More Monkey business

[Richuk]

So my uncle has completed the edge bender, it pulls 3 and 4 inch cold - no sandblasting required. Pulled the plans from the site, so thanks!



Re-working the mold today, will put it through the planner tomorrow and bend a few edge sets.

Oh yeah , I reckon carbide cutters will give a better edge to the fibreglass than what I'm currently using. Results have not improved as the epoxy cures. Two weeks or so on and the epoxy has really cured - not had any relaxation of the camber.

Update

Carbide will last longer but wetting out correctly solves the problem I'm having ... when learning you sometimes go round in a few circles. The camber did relax once cut out of the flash, but not by much. The second set did not relax at all - I completed a longer post cure cycle and let them cool over night. My press is insulated and I've been surprised how much heat is retained.

I'm going to re-cut the pattern I use to cut my base material - basically it is easier to shape the pattern to what the edge bender will do! Obviously this is the way to do it and if I'd had the edge bender from the start I would have done it this way round.

Bad photo, but I've worked out the kinks



After much swearing, I've noticed that cutting the edge after it has been cold rolled into shape makes the steel straighten back up. I guess this isn't news to many here.



Better photo.

[Richuk]

The base material has left Austria (2 June), but is currently in Finland (8 June) ... gone back to Germany before being sent to Sweden, now its in the Netherlands ... at last, in the UK (9 June). Happy days are now on the horizon!

I just need to go and shop for acetone or isopropyl alcohol to clean base and the edges before attaching to the base. I'm going to try and attach the edges and press in the same day - I'll be keeping an eye on the temperature, as I don't want to be a victim of a warped base. In the UK we do cold and damp. I'll probably let the parcel rest for a day or so before starting.

The edge bender worked



so I kept going - covers me for a few changes I want to make.



I've made a different core with the remaining wood I had in the garage - didn't have enough for the edges. I have a jig for shaping the edges, which means I can run it over the router table. The jig is screwed on the core - top, tall and in the centre. I'm going to attached two pieces of dowl to the base to centre the core, so no permanent damage. The one below wasn't done this way.



I'm thinking I can carry on building out with straight strips and trim, or I can shape the spine, outlined below and attach a number of strips, all curved when pressed together. I think I read somewhere on the forum that this is what stockli do? I have it in the back of my mind that this will inhibit vibration because of the interference patterns that would arise ... I need to think more about what is the most efficient use of wood as shredding your cash through the planner is painful.



Update

No problem with cutting the base - clamp it to a template and its done. Bond the edge on same day. Will be more careful next time round, they have to be perfect, as the press will not help you out.

[Richuk]

A few results to share ... it went in like this



but the press gave it a bit of a shake - it's interesting to see what can happen. I've seen that some custom builders hot glue CF tape into place.



I switched them from the bottom to the top and reduced the amount of VDS, it just covers the edge





Cut back on the amount of epoxy bushed on to the base on the second and third ski - I may be imagining it, but it had a tendency push the edge away from the base. If the effect exists, it's a marginal effect, but worth considering. Got me thinking about how I've applied superglue to the edge, I'd been spotting 1 every 7. That's fine, but instead of putting the glue under the edge, I should clamp and then apply a spot. I don't want the edge held on with glue ... I guess I'm going to have a few issues to deal with when I test ride them.

I've not put on a top sheet and have used a clear base so I can what problems I need to fix. I've made one set at 12mm, the second at 11.5 - the same amount of carbon and kevlar, with parallel placement variation.

The carbon fibre is still a little wavy - I think this is a general issue when dealing with CF tows as the kelvar tape minimised the issue; not for the reason for the tape. I might route a channel ... but I'm not crazy about that idea, on reflection I don't think its right. I just wanted to get on and get something out to see if I could complete the process and then refine the design and process next time round. Have been a bit too pushy, but that's ok, as I've got the next step of the process and it looks like a ski. Carbon tows are cheap but I'm hoping my approach will give a good feel for what material does what within a ski.

I'll cut them out later this week - I've been routing the edge of the trial core with a carbide bit, but if anyone want to send me a few 'fine finishing tips' now is the time to do it

Just gotta say thanks to all the info provided by the site and in particular Happy Monkey Snowboards - I'll keep at it, but I've a long way to go!

Update

Out of the flash, used a large hack saw and did it by hand - runs well through the fibreglass. The jig saw was just too aggressive - personal pref. Pleased to see that the core did not move - so I need to reduce the impact of the dowel, thinking of using a guide rail glued to the sidewalls of the core. Tipspacers, no movement - teflon really works. I'm going to re-work the top of the mold when I have time, I want the cat-track to roll out from the centre to the tip when the hose is pressurised. The medical tape tip rocks! I will router the edges in advance next time, not too close. Router is mounted on a wedge, as I have not been able to find the correct dovetail bit in my neck of the woods. I didn't like the step produced by the first router bit, you get a flat surface if the bearing and the blade are next to each other - no gap. Used belt sander to reveal the tips and edge from the flash, finished the tips by hand. Still getting a bit of feathering on the fibreglass - photos of layup showed the problem, me, wetting out it patchy because the warmed epoxy cools before spreading to all areas. Hmm same problem again. Funny because it looked ok - digital photo said no. Will buy a couple of the carbon heaters and a thin piece of plastic, say 1 mm to cover and pre-heat the materials to an even temp. To help with the delivery of the epoxy, I'm going to use a small paint tray - the roller type, and drill a number of holes across the top end away from the trough. This will ensure that the epoxy flows out across the fibreglass at a controlled rate. I won't heat the epoxy to much, as I am heating the materials, but I will have to speed up lay up!

Hmm what about a metal tray with holes in the right place?

[Richuk]

Here are a few photo's - as usual good and bad. Will add a bit of commentary when I have a bit more time.



You can just see the rubber I've placed on top of the ABS tip spacer ... cheapest source of EPDM I found was pond liner. It appears to bond better when cleaned with alcohol and not acetone. Flame treated, but still a weak bond by comparison.





Iroko edges sealed using base wax - dripped hot wax into white spirit to form a 50/50 solution and applied with a piece of cloth. Looks great and a month on and really impressed with the finish it provides. When the wax cools in the pot, its like butter, so it is easy to re-apply.









Poor fitting - my bad. Only one minor separation, not yet a delam.



I heated the materials when laying up this ski, sticking my neck out, but it seems to be show fewer errors. I'm going to find a metal tray and drill holes, something I can heat a little.







I think this what happens when you apply a little too much epoxy to the base - again, I need to do more before being sure.

[falls]

they look pretty nice Rich!

[Idris]

Looking very nice I will have to come and see them in person when I get back from Japan.

[skidesmond]

They look great!

[OAC]

Excellent finish!

[Richuk]

Thanks fellas, it's great to pass the first hurdle.

Idris - Japan - that's the right way to do it, go to come back. Shout when you smell the green, green grass of home.

[falls]

I checked out some Faction skis in a shop last weekend and your edge fit around the tips is on par with what they were puting out commercially. I was a bit suprised to see epoxy filled gaps between base and edge in skis being sold at a major store, but also encouraged that minor edge fit problems initially aren't the end of the world (especially for a homebuilder, for a commercial seller it seems like something you should have dialed).
I was in London and York last week. Fine UK weather for ski building!
I think an alternative to a heated press would be pressing in a central line tube carriage during a summer heat wave. Man does it get hot on those trains!

[Richuk]

Thanks falls - I'll crack this problem next time. I had it in the back on my mind that the pressure would help, but I suspect you need a real cassette for this effect. Working on a few quality issues at the moment - updated the mold for the planner with some good results.

The London tube is a nightmare - delayed, cancelled, overcrowded. London only ever worked for me when I could walk to work.

Feel free to shout if you ever near the north west of England (Manchester/Liverpool) happy to swap building tips.

[Richuk]

This doesn't exactly count as a trip report, as testing was completed at the local in-door ski centre - real snow at least.

So what did I learn:

Both ski set have edge hold reminiscent of the volkl P50, a real sense of the edge cutting deep into the snow. I suspect the hold was largely determined by the carbon tows placed along each edge set. My gut also thinks that the kevlar as partly responsible by limiting the flex along the edge.

Both ski sets were stiff - boot bang stiff. The Iroko @ 11.5 mm core was more stiff than the Maple @ 12 mm, but I don't believe this to be a reflection of the wood used. I suspect this is a reflection of how the carbon stringers were affected by the press i.e. loss of tension.

The rear of each ski set lacked enough pop to aid transition from one turn to the next - more noticeable when carving.

The Iroko set had on ski with carbon fibre tows placed on top of the core and one beneath. As a result, the pattern of one ski was still determined by the core profile supported by the carbon fibre. This resulted in a nice even resistance throughout the turn. The carbon fibre in the second resisted the core earlier and exerted a lot of control and then inhibited the flex when driving the ski through the turn.

Both ski sets were torsionally rigid, the likes of which I have never experienced. I didn't have enough room to ramp things up and take advantage.

The vinyl I'm using didn't seem to have a problem with adhering to the top of each ski. It is interesting to a number of air bubbles develop and grow - I guess the epoxy is still venting, but really slowly - maybe, as it could be I didn't apply it very well and this is trapped air. This cover does its job well enough, but its a bit pricey.

No catastrophic failures or delaminations.

Hopefully this evaluation is near enough to be true, feel free to post contrary opinions!

[Idris]

Well done on seeing it through to a real test, can't wait to see them in the flesh.

[skidesmond]

Nice report! So where is this in-door ski area? The only one I ever heard of is in Dubai.

[Richuk]

Cheers guys! It's a crazy experience, those first few turns are really rewarding.

This is where I went http://www.chillfactore.com/. I think we have about four in the UK. The one in Dubia is huge ... the ones we have in the UK are OK

Spending a bit of time at the moment adjusting molds and crib to increase accuracy. Looking forward to seeing a few more pics on your journal SD : )

Hopefully my next set will be closer to what you are used to Idris