggest that you get yourself a good respirator rather than using the white dust masks. That fiber glass grinding residue is really, really nasty stuff on your lung tissue. The dust masks are difficult to get a good seal with, especially when they have to go over your sunglasses, as in one of the pics. Little inhalation exposures here and there can add up to a lot of permanent damage over the long run. I've watched a lot of people die at a relatively young age from lung disease caused by chronic exposure to such irritants. Quality of life before said death sucks also. I don't want to sound like I'm harping, I just cringed when I saw that pic. Okay, I'm done now.

Thanks for putting out the effort to share your experience and knowledge. Good luck with your own venture.

G-man

Idris
Posts: 381
Joined: Wed Jun 29, 2005 3:34 pm
Location: Chamonix, France
Contact:

Post by Idris »

I hear you. that pic was the first time I used the sander. I moved onto a better one quick. Then let other people do the nastier jobs and avoided that one. It is also a job that no longer exists sice pat bought a nice vertical wet sander. But the concern is not just nice its nececcary. Thanks
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littleKam
Site Admin
Posts: 269
Joined: Mon Dec 13, 2004 7:43 pm
Location: SoCal

Post by littleKam »

Thanks for the post. I'm sure many will find it very, very useful. Glad to hear that the Bromodels are taking off!
- Kam S Leang (aka Little Kam)

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