The epoxy/tape combo that's 'strong as steel'?
As some of you may know I snapped the chainstay on my beloved Salsa a few months ago. It's been in the garage waiting to be taken to Argos in Bristol. Since money is being used for other things currently I wondered if it could be rendered rideable in the meantime using FiberFix. I mean removing it might be hard but that doesn't matter as the whole stay gets replaced when the time comes.
So two questions:
1) Is it really going to be strong enough?
2) How thick does the repair end up being? Don't want to foul the chainrings.
Sod it. It's worth £7 just to find out 🙂
I suspect you're about to become our resident expert, but knowing STW there's probably someone riding around on a set of scaffolding pipes held together with Fiber Fix.
We'll need pics and a full run down.
Oh, and someone will have to break it to cynic-al that he's getting demoted as head bodger... 🙂
It seems pretty strong, but in the videos people use loads of it. But there's not room for much on my chainstay.
It appears that some types of fibreglass can have tensile strength similar to steel, and some much less - but there's going to be far more material than there was steel originally, so that should cancel out.
Worst case scenario is it doesn't fit. Actually no, worst case scenario is it fits, I go on a long ride, and it fails in the middle of nowhere.
I would just skirt the edges of nowhere initially before venturing into the middle
Well don't come complaining if you crash and burn. I very doubt it will last very long, and a wayward chain stay isn't much fun. Good dental insurance ?
Wait to get fixed properly.
Personally I wouldn't take the risk, might make the bike worse or have a nasty accident (unless you're riding very tame stuff)
If you were to take the risk, wouldn't you brace the breakage with something else, and then use the fiberfix to stick the brace on
Wot you need is a spoon 😀
he's right you know 🙂
somethign to act as a splint for the break.
I've used the heat version to do big repairs/patches on car exhausts, and tbh it's proved stronger than my piss-awful welding. Not sure how suitable it is for this though
There's quite a lot of advertising for it devoted to fixing bike frames. Not chainstays though.
somethign to act as a splint for the break.
You mean in addition to the thousands of fibres in tension?
To answer your question, it depends how much clearance you have to play with. I would suspect the simple answer is not enough. You'd want to wrap three or four times a good few inches either side of the break, but as mentioned above you'd ideally have some form of brace, which is going to take up more space, unless you can do it inside the tube somehow.
But, it's definitely worth trying and if it doesn't work out fibrefix is very easy to remove as it only sticks to itself, not the piece being repaired.
Go for it. People have been making bamboo bikes with stuff that supposedly isn't as strong as fiber fix for years
But, it’s definitely worth trying and if it doesn’t work out fibrefix is very easy to remove as it only sticks to itself, not the piece being repaired
So what's resisting tension loading then to stop it pulling apart under load ?
It resists tension loading in and of and by itself. Not an engineer (can you tell?) but it compresses and 'shrinks' as it cures to form a very tight three dimensional binding. I was wondering about coating the surfaces in epoxy first but it doesn't seem to be necessary.
You're supposed to roughly sand the surfaces to provide a key. I'm assuming this means removing the paint from the chainstay.
I think the fix would be under almost entirely tension loads. It snapped behind the chainring, and it still supported my weight so I don't think the loads are that great.
Given it snapped at the crimp, there's a sort of figure 8 type shape. I may get two fat metal pins and glue them into the stay on the inside, then put the wrap on the outside.
As long as I don't end up wrapping the BB shell or possibly the chainstay bridge it should be fine as the whole stay's getting replaced in the future. Given that the stuff is only £7 and I'm not even using a whole roll this is really just for the hell of it.
Well, I did it.
Firstly, I totally forgot to sand the chainstay even to key into the paint. So there's that. Then I glued two pins inside the chainstay with Evo stick metal repair epoxy. Even as that started to cure it was pretty good in tension, which was nice. I tried to put some extra around the join. Then I applied a layer of Fiber Fix, a couple of rolled up wadded bits to fill in the indents where the stay was folded, then wrapped another layer around to press it all together. Wrapped it in their vinyl tape (which isn't sticky.. eh?) then a bit of my own insulation tape.
Seems pretty decent tbh. When I flex the stays at the dropouts the repaired one flexes maybe slightly more than the other, but not by much. And in all other aspects it's solid. The stuff won't peel off the painted stay at the sides, so it may be stuck down well enough. The only remaining question is whether or not I've left enough clearance for the chainrings.
To be honest, the main reason for doing this is so I can build the bike to get it out of the way, and to allow me to re-hang all the bikes on the wall so they don't clash. I may not actually ride it, but I might.
I think the pins inside will help with lateral loads, and the extra wadding on the sides of the joint will give five layers which will help with the tension. I'm optimistic.
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The King (cynic al) is dead long live The King (molgrips). Needs more spoons though.
Nice one! It'll certainly stand up to a bit of filing to create space for the chainring to pass freely if necessary.
There was plenty of space in the end. Went together easily, rode it up and down the road, all seemed fine, then I did a few bunnyhops and.. nothing. Still fine!
It looks pretty good tbh, confidence levels are high.
course, you won't count as a "manly man" 'til you've cartwheeled it off a big drop
You mean throw it into a quarry?
big(gish) drop, quarry - same thing innit
