Binding mounting myths:

[GeezerSteve]

Adding epoxy to a regular binding screw increased pullout by like 30% or something, whereas adding it to the inserts hurt the pullout strength. That doesn't add up. I think it would make more sense to do pullout tests on a synthetic material that was more consistent in properties and compare the numbers to that.

Yes, of course, pullout failure thresholds will vary from core to core and spots within cores. But, c'mon, 607 vs. 602 does not support a finding that epoxy "hurts" the insert pullout. You just said that we can expect different numbers from spot to spot within a core, right? 602 vs. 607 is insignificant.

You were going the right direction about variances from core to core and from spot to spot within the same core. But a test on synthetic material (other than, say, a foam ski core) would have limited relevance. An epoxy vs. no epoxy test on a non-porous synthetic material that doesn't soak up any epoxy makes no sense.

As Terry said, pullout tests provide, at most, a gauge.

[Zeno]

In my opinion, the withdrawal testing I did omits significant factors that influence real world failures. I've seen a number of shear fractured M5 stainless steel screws (in the front holes) of telemark bindings from G3 and Voile factory insert skis. To me, this means that shear forces developed from ski flex are quite high. I've also had my own mount of O1's to Voile Insanes loosen, but not pullout, this looseing or lateral slop is due to shear, not withdrawal forces.

So any loosening or fatigue due to vibration, load fluctuations or even high shear forces are not accounted for in the static withdrawal tests I did. Logically, loosening due to shear forces will reduce the pullout capacity. Since the testing didn't account for these factors, I personally don't give too much weight to 30% differences in results.

Regarding epoxy. As has been said, epoxy works really well at keeping water out of the connections. Epoxy is also strong, flexible and clean. G-Flex by West Systems is my current favorite becuase it is inexpensive, slow setting, has good strength, and has a low shear modulus (is flexible).

I always thought the result from Line 4 below was most interesting, because I drilled its pilot hole with a diameter wider than the screw threads i.e. the screw theads cut into nothing, but instead were simply "wet set" into the uncured epoxy. The no epoxy pullout strengh for line 4 would be nothing. This test demonstrates that epoxy alone, with no mechanical thread "bite" into the ski can provide a significant capacity.

Repost from here:
http://telemarktalk.com/phpBB/viewto...=screw+pullout

Table Notes:
The results are an average of 3 test replications.
Epoxy used was an off the shelf marine epoxy from Home Depot.
Around 10 days elapsed between when the epoxy was wet and when I tested.
The sets of data are for unique skis, e.g. Wood core(1) is a unique ski, all tests done with Wood core(1) skis used the same ski.

Regarding the myth. My 2 cents is that by using epoxy you keep water out the core, prevent screw corrosion, likely improve the shear strength and withdrawal strength of the connection. As a result, epoxied holes better maintain the integrity of the ski and binding connection to the ski.

[SgtSkidmark]

Heli-coils are somehow stronger than mounting as normal. <never, ever>

Never, ever?

Nope, because mine are definitely stronger than the original mount. And my skis are always mounted at the same year-round race shop (Ski Chalet for PDX mags) that has a good rep and old crusty techs (those are the good ones, right?). I'm 225# and pulled 916 heelpieces out of older gotamas and sumos (same construction-no metal) while carving. With helicoils, they have been through a lot of abuse and held up beautifully. I can't make the leap you made and say <always, always>, but I can disprove your conclusory and unsupported opinion. I think your comp rippin buddy had some shoddy work done.

[JayPowHound]

[/QUOTE]

The last four lines are interesting too, indicating that there's no retention gained by tapping skis with metal in them? Thought that was pretty much the standard...

[GeezerSteve]

I've seen a number of shear fractured M5 stainless steel screws (in the front holes) of telemark bindings from G3 and Voile factory insert skis.

M5, 10-32, etc. machine screws are available in grade 8 or grade 9

[SuperGaper]

I think dynafits and tele bindings share a greater shearing load, one through skinning, one through the lack of a heel piece. Alpine bindings not so much.

Should I charge double for a remount if I have to press a soldering iron to the screws to remove them?

DPS excepted, I just straight refuse the epoxy in Alpine mounts- have mounted many skis used by those people in movies and such, and they have not pulled out.

Of course my evidence is grossly anecdotal, but I am with the OP on that one.

At our shop, we charge $5 per heli-coil- usually to repair some other shop's shoddy work, so why resort to the epoxy-steel wool fix?

I don't do tele or Dynafit mounts, so I am also not qualified to speak about that, but the idea of shearing and how that stresses the mount more than an alpine binding is pretty damn clear to me.

[Jethro]

Gaper, I have found that almost all screws easily crack free with a screw driver. An impact driver would be overkill, but it would spin them all out. I have never used an iron. Given this, what could be your objection to using one of the best adhesives out there? Is it that it is more time consuming to mix and dab into the holes? My binding mounts, which more often than not are Dynafits, are a labor of love. I do not trust any local shop with them. How would epoxy hurt?

[SuperGaper]

Like I said, for ALPINE mounts, it is overkill, or wouldn't manufacturers REQUIRE it?

I find about half the screws break free, and I bet my sample size is bigger than yours.

No have impact driver in ski shop.

Fortunately there is another tech that will do epoxy for the super gnar folks that need it.

[XXX-er]

I think dynafits and tele bindings share a greater shearing load, one through skinning, one through the lack of a heel piece. Alpine bindings not so much.

Should I charge double for a remount if I have to press a soldering iron to the screws to remove them?

DPS excepted, I just straight refuse the epoxy in Alpine mounts- have mounted many skis used by those people in movies and such, and they have not pulled out.

Of course my evidence is grossly anecdotal, but I am with the OP on that one.

At our shop, we charge $5 per heli-coil- usually to repair some other shop's shoddy work, so why resort to the epoxy-steel wool fix?

I don't do tele or Dynafit mounts, so I am also not qualified to speak about that, but the idea of shearing and how that stresses the mount more than an alpine binding is pretty damn clear to me.

20 sec with a cheap soldering iron will crack all the epoxied screws loose but if you don't have a soldering iron just turn your drill bit around in the chuck and run the butt end of the bit at hi speed on the screwhead,the heat will bust the epoxy loose ,an impact driver is cheap and it works well on stripped screw heads

I got the impact driver I also got slow set 2-part & scrap FG so I can do it NOW but I ain't got a helicoil kit so to get a helicoil done I would have to pay for gas to drive to a ski shop the next morning have them thro my skis in a pile with a bunch of others to wait for some stoner to fix them and pay 5$ a spinner ,and last time I left skis at a shop they forgot to feed them thru the machine not once but twice,you read about all the horrow stories here ... I can get stoned & work on my own skis for free and do just as bad of job

[DropCliffsNotBombs]

I agree with Super Gaper.
Has anyone ever been able to reuse a binding screw or hole after it has been epoxied in? Sure, you can get them out (after using a soldering iron, impact driver, backwards high speed drill heating, etc,..) but most often the screws threads are completely cemented over with epoxy (or JB weld) and core material!
Since cleaning/chipping out all the screw threads is nearly impossible, I just chuck all the ruined (epoxied) screws and replace them with fresh new ones. That costs extra! I call it the "thought-it-was-a-good-idea-to-epoxy-the-screws-in" charge.
On top of that, the blown-out holes that have been epoxied don't hold new screws and now they all need to be heli-coiled. And that cost extra too!
Without epoxy, the screws come out clean. You can then reuse the screws AND the original holes too!

Epoxy does two things... It either fixes ghetto-repairs or it starts ghetto-repairs.

[DudeLebowSKI]

Has anyone ever been able to reuse a binding screw or hole after it has been epoxied in? Sure, you can get them out (after using a soldering iron, impact driver, backwards high speed drill heating, etc,..) but most often the screws threads are completely cemented over with epoxy (or JB weld) and core material!
Since cleaning/chipping out all the screw threads is nearly impossible, I just chuck all the ruined (epoxied) screws and replace them with fresh ones. That costs extra! I call it the "thought-it-was-a-good-idea-to-epoxy-the-screws-in" charge.
On top of that, the blown-out holes that have been epoxied don't hold new screws and now they all need to be heli-coiled. And that cost extra too!
Without epoxy, the screws come out clean. You can then reuse the screws and the original holes too.
Epoxy does two things... It either fixes ghetto-repairs or it starts ghetto-repairs.

Now THIS makes sense. I just changed the mount position on my skis and am stoked that I didn't use epoxy on the initial mount.

[GeezerSteve]

Dude, if you changed the mount position, why would it matter?

Re SuperGaper's comments: Agree that pullouts tend to happen with more frequency with Dynafit/tele bindings. It should be no surprise that some of the contributors to this thread have Dynafit and/or telemark (e.g., GregL, Zeno, Alpinord, me) for which pullout is a big issue. Also, Dynafit toe screws have a tendency to loosen on some mounts, and epoxy is the only thing that prevents that IME. And IME the only reliable way to prevent ripouts on O1's is to helicoil the two rearward screwholes (although those plastic pound-in inserts might also do the trick).

Answering DCNB's question about reusing epoxied screws and holes: Yes, I have done so numerous times (although I prefer to leave mounted bindings mounted). I did so last weekend. If I use a soldering iron, the screws/holes usually come out clean. If not, I heat up the screws and/or holes to clear the epoxy.

[DropCliffsNotBombs]

Now THIS makes sense. I just changed the mount position on my skis and am stoked that I didn't use epoxy on the initial mount.

My one-man crusade to abolish epoxy from binding mounting is finally catching on!

[DudeLebowSKI]

Dude, if you changed the mount position, why would it matter?

You are right. Normally I guess it wouldn't matter. I remounted 'hoping' I'd like the position better but worst case scenario, I was hoping I'd be able to move back to the original holes if I didn't like it. The screws came out clean and shiny and all the hole threads looked smooth and clean so I now have a back-up plan.

I'm not against using epoxy for extra strength at all. I just hadn't heard an explaination (till now) as to why the issue seems to get so heated.

[skimaxpower]

I agree with Super Gaper.
Has anyone ever been able to reuse a binding screw or hole after it has been epoxied in? ...
Epoxy does two things... It either fixes ghetto-repairs or it starts ghetto-repairs.

+1 TRUTH.

[GeezerSteve]

epoxy vs. wood glue battle reminds me of guys in rural high schools getting into fist fights re Ford vs. Chevy vs. Dodge

[skimaxpower]

epoxy vs. wood glue battle reminds me of guys in rural high schools getting into fist fights re Ford vs. Chevy vs. Dodge

+1 TRUTH. But my way is still best.

[GeezerSteve]

But the guy with the superior data (Zeno) makes a strong case for epoxy, which begs the question re who is pedalling the myth

[Zeno]

I used to use wood glue for ski mounts because I read it was "good". However, after having a binding pullout and seeing that the screws looked like this:


I realized the wood glue becomes brittle, cracks, and allows water in.

Perhaps our experiences differ because I'm in the PNW where bindings are almost always subject to water flow.

In all my experience remounting, it is very clear to me that epoxied screws come out much cleaner (no rust, no core damage) compared to non-epoxied screws that are usually rusty.

Having personally observed the corroded vs. non-corroded screws it seems clear that less water intrusion and subsequent corrosion occurs to the connection (screw and ski bearing material) when using epoxy. Yes, I've reused epoxy mounted holes, without problems. Not sure I'd want to remount into a rusty/corroded screw hole.

Removing epoxied screws usually requires the solder tip about 30% of the time, but they come out so clean and free of corrosion.

Perhaps we can just agree to disagree that using wood glue or no glue for ski (tele/dynafit) mounts is the best advice for long term integrity of the binding mount when subject to moisture.

[Zeno]

Sure, you can get them out (after using a soldering iron, impact driver, backwards high speed drill heating, etc,..) but most often the screws threads are completely cemented over with epoxy (or JB weld) and core material!

I've removed quite a few epoxied screws and have never seen this, "threads completly cemented over..." I guess our experiences differ for some reason. If I did experience this, then I would agree with you and not use epoxy either.

[Chugachjed]

I reuse expoxied screws and holes no problem.I've never had an issue with the epoxy sticking too badly to the screw. I just mounted some dynafits with inserts in some old foam core Havocs. Epoxy and inserts are my friends. You can buy 4 pairs of dynafits if you'd like, I however am not made of money, nor do I have a money tree.

[XXX-er]

this season I did 3 moves of bindings ,all the holes had been previously drilled & plastic plugged ,I was able to re-use all the holes and all the screws

I only had one spinner that I fixed with FG/epoxy as explained

if there is glue on the screw threads it is easily cleaned off

the only reason to not re-use a screw is if the head is fucked and
I would say if you don't use some heat to break the epoxy bond to the screw you are VERY likely to strip the screw head trying to get the screws out

If you have ever had to drill a screw out ironicaly the heat you generate in the process you will find ... has loosened the glue which caused you to strip the screw in the 1st place

[The Dark Side]

I've removed and reused holes that had epoxied screws several times with no issues whatsoever. 5-10 sec w/ a soldering iron is all it takes to get out. Very little glue on screws and holes are fine. I think the ski shop crowd is anti-epoxy with no reason (or I guess the slightly extra time it takes is the reason?).

[Jethro]

I would say if you don't use some heat to break the epoxy bond to the screw you are VERY likely to strip the screw head trying to get the screws out

I have never had a problem just cracking the screws free of the epoxy (no heat) with the proper screw driver. Whenever I remove a binding a shop has installed with wood glue it easily comes out a it is usually somewhat loose. Wood glue does not bind to metal very well. Epoxy does and keeps your bindings secure and water tight.

#3 posi in an impact driver and you will never mess up a screw again. With a good feel they drive the screw in well also. When the drill starts to impact, I usually stop if it is nearly in and do the final torquing by hand. if one does not have a good feel for the tool, he will strip a lot of holes though.

[AlpiNord]

In my opinion, the withdrawal testing I did omits significant factors that influence real world failures.

I've been wondering of more real world testing for moment and leverage forces versus shear and vertical pullout forces. Seems like an unattainable task since you could have unlimited directional and rotational forces combined with leverage relative to binding hole locations and number on top of ski construction type, skier weight, speed, resistance, etc.

How could a 'standard' be determined to test for 'real forces' applied?