#16
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I never heard of using Windex to clean the rim surface before but that's what concerns me. Sounds like there is a residue left behind that is causing blockage to good adhesion. Could be a very thin film of soap left behind. Nail Polish might have acetone in it but it could also have other stuff that is no good too, I don't know.
Goof Off is a good solvent for cleaning up old glue. In fact it can even be used to soften up the old glue making it reusable. Also, in almost all cases there is no need to clean up the old glue, it can even cause problems |
#17
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Sweet. 11.4 chimed in. And others. Thanks for the things-to-adjust recommendations!
I used the Windex and nail polish remover because I had them on hand and was working in the kitchen and didn't want to get all chemical. Shoulda coulda woulda. So now it's a trip to the store for acetone, and I imagine using it outside so I'll have to wait for the rain to stop. I stripped the original glue off because, as per 11.4's posts across the hall, mixing glue types could be seriously hazardous with something like a 40% reduction in adhesion, and I already knew that this tire/rim combo is sub-optimal so I need a bang-on glue job. I used spray-on (like a Windex bottle) Goof Off in a yellow plastic bottle with spray nozzle that I picked up at Home Depot. I'm in Canada, so the labels were all screwy with re-labelling either for French or for things that have different names or chemical lists or whatever, but I think it's the same product across the borders. Either way, the stuff was AMAZING. Literally sprayed it on, left it for 10 minutes, wiped the glue off like spilled jam. Seriously. Amazing. I feel like the glue job was a few years old (used wheels from a buddy no longer riding tubulars), the old tire was a Tufo with sealant, and it was a tough tire to remove. So the glue was old, but it literally wiped off. Took me a few more go rounds with a rag and wiping, and then the 4mm of glue residue that was totally stuck to the rim was totally gone. I had spent hours here and there with WD-40 and a rag, and Goof Off in the small metal can and a lot of rags. The spray stuff worked in minutes, and had absolutely no smell either! Anyway, note to self for next time. So then I started the whole glue up with Conti rim cement. Thought it'd be fine. Maybe it's an old batch of glue (dust on the can in the shop, imagine that!). Maybe I screwed it all up. I'm thinking I contaminated the rim surface. The tire pulled patches of glue up off the rim when I removed it, so I think is well prepped and glued, just the rim. Now I'll move to the rim bed, take off the remaining glue again with that spray, and sand the rim bed. Anodizing comes off too? And all this, whatever glue was on before wasn't a great job and wasn't holding across the whole bed, but it kept the old Tufo on no problem and was still difficult to remove. Better glue? Better job? Anodizing still there under the glue... Anyway, I'll send pics when I get to it. Acetone and sanding. Got it. |
#18
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Isn't that the likely culprit?
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#19
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i think you hit the nail on the head. :nod
My CX race wheels are D/A C24s. Narrow. My backups are all Mavic Open Pro/Reflex tubulars (same rim). Narrow. Mud wheels are Ritchey 38mm carbon tubulars. Narrow. I've never rolled a tubular. Only 1 of my glue jobs has ever been rolled and that guy rides like Mongo. (he rolled 2 tubulars at DCCX and flatted one. None my doing) Coupla thin layers of dry glue on the rim, two on the tire, then one thick one to install the tire, inflate, center, let dry over night, ride. I absolutely LOVE tubulars on gravel rides. Mo bettah than tubeless by far. 2 Hilly Billy-s ago I was experimenting with 30c Challenge tubulars and hit a rock just wrong. Dented my rim, but didn't flat. Good thing too cause that was towards the beginning of the race. As a note: 30c tubulars are a little small for that race. 33-35c work better M |
#20
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Both GoofOff and WD40 are combinations of lots of different fractions from petroleum distillation. That includes all kinds of oils. So when you use them, you basically contaminate your gluing surface, which has to be seriously oil-free and clean. Yes, that's likely the issue.
So now you have to scrub your rims carefully to get the stuff off. Start with hot water and some dish soap, just to get off the worst of the stuff and to get inside the spoke holes and other places where contaminants can re-emerge to poison your glue job. Rinse exhaustively, then let dry completely, including the inside of the rim -- best done in a warm room for several days, or in the sun for a couple days if it's warm. Then go over the gluing surfaces with a rough rag and acetone to scrub any last remainder off. Don't soak the rim or you could bring residual oils up onto the rim bed again. I'd try a thin coat of glue and let it dry a full 24 hours and see how well it sticks. You should be able to scratch it with a key without having it pull loose from the rim. |
#21
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#22
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i love this thread.
hoping for a little more time tonight to get to the re-gluing or just straight up cleaning. might have to wait for the weekend. so many people ask me why i'm even bothering with tubulars. i like processes, especially those that require learning and learning and still learning. all about it. as long as i can still go for a run and mull things over between learning frustrations. thanks for the points! |
#23
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Thinking more about it, I realize that the last coat of glue on all those tubulars I mounted was a few minutes before - it just wasn't what I would call "wet". We would make the last coat very thin. And we never stripped the rim down to aluminum with acetone or sanded through the anodizing. The majority of the extraneous glue came off with a wire brush, and peeling off the old tire was pretty self regulating for glue build up. If there is a 40% reduction in adhesion from mixing brands, I'd love to know where that number comes from. I sincerely doubt that the formulations of different tubular glues are so chemically different and incompatible. Every tire I or someone before me glued at Cronometro required a razor and channel locks to tear back off. I'm very confident we were doing one version of correct. |
#24
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Sorry, did not notice this dude was talking about CX tubbies.
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#25
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The reason in this case for cleaning off the rim entirely was the apparent contamination by WD40 and Goofoff. If those hadn't been on there, the glue job would presumably have worked and after the tire was peeled off, it wouldn't have required a complete rim cleaning. As for the 40% number, I've seen it a couple times but never used it myself and never seen the validation for it. However, even current rim cements can cross-contaminate and reduce the colloidal properties of rim cements. It doesn't necessarily prevent the glue from solidifying but it does reduce in several combinations the electrostatic attraction plus the simple elastic strength of the glue. It also can significantly change the resistance of the glue to water impingement and to deterioration from that. A lot of things go into a strong glue joint with rim cement and there are different ways to achieve a successful glue job. That's why there are sometimes quite variable methods that different people can use with equal success. Someone who glues lots and lots of tires can usually work it out and be safe. When someone who isn't experienced or is having defective glue jobs is being coached, I'd always stick to a conservative path so we're not throwing in more variables besides the ones the person is introducing. That's just a rigorous way to teach good gluing technique. Last edited by 11.4; 12-06-2017 at 10:58 PM. |
#26
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pictures. and updates.
alright.
finally got acetone. gave the whole rim a good once over with a rag and a bunch of acetone. scrub pad just left scrub residue so i stopped that real quick. more acetone poured into the rim through spoke holes, and left to run along the bed inside and out. wanted to get everything cleared up. so then i rubbed a bunch of the old glue off, but some of it wasn't ready to come off. i took this as a good sign - i want the glue to stick where it's sticking, and come off now if it's going to come off, rather than later when the tire is actually installed. granted this is a different rim from what i started this thread with (original was alloy); this one is carbon, but it's the same problem as exhibited by the removal process on the alloy rim. i did both at the same time. as the photos indicate - first, a bunch of the glue just didn't even stick to the carbon rim bed. it came off easily when i pulled the tire off after a full gluing. the i introduced the acetone, and cleaned the rim with a soaked rag and acetone and lots of rubbing. if glue didn't wipe off with vigorous rubbing, i left it on. then i tried duct tape. i stuck the tape to the rim, and then pulled it up slowly, allowing the adhesive to bring with it any glue that would readily pull up. i was disturbed by huge swaths of glue that pulled clear of the rim. i went through a bunch of tape, and cleared probably almost half of the rim. the rest of the glue stuck to the rim, and started to pull pieces of the tape off, so i figured it was a good strong glue bond. now, the rim is sitting in a warm, dry kitchen, awaiting my next move. my thought is: let it dry til tomorrow (it's not wet, but whatever, let the acetone evaporate fully overnight, even though it probably was gone in the first 90s). glue up the rim with full drying of at least 4h between coats (maybe more?). let the 2 coats on the rim dry overnight. test the coats to make sure they adhered. put on a 'wet' coat for install, and install the tire as usual. let it sit for a couple days. check it for adhesion then ride the piss out of it. ja? |
#27
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Well, you've been having problems, so I'd suggest you go back to the most conservative approach and do several thin coats with several hours between coat, ending with a wet one and then the tire. People can take shortcuts but part of why I always advocate the long-and-slow approach is that when shortcuts create problems you don't always know why glue jobs go wrong. Get it right, then once you're sure of that technique, start to experiment with how much you can pull it back.
I'd put on a wet coat and apply the tire. The wet coat will almost immediately make the glue surface sticky, but it'll be just enough to enable you to get the tire mounting correct. That's not only about getting it centered but also to pull up and let tighter parts of the tire relax so it's perfectly round and some areas aren't under more pressure on the rim than others. Someone mentioned above that glue wouldn't dry once there's a tire on it but that's not realistic. I've always mounted tires on a newly-applied top coat and it's always dried. It may dry slightly slower, but it'll dry just fine. To my original point, don't rush or shortcut the procedure and it should work fine; then you can at least be on the road. |
#28
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Totally agree, and very glad you chimed in before I even went to bed last night, 11.4! I'm not usually about shortcuts. I spent the last couple of years working to really engage in the process of everything, from marathon training to learning some new process at work. Either way, the long way works fine for me, except with glue removal. For that, I'm always looking for a faster, less-smelly, easier way. The reasons for finding shortcuts for that are myriad, but one of my main concerns is the fact that I work in our kitchen after the household is in bed, and I have to have everything cleaned up and put away by lunch-making time the next day. Anyway, I found the spray-on Goof-Off to be the most amazing 'shortcut' to glue removal yet. Perhaps its oily residue makes it too good to be true? Maybe the residue is from the WD-40. Hopefully, I'll never know as the glue jobs I'm about to take the very long way around on will stick forever. Here's hoping... Also: what gloves don't get dissolved by acetone? I went through two pairs of the blue gloves yesterday, maybe nitrile...
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#29
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Chisholm's Custom Wheels Qui Si Parla Campagnolo |
#30
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hard to tell what prep was done from the pic, but with a new carbon tubie - it's best to scuff up the carbon with sandpaper a little, and then wipe down with acetone, gives the glue a little something to "bite" onto.
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http://less-than-epic.blogspot.com/ |
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