HB (Hansen Boards) - Page 15

I have good experience when constructing cores like yours in using two ash stringers running from tip to tail and place them where the binding screws go. Center and outside of the stringers is paulownia or fir. The short sidewall under the bindings is ash again.

For the taper I use a circular arc that is tangent to the narrow part of the core and ends in 45 degree angle to the sidecut. I would make the taper even gentler (larger arc radius), which also helps draping the fibres and topsheet in that area.

Thanks for the share. I had a similar break in a full paulownia core, (snowboard). Right between two reinforced areas. Strangely I have another board with the same lay-up but with veneer, and the veneer has prevented the topside from buckling. So maybe I would not only feather out your binding area reinforcements but also extend veneer a bit further and make the taper more gradual. (I mean don't have the tapered core as abrupt or right next to the rigid binding plate)

Bottom line though, a full Paulownia core asks a lot from the composite not to buckle in a deep bend. It just crushes fairly easily. I've thought about maybe a 2mm inlay of hardwood but will probably just stack more unidirectional composite with long tapers in the risk areas.

It's wild how the fracture in the carbon cloth runs up and down on the 45 axis as it crosses the ski. Oh I see, that is black basalt. If you can find it, Try a thin layer of Textreme over the Basalt and you get a real smooth finish without pinholes, looks really cool in the sunlight too.

Finished my replacement skis..

Core is different.. more Ash.

I'm not totally happy as I had some core shift..

I can still ski them though I think.. Will try them tomorrow.

Hi, they still look nice! Did you use the dovel method to keep the core in place?

They certainly look good! I have no idea how you make that many skis in such short amount of time!

Dude! Awesome looking skis, but man you gotta get that core shifting issue under control. What are you doing to align your cores?

I always reckon keeping those basic parts of building as simple as possible is the best way.

> pmg wrote:Hi, they still look nice! Did you use the dovel method to keep the core in place?
No, and that was my downfall.

I decided to try without, as that was where the last pair broke. I realize now that I could have easily aligned my cores using blocks glued to my press as these skis have sidewalls in the middle.

I'll chalk it up to learning and make sure it doesn't happen again.

> SleepingAwake wrote:They certainly look good! I have no idea how you make that many skis in such short amount of time!
I sleep awake.

> Akiwi wrote:
> SleepingAwake wrote:They certainly look good! I have no idea how you make that many skis in such short amount of time!
I sleep awake.

Another pair of skis finished..

This is an everyday on piste cruiser.

It is my first ski with a full sidewall. Normally I did a cap.

Also I stained an ash veneer green and airbrushed the graphics onto that

Then used a 2 component Matt clearcoat over that..

Ash core 1.5 - 12 - 1.5

600 Triax & Carbon stringer layup top and bottom.

Fiberglass weave under foot.

Result is very stiff.

But for on piste blasting that should be OK

Such thin tips! Excited to hear how these ride.

Does you core extend all the way to the tip and tail?

> burnside wrote:Such thin tips! Excited to hear how these ride.

Does you core extend all the way to the tip and tail?
Yes, the core goes right to the tip about 3mm short.

I changed to cap construction on the tip as I didn't want the core exposed where it was cut through the fibres of the wood. On the sides the grain runs parallel to the cut so it should remain relatively waterproof. On the end grain the wood would not be so water resistant, therefore I don't expose it there.

Here is a video of the skis in use.

They are fantastic to ski on.

Stable smooth and easy to turn.

https://www.youtube.com/watch?v=5Bn3rw8pTik

Nice carving!

> skidesmond wrote:Nice carving!
Thanks.. It was difficult picking my way through all the people. But I found a way ;-)

We have been using HB for building longboards for the last year, so I guess we can keep it for skis and snowboards.

As the summer sports season has finished at last, I don't have to spend my weekends driving kids around to various smorts activities, so at last I have some time to get into the celler workshop (Manhole) and start on my new project to build some skis / snowboards befor the winter..

That is the plan anyway.

My first job is to build a Profilinf table.

But before I could do that I built a table with adjustable gate for my drill Press.

So building tools to help me build tools.

Thisw is something I have been needing for ages. I made an adjustable gate with a rail where a block can be tightenend to help with positioning when multiple holes are needed in the same place.

Also a replaceable puck in the middle where you can drill into.

That was my Thursday Friday evening project.

Now I have started on my profile table.

I will use the router bridge technique, as I have a router, and don*t have a Planer.

I have decided to build an adjustable vacuum router bridge for snowboards and skis.

My first job is to build mark out, and drill all the holes for the vacuum

My 22mm MDF board is 40 cm wide, 200 cm long.

I hsed my drill press for drilling holes in the long axis.

Vacuum cleaner is set up to remove dust immediately.

As I got further in, my gate turned out to be too thick So I went as far as possible using the Drill press.

The middle 3 rows I had to drill with the cordless drill, SO I decided to leave the middle without holes.

I drilled 1380 holes. My friends think I am mad. I am starting to think so too.

Lastly I flipped the board and cleaned up the holes ion the inside.

Now on to make the vacuum box.

So glad I have a cnc to drill all those holes

> chrismp wrote:So glad I have a cnc to drill all those holes

My Arm would agree with you.

My wallet (and wife) wouldn't.

A CNC would make a lot of things easier. But it is not in my short term plans.. or budget.

> Akiwi wrote:
> chrismp wrote:So glad I have a cnc to drill all those holes

My Arm would agree with you.

My wallet (and wife) wouldn't.

A CNC would make a lot of things easier. But it is not in my short term plans.. or budget.

same here. I did this on the CNC.

However, I still had to go back with a drill and dress up each hole, my arms were super sore, it took a couple nights.

Ok, Table is nearly finished.

I tested it and it holds quite well. Maybe I need a little more powerfull vacuum

Nice railsystem. If it works I might copy it.

hope this rail system will work for you. Unfortunately it didn't work for me. Wonder what kind router bridge you built.

Also I don't think MDF good choice for material to make vacuum table.

I tried holes 1" apart like you at first and didn't find table create enough suction.... had to triple amount of holes

It might help to seal the MDF top and sides with paint or varnish to direct as much vacuum through the holes as possible. MDF is porous.

Also I think I would go to the extra trouble of drilling out the holes in the middle. After all that's where your material actually is and it's the holes under the core that actually hold it down.

Looks like a great effort so far.

Good tips.

I sealed the inside of the vacuum box by mixing wood glue and water and painting that over the MDF. I will do the same on the top and sides.

I'm off to get some Plywood to do a test run.

I'll let you know.

Very happy with the results. It worked perfectly.

Here you can see detail of the bridge I built. I added angle iron to make it good and stiff yo I wouldn't get any sag.

I also taped up the exposed holes.

The board was held so tight I could lift the whole table with it. Great success.

I decided to use a double layer of nuts instead of wingnuts on the top, as you can lock them together better. I figured the wingnuts could turn by themselves because of the vibrations. Using a spanner and wingnut on the bottom it was pretty easy to adjust the rails to 1mm or finer.

The first core I made worked well. Maybe the flat bit on the tip which should be straight at 3mm for 20 cm wasn't perfect.. I can fix that with the sander, and tune it for next time..

I need to work something out to reduce the amount of dust.. My workshop looks like a bomb went off.

Damn!!!

I was doing my second core, and obviously something came loose on my router and it sank a bit, cutting the core right through. At about 30 cm from the tip. Grrrrr!!

I probably do need a new router. that one in the photo I have had for about 30 years. It is good, but not very powerfull, and difficult to adjust / lock etc.

The last couple of nights I have been experimenting in my celler making an edge bender. I think I have it working now. Tested on a short piece and can bend it how I want. Tight enough for skis.

It is mainly made of 20 x 4mm steel. Then at the top is bit of 20 x 20 to hold the arm centered.

I'll practice a bit with it and if I am satisfied with the results I'll do a video.

No comments on my welding. I bought a welder last year and taught myself.

Looks good! I guess you had inspiration from the bender Apex are using?

The modified tile nippers which are very common on this forum are a great addition to any bender for fine adjustments btw. Plus they cost next to nothing and are easy to make.

> chrismp wrote:Looks good! I guess you had inspiration from the bender Apex are using?

The modified tile nippers which are very common on this forum are a great addition to any bender for fine adjustments btw. Plus they cost next to nothing and are easy to make.
Yes, I saw the Apex thing and flipped the direction, as their one the machine would be in the way for tight curves.

I was at Hagebaumarkt yesterday and wasn't sure what to buy. The tile snippers looked so small, so I was thinking the Nail pullers might be better.

Opinions?

What would be better.

A Kantenzange like this:

http://www.obi.de/decom/product/LUX_Kan ... ageSize=24

Or a Rabitzzange like this:

http://www.obi.de/decom/product/LUX_Rab ... ic/5255997

> chrismp wrote:Nice skis! What thread did I miss regarding the skibuilders get together?! I will be at Hochkönig this weekend. Any chance the meeting is there?
Hi Chris, the get together is organised by Georg from Skibaumarkt.de.

We will be in Der Tauplitz in Steiermark. Meetig between 8:30 and 9:00 on Saturday. Details on the website.

It's Much closer to Vienna than Hochkönig!! ;-)

Nice skis Akiwi.

I built very similiar ones as well. Used 2.5 mm balsa for the thin parts. Used the laser cutter at Makerspace in Garching/Munich to cut them out. Unfortunately the core shifted a bit and I have some Balsa exposed after flashing. How smaller is you core compared to base with edges?

I will post some pictures as soon as I have enough posts.

> Jonsn wrote:Nice skis Akiwi.

I built very similiar ones as well. Used 2.5 mm balsa for the thin parts. Used the laser cutter at Makerspace in Garching/Munich to cut them out. Unfortunately the core shifted a bit and I have some Balsa exposed after flashing. How smaller is you core compared to base with edges?

I will post some pictures as soon as I have enough posts.
2mm a little more on the tip and tail.

I used the same template as I used for the bases without the edges.

Thanks for your answer!

I'm surprised your blade was able to deflash more than one ski. The Wood blade I used would not be able to cut that much fibers. Maybe I should give it another try.

> Akiwi wrote:
Hi Chrislandy, When do you do that with the APF7? After the layup and before clear coating with time for it to dry?

yep, before clear coat think of it as a invisible pinhole filler

as it blends into the carbon. wait for it to cure then clear coat

> satch wrote:You can Transfer a printed image onto wood using acrylic gels.

Pls can you elaborate, sounds interesting

https://m.youtube.com/watch?v=kMcgJOW7b1A

This video should explain it. I have never tried one of these transfers gels but seen results with photos and they were pretty good. You can also use acetone or paint thinner but the results are not as clean.

nice work on that profile table

I broke one:

Was with some amazing skiers at the Skibuilders meeting on Saturday, and I broke one.

We were off piste at the top of the mountain skiing through the windblown waves, and suddenly I heard "Crack"

Looked down and there was a crack in my right ski.

I had to ski 1.5 hours back to my car with the broken ski.

Luckily I had a second pair with me.

I was also not 100% happy with the result, so I am not too upset.

Live and learn I hope.

I see that the break was where I drilled and 8mm hole through the core and used a dubel to center the core on the base. probably wasn't the best place to do that.

Even if you didn't like the way it skied, it's always a pity if they fail.

Perhaps you shouldn't taper the core as much. For your next pair i Would recommend to widen the middle part of the core. The way you did it there is a pretty big difference in stiffness right in front of your bindings!

I'd move the taper forward about an inch past where you cracked it, yes that may have been a weak point because of the plug but that looks like bending failure rather than core shear failure, so basically the compression side (top face) exceeded it's limit debonded and buckled.

I was going to say just basic bending failure of the compression "flange" but unless you changed the layup in that last inch or so then it would have failed probably a bit closer to taper

Yes, I intend to do a more gentle taper , and I will run an Ash stringer the full length of the ski with Paulownia left and right for lightness... and do without the plugs, or put the plug in the widest part of the ski.

I went back and looked at the pic of your cores. The finger joint in your core is right at the spot they broke.

A couple things I'd change

1. If you finger joint, make sure this does not terminate right at the binding.

2. Definitely make your mounting area not taper as quickly.

3. Possibly make your composite stronger and it add a second layer of lighter fiberglass under the binding mount that extends several inches past where your screws will be. Taper this binding may to a point for that it kind of "feathers" out the flex a bit and doesn't create a point in your laminate that is just suddenly stiffer.

4 if you use a dowel for base/core alignment don't put it anywhere near your bindings.

Thanks for the good tips.

1. The break is actually in front of the finger joint.

2. I will taper further along the ski, and run one piece of Ash, 2cm wide from tip to tail.

3. Good idea with the extra layer around the binding area. I will do that.

4. I'll try to do without the dowel completely. And if I use one I'll get some thinner 6mm ones. Is also easier to get the fiberglass around them.

> Akiwi wrote:1. The break is actually in front of the finger joint.

Afaik finger joints themselves are not the weak parts...in fact the wood usually fails before the glue joint does. You can think of the glue joint like a knot in the wood that is harder to break, so the softer wood surrounding it is what gives way under load.