id be interested in a build thread if its not done yet!
My group for a composites mfg class decided on making a set of skis for a project. I was curious if anyone in this high paced sub-forum has made themselves a set of skis? If anyone is interested I could also do a 'build thread' of progress. It should be a pretty fun and challenging project!
I bought a pair of 0N3P skis and after looking at there shop build pictures when they first started I would say its a huge undertaking. I'm all for DIY but it seems like a ton of work for a pair. I guess after trial and error you may have quite a few pair. good luck.
Alright so we got a little bit of progress on this. Here are a couple shots of what we have got.
So far we have everything designed and are working on either finding a source for cores or laminating our own.
Parts to the mold we are using got cut out with a shopbot (cnc type woodcutter) this morning and we still have a bit of work to do on cleaning up the edges and getting it all together.
A few cell phone pics for your viewing pleasure--
getting the shopbot started- we are using 3/4" MDF
a shot including the shopbot controller...
cut out product to be used as a mold for the camber of the skis
More updates will come in the next few days!
Last edited by scubasteved; 10-27-2011 at 10:57 PM.
Another update on the mold,
-Finished router work on the lower mold, core profiler and base template
-cut up a bunch of spacers for the mold
-drilled out holes for the lower mold
-got the lower mold sort off together
The base template is on the left of the mold. A sheet of plastic will be going over the wood btw.
finishing the mold tomorrow!
Time for another update-
The mold is essentially done. All of the materials for the skis have been purchased, so the next thing to do is to start work on the cores. Making the cores looks to be a relatively simple, but somewhat time consuming process. You need to laminate several boards together, take a couple of slices of the laminate and glue some sidewall material(UHMWPE) on. Once that is done, we have a router setup to shape the core.
We are attempting to use fire hose as a bladder between the upper and lower mold, to get added pressure for the layup. hopefully it works!
Lower mold completed
Ski mold by scubasteved, on Flickr
Base template sitting on the mold. These are som WIDE skis!
PB026049 by scubasteved, on Flickr
Simple side shot, showing the camber profile.
Ski mold by scubasteved, on Flickr
I will have a bunch of updates coming soon. we have two pairs than need to be DONE by the 29th. we are working on the cores right now and just got a shipment of goodies(edges, base mat'l, etc)
the cores very well may be the most difficult part.
So as an apology for the lack of ski updates you get a glimpse of another project for my composites class. We are comparing different layup techniques and materials, my group is using 20oz Carbon fiber with vinylester resin. We used two different layup methods the first is a simple vacuum bag-
Next up is the infusion process where the fibers are layed down on the tool and resin is pulled through the fibers, giving you a very good resin/fiber ratio.
So you let them cure for 24 hours and enjoy a nice sunset over Bellingham bay
come back and send them of to the waterjet. sorry no pics of that although i can get some if you really want. Anyway when they get back from the waterjet they are cut into nice standardized tensile bars. Our samples are about 0.1" thick and .385" wide. We cut and test the bars in our tensile tester.
here is a picture of a sample in the jaws...
So here are a few numbers for ya. our best samples that were oriented with fibers running the full length of the test bar held out at a little over 2900lbs of tensile force. CF is no joke! Although fiber orientation is critical with the fibers running only +/- 45 degrees to the stress direction the bars held up a measly 250lbs...
Anyway that is all for tonight.
Hope some people are enjoying this.
I guess I lied when I said last post for the day. went back to campus and ended up cutting out the base material and bending some of the edging. The edging sucks. It is an absolute pain to bend semi accurately. Anyway we 'finished' bending four lengths of the edging and need to do another four for the second pair, hopefully we find a better way.
Tomorrow we are going to cut the sidecut of the cores and laminate a layer of HMWPE on the edges. We should also get around to gluing the edging to the base material.
here are the base sheets cut out. Its pretty thin UHMWPE. 1.33mm I think.
Using the base template to bend the edging to where it needs to be.
And finally, a shot of the edging where it will be at the end.
The further along we get the harder things are getting. Im just glad we have a fairly large variety of tools to work with and a lot of knowledge walking around the building.
Today we planed down the core material, cut the side profiles in it and attached the sidewall material. Took about 6-7 hours. woohoo overnight cure from here.
A nice looks at our core(s). The sidewalls are UHMWPE. The whole piece will be cut in half to form 2 1/2" thick core blanks that will need to be formed with a router and a guide tomorrow.
I wish we had more clamps that fit.
No brilliant sunset tonight. Starting to get pretty stormy! Bellingham Bay view from campus.
When I saw the first post I wondered where you were going to school. When I was in the VRI one of my friends pressed his own skis in the composites program. I wish I had done that too, it would have been a lot more fun then the stuff I'm doing now. Hopefully you can get out of classes for the day tomorrow.
Lately I have been testing "tip-in events". Just the tip-in. Just to see how it feels. Response time is typically on the order of 2-3 seconds. Sometimes the injection timing is a little off...
definitely not getting out of classes tomorrow even though my only class is an electronics lab. WAY too much work left on these skis. They need to be vacuum bagged by tuesday. We got a ton of work done today and ill do an update tonight but i need to head back to campus for more work on the other stuff i posted. What year did you graduate from the VRI?
So finally getting around to getting this up. Things are taking shape! we got our core cut in half, its now 2, 1/2" thick planks. They will be getting shaped to the final profile tomorrow. We also put the edging on the base material. So, a few pictures.
Clamps, and a few more clamps. might as well throw a few more on.
shot of the edging from the bottom.
and from the top.
a bit clearer shot of the cores and base with edging.
Core profiling day!
lunch break update- one core is done aside from trimming the ends for the tail/tip spacers.
Core #2 is getting there.
Basic idea of our profiler, use a router that slides along a guide.
Works great aside from taking awhile and making a huge mess.
Cant tell super well from this but the center of the core is .5" and the tip and tail get down to about .15"
back to work.
nice. that was a few years before i started up here.
Shop is closed for the weekend so i get a bit of a break from this project. We realized that the ends of our cores are most definitely not the needed 2mm thick... We found out that we cut our core profiler wrong and the ends are 5mm thick. a bit of rework on monday will be needed for that. We need to have everything laid up on tuesday though, so times are a bit stressed...
lunch update. core got fixed after awhile, we may just finish one ski as we are noticing more and more difficulties that lie ahead. Tip and tail spacers are cut and what not. Our tooling was not designed exactly how it should have been so we may need to envelope bag the entire tool rather than being able to just vacuum bag the surface. Anyway I need to head back up to campus to work troubleshoot the myriad of issues we just realized we had so I will leave you with pictures.
The actual thickness it was supposed to be...
One of the issues, the core lifted up in the center(we have it screwed down at the ends) and I took off too much material, should be 'ok' but we may add an extra chunk of something there.
Trimmed up for the spacers, and a reference for the length.
a sample of what another group is doing. It is a sled, a lot more complex than it looks just from this picture though. The black is carbon fiber and the yellow is aramid (kevlar).
and here is the tooling for the other part of their sled (still being vacuum bagged)
Layup day! I dont have a lot of pictures as my hands were covered in resin for a large portion of the time we were working on the ski. It shouldnt be too much more work to finish the other ski, it was just too much work to finish before a deadline. anyway, all of the final touches that needed to happen before the ski was laid up happened and then we laid it up!
putting the top sheet on.
How it looked with the top sheet, the fiberglass gets nice and clear.
Envelope bagged for the long weekend.
Well the ski is done! sadly we wont be making a second one anytime soon and therefore cant really test the out. The flex seems spot on though, and if we ever have time/resources to get the second one done we will!
The full ski, I really went all out on clearing the room for this pic...
Sidewall/profile/camber of the ski.
the core and what not
Also another project that I just finished, this one for a CNC class.
Last edited by scubasteved; 12-02-2011 at 05:53 PM.
In case anyone was wondering, we had some issues with delamination on the tip and tail. So we had to rivet them together. Not the best solution but it works... The material we used for the tip and tail spacers(Polystyrene) was a bad call on our part. The epoxy just isnt a fan of sticking to it. Something we should have known, but we were to rushed to actually think of. If anybody has any questions i would be glad to answer them too. This ski might not be the prettiest but if we made another we learned enough to make a darn good ski.
Toda's Worcester Telegram-Gazette has an article on a company in Worcester that makes handmade skis. Thought you mighth be interested.