Tubular glue-up not working yet.

[giverdada]

Hey friends:

So, I have two glue jobs ongoing at the moment, one on a China carbon rim that seems nice and wide, and one on a very old Cane Creek that has a tubular 'Aerohead' laced with titanium spokes to a Cane Creek hub. Classy.

I've glued tubulars before, none have rolled, and they have been for both cross and road use. I only glued alloy rims, and have yet to venture on the carbon.

Anyway, my problem right now is with the alloy rim. It's a pretty narrow rim bed that I'm hoping will hold the Challenge Fango I'm gluing onto it. I put three coats of Continental (non-carbon) rim cement onto the rim, two onto the tire, using a new acid brush each time. The tire is new. (The rim was cleaned of all old glue, down to anodized metal, and gone over with Windex and then nail polish remover. All this was left to dry for a couple of hours in a heated kitchen before any of the 3 coats of glue were put on with a new acid brush from a can of Continental rim cement.)

So I did all of the stuff, three separate coats on the rim, two on the base tape, one more 'wet' coat before mounting, mounted the tire, seated it in the rim bed, pumped it up to 80psi, left it over night.

A day and a half later, some of the glue job looked great, some was questionable and pushing back from the rim more easily than I would like. I left it another day, then pushed the whole damn thing off with my thumbs and the tire at 20psi. ***.

Looking at the rim, a bunch of the glue is still there, and nicely stuck. A bunch of patches are totally bare, no glue whatsoever, clean rim. Some all the way to the edge, some in from the edge, some all the way across the rim.

Taking your suggestions...
(One thing I usually like to do is roll the whole thing back and forth over a broom handle to get a good round-profile-pressure on the glued surfaces, but the tire had so much volume it kept slipping off the handle at every psi, so I just pumped it all the way up and left it overnight.)

[bicimechanic]

I use Belgian tape in addition to Mastik one when gluing up a larger 'cross tire on a narrow rim.

A few years back had a clients brand new rim (from his stock) that would not hold a tire/glue. Cleaned it multiple times, different glue, etc. Chalked it up to some type of contaminant on the rim. Rebuilt the wheel with a new rim (same model/age) and had zero problems.

[nooneline]

in my experience, Challenge tires have a really thirsty basetape. I don't know if it's thicker or different from other basetapes or exactly what is going on, but it takes a bit more attention to make sure that the layer on the tire is actually fully soaking the basetape, and not just getting absorbed and reducing the amount of glue contact.

also i wonder if you did too many coats of glue. sometimes building up too much of a layer changes the profile of a rim so that it doesn't match the profile of the tire too well, and you wind up getting areas that just aren't really touching each other.

but without seeing the thing it's hard to know. just speculating here.

[oldpotatoe]

Originally Posted by giverdada

Hey friends:

So, I have two glue jobs ongoing at the moment, one on a China carbon rim that seems nice and wide, and one on a very old Cane Creek that has a tubular 'Aerohead' laced with titanium spokes to a Cane Creek hub. Classy.

I've glued tubulars before, none have rolled, and they have been for both cross and road use. I only glued alloy rims, and have yet to venture on the carbon.

Anyway, my problem right now is with the alloy rim. It's a pretty narrow rim bed that I'm hoping will hold the Challenge Fango I'm gluing onto it. I put three coats of Continental (non-carbon) rim cement onto the rim, two onto the tire, using a new acid brush each time. The tire is new. (The rim was cleaned of all old glue, down to anodized metal, and gone over with Windex and then nail polish remover. All this was left to dry for a couple of hours in a heated kitchen before any of the 3 coats of glue were put on with a new acid brush from a can of Continental rim cement.)

So I did all of the stuff, three separate coats on the rim, two on the base tape, one more 'wet' coat before mounting, mounted the tire, seated it in the rim bed, pumped it up to 80psi, left it over night.

A day and a half later, some of the glue job looked great, some was questionable and pushing back from the rim more easily than I would like. I left it another day, then pushed the whole damn thing off with my thumbs and the tire at 20psi. ***.

Looking at the rim, a bunch of the glue is still there, and nicely stuck. A bunch of patches are totally bare, no glue whatsoever, clean rim. Some all the way to the edge, some in from the edge, some all the way across the rim.

Taking your suggestions...
(One thing I usually like to do is roll the whole thing back and forth over a broom handle to get a good round-profile-pressure on the glued surfaces, but the tire had so much volume it kept slipping off the handle at every psi, so I just pumped it all the way up and left it overnight.)

Could be that the concave-ness(is that a word) of the rim and the 'arc' of the tire is different enough that the tire isn't actually getting all the way to the glue on the rim. BUT it also sounds like some glue isn't sticking to the rim at all,

A bunch of patches are totally bare, no glue whatsoever, clean rim

I would try roughing up the rim some(may be tough with glue already on it)..with emery paper, mild sand paper and when you glue the tire, try to make a little ridge in the center as you build the glue up. I've done this successfully with some cross tubies on narrow rims.

Doubt it's the glue but never been a fan of Conti...Vittoria or my favorite, Panaracer(take a trip w/o leaving the farm')..use in well ventilated area..

[ultraman6970]

Well could be way too much glue aswell, dude is puting like 3 coats of glue in the rim is like too much IMO, you can get continental to glue like a wastard with just one coat at the rim and at the tubular. Doing this since I was 13 y/o. Last tubbie had to unglue had to cut it to be able to remove it from the f.. rim... im impressed with how sticky the last generations of glue are.

What i think is going on is that by the last coat the 1st 2 coats are pretty much dried at that point and honestly 2 coats in the tubular is overkill it as well because the tape will absorb what ever is there and you end up pretty much putting like a intermediary coat that is dry and doesn't stick to anything.

The other thing, you are putting so much glue that wonder how you aren't complaining of ending with glue even in your underwear and that kind'a makes suspect that the glue is pretty much dried at the time you are mounting the tubular in the rim.

You do one light coat to the tubular, than you do 1 wetish coat to the rim, you mount, 80psi, wait a couple of hours and good to go.

Hope this helps.

ps: the concave of the rim is important too, some rims are super flat and you get like weirdness at the sides of the tubular because is not like super glued, what you do in those cases is mount inflate like 40 psi and then roll the wheel back and forth so the tubular conforms the rim.

[giverdada]

Originally Posted by bicimechanic

I use Belgian tape in addition to Mastik one when gluing up a larger 'cross tire on a narrow rim.

A few years back had a clients brand new rim (from his stock) that would not hold a tire/glue. Cleaned it multiple times, different glue, etc. Chalked it up to some type of contaminant on the rim. Rebuilt the wheel with a new rim (same model/age) and had zero problems.

Yeah, I tried to switch to Mastik but the shop only had a can of Conti, and I wanted a can rather than a box of individual tubes of Mastik, so I went with that. It does seem like the rim is not accepting the glue somehow, so I'll try OldP's suggestion of roughing it up a bit, though it will be tricky with some glue still on there. I'll try to post pictures tonight. Thanks for the suggestions folks!

[Kontact]

I don't think the wet coat before mounting is a good idea. The glue needs to tack by being exposed to the air, and a wet coat is not going to dry right between the rim and tire. So that may be your problem - the last coat is acting like a solvent.

The shop I worked at (that invented that Cane Creek wheel you're using) always did three thin coats to both rim and tire. We did not remove all the old rim glue, just the big chunks. Never had a problem - even when we took clients to the Pyrenees for long, fast descents.

[giverdada]

weird. i thought most people were on board with the whole 'one last 'wet' coat' to ease with alignment after mounting. this is not a good idea, in case it's further dissolving the glue on both tape and rim, and then not letting good curing happen? might help explain why some patches didn't stick at all to the rim when i pulled the whole thing off...

[chiasticon]

Originally Posted by ultraman6970

You do one light coat to the tubular, than you do 1 wetish coat to the rim, you mount, 80psi, wait a couple of hours and good to go.

80 psi will destroy a handmade cross tub. your described method might be OK for road, but is nowhere near strong enough for cross. unless maybe the rider is terrible at cross, rides at 50 psi, and never leans their bike...?

OP, can you post a pic of the rim, so we can see how concave it is? and what your glue aftermath looks like?

my guess - without seeing pics - is you need to build up the middle for more contact. you can use CX tape or the butter tape for this. for the latter, see the video below.

https://www.youtube.com/watch?v=OkAJmHGKQUk

[Kontact]

Originally Posted by giverdada

weird. i thought most people were on board with the whole 'one last 'wet' coat' to ease with alignment after mounting. this is not a good idea, in case it's further dissolving the glue on both tape and rim, and then not letting good curing happen? might help explain why some patches didn't stick at all to the rim when i pulled the whole thing off...

Hey, it's been a few years and I could certainly be remembering wrong. I bow to the majority opinion.

[oldpotatoe]

Originally Posted by Kontact

I don't think the wet coat before mounting is a good idea. The glue needs to tack by being exposed to the air, and a wet coat is not going to dry right between the rim and tire. So that may be your problem - the last coat is acting like a solvent.

The shop I worked at (that invented that Cane Creek wheel you're using) always did three thin coats to both rim and tire. We did not remove all the old rim glue, just the big chunks. Never had a problem - even when we took clients to the Pyrenees for long, fast descents.

Well, tubie glue is just ‘contact cement’ and that is designed to be used/assembled ‘wet’. Plus 2 layers that are just past tacky, together and it’s ‘almost’ impossible to center the tire.

Imho of course ’pal’

[chiasticon]

Originally Posted by Kontact

I don't think the wet coat before mounting is a good idea. The glue needs to tack by being exposed to the air, and a wet coat is not going to dry right between the rim and tire. So that may be your problem - the last coat is acting like a solvent.

my understanding of this approach is that the "wet coat" isn't really wet. it's just sticky enough that you can touch it without getting glue stuck to you. so... a few minutes old-ish. not being 100% dry, it allows you to maneuver the tire a bit more when mounting it. maybe the OP is doing it differently though...

[batman1425]

Perhaps the pressure during cure (80psi) combined with a narrow rim bed was enough to pull the glue off the rim surface. You might have gotten good contact and adhesion to start with. However, the high pressure is applying ALOT of force to make that tubular round while it's stuck to something with a smaller radius. Could be enough force that it fails during the cure.

I'd try what oldspud suggests - remove as much of the new glue as possible, scuffing the rim bed lightly with a 3m pad. Then I'd do whatever your normal glue up that has worked for you in the past, and during the cure, only put in enough pressure to ensure good contact, don't go crazy Leaving it a little soft will help the bed conform to the non-matching radius.

[11.4]

How about starting over? But first, let's figure out what went wrong.

First, your tire has to have enough thin coats so that it isn't just a fabric surface any longer -- it's like it has a rubbery coating and at least a significant amount of the fabric texture is gone. Base tapes absorb glue and even a couple coats sometimes will just get sucked in and then provides no adhesion. I'm guessing that's what happened here, since you had partial adhesion.

Second, your rim may not have been consistently clean enough. Skip fingernail polish remover, which is partially or totally aqueous. Go to Home Depot and buy a can of acetone and clean the rim bed thoroughly with that before you glue. Definitely spray household cleaners won't do the job and can even contaminate the surface.

Third, it's ok to put on a wet coat. It helps reposition the rim and it'll cure overnight.

And I'd look at it differently from Spud and not score the tire bed on the rim. Here's why. First, rim cement has to work by two different methods. To attach to the rim, it bonds electrostatically -- that means it just needs a super-clean surface to bond to. Give it a pure, clean, raw aluminum surface and it'll stick so hard it's almost impossible to get off without cutting the tire. It doesn't need any "teeth" to hook into. It doesn't bond quite as well to carbon, but still does a respectable job by the same method. One thing you DO want to do is use some fine sandpaper to sand the tire bed -- something like a 400-600 grit carbide paper -- and sand til most of the anodizing is gone. You're trying to remove the teflon-based lubricants used when the rim was originally extruded. Those lubricants don't come off with acetone or anything else, so you literally have to take off a very fine layer of metal that the lubricants are still on. The rim manufacturer is supposed to clean the stuff off, but never gets it all.

On the tire side, though, the electrostatic bond is much weaker (metal is stronger than carbon which is stronger than fabric). What you have to depend on there is that the rim cement is basically tough, doesn't tear apart easily, and relies mostly on developing locking "fingers" that hook into the fabric of the base tape. This is why you used to have to scrape off heavy latex on the base tape before gluing, or it wouldn't develop the fingers and it wouldn't stick well enough without them. So do thin layers until you have built up enough to obscure most of the tire texture. With some tires that have base tapes that absorb a lot of glue, that can mean four or more thin coats. And if your coats are too thick, they gum up the surface rather than making a good base on the tire, so it doesn't lock in well and comes loose easily. You really want to scrub it into the base tape with the brush or a finger covered in a glove. (In your case the glue seems to be coming off the rim, not the tire, so this isn't likely your issue. You most likely have a problem with the cleanliness of the rim.)

Beyond that, you have a pretty narrow, deep rim that barely matches the tire curvature in the middle. You have to be sure you have glue on the rim right out to the very edge and you have to be sure the tire fits the rim. You can add a piece of tape to help fill the gap, but it's still not as good an approach as using a tire to fit the rim. You're just not using a particularly good rim profile to go with a cross tire and your glue job will always be somewhat compromised. You can bridge the gap in the center of the rim bed somewhat, but just adding glue isn't all that effective.

I'd pull the tire, clean all glue off the rim, sand it as described above, use some pure acetone and do a serious cleaning of the rim bed, and then start some glue layers. Completely redo the glue on the rim, obviously. Pull everything you possibly can off the tire, then paint any bare places with new cement and keep covering the whole tire until everything is smooth as described above. The new rim cement will help stick the old stuff together as long as it's still bonded well to the base tape. Consider getting some Belgian rim tape and follow the directions for mounting it (basically you glue under it, apply it, glue over it) to help with your particular rims. From then on you should be happier.

[Kontact]

Originally Posted by oldpotatoe

Well, tubie glue is just ‘contact cement’ and that is designed to be used/assembled ‘wet’. Plus 2 layers that are just past tacky, together and it’s ‘almost’ impossible to center the tire.

Imho of course ’pal’

Contact cement is designed to be used dry to the touch. And I'm not saying that tubie glue has to be, but contact cement is supposed to dry for at least 5-10 minutes before using bonding.

http://drentha.com/2015/07/17/tutori...ontact-cement/


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