rpenmanparker 

From time to time this issue comes up. Is tube patch vulcanizing fluid a specific formulation for "gluing" patches onto tubes containing vulcanizing chemicals needed to make the bond between the patch and the tube? Does plain rubber cement (like Elmers) work just as well? Are they the same thing?

As a plastics/rubber chemist I have long thought that vulcanizing fluid was just a rip off. Nothing special. IMO the vulcanizing chemicals are in the patch. The rubber cement just mobilizes the chemicals and supplies natural rubber to act as a bridge between the tube and the patch. Natural rubber is more reactive than butyl rubber used in most tubes and could speed up the bonding of the patch to the tube.

But that opinion is by no means widespread and is unsupported. So I decided to undertake some investigation to see what I could learn and/or demonstrate. I used a Performance Forte brand patch kit containing a tube of glue and Rema type patches. I cut four, four inch lengths of butyl innertube and slit them open. Then I cleaned the outside surfaces of the tube specimens with the abrasive paper in the kit.

I applied Elmer's rubber cement to two specimens and Forte glue to the other two. After letting the glue nearly dry I folded one specimen with each glue over on it self and weighted the folded specimens for 2 hours. I applied Forte patches to each of the other two specimens and pressed the patch and tube tightly together. After two hours I examined all the specimens. The folded specimens were easily unfolded. The bond was minimal and very similar for both glues. The appearances of the glue residues were identical.

The patches were both tightly bonded to the tube specimens. There was no apparent difference between bonding of the patches with the two different glues.

I should mention that the Forte glue was actually labeled "rubber cement". It looked and smelled just like the Elmer's. There was actually a formula for it on the tube which showed two solvents and natural rubber as the only ingredients as you would expect for plain rubber cement. The two rubber cements looked identical.

So without the special patches, neither glue was able to bond two pieces of butyl rubber together. If the cement really contained vulcanizing chemicals, some bonding of the two rubber surfaces would have been expected.

Although this experiment does not involve quantitative results, I think it provides ample evidence that the rubber cement commonly supplied for patching bicycle tubes is just plain rubber cement. If you have a bunch of tubes to patch, I recommend purchasing both quality patches and plain rubber cement in bulk. The idea that tube patch "vulcanizing fluid" is a special formulation containing chemicals that activate the vulcanization appears to be false. It is still my belief these chemicals are actually in the patch.

Done and done.

noodle soup

You have way too much time on your hands. I want back the time it took me to read this.

Bah Humbug

I, on the other hand, loved it. YMMV.

datlas 

Did you sniff the glue??

rpenmanparker 

Just analytically. The two were very similar.

3alarmer 

...did you read the Materials Safety Data Sheets I gave you in addiction ? Do you think that it does not matter how aggressive the solvent is in this application ? Also, did you light any of your experimental repairs on fire ?

I really think that in the interests of science you ought to light a couple of these on fire. Science is better and more convincing with fire included.

Lastly, did you inflate any of your experimentally patched lengths of butyl slices ? I want real world experimental design, sir.

rpenmanparker 

Don't tell a chemist about fire. In order to get the degree you have to have an intimate familiarity with that particular phenomenon.

datlas 

BTW I use "Rema Cold Vulcanizing Fluid" for my patches. Now whether this is really rubber cement or something more, I don't know.

rpenmanparker 

I agree. I don't see how to answer that question. But the fact that a commercial kit (the Forte) contains just plain rubber cement suggests to me they all probably do. After all, this isn't a new technology. It goes back nearly to the invention of the automobile.

3alarmer 

...Forte patches suck donkey balls. The only patches that consistently work are the Rema's. You would know this if you were not so affluent.

rpenmanparker 

Are you talking about Forte vulcanizing patches or the self-adhesive kind? I'm using ones that look and behave just like Rema. Orange edge and everything.

I think I have some Rema patches. I will give one a try with the rubber cement.

Doctor Morbius

I fail to see the logic in this argument.

3alarmer 

.
...I'm hungry. I'm gonna go eat some library paste.

f4rrest

No, the objection was that rema vulcanizing fluid is superior to both rubber cement and forte rubber cement.

Trying a rema patch with rubber cement won't answer the question.

rpenmanparker 

Not exactly. That was not an objection, just a question. But if I get a decent bond with rubber cement and Rema patches, what more is there to ask for. I'm telling you that in all likelihood "Rema vulcanizing fluid" is just a marketing scam. Rubber cement works and is what is clearly being supplied by at least one major player. It is most likely the stuff everyone uses. Why is this so hard to believe?

Without instrumentation it won't be possible to quantify the relative functionality of Rema fluid and rubber cement, but qualitatively, the rubber cement just works.

woodcraft

To make this a really classic thread, they should be lit on fire while on the bike.


Kudos for the inquiry.

RPK79

Subscribed.

johnny99

8 ounce bottles of tire patch glue are a few dollars in auto parts stores

wphamilton

Durability of the bond may differ. I've worried about this also since I know that the majority of my patches have used "rubber cement" and not "vulcanizing fluid".

You're the chemist, so is this true: rubber cement is non-vulcanized rubber mixed up in a volatile solvent. After the solvent evaporates, the uncured rubber left over is malleable and sticky. Vulcanizing fluid also has curatives to vulcanize the rubber - in the polymer links. Sulfur, metal oxides etc. So in theory, there is a chemical difference, right?

I'd be interested if you purchased some explicitly labeled "Vulcanizing Fluid" and repeat the test. See what it takes to pull the patch off. How does it respond to heating from a heat gun?

nycphotography

I have run out of patches. Where can I get "quality patches in bulk"??

(Seriously, I am ready to order asap, as I need to glue one inside a tubeless tire that won't seal).

RPK79

Amazon. I bought a pack of 48 patches back in 2014 for $2.39 from China that I'm still working on.

https://www.amazon.com/Joylive-Bicyc...395W5T8TT7K00E

Looks like they've gone up in price.

WhyFi

datlas 

Use google to find cheapest source for Rema patches, I bought 100 a couple years ago. I think the Rema patches may be better than generic ones.

drewguy

Same. Useful question to try to answer.

I've been using rubber cement, as I ran out of the included glue. Hasn't been a problem . . . yet.

rpenmanparker 

I don't think there could be curstives already in the fluid. If those chemicals were in the fluid, they would react with the uncured natural rubber in the fluid and harden it. What would keep that from happening? Basically the idea is a non-starter. I'm telling you that vulcanizing fluid is just rubber cement, period.