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Official Ski Pressing/Shaping/Building/Constructing Thread
All of us have thought about building your own shit at one time or another, but how many of you actually have? This thread will be dedicated to those who actually build your own gear from scratch, surely there are some of you on NS. Now I can't contribute to this thread much because I've never built anything and I only have a small amount of time working with fiberglass, but would sure love to see some info from you dudes who actually do, whether you build in your basement, or for a living. So if you can legitimately contribute please do.
No need to group buy for edges I just got off the phone with c.d in Ohio and the guy said no min order needed. Thicker bases on the other hand to fit the edges has to be a group buy. it is a custom run at a min of 300 meters.
I was wondering about this. I met a local board builder after my ski durability article was tossed around on Facebook and I asked if he wanted to do a split one time. He said CD Warholz or whoever the edge people are didn't have any minimums, even on the 2.5"x2.5". The base, is that a custom run from Crown or? I might be out of a group buy on that one to because of the other local builder and splitting with him.
Trying to make my mold ribs for my camber section. What am I looking to do here? Since my tip and and tail negative camber sections end with the tangent line being horizontal, do I need to go back up from a flat tangent with my camber section?
I am just not sure how to model curves that go from convex up to concave increasing to concave decreasing to convex decreasing.
Modeling wouldn't be that difficult but then putting accurate dimensions for when I hand it over to he machinist at my school for the CNC I don't want them to be like what the fuck is this
I have to model it in SolidWorks. No other option for the shop guys.
My question is do people actually make that transition? I am only doing 5 mm of camber, do I even need to set up those tangent arcs or can I go right to the bow shape? It's just so insignificant I didn't know if it mattered
I'm not sure if SolidWorks has it but AutoCAD has a tangent tangent radius function that allows you to place a cicle of a certain radius along two different arcs or lines with different trajectories, right at their tangents. The command line abbreviation for it is just 'Circle' ---> 'TTR'. The. I just use the lines I placed the circle on to trim it.
This is the function I'm using to smoothly blend arcs into eachother. A bigger radius generates a smoother and longer transition, shorter is more abrupt. If it's not possible to do that or similar I'd maybe consider using a 3 point arc, and just eyeballing the transition smooth. I think you can setup an arc like that similar to TTR but I'm not sure how.
Thanks! I will look into it. The programs are identical. The machinists are good guys but this is my first time they are doing work for me, and I don't want to give them a shit drawings with indiscernable arcs everywhere
For finding the effective length of the base I normally use a simple projection of the tip profile. Use the circle command start in your tip rising point and then go to the apex. Always worked for me.
Speaking of another topic, I'm starting to use plastic sidewall I've done experiment with urethane but is kinda hard to get everything done with a liquid bicomponent plastic. So i'll probably move to uhmwpe so my question is how do you guys flame treat the plastic before bonding it? I've read opposites opinion on skibuilders about this process,a lot of people don't think that could be done by hand...
Oh and about the core length Pudge it really depends on how you want your skis to behave. For my experience the longer the core is the better the ski behave. I'll normally use 10cm spacers in the tips, the remaining length is all zone
@Tero, I was not looking for the effective length. But following pressing I want my skis to be accurate as far as a straight tip to tail pull. So I have a moms where that is the case, it is a few formulas that would be too insane to do some calc with. I could use the formulas to find an arc length. Meaning that although my ski is 184, the length of the arc might be 190. So I could account for this with a base with a length of 190. Once pressed, it would be a 184 straight tip to tail pull. Just wondering if anyone has approached this method?
Also, running into a problem that my school doesn't want me using MDF in the CNC. I hadn't been aware of this issue. I thought it was pretty thoroughly practiced. What's the deal with wood in CNCs?
I still don't understand perfectly your problem about the base length... the length of the base for having a correct final dimension I personally do that every time. And I find the "effective" base keoght
Sorry for the incomplete message it's my stupid phone fault. If you can rephrase the question in I a simpler way I can probably help you better.
For the cnc it's the one at your school watercooled? Cause that could be the only problem, the rest it's only a matter of using a wood bit.
I have a tip and tail section that are identical, and a camber section that is, for all intents and purposes, flat.
My camber section is 100 cm. Since it is flat, the length of base material needed to make this section of the ski will be 100.
My tip and tail sections each have a straight, horizontal length of 42 cm. However, it will take more than 42 cm to make this section of the base, because it is curved.
(imagine if my rocker section was a triangle rather than a circle of large radius)
My enquiry was if anyone used calc and arc length to determine the appropriate amount of base. If someone did not adequately account for the curved sections of their ski, it would not be true length when taken out of the press.
Understood, I personally don't use arc and calc command as it' easier for me in autocad to do it with the projection method that I've explained before, but it's for sure a step to take when drawing the base shape.
Finishing the cnc explaination if your machine it's water cooled the dust (especially if you use mdf) will close up the recicle path of the cooling liquid which can cause failure.
LoafRiderMade a tumblr to post my ski making. Still getting the hang of tumblr so I apologize if it sucks. http://smartskis.tumblr.com/
Beauty! Super jealous of the core template. Just making the switch to sidewalls this summer and that would make life super easy. If I had access to a CNC I'd be down for that but I don't, so I'll just keep offsetting my ski template.
NinetyFourBeauty! Super jealous of the core template. Just making the switch to sidewalls this summer and that would make life super easy. If I had access to a CNC I'd be down for that but I don't, so I'll just keep offsetting my ski template.
The core template is needed because I'm going to be making a poured urethane sidewall. Going to be using the CNC again to be making my mold, but that is going to be down the road at some point.
LoafRider let us know what kind of urethane are you going to use, since I'm also in the process of poured sidewall and i've got mixed result with smooth-on products ( incredibly good with the 305, which is too hard although as a sidewall material, fuckin horrible with the 85a version).
I'm looking forward to have other people opinion on this process.
I'd like to know as well. I'm exploring sidewalls, not sure if I want to be buying slabs from Crown and gluing them on, or making my own by some mix and pour method.
I've also got some slabs of uhmwpe for testing but I'm teying to figure out a method to properly flame threat it, since standing to what is written on skibuilders is a though process to get done properly...
The plan is to build 3 identical pairs whit wood, urethane and standard sidewall and see which holds up better, in four days I'll have the wood proto out and then move to the others.
Sorry this post is going to be quite long but hopefully it will interest people.
It's been too long since I properly posted and I never got round to posting how my build went. If you've been following the #diyskis on Instagram you would have seen some stuff. Since my last post in November I finished my build.
I got a rod of ash that i needed to glue into the mistake made by the CNC when profiling my core (don't know if I said but the CNC decided to take a running lap around my core cutting through 80% of the height of one corner) hand planed and sanded the repair to profile of the rest of the core.
Glued down my 3/4 wrap edges with a special polyethylene glue
Painted 2 layers of Rubber shed selant to the back side of a piece of ply to seal it to be the lining of the mould. Screwed that down. And painted on a few coats of pva + water mix for helping with sticking sealant tape down and a bit more sealing.
Using painters tape sealed off the pattern for my veneer top sheet and stained it using two light coats applied with a sponge, had minimal bleeding of pattern stain, just enough to know they're hand made
I got delivery of my vac bag stuff after a fail in thinking about what I need which resulted in a second order of some tubing and a fitting. Ended up with 4x1m of peel ply, 2x0.6m wide tube of vac bag plastic, 10m of vacuum sealant tape, 3m of reinforced hose, female quick release fitting and a breaching unit with male fitting.
Then we move onto the saga of trying to find a vacuum pump to hire as time was running out on me so couldn't build one like Logan. I had just over a week and a half to get sorted for and lay up my skis before moving away to Austria for the season. I was struggling to find anywhere that had a suitable pump to hire within 50 miles of my house. I asked mechanically orientated friends if they knew who had one or had one themselves; answer I got back was most were too incorporated into autoclaves to disconnect or build one myself. Ended up through a work colleague of my dad that I could get a 900l/min dairy vacuum pump which was a little excessive and power hungry for a 0.2m^3 volume to deflate and leave running for a day or two. So pulled the trigger and bought one. Cost me just over £200 after tax; which wasn't as bad as I had feared it was going to be. The pump arrived Monday afternoon. I tested it, seemed ok, a little weak so had some sand bags on hand for if shit hit the fan and I ended up with no pressure. On Monday evening I got my shit together; laid the sealant tape; cut the peel ply to shape; did some core bending with a heat gun; and then it was go time.
Laid up with my peel ply; my 3/4 edge wrap base double sided tape sections stuck to the mould; Vds tape; layer of triaxial fibreglass; pre bent cores; another layer of triaxial fibreglass and my wood veneer top sheet. Folded over the ply to form an envelope and sealed down the vac bag in a busy but not rushed 45 mins.
Had help from my dad with weighing out and spreading out the epoxy while I was busy spreading epoxy on other sections. We used panel pins around the outside of the core to hold it in place. Fired up the vacuum pump; bag deflated nicely and pulled all the materials together alot better than my dad was expecting; got the ski shaped down into the mould nicely and no noticeable bag leaks or slipping of the upper layers.
Covered her up with blanket, electric blanket, sleeping bags and duvets and left the heat and pressure do their magic. After checking on the temperature of the lay up a bunch with an average temp of about 28degrees Celsius we left the bag under pressure for 44hours. From the epoxy data sheet it was de mouldable after 48 hours at 20C and 24 hours at 23C but figured there was no harm in giving it some extra time. Pulled the skis out the mould, after a little crowbar work because of the pins we used to stop core shift. The layup had taken the rocker profile really nicely and looked as if the laminate had wetted out really nicely.
I had to leave before the epoxy had fully cured and I was able to cut them out and finish them so my dad did the final finishing stuff.
First was a rough cut with a jig saw. It killed one blade and then on the last cut, the saw.
After that they were taken to a local joiners who is a family friend for a fine cut and sidewall tapering.
(Tapered sidewall pics)
Then to seal off all the wood they got 6 spray coats of marine varnish.
They were then sent to me by courier to Austria. When I got them I mounted them up with some z12s so I and anybody else could try them, removed the base protection tape and filled the edge gaps with 2 part epoxy. Then took them to my work where they were put into our wintersteiger discovery on the wide ski setting and set going. I stood confused as they moved through the machine not touching the belt grinder or the stones and headed toward the edge discs, so had to run and emergency stop the machine so as not to rip out my 3/4 edge wrap with 1500rpm ceramic discs. Retrieved them from the belly of the beast, Fixed the sequence, ground them a good few times, waxed them a good few times and they were ready.
apologies for any sideways pics
I wouldnt say its a necessity but i was woried about not getting the pressure i needed to get the lay-up to mold to the rocker profile which is fairly severe also using a full wood core and sidewalls lay-up its difficult to get it all lined up properly when there is an air gap between your layers. One of them i pre-bent more than the other and it took the rocker profile a bit better. Not a whole lot but if you're looking for it there is a difference between them.
s-handhow did you shape the core? I cant seem to figure it out by looking at it
i shaped the core plank using a CNC router to profile it to the thickness rather than using a plane or router table and rails. its a simple top down cut pentagon with 11.5mm to 3mm from under foot to tip and tail. the cnc does a running tool path up and down the core and by using a large-ish bit it ended up with a rough-ish lined finish to help with the epoxy bonding.
razors - one thing that they preached about on ski builders is connecting both edges to the ski at the same time. they were saying not doing so can actually warp your base and change your shape slightly. food for thought for the next pair!
that definitely could explain the waves in my bases. i had a few ideas as to what caused them like heat in the press expanding the base and because it was taped down it waving instead, the time between cutting and laying up was like a month so warping over time was an idea. Also another was the possibility of an uneven layer of epoxy on the base or an uneven pressure from the vacuum between the skis. hopefully try to take account of all of these will give me a more even base next time.
loganimlachprofiling the core is definitely the most tedious, but as long as you're deliberate in everything you do and have patience it's not too bad.
the most stressful is definitely the layup. but after the first couple it's not too bad.
I find profiling cores to be more stressful than layup, I think that will be even more true when I switch to sidewalls. I haven't run a core through my new planer setup though, so things may be less stressful than they were. Layup on the other hand is just an easy going, paced process, I definitely prefer it over layup.
Skis also look sick Chaz! I really like your stained veneers. How did the marine varnish do in sealing them?
Thanks for the replies! i found a place that does CNC machining nearby, can they do all of that with their fancy shmancy machine? and is it worth however much it may be?(doubt it will be that much)
GoldsteinThanks for the replies! i found a place that does CNC machining nearby, can they do all of that with their fancy shmancy machine? and is it worth however much it may be?(doubt it will be that much)
start at skibuilders.com my friend. look at their how to section, if you think a router sled setup or a planer sled setup isn't in your means, then by all means go get them CNC'd.
but seriously, I read almost every thread on that entire site before I started my journey, there's some pretty valuable information in there.
NinetyFourSkis also look sick Chaz! I really like your stained veneers. How did the marine varnish do in sealing them?
the varnish did pretty well in sealing them I've had no delam or soggy-ness of the veneer after 15+ days of mixed fresh snow condition riding on them. the only thing is chipping that i fixed with a little epoxy but would say it would be better to re-varnish the sections to stop any water getting into the laminate.
loganimlachstart at skibuilders.com my friend. look at their how to section, if you think a router sled setup or a planer sled setup isn't in your means, then by all means go get them CNC'd.
but seriously, I read almost every thread on that entire site before I started my journey, there's some pretty valuable information in there.
I agree is logan and feel like i should have read more. there is a huge wealth of knowledge on there. The question i get alot is how did i go about learning to build skis and in one way or another ski builders is the answer.
GoldsteinThanks for the replies! i found a place that does CNC machining nearby, can they do all of that with their fancy shmancy machine? and is it worth however much it may be?(doubt it will be that much)
I tried to get my stuff CNC cut but they wanted a ton of cash, so def price check first.
Finally i get to post some news on my builds.
These are the latest out of the press, a new shape and a new mold.
175cm, 115-94-115, r15.5m, with early rise. really curious about how well they will handle on an "allmountain" aspect.
the core is a hybrid of ash and pine with a medium to stiff flex.
A shot of the base:
sorry I hadn't take a photo of the camber profile... (dumb)
Next up is the same setup but with urethane sidewall, routed out the channels with a cnc and poured:
the urethane is a Smooth on 305, 100a hardness, it machines really well and pour really easily, also a lot of people on skibuilders had good results with it.
the last thing that I'll try new bases:
tried some self made die cut, we'll see how it turns of at the moment of the layup.
as always sorry for the lenghty post but I'm stoked about how these skis turned out and I can't wait to try them this summer.
(by the way there is some european builder here? and maybe someone who's going to Les deux alpes this summe?).
did you put your urethane in a vacuum chamber before pouring? how was your overall experience with it? i've been intrigued by trying that (wouldn't be too difficult to router a channel without a cnc) but it seems like a pain in the ass kinda.
SUnfortunately I haven't use a vacuum chamber. Following a tip that someone wrote on skibuilders I've done a couple of passes with a flame torch when the material was curing. It pulled out a lot of air but there are still some bubbles (I need to figure out better for how long the flame is needed and the intensity of the flame).
At this point I would recommend a vacuum chamber if you manage to build one.
Also I've noticed that softer urethane formulas tend to develope less bubbles, althougt from my experience more instable (doesn't always cure well when poured in big quantities).
As far as the machining part goes it's just like wood, especially in this hardness. It planes and cuts just perfectly, it also create a very strong bond whith the wood in the channel.
I'm quite happy with it but we'll see how it performs.
Hope it helps, if you need other info just ask.
have you thought of channeling it out and using it for tipspacer material as well? I'm not sure if the bond would be the best seeing as the connection is so thin at the tip, but to have continuous sidewall/tipspacer with no meet would be sick.
From what I understand you need to use a pressure chamber to properly de-gas the Smooth On urethane. Although I don't understand why a vacuum chamber wouldn't work. I'll have to re-read any see if anyone has attempted that. If not it would be extremely easy to make one from some sewer pipe.
Logan I've thought about that but my current profiling jig for the planer isn't long enough for profiling a 175 cm core, I don't think working the material at that thickness will be an issue... It's for sure something to try as it would eliminate a possible point of failure, maybe in the the future.
94 I remember a post on skibuilder on a vacuum box made out of plywood, in which way you can make something similar out of tubing? You want to degas the urethane and then pour it in the cores?
NinetyFourFrom what I understand you need to use a pressure chamber to properly de-gas the Smooth On urethane. Although I don't understand why a vacuum chamber wouldn't work. I'll have to re-read any see if anyone has attempted that. If not it would be extremely easy to make one from some sewer pipe.
i remember one of the guys on SB was using an old pressure cooker as a vessel but I could have sworn he was putting it on a vacuum. I've definitely been wrong before though.
