Chronicles of a home-made plate system

[Corey]

Jack, he mentioned a 1mm spacer in the 2nd paragraph.

[SunSurfer]

Version 2 hinge & hinge/slide units now completed.

Units are made of predominantly 3 mm aluminium plate, bonded with Araldite & screwed together.

Fixed hinge unit shown in this post. Has 5mm marine 316 alloy stainless steel hinge pin. Mounting screws are in the 4cm x 2cm standard inserts on my Riot snowboard but are not the final mounting screws that I will use. Outermost inserts are 50 cm apart on this board. Plate attachment part of the hinge unit has stainless T-nuts epoxyed to it. Unit has a 1.2mm sheet of P-Tex from an old snowboard base underneath it, base aluminium plate is 3mm, and hinge extrusion is 15mm, for a total height of 18.2mm. This unit weighs 372 gram.

See following post for detail of sliding hinge unit.

[SunSurfer]

This unit is constructed identically to the fixed hinge unit except for the slide features.

Base is again 1.2mm P-Tex from an old snowboard.

Four rectangular cutouts have been made in the unit. 1cm thick, extra abrasion resistant, ultra-high molecular weight polyethylene inserts have been made (see photo) and placed in the cutouts then screwed into the binding moutings. Epoxy has then been poured into the gaps to create an absolutely precise fit between UHMWPE and the cutout sides, taking great care to avoid getting epoxy on the snowboard. Epoxy doesn't effectively bond to the UHMWPE so it's an easy task to tap out the plastic and trim the rear edge of each peg that goes into the cutout. Only 2-3 mm of space is needed to accommodate the sliding motion of the board when carving (see thread on Sagitta Arcs Chords).

To finally hold it all down an aluminium plate with yet another layer of 1.2mm Ptex between it and the sliding unit will be screwed onto the UHMWPE inserts and into the board.

In this way all the sliding surfaces will be P-Tex/UHMWPE based and wear should be minimised.

Weight of this unit without the final attachment plate is 382 gram. Stack height is the same at 18.2 mm. Obviously the thickness of the chosen plate needs to be added to this.

I am planning on attaching the binding heel & toepieces directly to the plate that sits on top of these units. The resulting weight saving for my Front & Rear bindings combined is 425 gram total.

My nearest ski field is planning to open in late June, weather permitting so no ride reports for a while yet.

I have no commercial interest in this design. My day job pays all the bills. I hope that this sparks peoples interest in plate design and that we see more detail of other "homebake" plates!

Like some others, I just like problem solving and playing around in my workshop.

Like bj vircks, I had figured out the general layout of the Apex Composites plate (see plate designs thread), and also looked closely at the Karl plate. There had to be other ways of solving the same problems with the materials I could lay my hands on.

I have some ideas for trying to fabricate an Apex Composites style design but haven't begun to work on those yet.

The only power tools used in the making of these were a circular saw with a tungsten carbide blade, a Black & Decker hand drill, and more recently a second hand drill press.

SunSurfer

[NateW]

Looks like a good design, but I'd be really worried about tearing the top off of that plastic 'bridge' that holds the assembly to the board.

[lowrider]

Little aluminum strip over pastic bridge.

[SunSurfer]

Read the description gentlemen.

The plastic bridge is approx 1.5mm thick. I'm still not finally decided about whether to keep it. But the whole thing will be covered by an aluminium plate, 3mm thick, held down with the mounting screws that go through the UHMWPE inserts and into the board. Between this fixation plate and the sliding unit is another layer of 1.2mm P-Tex. If I leave the plastic bridge in then I have to make a cutout in the P-Tex. If I remove the bridge then the P-tex layer is only perforated by the mounting screws.

The pictures don't show the plate to allow you to see the slide mechanism.

[lowrider]

The picture changed from the large square slide (which i thought was pretty cool) to the smaller slots with the bridge piece and the different hinge. Therin lies the confusion. The ptex top and bottom will give excellent slide surfaces. Clocks ticking, our snow is gone now can't wait for you to try it. Have you tried a plate before?? I'll never forget the look on my sons face first time he rode one.

[SunSurfer]

Final plate to secure hinge/slide now shown, together with slide forward and back. Final slide shows the crucial <1mm gap between this final piece of aluminium and the unit below which allows the sliding motion to occur.

In the end I cut off the bridge between the UHMWPE inserts but left them protruding about .5mm above the hinge/slide unit top surface. This allows the securing plate to be firmly screwed down but still leaves the gap.

Now have to wait a couple of months to find out how durable this all is!

SunSurfer

[SunSurfer]

This is the Mk. 1 version.

Since the previous post I found that using 4 approx. 1x1cm UHMWPE posts still allowed the front unit to wiggle more than I was happy with.

In version 3 I turned the 4 holes in the aluminium into 2 parallel slots. UHMWPE sliders are now nearly 3cm long each. Then beefed up the securing plate to 6mm aluminium and bonded on the P-Tex underneath it.

Result: NO WIGGLE. Slides well.

Photo shows unit with the securing plate to one side.

SunSurfer

[SunSurfer]

Now for the first plate. (Mk.1 version)

Made from marine grade 7-ply plywood, with a fibreglass/epoxy laminate to either side, epoxyed and screwed into an aluminium channel extrusion on either edge.

Bindings are attached to stainless steel T-nuts epoxyed into the underside of the plate. I use SnowPro Race standard at the front & F2 Intec Race at the rear, heel & toe pieces only.

Rear foot wedges shown are set at 6 degrees, made from the same marine ply - 'glass - epoxy materials.

Final weight comparison: Conventional (SnowPro & F2 bindings used normally) vs. Plate (Hinge Units, Plate & Binding heel & toe units including all screws/bolts etc. used to hold it together)

"Plate" is 1416 gram extra weight.

Note that Conventional setup minus screws to attach bindings to board weighs 1508 gram

SunSurfer

[pokkis]

Do you think that when you give pressure for toes or heels on binding ,then these plates which are hold parallel to board with those aluminum channels, would not twist up or down?

I have someway similar plan as yours and that is still my worry-list

[lowrider]

Vary length of plate front and rear, stiffen aluminum rails or produce a plate of various thickness.This point is the one that is probably the deal breaker when it comes to personal choice as to whether or not most people will embrace the use of a plate system. It all boils down to your own personal preference as to the feel of your ride.You can only make that choice once you have tried a variety of plate combinations.Nice work SUNSURFER now get out and ride! :)

[SunSurfer]

The design of the plate has as much, if not more room, for experimentation & personal choice than the design of the system that attaches it to the board.

1/ Plate attachment points to board in relation to attachment points for bindings.

2/ Heel & toe pieces only vs. standard binding inserts and full binding rotation variability.

3/ Plate Flex:

Flexible plate -

a) what materials

b) how much flex (rider weight & ability)

OR

Non-Flex plate

a) what design, including how much torsional rigidity to build in (torsion box?).

b) what materials

4/ How much adjustability do you want in the design and at how much extra weight for those adjustability features.

Pokkis, the initial plate I've built has significant torsional rigidity coming from the channel section aluminium. The amount of twist in the ply/glass sections at either end is also limited by their attachment to the hinge units below as these run across approximately the middle of the length of each piece. I debated building a torsion box design plate but decided against it on the basis of the extra weight involved.

I can always build more plates with different designs, because the hinge/slide mechanism is not in the plate with this design, and new plates can be easily attached/detached.

How it will actually perform I have to wait to find out. Our ski fields in NZ will not open till mid June at the earliest.

SunSurfer

[pokkis]

Have you tried to give some preasure for toes and heels on carpet, that could already give some indication how it would survive.

Agree your concept is good cause you can easily change plate

[SunSurfer]

Hi Pokkis, Thanks for your interest.

I booted up and laid the board down on the floor.

Lateral pressure is directly transmitted to the edges through the hinge line with relatively little flex in the ply/glass laminate.

Forward and rear pressure produces definite flex, but nothing that I think the plates can't handle nor anything likely to cause permanent deformation of the alloy channel.

We'll see what actual riding does. It certainly seems strong enough to me to stand up to routine carving. I figured that the boards we ride have wood cores and glass laminates and they hold together (most of the time).

I'm particularly interested in the durability of the interface between the 2 UHMWPE slider guides and their epoxy surrounds. I haven't been able to come up with any other way, so far, to produce a fit of this precision using the tools in my garage.

I'm not planning any deliberate crash testing! but I'm sure it will happen knowing the standard of my riding.

SunSurfer

[KingCrimson]

When you're testing stuff like this (or using scary cracked bindings if you're cheap) it's really nice to double leash your feet to eyebolts threaded to the board. I bought some of these M6x1 eyebolts off McMaster for that purpose. http://www.mcmaster.com/#eyebolts-and-eye-nuts/=6vddud

Now, the only thing is I ran them in my Hangl inserts. Not sure how much you care about the board, but you might consider getting a coarser thread and tapping your board for them. Anything to save the board should the plate rip off.

[pokkis]

I'v ebeen using those eyebolts for another purpose in my boards, they are good way to use with cable lock when you dont have bindings on board or have just second board kit installed

[SunSurfer]

One thing I've been thinking about through this whole process is the possibility of adding new, lateral mounting inserts into one of my current boards.

I've looked for externally threaded inserts that might allow me to put some in without making holes in the P-Tex base. There are essentially none suitable available in NZ, and those listed on the Web seem extraordinarily expensive.

Putting new inserts in through the base clearly involves making a substantial hole in the base which you want to be able to soundly and smoothly repair.

I've searched the Web for info on home repairs for "core shots" and most of the fixes involve using part cured epoxy below the P-Tex patch. My concern about this is that very few adhesives actually stick well to polyethylene. Clearly whatever board makers use to stick the P-Tex on works well, and from what I can see from the "roll-yer-own" snowboard sites is that they use just straight marine epoxy to bond the boards together.

Is this actually correct? Can either of our resident board makers confirm that the epoxy used in construction is just a standard epoxy, OR does it have some special sauce to help the P-Tex stick?

Does anyone else have any experience in really successful core shot repair. I don't want to go down the path of making holes in my bases unless I KNOW I can fix it well.

SunSurfer

[tufty]

My concern about this is that very few adhesives actually stick well to polyethylene. Clearly whatever board makers use to stick the P-Tex on works well, and from what I can see from the "roll-yer-own" snowboard sites is that they use just straight marine epoxy to bond the boards together.

The epoxy generally used is not "marine" epoxy (which, although waterproof, is not designed for extremely low temperatures combined with heavy flexing), but it varies from manufacturer to manufacturer. Most of the US-based DIYers use West System epoxy of one type or another, which is, if nothing else, relatively easily available. If you're only worried about repairing a core shot rather than laminating a whole board, then you can most probably get away with using any old epoxy.

As for making the ptex stick, you're right - bugger all sticks to HMDPE, which is part of what makes it so good as a base material. It needs to be flame / abrasion treated to make it "stickable". Once treated, the ptex sticks perfectly well using epoxy. I have a load of base material here and would post side-by-side shots of the treated and untreated sides, but my camera's on the fritz. Again.

If you're wanting to add inserts, then you probably want pre-ptexed inserts of the correct size and depth, which can be purchased relatively cheaply - Worden in france, for example, will sell you a set of 10 pre-ptexed 9mm deep inserts for 15.40€.

[SunSurfer]

Thanks Tufty.

Your link explains this photo of Roland Fischnaller's base with a Karl type plate in use in an FIS race 2008-09 season (from the FIS Smugmug site).

SunSurfer

[SunSurfer]

http://www.maislinger-snoli.com/nc/de/produkte/browse/1/select_category/25.html

Snoli make the stuff, and a few places in Europe seem to sell it.

Drill a pilot hole from the top. Drill the base using the countersink to create the socket that matches the profile of the pre-PTex'd plug (7 or 9mm depth), thin layer epoxy, drive the plug home into the board. Wait for epoxy to set and base grind your board.

Haven't yet found any place outside continental Europe that sells the plugs, countersink, or snowboard mounting kit.

SunSurfer

[Boarder_Ted]

I found the p-tex inserts at Joe Jones in Scarborough, Maine. Guy just gave me a couple. Said that hadn't used them in years. They used to use them retrofitting 4x4 insert patterns into older boards. I used one on a board I got that came from the factory missing an insert. A countersink I had in my shop worked just fine. The rest went just as described above. I've been using the board like that for a few seasons now without a hitch.

So they are out there...just have to know where to look. ;)

[SunSurfer]

The ideas flowing around in this thread, the Alpine Snowboard Plate Systems thread, and from some personal communication with Lowrider have led me to a new design.

The three features that will make the Mk.2 a distinct improvement on Mk.1 are -

1/ Ability to add lateral mounting inserts to my existing 4x2 & 4x4 pattern boards (You could even add them to a Burton or Hooger mount pattern board). I have 30 pre-Ptex'd multi-inserts ordered and on the way from the Worden site.

2/ Lateral inserts are mechanically so much better than the 4x4 that I will be reducing the amount of aluminium in the custom width hinges I build. I no longer need to try to build in the stiffness to hold down the outside edges of the hinge. This will reduce the weight substantially, and reduce the footprint.

3/ Lowrider's current design has the sliding motion required dealt with in the plate, rather than in the hinge unit as I had in Mk 1. For Mk.2 I have taken this idea and, I think, improved it by coming up with a way for the home builder to create an accurate sliding bearing in the plate, similar to the one used in the final Mk.1 hinge, but with all P-tex contact surfaces.

Time to close off this thread, Mk.2 photos and construction details will appear in the near future.

SunSurfer

[lowrider]

Any one want to join a plate therapy group?:lol: