Tired of inserts...

[pfluffenmeister]

Instead of epoxy? That stuff is brittle and doesn't tend to bond that well, I can't imagine it would be any better.

I would also wager that this could be solved by reverse threading the inserts so that they are self-tightening when removing screws. Anyway, too much hassle for me. More dynafits...

Not instead of epoxy.
After tapping the hole put in a bit of thin CA glue and the wood. being fibrous, will absorb the glue thus making the tapped threads stronger.
Then apply epoxy as normal.

The person who mentioned the extra step noted that this is a tried an true method of strengthening specific areas in wood models.

for example when a screw needs to be placed in balsa wood.

[bfree]

Ah, got it. Locally hardening up the wood in a sense. (...TWSS)

[Cocximus]

For fucks sakes stop over tightening. These are skis not a 2-troke single cylinder engine.

Agreed on this. Degrease before shipping and charge me a few cents more per insert. I've seen blown up high-res macros of the inserts before and they looked nice and rough, but perhaps not enough.

Chances are they will get dirty at some point so you should clean them anyways. No biggie, if you can install an insert you can clean them.

1000-oaks is bang on, machined parts have cutting oil on them.

[Vinman]

The reverse thread idea would be spot on. But I see a lot of people screwing this up, pun intended.

Oil on the stainless steel that is being shipped to customers without telling them about it is not a good idea. At least mention it if cleaning them is a required step.

[TheDon]

I'm getting tired of inserts and this thread.

[GeezerSteve]

FTR, I beadblasted the outside threads on some inserts, then washed and dried, then installed. Epoxy seems to stick better to blasted SS.

[BaNosser]

Bummer to see this occur... but the OP's inserts came out so cleanly.. is it possible for him to clean (as mentioned above) new inserts and reinstall with liberal amounts of well mixed 72 hr expoxy? Then use Vibratite on the screws..

[1000-oaks]

Another installation issue could be inserts not flush with or below the topsheet of the ski. If the inserts are flush or slightly below, all of the force on them is upward (screw tension + skiing forces) and relatively consistent. If the inserts protrude a bit and the binding is resting on top of the inserts, there would be an up-and-down force on them every turn, which could eventually loosen them in the soft core of a ski.

Who knows though, just brainstorming.

[Cocximus]

^^^ agreed.

i also like the tip of applying thin CA (cyanoacralate?) glue after tapping to wood cored skis.

Really dont think this is a good idea.
This way you have epoxy sticking to CA, which is brittle and weak. The CA layer stops the epoxy from penetraring in to the wood. Basically you ad a weak link between the wood and epoxy.

[pfluffenmeister]

if i read the the tip correctly the CA gets absorbed into the fibers of the wood, hardening the wood itself.

[angrysasquatch]

Where do you guys even get 24+h epoxy? There is none, and i mean none in the half-dozen auto, hardware and industrial places in town, and none can get it. The one place I found it was buried deep in the Ackland-Grainger catalog (Canada's not-as-good version of McMaster-Carr), except they won't ship to people without a commercial account, so effectively it's unavailable from all the avenues I could think of. Wonder if the 5-min epoxy will let my inserts spin when the time comes...

[Lindahl]

Home Depot has the dual-tube plunger version, at least out here.

[Hugh Conway]

if i read the the tip correctly the CA gets absorbed into the fibers of the wood, hardening the wood itself.

if it's "hardened" there's CA present. epoxy/ca bond isn't as strong as epoxy wood (or so daught says, hes probably right). How much CA is absorbed would be species and grain orientation dependent; paulownia at the lots end maple at the little

If you are going to get pissy about what kind of adhesive you are using... get good stuff, not the shit that's dubiously stored/QC'd at hardware stores. 5 minute vs. 24 hr doesn't matter so much.

All kinds of overkill so you can save a few $ on bindings I guess. Pita for a pointless product.

[Vinman]

agreed on the CA glue thing. The wood epoxy bond would be much stronger than a epoxy-CA glue bond.

CA glue would "harden" wood so to speak but it would prevent the epoxy from penetrating the pores in the wood...weak bond.

This is not something I'd ever do when mounting bindings.

[The Suit]

The person who mentioned the extra step noted that this is a tried an true method of strengthening specific areas in wood models.

for example when a screw needs to be placed in balsa wood.

In my experience with toy airplanes you might use this technique if you are going to bolt something (often using a nylon bolt) directly into wood without using some sort of metal blind nut. You'd never do it for an application where much force will be applied.

Sometimes you'll soak a wood area with CA to harden/strengthen it, but not if you plan to subsequently bond with epoxy.

[Cocximus]

Wonder if a liquid gasket maker would'nt be better for inserts. No doubt, epoxy is very strong, but it's brittle, threfore it can crack. Gasket makers are designed to work with expansion and vibration. They might perform much better over time.

Only q is if an anaerobic like loctite 518 is better or an rtv (hondabond is best, but permatex ultra grey is close) is better. Would inserts in skis be considered an anaerobic condition?

[Ivan Oder]

I've done it dozens of times. It works fine. The wood is still coarse enough for a tight bond between the threads.

As to the OP's problem this looks like a case of crappy/wrong/badly mixed epoxy, not enough epoxy, unclean threads, too much threadlocker, Hulk install screw! or any combination of those things.

I had an insert come out clean like that once and the cause was that I over tightened it. Heard it crack when installing but skied it anyway.

I believe that is actually how you can pull them out to re-use them, turn hard and break epoxy bond.

[pfluffenmeister]

In my experience with toy airplanes you might use this technique if you are going to bolt something (often using a nylon bolt) directly into wood without using some sort of metal blind nut. You'd never do it for an application where much force will be applied.

Sometimes you'll soak a wood area with CA to harden/strengthen it, but not if you plan to subsequently bond with epoxy.

fair enough.

i have not tried it myself (and now won't).

[xyh200]

+1 to inserts backing out on some Wailer 112rp's. Not sure which of the previously mentioned mechanisms was at work for me, but this will be the last time I try inserts for a while. Skis more difficult to sell with an insert mount as compared with binding only mount.

[XXX-er]

Where do you guys even get 24+h epoxy? There is none, and i mean none in the half-dozen auto, hardware and industrial places in town, and none can get it. The one place I found it was buried deep in the Ackland-Grainger catalog (Canada's not-as-good version of McMaster-Carr), except they won't ship to people without a commercial account, so effectively it's unavailable from all the avenues I could think of. Wonder if the 5-min epoxy will let my inserts spin when the time comes...

Ya it is tough to come by slowset in small town BC, I couldn't find it in smithers but I got mine from the big city of prince george

http://ippnet.com/fibreglass/epoxy-r...-products.html

I have always used stuff from these^^ people and maybe you can get it from kelowna or calgary?

[1000-oaks]

WEST SYSTEM G/Flex 650 Liquid Epoxy, 8 oz, $21.99
http://www.westmarine.com/webapp/wcs...0#.Uol8siclj5k

[vanisle]

Where do you guys even get 24+h epoxy? There is none, and i mean none in the half-dozen auto, hardware and industrial places in town, and none can get it. The one place I found it was buried deep in the Ackland-Grainger catalog (Canada's not-as-good version of McMaster-Carr), except they won't ship to people without a commercial account, so effectively it's unavailable from all the avenues I could think of. Wonder if the 5-min epoxy will let my inserts spin when the time comes...

industrial plastics and paint in either Kelowna or Calgary will have West systems and G-flex, both great options for epoxy
It hasnt been noted yet but care should be taken in handling the inserts even after degreasing as the oil from your fingers can affect the epoxy bond.

[Ivan Oder]

I like the marine epoxy myself, but slow cure / extra handling time epoxies are the best. None of this 5 minute stuff. Generally the slower it cures the stronger it is.

http://www.homedepot.com/p/Loctite-0...5#.UomZVsSsj2w

Also another good idea is to set it up in a warm dry environment to cure, eg not a garage or outside etc... Maybe consider cranking the heat up a few degrees while you do this.

When I do my inserts I attach the bindings immediately and tighten the screws just so that the binding doesn't fall off.
That way I can see if any of them are not going to line up or if there will be spaces under the binding.
Sometimes inserts will wobble in their holes and this makes sure they cure straight.
Better to know at this point then when the things have fully cured. Also having them cure while under a little bit of tension helps.
The only caveat is you cannot take the bindings off for DAYS while it fully cures. I usually give it whole week. Break out the rock skis and hit the park or something.
Takes almost two full weeks to do a double binding mount for swaps.

[jono]

^^^This. Cure temp is hudge...bigger deal if the epoxy is decent. Pick your combination of factors.

[Shorty_J]

Where do you guys even get 24+h epoxy? There is none, and i mean none in the half-dozen auto, hardware and industrial places in town, and none can get it. The one place I found it was buried deep in the Ackland-Grainger catalog (Canada's not-as-good version of McMaster-Carr), except they won't ship to people without a commercial account, so effectively it's unavailable from all the avenues I could think of. Wonder if the 5-min epoxy will let my inserts spin when the time comes...

It took me a while to find, but West Systems G-Flex epoxy can be found in Calgary for about $30-ish. Can't remember the store I bought from, but it was some backwoods shop in the NE. Sounds like a lot of money, but I bought some about 5 years ago and haven't even used half of it.

Google it and you'll find some pretty amazing results. There's a video out there where they cut a kayak in half and epoxy it back together with this stuff and then do things like throw it off a bridge and it holds. It's a true long-cure epoxy and I haven't had a problem yet.

Edit.. Found this:

Alberta Plastics & Paints
2355 Pegasus Way NE #2, Calgary, AB, Canada
403-204-1923

I've also seen West Systems products here, but I don't know if they sell G-Flex or not...

http://ippnet.com/calgary.html




I have no affiliation with either shop.



Double Edit... check this out:

http://www.youtube.com/watch?v=2a5RlcP-4JE


I forgot about the last test (gravel pile to flat) which is perhaps the most impressive regarding the forces on the repair and what it can stand up to.