Ski Builders Forum

Maybe its just the picture... but that base looks really shiny! Is that the abraded side?

BS Tech wrote: ↑Mon Jun 01, 2020 8:19 am Maybe its just the picture... but that base looks really shiny! Is that the abraded side?

Yeeeaaaaah so we messed that part up, the guy who has been helping me works in a ski shop is used to the more abrasive side being down for the wax and such. Either way, I didn't do enough research on base preparation so next time we are going to be better about the base prep and flame both sides.

We finished our first ski today and it is obviously the first time we have done this but, we learned a lot from it. there are a few things to fix to get ready for our next layup. I'm pretty happy with the results of the first ski but its not going to last. so for our next set up we are going to change a few things.
1) We need to make the waist of the core a little slimmer so the cap can get come down to the edge better, this last one had some sections where the cap didn't come all the way down and left some core exposed when the ski was cut out of the flash. we will make a temp fix with some fast set epoxy to seal it for now.
2) I missed some steps on my base prep, I got a little complacent and thought that having the base flamed before shipment would be fine and not need more work. Our skis currently are showing signs of base delamination but that is how it goes.
3) We are going to moving to a 3/4 wrap for the edges because getting the full wrap was a bit of a pain.
4) We also need to use more mold release and might put vinyl on the bottom of the base to protect the base more from the epoxy.
5) We lost some of our camber and tip rise out of the mold, we will exaggerate the amount next time and hope we can get a system to keep what we need
This was a learning experience for sure but I am happy with the shape and flex. I think there are a lot of things we can improve upon in the next layup which is all we could ask for out of our first layup.

Your base delam is likely due to attaching your edges to the smooth side of the base if you did not fix that before layup. Attach your edges to abraded and flamed side of the base. Flame treating the smooth side will not work.

vinman wrote: ↑Wed Jun 03, 2020 4:09 am Your base delam is likely due to attaching your edges to the smooth side of the base if you did not fix that before layup. Attach your edges to abraded and flamed side of the base. Flame treating the smooth side will not work.

Yeah, we got that messed up for sure but I will be more mindful of which side I am attaching my edges too and I will still flame before layup and attaching the edges.

With all things considered we were able to fix some of the base delam and take the skis out for a summer ski session at Beartooth Basin. They turned out better than I could of ever expected and it was alot of fun to get ride them for a day.

Nice work. Any skiing on your own skis, in June, in one of the worst years in history, is a good thing. FWIW, I have had base material wrapped up in a bag for a few years without reflaming and never had an issue with bonding.

I always re-flame base ands tip spacer. It may not be necessary but it is something that I have always done and will always continue to do.

If you are using UHMWPE sidewall its is absolutely necessary to abrade with an 80 grit sanding drum and flame both the top and bottom until a water drop does not bead when dropped onto the sidewall.

Im with the DR. on this one.
Ive never had to reflame uhmw base or tip fill either, just a good alcohol cleaning. Never had any delam issues.
But beware!!... the white polyester (without fleece backing) or clear topsheet thats been corona treated... thats got a shelf life of only about a year!
I used some that was a couple years old, no bueno!! Delam city!!

Just curious, how accurate did you get your core profile with that planer jig? I'm using a different set up with adjustable shims to create the spacing and not getting super accurate with the thickness. I think I'm within reason, but will try to get better. Possibly a more rigid setup like you have is more accurate?

Pheeps wrote: ↑Wed Aug 12, 2020 3:46 pm Just curious, how accurate did you get your core profile with that planer jig? I'm using a different set up with adjustable shims to create the spacing and not getting super accurate with the thickness. I think I'm within reason, but will try to get better. Possibly a more rigid setup like you have is more accurate?

Core profiling is something im going to work on this Fall. it wasnt the best but it was suitable for my first two builds. I think I might remake my crib with some shorter ribs and get the cuts a little more precise and get new planner blades. overall i think its a good system I just need to fine-tune it some more.

This a bit of an overdue update but I have now finished up my second pair of skis. On this pair I focused on improving my process and set up. To start I got the tip of my cassette bent up to get more of a shovel tip as the first pair was more of a linear rise from the contact point to the termination. after that, I made the core 2mm narrower on each side than the base so the cap could come down more on each side. The first pair had some separation on the cap going around. this pair I ended up not reflaming the bases but I was more careful in my prep and also sanded the top side and I see much better base adhesion as a result. Those were the main changes in the process, other than that I tried out some rice paper graphics and used a two-part clear coat on top. I did have some issues with my bag and my nozzle this layup and im not sure what that was about so I am going to get a new nozzle and be more careful in the layup.

Some additional comments to the last update: I think everything came out great and im super happy with the look of the skis, it will be fun to ride them in the coming months. Still had some sidewall separation but i filled in with some more epoxy on the sides to try to seal the core for longer. i think i need to get the edges of the fiberglass wetter during lay-up. I am also using two layers of 8.7 oz biax fiberglass and now i want to try playing around with different materials. what I am looking to do this winter would be to get some 22oz triax fibergalss, sidewalls, and maybe ash core ( i am using a 9ply baltic birch) so I can test the difference in each thing and find out what I like. To start I think I am going get some triax fiberglass and see how that feels but leave the core the same. once I have that picked out I try the difference in the plywood baltic birch cap compared to a vertical laminate ash core with sidewall. I think the ash and sidewall will be better but i want to look at the difference in price and time as a factor on what i settle on.

Well, it is time for me to start messing with materials and such in my design. I bought some vectorply 23.55oz triax FG, I want to see if I can feel a difference. The only issue is that I am going to also add sidewalls to this next set due to the cap issues I have been having. I got hard maple for the sidewalls and already got the bases and sidewalls cut. I need to stain the sidewalls before I do the core so I can glue them to the sides so thats my next step.