Sealant/Glue for Bindings... and other mounting secrets.

[GrimSurfer]

Manufacturer advice seems to run the range from wood glue to hot glue to polyurethane glue. The common goal appears to be to keep moisture out of the substrate of the ski.

For this reason, I’m not a big fan of wood glue because it is usually water soluble. I’ve used hot glue before, which seems to work. Hot glue doesn’t expand or crystallize, so screws can be removed more easily without damaging the ski.

I’d certainly be open to a drop of polyurethane glue (like Gorilla Glue) provided that the hole was swabbed out with a damp Q tip (dampness activates poly glues). Poly glues will crystallize and harden, so removing screws later without damaging the ski might be an issue.

I’m very familiar with helicoil (am a vintage car owner). It works great in metal for situations in which fastening and unfastening is essential. I don’t think it is necessarily the best choice for a ski though. My concern would be loosening of the coil because of the grossly dissimilar expansion qualifies of metal and wood/Fiberglas. The screw might also back out, unless Loctite was applied. Once you go down that road, however, you might as well use polyurethane glue.

[fisheater]

I just pulled a binding mounted with Gorilla Glue, which is a polyurethane. I put a drop of water utilizing a toothpick when I did the mount. The glue did expand with a foaming action. They were the easiest screws I have ever pulled. I’m not quite sure what to think. I’ll let you know what I use for the remount.

[GrimSurfer]

Ha ha, yeah I just put the Titebond 3 up there for discussion, I've never used it. I'm a contractor and there aren't too many days that pass when I don't drive a screw. For whatever reason I always have my local, Continental Ski and Bike, do all my mounts. There is an older gentleman who does the tele mounts and he uses heli-coils and epoxy on those. They don't charge much and have the responsibility, so it seems worth it. I also enjoy stopping there, talking gear and picking up yet another kind of wax.

You just had to say "helicoil". Now I'm wondering if I want to helicoil the bindings. Clearly, it would let you remove and repair/replace the binding much easier but it would also make for a much stronger bond to the wood itself. I'm guessing you might also want to Loctite the screw you put into the helicoil? I've never put a helicoil into wood before... Then again, I've got some Titebond II on the shelf and the ski all prepped for drilling and install...

I don’t believe you want to helicoil your bindings. I’ve used helicoils. They require an over drill (larger size) and then tapping out. They screw into the threads cut by a tap. This only works in metal.

A helicoil thread is non interference. So screws with an appropriate thread can be turned in by hand. The hold is accomplished by torquing the faster… or fixing it with a thread sealant.

Thread sealants such as Loctite create a pretty strong bond. Even the lower strength varieties benefit from a little bit of heat or a really good tug on a wrench or socket, which is way above the torque specs for a ski.

So to recap, helicoils aren’t for wood, fibreglass etc. Any machine threaded fastener tightened enough to hold would be way above the yield strength of a ski. So no/not advisable.

[Stephen]

So to recap, helicoils aren’t for wood, fibreglass etc. Any machine threaded fastener tightened enough to hold would be way above the yield strength of a ski. So no/not advisable.

Do you feel the same about ski binding inserts?
Not the same, but similar.

If I was thinking about using a helicoil, I would be using an insert, instead.

[JohnSKepler]

So to recap, helicoils aren’t for wood, fibreglass etc. Any machine threaded fastener tightened enough to hold would be way above the yield strength of a ski. So no/not advisable.

Do you feel the same about ski binding inserts?
Not the same, but similar.

If I was thinking about using a helicoil, I would be using an insert, instead.

The ones sold by BindingFreedom aren’t helicoils. They do sell helicoils but If I used anything I’d use their inserts. They are basically ‘cups’ threaded on the inside and the outside. You tap the wood and use an epoxy when the insert is installed. Then the binding screw gets some Vibratite. It is similar to Loctite but doesn’t bond to the metal and can be reused a few times. It just provides resistance.

[snow-mark]

I think I’m going to use Titebond III. It’s waterproof and seems to work for lots of folks.

[GrimSurfer]

So to recap, helicoils aren’t for wood, fibreglass etc. Any machine threaded fastener tightened enough to hold would be way above the yield strength of a ski. So no/not advisable.

Do you feel the same about ski binding inserts?
Not the same, but similar.

If I was thinking about using a helicoil, I would be using an insert, instead.

I’d be open to an insert, provided that the thread pitch and depth was similar to the original binding screw (and made for wood). There’s a whole science behind threaded fasteners and what materials they’re used for. Thread pitch, depth, tooth design, even the metal hardness and elasticity play a major role in how fasteners perform.

It would be convenient if an appropriate insert came in the exact same length as a binding screw. Before cutting one down, however, I d want to confirm that I wasn’t destroying the driving system (some use an oversized hex of pretty limited depth).

In any event, I’d want to use a pretty strong glue for that. Epoxies are very strong but I know from my surfing days that the solvents used in epoxies don’t always play well with all laminates (you can dissolve a board using the wrong types together). So I’d gravitate towards a polyurethane glue, which does a much better job of expanding to fill thread voids and is plenty strong.

I guess the other thing to keep in mind is that glues, epoxies, etc are only as strong as their bond and the surrounding material. A 10,000 psi epoxy in a 5,000 psi substrate is going to be no stronger than 5,000 psi. Probably less, because the substrate has been penetrated by a screw… and that creates a lot of stress risers (any notch or void acts as a focal point for mechanical stress unless treated by things like chamfering).

To get the most from a glue or bonding agent, one has to be maniacally clean. Even oils from skin can degrade things, not to mention residual oils from manufacturing and preserving fasteners.

The fastener thing is interesting. Obviously, you have to use whatever thread pitch the insert specifies. This is where you need to avoid dissimilar metals or metals that will gall (because using antiseize compound would probably defeat the purpose of locking in such a small screw). I’m not sure if I’d use Loctite or not. On one hand, the bonds can be awfully strong, which can prevent easy disassembly. On the other, the brand has products to cover every conceivable use-case and there’s even pre-cleaners to prep fasteners and solvents to remove old Loctite residue (no idea how this might affect the top sheet though).

I’d really like to see the day when binding manufacturers could agree on a binding plate. This ideal, particularly for BC applications where you’re using thick soled boots (so the vertical distance between the foot and top sheet isn’t a huge issue). The binding manufacturers would lose a fortune because there’s more profit in selling multiple bindings than selling plates.

[wabene]

Aren't these "inserts", as Altai calls them, heli-coils?

[Jurassien]

To get the most from a glue or bonding agent, one has to be maniacally clean. Even oils from skin can degrade things, not to mention residual oils from manufacturing and preserving fasteners.

There you go………..and I thought I was OCD by immersing the binding screws in solvent to remove any trace of oil from the manufacturing. Not only that, but I wait till the next full-moon before inserting the screws and ensure while doing so that the ski tips are pointing towards the East.

[GrimSurfer]

To get the most from a glue or bonding agent, one has to be maniacally clean. Even oils from skin can degrade things, not to mention residual oils from manufacturing and preserving fasteners.

There you go………..and I thought I was OCD by immersing the binding screws in solvent to remove any trace of oil from the manufacturing. Not only that, but I wait till the next full-moon before inserting the screws and ensure while doing so that the ski tips are pointing towards the East.

Ha ha. I draw the line at using MEK to clean fasteners. Nasty stuff. Even lacquer thinner is like cancer in a can. No wonder ski and wax techs wear masks,