Jonrezz’s Build Log

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Jonrezz
Posts: 73
Joined: Thu Feb 13, 2020 1:14 pm

Re: Jonrezz’s Build Log

Post by Jonrezz »

Snowboard is in the press cooking right now! I made a cool timelapse of the layup, thought I'd share!

https://i.imgur.com/ouiZZAm.mp4

...featuring my dog pajama pants lol! :D
Buckow
Posts: 20
Joined: Mon Dec 30, 2019 8:55 pm
Location: Switzerland

Re: Jonrezz’s Build Log

Post by Buckow »

Nice work! How did it come out?
Jonrezz
Posts: 73
Joined: Thu Feb 13, 2020 1:14 pm

Re: Jonrezz’s Build Log

Post by Jonrezz »

Thanks! So it’s been a while since my last post, but I’ve been hard at work!

The snowboard from the time lapse came out with these crazy epoxy bulges!!! Oof! I must’ve used too much epoxy between the plastic topsheet and the veneer. Never again, I think for now on no plastic over veneer, oil based polyurethane finish instead.

Here’s the pic out of the press:

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So my attempt to fix it was not the most successful, but not horrible either. I considered repressing a new topsheet onto it, but I decided to just make it rideable, have my friend try it out to see how it rides, and then try again with any changes he may want. Was definitely a learning experience.

Sanding off the plastic topsheet:
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Took a whole day carefully sanding and trying my hardest not to breach the veneer. Unfortunately, there are a few spots I did despite my best efforts not to. The worst one is between the feet, and a couple smaller ones around the edge. I tried to hide it by blending with ebony stain, but it’s not going away.
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Here she is with a couple coats of polyurethane and mounted bindings:
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It’s at the tuning shop now getting a base grind and sharpen. One day I’d like a base grinder, but geez are they expensive!

And now on a lighter note, the rosewood skis came out beautiful! Cant wait to see how my other friend likes them!!! Pics of course:
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After these builds I spent some time upgrading the shop- new hepa filter mod for the dust collection, new metal blast gates, new outlets in the shop, new storage shelving. It’s really coming together! I’m addicted as heck to this hobby! Here’s a recent pic:
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I am currently designing another ski concept, and will update y’all on that build when it begins! I’ve also been researching laser engravers, I thought it would be cool to mess with engraved designs on veneer, and was also thinking about trying Miller studio for some sublimated graphics! One day I would like to figure out sublimation, but gotta let the wallet cool off a bit first..
sammer
Posts: 933
Joined: Wed Dec 19, 2007 10:37 pm
Location: Fernie B.C.
Contact:

Re: Jonrezz’s Build Log

Post by sammer »

Use a J-roller to push the excess epoxy out. This will also help smooth out some of the transfer you're getting from your X's of carbon that show in your ski pic.
You need to have somewhere to push that excess to. I've used breather along the sides or at the tip and tails and roller-ed all the excess there.
Start with heavy pressure them lighten up and do full length passes of your layup to equalize anything that's left.
I use quite slow hardener so have lots of time to work.

sam

Edit to add... J-roller after you pull a full vacuum.
You don't even have a legit signature, nothing to reveal who you are and what you do...

Best of luck to you. (uneva)
Jonrezz
Posts: 73
Joined: Thu Feb 13, 2020 1:14 pm

Re: Jonrezz’s Build Log

Post by Jonrezz »

Thanks for the tip sammer! and thank you all for all of the help along the way! I'll give the roller a shot on my next pair that gets plastic topsheet.

some additional updates:

I have devised a new plan for sidewall beveling to allow me to get the "step" in the sidewalls like many brand name skis achieve:

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hopefully will get something like this:

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I'm going to stick it on a router table and create a wooden ridge for the ski to ride on similar to chrismp's post a while back - very clever solution.

I'm also nearing completion on my 2nd snowboard, and it's the best build yet! no flaws in sight! just need to drill out the binding inserts. I ordered some magnets with holes in them to locate and mark the insert centers.

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next pair is going to be some skis again! (yay). the plan for this is to try some inlays and laser work instead of just plain veneer for the topsheet. they're going to be 170 cm all mountain skis - about 95mm at the waist and 17m radius.

I got a laser engraver on aliexpress (neje master) and it's been pretty simple to set up! I used the software it came with to control it, and made dxf files in autocad for the vector graphics:

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worked pretty well in scrapwood for the tests! I'm hoping to do more large and complex inlays for the the ski, and experiment with stripes as well (gonna try veneer tape and a veneer saw with a straight edge) for the actual build.

in order to sort the base/core alignment issues I've been facing, here's the plan:

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they're just dowel pins from the big box store and I drilled matching holes outside the ski for them to slip into. the pins are superglued into place on some scrap ptex in a similar manner that snowboard binding inserts are used for alignment.

lastly - my friend who I made the last board for and I took our equipment to gore last weekend! he liked the board!

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hope you all are having a great winter! Cheers!
SleepingAwake
Posts: 175
Joined: Mon Oct 11, 2010 11:06 pm
Contact:

Re: Jonrezz’s Build Log

Post by SleepingAwake »

Man i hope your laser safety goggles are up to snuff. These lasers without enclosure scare the living bejeezus out of me...
Jonrezz
Posts: 73
Joined: Thu Feb 13, 2020 1:14 pm

Re: Jonrezz’s Build Log

Post by Jonrezz »

Couple of updates!

The laser is a bit scary haha! Ive been using the glasses that come with them, they seem ok. I look forward to incorporating the laser in a build in the near future!

Regarding the sidewall router jig with the bit combination I found, I am pleasantly surprised! check out the result :D

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and here's some progress pics from my latest ski build, it's a 170 cm all mountain for someone who is on the lighter side (155 lb) - 2/8/2 mm poplar core with two 19mm maple stringers, 130/95/121, 1" carbon tape between the base and bottom fiberglass, 20 oz/yd fiber. It's got 7mm of camber and a tip rocker section.

I used some offcut base material with wooden dowel pins for core alignment - worked great!
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Mid-layup. The sidewalls are smooth-on 300 but I've died them black with PU pigment
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Topsheet has two cherry bands on the outside with a rosewood strip in the middle. Used some veneer tape underneath to joint it:
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Into the oven:
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and out:
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So regarding previous comments about not using bleeder - I've more or less been able to contain the epoxy squeezeout in the tip and tail areas - it pretty much just makes its way over the cassette and gets trapped between a heavy plastic film and the metal. seems to be working out well - haven't damaged the mold in the last couple presses (*knocks on wood):
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Cleaned up:

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So the one thing that caught me by surprise was - the skis are a bit softer than I thought they would be - I had calculated that this ski should come out in the normal stiffness range as outlined in my ski mechanics textbook:
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however they came in at 22 N/cm deflection. my testing apparatus:
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Today I added some paint lines:
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Finally they will get some spar, poly and wax to finish off the toposheet.


also finally got a tune and bindings on the original rosewood skis!

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comet
Posts: 4
Joined: Mon Feb 08, 2021 8:15 am

Re: Jonrezz’s Build Log

Post by comet »

I'm very interested in that textbook figure (which book is that?). I chose 2.2 - 11.5 - 2.2 core thickness somewhat arbitrarily for my first pair that I'm working on. My spreadsheet indicates that should result in around 30 N/cm. I'd have to go up to like 14mm under foot to get to 45 N/cm (center of range) which seems pretty high compared to what people are doing here. Maybe that data is racing ski specific? It doesn't seem to account for length either since a longer distance between contact points will yield more bending displacement when all else is the same. You said your latest came out softer than suggested there. Are they too soft?
Jonrezz
Posts: 73
Joined: Thu Feb 13, 2020 1:14 pm

Re: Jonrezz’s Build Log

Post by Jonrezz »

Hey Comet -

The book is "Skiing Mechanics" by John Howe. The chart says 30-60 N/cm typical stiffness for race skis in the footer note to the left - however - I have measured the deflection of the 6 factory made skis I have laying around - some race skis but some not - and they all fall within the range -

Rossignol experience 83 (168cm) - 40 N/cm
Head Mojo 80 john olssens (170 cm) - 39.2 N/cm
Fischer RC4 WCSL (165 cm) - 47.7 N/cm
Fischer RC4 WCGS (180 cm) - 39.2 N/cm
Volkl Supersport (154 cm) - 49.2 N/cm
Rossignol temptation 76 (146) - 38.1 N/cm.

I think the last pair I made came out too soft - and definitely softer than I calculated it would, but I'm waiting to see what my friend thinks of them - he's lighter than me and beginner/intermediate so he may end up liking them.

I think the deflection range is intended to be more of a rule of thumb / engineering check than a rule to live/die by. I'd be willing to bet there are great skis outside the range too.

As far as what you figured for your pair - you're right 10-12 is inline with what people are doing here. I think 14 would make for too heavy/stiff of a ski - what composites and wood type are you factoring in? The pair I'm working on now is 20oz fiberglass top and bottom with 2.5/11.5/2.5 core and 187 cm, no carbon (also for someone else) - I'm curious where this ski will fall on the scale - I calculated 60.7 N/cm but my calculations have been pretty off historically so we'll see :D

here's the stiffnesses / specs for the ones I've made so far -

first pair (grey dyed oak carving ski) - 2/10/2 core - 22 oz fiberglass top/bottom - 1" wide 373 gsm carbon stringers top/bottom - 66.7 N/cm
second pair (rosewood) - 2/9/2 core - 20 oz fiberglass top/bottom - 1" wide 373 gsm carbon stringer bottom & "x" shapes top - 31.7 N/cm
third pair (stripes) - 2/8/2 core - 20 oz fg top/bottom - 1" wide 373 gsm carbon stringer bottom - 22 N/cm

my favorite pair is the first one - I don't really have anything bad to say about them other than maybe the binding placement needs some adjustment - I tried the second pair and it carves well but feels a bit noodly when going straight & fast - maybe because its too soft? I'm pretty sure I wouldn't like the third pair because of how soft they are, but maybe my friend will, time will tell.
comet
Posts: 4
Joined: Mon Feb 08, 2021 8:15 am

Re: Jonrezz’s Build Log

Post by comet »

I've been using a modified version of the spreadsheet I found on the forums a while ago. It does not factor in base material, edges, or top sheet so it could just be an underestimate for actual stiffness. Do you factor those in your calcs?

https://docs.google.com/spreadsheets/d/ ... sp=sharing

My setup is 180cm overall length, 146cm effective length, core is 2.2 - 11.5 - 2.2. Vectorply 22oz triax (actual weight 23.55oz) top/bottom. No carbon.

That gives 29.3 N/cm which I think might actually be good since this pair will be pretty fat at 105mm waist. Not exactly a carver. It is nice to have some points of comparison, though. I'll definitely do a test setup like your dumbbells to see what the real result is.
Jonrezz
Posts: 73
Joined: Thu Feb 13, 2020 1:14 pm

Re: Jonrezz’s Build Log

Post by Jonrezz »

Interesting. My gut is telling me that the spreadsheet is underestimating how stiff those will be

I just took the 2.5/11.5/2.5 ones out of the press yesterday - I'll let you know what the result is in a day or two when I've cut them out!
Jonrezz
Posts: 73
Joined: Thu Feb 13, 2020 1:14 pm

Re: Jonrezz’s Build Log

Post by Jonrezz »

Ok Update time!

I just cut out some FAT powder skis! now everything didn't go as planned with my new sidewall router and so I will be redoing this set. I think a wider center rosewood stripe will look better anyway for the redo, since these skis are so wide..

first off - here's how they look right now (the pair on the right) - I still need to paint and finish the topsheet -

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and before I get too far into it this post - Comet - these came in at 47.7 N/cm. The dimensions are 187 length, 2.5-11.5-2.5 core, 140-115-128 tip/waist/tail, 20 oz fiberglass top and bottom (I also included a 500 mm long 20 oz fg binding mount sheet under-boot), ash core with two 19mm wide maple stringers for binding screw retention, so I think the spreadsheet is underestimating by a decent margin.

so for the things that went right:

camber profile came out as intended - I've been getting good at predicting how much I need to exaggerate the camber in order to make top only heat feasible!

I was really proud of my tip wrap job - although while I was doing it I was cursing at how much of a pita it is :)
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and now for what went wrong

Since these skis are sort of a unique animal compared to what I've been making with their long early rise in the tip and tail, I whipped up a new set of tip and tail molds and slapped them on my adjustable rig. The mold has served me well, but I ran into a new issue - I think due to the sheer size of these new tip molds. I think the pressure pulling them together, since theyre so big, caused the tip blocks to bend towards eachother with enough force that it actually cracked one of them! what ended up happening is when the tip mold pulled inward, it exposed the sharp corner of the aluminum cassette to the silicone sheet - causing a new tear. fortunately I was able to stick some tape on it and keep the vacuum at around -28in and finish the skis ok - but lesson learned - place some wood pieces between the tip and tail molds to avoid this potentially happening in the future:

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Next - I tried to take my new sidewall routing jig for its maiden voyage on this pair - and - well - I need to add a hold-down wheel or safety mechanism to it because while for the most part it worked great, it's prone to doing this (it happened in two spots):

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with that said - where it didn't gouge my skis - it actually went really well!

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but yeah, I think I'm going to add a hold down wheel to avoid the jumping issue - since the ski only rides on like a mm of bearing. or maybe a fence, haven't really decided yet.
Jonrezz
Posts: 73
Joined: Thu Feb 13, 2020 1:14 pm

Re: Jonrezz’s Build Log

Post by Jonrezz »

So I am taking a break for a couple of weeks from ski building due to an ACL reconstruction surgery I had last Friday. Since I'm stuck in bed with my leg elevated, time to update my build thread!

So following up from my last post, I have rebuilt the last pair of powder skis that I messed up on my first try, here they are!
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Just needs the topsheet painted and finished, laser engraving and a tune and they're ready to go! I am going to try a new finish for the topsheet - entropy clr/clx to get a more glossy and hopefully more resilient finish than the poly and spar I've been using.

What I'm really excited to share is my next build - I feel like a lot of new stuff came together and brought things to the next level! I pressed my first marquetry inlayed topsheet design!

so the inlay is a trace of the matterhorn mountain from a vacation photo I took years ago. I did the tracing in autocad:
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Next, I cut out each shape in different veneers using the laser and eported dxf files for each mountain shape and carefully assembled them like a jigsaw puzzle. the painters tape is temporary and then I flipped it over and used veneer tape with holes in it to seal the seams from underneath before pressing:
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everything layed up on the casette:

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in the press:

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and here's the result from layup!

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looking forward to recovering from surgery in the coming weeks so I can cut them out and finish the build up! the build is an all mountain shape, 95 at the waist and 17m turning radius. 2.2/10/2.2 tip mid tail core thickness, 20 oz triax fiberglass with a 1" wide unidirectional carbon stringer under the core. really looking forward to seeing these through to completion!
mammuth
Posts: 449
Joined: Tue Oct 28, 2014 3:48 am
Location: somewhere in the alps

Re: Jonrezz’s Build Log

Post by mammuth »

Regarding you sidewall problem. Chrismp has a similar setup, Router from below and the little hump you have. I know he is using it a lot without problem. I used it a few times and i hated it, exactly because of the risk you encountered (i had the same problem).

One solution is a Rollerblade/Skateboard wheel on a lever with a big pressure spring to hold down the ski. Even better would be two rolls on the bottom (instead of your table) and one pressure roll on top. I had this on my plan but the simplicity of the following solution prevented me to do it.

I went the other route and use a straight bit with a Makita router with tilt base. At first its scary to do it freehand like that, but when youre used to it its supereasy, quick and quite safe. The only problem i had one time was when the router bearing came loose.

But hey, what is skibuilding without that adrenaline when you do the last steps on a perfect ski ... drill the inserts and route the sidewall ... perfect to dded it up ;)
Tom
Jonrezz
Posts: 73
Joined: Thu Feb 13, 2020 1:14 pm

Re: Jonrezz’s Build Log

Post by Jonrezz »

Thanks! yeah my setup is loosely based on chrismp's. I was thinking about modifying it like I drew in the picture below. I can understand the appeal of the hand router version's simplicity, and I'm all for simple solutions, but I really want to achieve that "step" look that comes from having the bearing against the edge. :D

I might do some rollers on the bottom like you suggested - did some shopping and it's not easy to find rollers that are low profile enough to face mount onto the table. maybe if I recess them or mount them sideways off the end of the table or something. going to think about this more before I follow through with the modifications.

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