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UUHHHGGG! Screwed up binding screw holes

post #1 of 33
Thread Starter 
OK so I am doing woodworking all year round. I am so used to sizing drill bits as per woodscrew dimensions, and I went a little fat on a screw hole. Not by much though. There was still enough material for the threads to grab into, but A red flag immediately went off in my head when I started screwing the screws in with my #3 posi driver. I did not feel the characteristic resistance that I normally feel when installing the screws on a typical binding. It was a little TOO easy, but I was still able to crank down and not strip anything.
The hole required a 4.1 mm bit, and I used something aroung 4.5mm.
Should I plug and redrill? Should I roll the dice and go with what feels like a solid connection?
It is a fiberglass ski, so I don't feel 100% on this one.
Any advice?????
post #2 of 33
If you are confident the screws are snugged down tight and the holes didn't strip, my advice would be to not fuss with it anymore. If the screws were going to strip out, they would have when you cranked them in. That load far exceeds the load you'd get by trying to rip the screws out another way. So if it didn't strip when you screwed in, it's probably holding pretty good.
post #3 of 33
Did you use glue? If it was me, I'd glue them and take 'em for a test drive to see what happens...as much out of curiosity as a gut feeling . If they blow out, the fix would be similar to 'preventative fixes' that may not be necessary as skier219 suggests.
post #4 of 33
If you are really concerned, what I would do is remove the screws. Mix up a bit of a good two part epoxy. Using a toothpick, run a small amount around the inside of the holes and let is cure. Don't fill the hole, as you would have to re-drill, but use just enough to coat the inside of the hole, which should make up the amount that you over-drilled.

If you epoxy the screws in, i.e. inserting before it's cured, you 'd never get them out! :
post #5 of 33
Let me start off by saying I am no means an expert in binding mounting...I have never even drilled for my own bindings.

That being said I do a lot of work with all sorts of materials as a hobby and former contractor. Machinable epoxy or JB Weld might save your holes. If they are too far gone, you can always use a helicoil.

Have you considered simply using a larger diameter screw?
post #6 of 33
Thread Starter 
Quote:
Originally Posted by skier219 View Post
If you are confident the screws are snugged down tight and the holes didn't strip, my advice would be to not fuss with it anymore. If the screws were going to strip out, they would have when you cranked them in. That load far exceeds the load you'd get by trying to rip the screws out another way. So if it didn't strip when you screwed in, it's probably holding pretty good.
Ah, yeah, good call on the physics of the actual situation. My inclination is to leave it alone.
If this was a piece of wood core metal sheet ski, I would have not been concerned at all, because the screw has something to hold onto inside the core.
Does foam in a foam core ski even grab the screw at all?
post #7 of 33
Foam holds no screws!

Use epoxy "hard points"

:-)

CalG
post #8 of 33
Actually, even the core of a wood ski offers very little bite in most cases. Most of it is in the topsheet. What skis were these?

The hardest thing with binding screws is to know when to keep cranking and when to walk away. I like tapping my holes since it makes that distinction a bit clearer. Definitely walk away when the binding is flat and the screwdriver doesn't budge with a loose gripped check-twist. Once I get that confirmation that the screw is good, I never fiddle with that screw again.
post #9 of 33
Thread Starter 
Have you considered simply using a larger diameter screw?[/quote]

Yes, absolutely. All the different binding screws, helicoils, repair stuff I found at slidewright. So I was originally thinking of a longer screw, but as confirmed it is all about the topsheet connection and that a longer screw is not really gonna matter in a foam core.
Anyways the skis are Atomic telemark variety pre magnesium topsheet tm-22 with fritschi bindings.
No glue was used so I still have options left, should something happen down the road.
At this point for the binding to rip out of the ski, ALL 4 of the screws in the toe would have to pull out simultaneously. The remaining 3 screws in the heel assembly were done with the correct size bit.
post #10 of 33
For what it's worth, you sreally should always glue your screws in the ski.

But I think you'll be fine, especially now you've mentioned the others done correctly.
post #11 of 33
Quote:
Originally Posted by Simplemind View Post
If you epoxy the screws in, i.e. inserting before it's cured, you 'd never get them out! :
I haven't actually tried this, but I believe it was from Lou Dawson's site that he stated using a heat gun will ease the removal of screws in epoxy.

In all the skis I've mounted (AT, tele, skate & touring) I've used glue, either wood, binding or Gorilla glue to boost confidence and have had zero problems. I'd think you'd want to at least include glue or epoxy as an easy 'ounce of prevention'.

I don't think I've seen (nor look for) a definitive list of compatible or incompatible glues or epoxys relative to ski cores. Any insights or links?
post #12 of 33
I suggest swapping out the alpine binding screws with the "toothier" threads of tele binding screws. More bite!
post #13 of 33
By my limited understanding of the chemistry behind Epoxies, I do know that some of the chemicals are pretty nasty. I'd trust gorilla glue over an epoxy... or make sure you use an epoxy that has been used for this application many times..
post #14 of 33
Fill, re-drill, but move the holes fore/aft. You'll be fine. Use the right bit, and ALWAYS use glue. I probably wouldn't use the same holes however...

I NEVER use the 4.1 bit unless there is a LOT of metal in the ski. Stick with a 3.5.
post #15 of 33
Generally, the manufacturer sanctioned binding glues are very much like a wood glue or a white Elmer's glue, though some are improved in that they dry quicker in a screw hole without the presence of air. The purpose is to lube the screw when going in and then to seal the core from water. I have never seen glue recommended as an adhesive in the context of binding screws *unless* it was a repair rather than a simple mount.

The danger of epoxy is that it can react with the core and/or topsheet materials. I am sure someone on Epic has a story of using epoxy for binding screws, only to have it dissolve the foam core of their skis! Epoxy can also generate intense heat when it cures, which may have other side effects. I only use epoxy in repair situations, and only when I am sure it's safe for the skis.

BTW, you can remove an epoxied screw by first heating the head of it with a soldering iron. It will break the adhesive bond between the epoxy and metal.

Most skis have a drill bit recommendation marked on the sidewall or topsheet. For instance, the Fischer Wateas I mounted a couple weeks ago called for a 4.1mm bit and also had a cartoon indicating the use of glue. These skis do not have a metal layer, but have a very thick fiberglass composite topsheet that might have puckered if the smaller (3.6mm) binding bit was used. When the topsheet puckers, it's bad news. At the very least the bindings will be impossible to screw down flat. In the worst case, the topsheet will pull away from the core.

Some people counter-sink or pre-bore the screw holes to avoid the pucker, but this removes precious topsheet material which is the main place the threads engage. I like using the right bit, and tapping if necessary, to get clean threads into the topsheet. After drilling and tapping, you can use a 1/4" wood chisel to trim the burr around the top of the hole.
post #16 of 33
Quote:
Originally Posted by hydrogen_wv View Post
By my limited understanding of the chemistry behind Epoxies, I do know that some of the chemicals are pretty nasty. I'd trust gorilla glue over an epoxy... or make sure you use an epoxy that has been used for this application many times..
I wouldn't use gorrilla glue. It is fine for gluing two porous surfaces together ie wood to wood or cement block to block. The gorrilla glue turns to foam when it hardens.

In my experience the best type of glue is 2-stage epoxy. That is if you are worried about loosening.

Other alternatives, Loc-tite.

If you just don't care about ever removing the screws, liquid nails.

I'll look for the link where they did experiments (Line skis) with epoxy. It did no damage to the cores.

OK how about Black Diamonds.
http://www.wildsnow.com/?p=598

This is also being discussed at TGR as we speak. Pretty useless though.

This is kind of interesting for inserts on wood cores.
http://www.skibuilders.com/howto/skicon/inserts.shtml
post #17 of 33
HEY!!! Just use hostage systems!! No drilling required!
post #18 of 33
Quote:
Originally Posted by axebiker View Post
HEY!!! Just use hostage systems!! No drilling required!
What is that? My solution is K2. Threaded inserts built into the ski, but they only fit 4 hole telemark standard.
post #19 of 33
So you drilled it .4mm oversized. That is equivelent to .015" or .0075" per side. That is the same as 2 sheets of notebook paper. If you screwed 'em down tight without pulling threads, I would say you're good to go.

Karl
post #20 of 33
Thread Starter 
What about some of the polyuerethane glues, like gorilla glue?
OR marine epoxy--the white stuff? This seems like the best choice, no? It dries rock hard, and sticks to metal pretty good.
post #21 of 33
Thread Starter 
Quote:
Originally Posted by orionxprss View Post
So you drilled it .4mm oversized. That is equivelent to .015" or .0075" per side. That is the same as 2 sheets of notebook paper. If you screwed 'em down tight without pulling threads, I would say you're good to go.

Karl
yeah, true, but the problem was that the ski topsheet is fiberglass and could have actually used an even smaller bit @ 3.5 mm
It is borderline, but still good to go.
I'm just gonna have to use some glue.
post #22 of 33
Quote:
Originally Posted by skier219 View Post
I am sure someone on Epic has a story of using epoxy for binding screws, only to have it dissolve the foam core of their skis!
Pics or it didn't happen. Stop repeating wives tales you can't back up.
Quote:
Epoxy can also generate intense heat when it cures
Exotherm is a problem if you mix too large a batch at once, or try to cast parts from the stuff, or use completely the wrong system for the job. Too large a batch as in the kind of batch you'd use making full scale composite parts. Again, lets not repeat wives tales. You aren't going to have a problem mixing the quantity needed to coat some screw holes.
Quote:
Originally Posted by orionxprss View Post
So you drilled it .4mm oversized. That is equivelent to .015" or .0075" per side. That is the same as 2 sheets of notebook paper. If you screwed 'em down tight without pulling threads, I would say you're good to go.

Karl
I've seen more than a couple skis that were drilled and mounted correctly except by using a 4.1 instead of a 3.5/3.6 that had bindings pull out. Bigger than 4.1 in a ski without metal...
Quote:
Originally Posted by Atomic World View Post
It is borderline, but still good to go.
I'm just gonna have to use some glue.
...good luck with that.
post #23 of 33
After the last foam discussion, I went and found the reference I was remembering.

http://boardlady.com/dumbnesses.htm

Turns out epoxy is the right glue for foams. Its some types of single-part solvent-based glues that eat foam.
post #24 of 33
I think I would determine what the risk factor is should the binding should pull off while skiing!

If you are out in the BC, are you willing to risk pulling it off and losing part of it, and having to swear your way back to civilization?

Or are you mostly inbounds, with support nearby to help out when it comes apart?

Either way, if it was me, I wouldn't even think twice about pulling the binding back off, throwing in some helicoils, and knowing that it is safe and secure.

The last thing I would do is create a potential hazard for myself by knowing that the binding could blow at the worst possible moment, and that I could have done something to prevent it!
post #25 of 33
Quote:
Originally Posted by mdf View Post
After the last foam discussion, I went and found the reference I was remembering.

http://boardlady.com/dumbnesses.htm

Turns out epoxy is the right glue for foams. Its some types of single-part solvent-based glues that eat foam.
Quote:
Originally Posted by Johnnys Zoo View Post
In my experience the best type of glue is 2-stage epoxy. That is if you are worried about loosening.

http://www.wildsnow.com/?p=598
Contact cement is BBBaaaaaD!!!! I found this out the hard way. I once glued a headliner to the roof of fiberglass car using it. It dissolves the resin in fiberglass!:

Gorilla Glue is way overrated. I do like Gorrilla Tape though. I have tried to use it on plastics and it didn't hold. It might seal out water. It turns into a small cell foam whan hardening. It would put money on it splitting under the pressure of a binding screw.

If you are still worried about loosening and hazardous effects of epoxy (which don't really seem to exist) use some Loc-Tite. Or even some teflon thread tape?
post #26 of 33
I always shrug my shoulders at the choices of glue I see around here. Especially when I have yet to see a manufacturer recommend anything other than XXX brand white glue.

I have yet to have a screw related binding problem (knock on wood) on either foam- or wood-core skis, and I've never used anything other than either the Salomon white glue or Elmer's Carpenter glue.
post #27 of 33
Sheesh...
Some 2 part..fast set/5 minute epoxies use a lot of tolune. sp? This attacks foam. Someone said it didn't so I tried it. Try it. Go for it. See just what can happen.

The very best way to deal with this..I do it all the time:
Get some fiberglass resin. If you insist on an epoxy resin just remember that it is next to impossible to stick to most epoxies AFTER you have done the job if you ever need to again. Some will stick better after you have scuffed it. Scuffing the inside of a hole. Right. Use the fiberglass resin. Anything will stick to it.
Get the resin and hardener from a plastic supplier. Forget about most retailers. A boat place you trust.
Mix enough that you can get an accurate measurement. get a measured eye dropper from the drug store.An ounce in an old tin is good. Beware of using plastics containers. Not all plastics will tolerate this.
You can use the eyedropper to add the hardener. And re-use it for the resin. If you are fast. Mix the stuff up good. Put resin in hole. Poke it down with a toothpick or nail to get the bubbles out. Don't ovefill the hole or this will leave a round surface to drill on/into.
If by chance you can't fill the hole. The resin is dissappearing. You have found an air pocket/channel. Stop. What I do is to simply mix the resin with sawdust to make a paste. Put as little of this paste in the bottom of the hole just to seal it so you can get the liquid in there on top of it.

Done right. No one will ever know. Even when you peel off the bindings.

Ultra paranoid about the strength of this? A much larger/torn out screw. Do the above but into the liquid resin in the hole stuff the hole full of vertical short strand fiberglass. Use a straw and something inside the straw to push them down/in.

Really torn one out/wrecked. Drill the hole larger. Use a small drill bit to drill UNDER and around the hole at an angle. The idea is to have the area larger underneath than the diameter of the new larger hole. This is to make a "plug" that can't pull out of the hole.

Mix up a very stiff batch of the resin and short strand. Make sure it is still liquid and well saturated. Stuff this into the hole with a bent wire that you can really poke around in there.

Gotta go skiing.
post #28 of 33
Its Toluene.

http://www.wildsnow.com/?p=598

Since no one wants to click the link.

For years, we’ve used epoxy for the screws when mounting ski bindings — telemark and AT randonnee. Doing so yields a trouble free mount that never loosens, has better pull-out strength, and is totally sealed against moisture.

“You can’t get the screws out,” they said, “and epoxy will eat away the core foam of some skis, especially Black Diamond models.”
Well, we got tired of all the nagging.
Our experience is that hardware store 5-minute and 1-hour epoxy worked fine with ANY ski we’ve ever mounted, and if you count the ones I worked on back during the 1970s days of Company 3 and their distribution of the Ramer binding, and dozens since than, that means HUNDREDS of skis — everything from wood x-c skis to metal sandwich construction, to honeycomb core, to modern AT skis, and on and on.

Now I'm beginning to understand why the "old bull" bears are kind of grouchy.
post #29 of 33
Quote:
Originally Posted by axebiker View Post
I always shrug my shoulders at the choices of glue I see around here. Especially when I have yet to see a manufacturer recommend anything other than XXX brand white glue.

I have yet to have a screw related binding problem (knock on wood) on either foam- or wood-core skis, and I've never used anything other than either the Salomon white glue or Elmer's Carpenter glue.
I should clarify here: I'm only talking about Alpine bindings, not AT or Tele.
post #30 of 33
JZ: I worked in a machine/model shop when I was in college, and we often worked with typical boat building materials when making wind tunnel models and prototypes. There are types of foams and types of epoxies that DO NOT get along. I'm not saying it is going to be the case with all skis, or even some skis, but I can tell you that some epoxies and foams do not work well together. I have no doubt the infamous "that epoxy ate my ski core" tales emerged from such combinations. There are a lot of different types of foams, and I don't think you can generalize that epoxy is safe on all of them.
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