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kendokelso
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Group: Forum Members
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Hi there, I bought some 2nd hand carbon rimed (braking surface too) bicycle wheels from eBay. The front one is showing what I believe is some signs of age and impact damage. I'd like to attempt to repair these but have never worked with composites before. I'm thinking of getting some low viscosity resin, trying to inject into any cracks / gaps with a syringe, bag and clamp and then sand down with high grade of wet or dry. Does that sound like it might work to someone more experienced than me? I'd spotted the product linked below and wondered is that the best thing to use to attempt the repair with? Any help or advice welcome, I've attached an image to this thread also so you can hopefully see the issues I'm trying to correct. Thanks in advance. https://www.easycomposites.co.uk/300g-22-twill-kevlar-cloth
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Lester Populaire
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Group: Forum Members
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+xHi there, I bought some 2nd hand carbon rimed (braking surface too) bicycle wheels from eBay. The front one is showing what I believe is some signs of age and impact damage. I'd like to attempt to repair these but have never worked with composites before. I'm thinking of getting some low viscosity resin, trying to inject into any cracks / gaps with a syringe, bag and clamp and then sand down with high grade of wet or dry. Does that sound like it might work to someone more experienced than me? I'd spotted the product linked below and wondered is that the best thing to use to attempt the repair with? Any help or advice welcome, I've attached an image to this thread also so you can hopefully see the issues I'm trying to correct. Thanks in advance. https://www.easycomposites.co.uk/300g-22-twill-kevlar-cloth You need a very specialized resin to cope with the heat on a breaking surface. I only know of one resin that is not made for prepreging and has a Tg high enough that i would trust it, but can't think of the name now. I wouldn't recommend to fix that, especially with no experience with composites.
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kendokelso
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Group: Forum Members
Posts: 4,
Visits: 7
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+x+xHi there, I bought some 2nd hand carbon rimed (braking surface too) bicycle wheels from eBay. The front one is showing what I believe is some signs of age and impact damage. I'd like to attempt to repair these but have never worked with composites before. I'm thinking of getting some low viscosity resin, trying to inject into any cracks / gaps with a syringe, bag and clamp and then sand down with high grade of wet or dry. Does that sound like it might work to someone more experienced than me? I'd spotted the product linked below and wondered is that the best thing to use to attempt the repair with? Any help or advice welcome, I've attached an image to this thread also so you can hopefully see the issues I'm trying to correct. Thanks in advance. https://www.easycomposites.co.uk/300g-22-twill-kevlar-cloth You need a very specialized resin to cope with the heat on a breaking surface. I only know of one resin that is not made for prepreging and has a Tg high enough that i would trust it, but can't think of the name now. I wouldn't recommend to fix that, especially with no experience with composites. Thanks for the info. I'm an engineer by profession, I've done all sorts of work with various materials and resins, just never composites. I suspect paying a professional for repair may cost more than the value of the wheel and if it's a write off now then I may as well have a go, at least after if the repair fails, the wheel will still be a write off but I'll have gained a little experience with resins and composites...that's my logic anyway...
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scottracing
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Group: Forum Members
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As lester has said repairing wheels in any way needs a high temp resin, as the friction area is always susceptible to delamination. Just applying a resin wont fix this problem it needs the carbon material removed and new plies applied and cured.This is possible but I certainly wouldn't use the wheel on the road unless you have used the correct materials. https://carbonbikerepair.co.uk/#about
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kendokelso
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Group: Forum Members
Posts: 4,
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+xAs lester has said repairing wheels in any way needs a high temp resin, as the friction area is always susceptible to delamination. Just applying a resin wont fix this problem it needs the carbon material removed and new plies applied and cured.This is possible but I certainly wouldn't use the wheel on the road unless you have used the correct materials. https://carbonbikerepair.co.uk/#about Is braking temp the main issue? Could I use them on a track bike or fixie after a poor to mediocre repair?
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Lester Populaire
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Group: Forum Members
Posts: 311,
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+x+xAs lester has said repairing wheels in any way needs a high temp resin, as the friction area is always susceptible to delamination. Just applying a resin wont fix this problem it needs the carbon material removed and new plies applied and cured.This is possible but I certainly wouldn't use the wheel on the road unless you have used the correct materials. https://carbonbikerepair.co.uk/#about Is braking temp the main issue? Could I use them on a track bike or fixie after a poor to mediocre repair? Yes if is mainly about the brake surface. It is actually a pretty stupid use case for composites with the bad heat transfer and the limited temperatures they can handle, directly in the most stressed area. Imagine the tire rolling of the rim in a hairpin on a big descent. It's gonna result in a bad week... For a track bike, fixie or with disc brakes i think you should be fine!
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kendokelso
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Group: Forum Members
Posts: 4,
Visits: 7
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+x+x+xAs lester has said repairing wheels in any way needs a high temp resin, as the friction area is always susceptible to delamination. Just applying a resin wont fix this problem it needs the carbon material removed and new plies applied and cured.This is possible but I certainly wouldn't use the wheel on the road unless you have used the correct materials. https://carbonbikerepair.co.uk/#about Is braking temp the main issue? Could I use them on a track bike or fixie after a poor to mediocre repair? Yes if is mainly about the brake surface. It is actually a pretty stupid use case for composites with the bad heat transfer and the limited temperatures they can handle, directly in the most stressed area. Imagine the tire rolling of the rim in a hairpin on a big descent. It's gonna result in a bad week... For a track bike, fixie or with disc brakes i think you should be fine! Thanks, that's all really interesting info. Good point about stupid use case. I prefer an alloy braking surface anyway, more feel and more progressive, carbon tends to be a bit "grabby". Totally right about tire coming off rim, gonna be a very bad week. Thankfully I live by the coast and have a selection of bikes, plus I don't ride fast or hard these days. So seems my options are: 1: Try and find this resin that is not made for prepreging and has a Tg high enough, do best repair I can, if successful then only use on flat roads and never aggressively, lots of rear brake (good rim). If not, bin wheels. 2: Start a little pet project track / single speed build, repair with a fairly standard low viscosity resin just to make use of these wheels. 3: Continue the long search on eBay for a matching good condition front replacement. 4: Bin a nice carbon wheelset and cry myself to sleep ... I do appreciate your comments and advice however, so thanks for taking the time. Just really don't want the answer to be option 4!
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Buchado
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Group: Forum Members
Posts: 30,
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+x+x+xHi there, I bought some 2nd hand carbon rimed (braking surface too) bicycle wheels from eBay. The front one is showing what I believe is some signs of age and impact damage. I'd like to attempt to repair these but have never worked with composites before. I'm thinking of getting some low viscosity resin, trying to inject into any cracks / gaps with a syringe, bag and clamp and then sand down with high grade of wet or dry. Does that sound like it might work to someone more experienced than me? I'd spotted the product linked below and wondered is that the best thing to use to attempt the repair with? Any help or advice welcome, I've attached an image to this thread also so you can hopefully see the issues I'm trying to correct. Thanks in advance. https://www.easycomposites.co.uk/300g-22-twill-kevlar-cloth You need a very specialized resin to cope with the heat on a breaking surface. I only know of one resin that is not made for prepreging and has a Tg high enough that i would trust it, but can't think of the name now. I wouldn't recommend to fix that, especially with no experience with composites. Thanks for the info. I'm an engineer by profession, I've done all sorts of work with various materials and resins, just never composites. I suspect paying a professional for repair may cost more than the value of the wheel and if it's a write off now then I may as well have a go, at least after if the repair fails, the wheel will still be a write off but I'll have gained a little experience with resins and composites...that's my logic anyway... Well, there must be a reason why the repair is expensive. I would bet on too much expertise necessary to properly execute it, or expensive materials (less likely).
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