Ski building awesomeness 12/13

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MontuckyMadman
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Post by MontuckyMadman » Wed Jan 16, 2013 5:18 pm

Dont put tape on the base unless its for diecut. The warping is eather the mold or cassetts or over heating.
Takes a bit to break in the al sheets or casstes. Your on you lr way.
sammer wrote: I'm still a tang on top guy.

MadRussian
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Post by MadRussian » Wed Jan 16, 2013 5:37 pm

skimann20 wrote:Thanks Madrussian if I see one on c-list (which i think i saw one) i'll take you up on that offer.
my project moving forward in much slower pace than yours :( . I will have some time soon phase converter or frequency drive to run sander. Currently I don't have any. just trying to help

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vinman
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Post by vinman » Wed Jan 16, 2013 6:25 pm

55-60psi is pretty much what most of us press at and seems to give me good results.

Your heat differential might have something to do without your results. I would sandwich your top blanket between an aluminum layer and a layer or 3/16 masonite. This is what i do. I also have a layer of think rubber matting over the masonite. For me this is mainly to act as a buffer layer to minimize the waviness of my ghetto hockey stick cat track. This is one component I'll be upgrading this year I hope.

I usually let me skis post-cure in the mold down to ~130-140 deg then pull the laminate and put in on edge so gravity can not effect the camber. (tip from a buddy in a big time snowboard biz in VT) I let them cool to room temp and cut them out same day if I have time. No issues with flatness or shape conformity.

Some spots stay a little opaque but as long as they look wet it should be fine. If you applied enough epoxy to make everything transparent you'd likely be applying too much.
Fighting gravity on a daily basis
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barnboy
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Post by barnboy » Wed Jan 16, 2013 7:38 pm

A sheet of FG above your top blanket (and below your bottom blanket) will help tremendously with heat loss too. Also, where on your blanket are your TC wires reading from? Remember, that's the spot your getting all your temp information from, so if they're near the ends of your blanket (which they probably are), you have to remember to have them under the same pressure (inside your cassettes, call-plates, etc...) as your build. This is key, as it will keep them from over firing, and give you far better data as well.

I spent a decent amount of time compiling heat data during my build season this year, and it vastly improved our ability to "get" the designed geometry out of our ski forms. I've been meaning to take pictures of the set-up that allowed us to do so. But in caveman terminology, you need a decent run of TC wire, with a connector at one end and stripped at the the other, with the stripped wires coiled around each other. Then you'll need a thermocouple/temperature sensor...

http://www.mcmaster.com/#thermocouple-readers/=l2grre

Now, include a small "mock" ski in your builds, (I used a piece of foam between two pieces of a paint stir stick, all wrapped in VDS) with the coiled end of the TC in the middle of it ( I taped it to the foam "core"). Place the small mock ski in the middle of you cassettes. This will give you a far better idea as to what's really taking place inside your rig, temperature wise.

I'm not sure what sort of ramp up cycle most folks use, but I find a fairly gentle ascension works well (40 def F at a whack or so). Anyhow, you do the mock-up 5 or so times and you'll have a decent little amount of data, and you'll have a much firmer handle on what the numbers on your thermostats actually correspond to inside your rig.

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skimann20
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Post by skimann20 » Sat Jan 19, 2013 7:45 pm

Montucky: really? I thought i read on there that it will help keep the epoxy off the base? I'm I incorrect??? but all honesty I was kind of thinking this is what caused the unevenness of the base but when I pulled the skis out of the press the tape was very flat.

Vinman: Right on. all good info

barnboy: My TC are right in the middle of the ski but are toward the outside of the blanket. great point. they are close to the ski but certainly not right over the ski. I actually have temp sensor at work that I'm going to borrow to make sure everything is calibrated before the start of the next run. I like the idea of doing little mock temperature runs. I might just do it with a ski and all the guts but without the epoxy.

I got my skis back from being mounted. they look great. I'll get some photos of the basses and improvement points up tomorrow.

One thing that perplexes me is the rabbeting. If I take the tip of the core down to 2mm and my tip material is 2mm thick if I rabbeted the sidewalls for the edge tines shouldn't the core sit lower than the tip spacer? This was not the case with my skis and I'm at a loss. can someone please explain this?

(on a side note: I cut four more cores up tonight, looking forward to running some uni-carbon)

Cheers.

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skimann20
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Post by skimann20 » Sun Jan 20, 2013 11:07 am

you know who is stupid excited? this guy!

i finally figured out how to get a great core with uhmw sidewalls without the planer monster eating my cores Woot Woot!

Image

skidesmond
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Post by skidesmond » Sun Jan 20, 2013 11:54 am

Well, how do you do it? :)

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skimann20
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Post by skimann20 » Sun Jan 20, 2013 12:19 pm

As promised, here are some pictures of my errors.

you can see the gap above the sidewall.
1.) Its like there was no fiberglass there, I wonder if it was ripped out when I did the 7 degree sidewall?
2.) this is the side of the ski that had the wrinkled top sheet.
3.) didn't wet the epoxy out well enough?

Maybe the VDS layer on both sides with the next pair will get rid of this. How the heck to I get epoxy in there now?
Image

Tails turned out great!
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Ski base one:
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ski base two, you can see the concave section in the base. It's directly after the edge teeth:
Image

flatness:
Image

Final Product (I'm very pleased):
Image

skidesmond
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Post by skidesmond » Sun Jan 20, 2013 1:06 pm

Those came out fantastic! When do you take them out for a test ride?

The gap - Unless the FG has no epoxy in it I'd say you'll be ok. Not sure if it's worth trying to fix. You could try putting tape on the topsheet and base to create a dam, then drizzle some epoxy in the gap, let it harden and re-route the sidewall, but I would probably leave it alone.

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skimann20
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Post by skimann20 » Sun Jan 20, 2013 1:48 pm

skidesmond wrote:Those came out fantastic! When do you take them out for a test ride?
If I can sneak past the guard... Monday night. ;-)

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MontuckyMadman
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Post by MontuckyMadman » Sun Jan 20, 2013 8:21 pm

How did you get that crazy texture on the sidewall?
Looking at that now I would say rabbet is not deep enough and the core needs to be thicker than the tip spacer to account for the rabbet it will compress and be hidden.
sammer wrote: I'm still a tang on top guy.

twizzstyle
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Post by twizzstyle » Mon Jan 21, 2013 2:52 pm

skimann20 wrote:Montucky: really? I thought i read on there that it will help keep the epoxy off the base?
If you're going to be grinding the bases anyways, you don't really need to care about epoxy on the base. I get tons of epoxy on my bases, but its so thin that it grinds away completely in the first few passes.

barnboy
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Post by barnboy » Mon Jan 21, 2013 4:41 pm

Nice!

But... is that a sticker on your AFD????

How much excess material was there post press? Was there any FG proud of the ski, and if so, was it dry?

As far as getting epoxy into your void, I've had success running an x-acto blade, to prep the area, then use a sanded down piece of aluminum flashing as an applicator. You'll have a bit of clean-up after, but if you tape off the area pretty well it shouldn't be such a big deal.



They look great.

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skimann20
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Post by skimann20 » Wed Jan 23, 2013 5:02 am

Skidesmond: took them out on Monday. zero issues.

MM: the crazy texture is from the router bit with a single pass. I'm sure if I did more than one this would go away. I'll also keep in mid to keep the core thicker in the tip and tail. it looks like most people make the tip 2.2 and do a .7mm rabbet. that would still be more thin than the tip spacer so 2.7 in the tips and tails if your doing a rabbet. I hope to get away from the rabbet with adding uni-carbon to the ski. that whole process freaks me out.

Twiz: good point but "tons"? I thought you only use 700g? sorry the morning coffee is starting to kick in...

Barn: thanks, yes that's a sticker... they actually put in on my ski, i was not happy about it but no complaints on their service at all, so i figured I'd give them some props. Good question with the FG being dry. there was plenty of extra left over I just can't say if it was dry. I would guess no. there is so much more to pay attention to on the next pair.

twizzstyle
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Post by twizzstyle » Wed Jan 23, 2013 7:29 am

skimann20 wrote: Twiz: good point but "tons"? I thought you only use 700g? sorry the morning coffee is starting to kick in...
Sorry I should be more careful with my use of words - when I say "tons" what I really mean is lots of coverage, i.e. much of my base has epoxy on it, if not most of it, but the layer of epoxy is so incredibly thin (it's been pressed at nearly 60,000lb after all) that it's no big deal. It just looks bad if I've pigmented the epoxy, it can be shocking when I first pull the ski from the press. A few quick swipes on the base grinder, and its all gone.

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