icemilkcoffee 

That would be ALAN- the tubing and the lugs are threaded and the tubing screws into the lugs. TVT & Look just have plain glue joints if I understand correctly.

icemilkcoffee 

You bring up a good point. Some components will still have to be brazed on. But typically these don't require as much precision. So even a sloppy welder without professional fixtures can still braze these things on.
The big problem with the frame itself is that the alignment has to be spot on. I've never done brazing, but I've done some welding, and the act of welding throws enough heat into the material that everything is distorted to heck. Also, the weld itself will shrink back as it cools, ruining whatever alignment you thought you had.

genejockey 

Look at the lugs on something the Alan aluminum frames - MUCH more surface area than in the usual steel lugs.

rosefarts

I definitely see where you are coming from. And to a certain degree, industry has followed, just not the bike industry.

Seems like most new plumbing is PVC. Glue it up, no more heating and soldering.

Even a lot of copper is now crimped with a new type of joint.

If you want to get into frame building without the heat, seems like bamboo is the way to go. Especially from a diy in the garage type of situation.

CliffordK

Did you miss a couple of decades? I thought PEX was the big thing in plumbing.

Soldering copper usually isn't much of a problem, and the tools can be cheap.

Galvanized can be a bit more of a pain to work with, and be careful with the copper to galvanized joint.

LarrySellerz

I bet the reason isn’t that its particularly difficult, just more difficult that brazing and welding. The reason those other frames are glued is because brazing and welding those materials isn’t trivial.

i want to push back on your assumption that a layperson would be more equiped to glue a frame together than weld it. The epoxy might need mechanical mixing, probably needs degassing or centrifuging etc. it would be an operation, not arts and crafts with elmers glue.

Someone selling a DIY kit has to be sure they won’t end up killing someone too right. I glued together an aluminum frame that cracked on me and it didn’t work at all lol, but that’s not really related.

wolfchild

Unibody frames are spot welded together with thousands of spot welds and not glued.

rosefarts

Weird flex bro

I’m not a plumber. Just saying what I’ve seen around. Doesn’t really change my point though.

Trakhak

The OP was probably asking whether glue could be used in place of brazing material to build a steel frame by the use of conventional steel lugs and frame tubes, i.e., lugs and tubes that were designed to be brazed together. Short answer is no---not using off-the-shelf tubes and lugs. Too little surface area for a strong bond, among other roadblocks.

But, as noted earlier in the thread, Raleigh used their Technium process to build at least a few frames with Reynolds 753 tubes inserted over and glued to fairly long internal steel "lugs." So it can be done.

Bit of Technium trivia, told to me by our shop's Raleigh sales rep: Raleigh USA built their factory in Kent, Washington, near the Boeing factory, expressly to make it easy to recruit Boeing aerospace engineers, who were, of course, fully up to date on design considerations for glued-together, highly stressed structures.

The Raleigh dealership where I worked sold a lot of Technium bikes. I don't remember ever seeing a Technium bike with a failure of a glued joint, though it's possible, maybe through inadvertent contamination during the joining process.

By the way, I'd love to know the real story of why Huffy eventually decided to pull out of the business of selling Raleigh USA bikes to bike shops. Could be that the volatility of that market and the head start of their main competitors in that market turned out to make that market segment be too much trouble to bother with, Selling exactly the same lowest-of-low-end Huffy bikes to department stores, year after year after year, must have seemed a much more reliable business---at least, until they began to be undercut by even cheaper bikes from Taiwan and mainland China.

maddog34

The ALAN is the most famous "screwed and glued" frame... i have one... it's fine... some came loose early on in life... the rumor is "if it made it this far, it will be fine!" ... no clunky lugs on mine... yet.

Atlas Shrugged

Or carbon has made this redundant. Development of steel technology within cycling is pretty well at a dead end and has been replaced by Carbon which by all indications still has a way to go. Take a Specialized Aethos a mass production bicycle frame under 600 grams and reliable as any other.

rollagain

I owned a Raleigh Technium once, bought used; it had aluminum tubes glued into steel lugs--or maybe not glued; a quick search claims they were thermally bonded. Either way, it was a sweet ride.

rollagain

All the equipment you need is some flux, some appropriate brazing rod, and a common propane torch. If you want to try it, find some scrap parts and go look for instructional videos on youtube. It isn't hard.

zandoval 

Easy Answer: Cause it is so easy to Braze or Silver Solder steel to steel frames. And in many ways its forgiving too as you can un-brase and adjust the frame if needed.

As far as using adhesive?

Hey Man... It's just an engineering problem. And most likely solved with off the shelf adhesives too...

tcs

Hmm. Maybe MAPP gas rather than propane. From Lugged Bicycle Frame Construction, A Manual by Marc-Andre Chimonas:



The 3D printing community has 'discovered' that if you take a design in steel or aluminum or even zinc and reproduce it directly in printed plastic, it often fails, but, and it's a big but, if you consider the function of the part and redesign considering the material properties of 3D printed plastic, it can work just fine. As several others have pointed out upthread, same thing applies in this inquiry: redesign the lug/tube interface for adhesive bonding.

rosefarts

Carbon is here to stay. Even on our best steel examples, like a 5.5kg Rodriguez, it’s pretty much all carbon but the frame. It’s an amazing material. I ride steel frames, other than my vintage stuff, there’s lots of carbon fiber parts.

I’d love to see a better system in place for recycling it and fiberglass. Between the auto industry, aviation, wind power, and bikes, it sure would be nice to figure out something to do with those broken parts. That’s my only complaint with carbon fiber.

Then there’s this older article

https://bikerumor.com/thyssenkrupp-s...tweight-steel/

Its been 4 years. I haven’t heard anything else. Meanwhile carbon is getting more cost effective. Still holding my breath for a monocoque stamped steel aero road frame. Material properties being what they are, it’s already lost to carbon.

Jeff Neese

It's not a dead end. It's called "fully mature and time-tested."

smd4

Exactly. It's like saying wood is a dead-end for guitar production.

Atlas Shrugged

As was the rotary dial telephone mounted in the kitchen.

unterhausen

Once you start gluing, I would think moving on to titanium or carbon tubes would be a natural next step. And you can do that. But the problem is nobody is going to sell you the lugs if you aren't a framebuilder. 3d printed lugs are still pretty expensive.

nomadmax 

I had three Technium frames come unglued on my work bikes. And another that snapped at the down tube (none were involved in crashes prior to the failures, the DT snapping DID cause a hellofa crash). Since then, the only thing I want "glued" is a tube patch.

zandoval 

Yep... And that too is just an engineering problem. I hope soon that those special mediums and carbon/hydrocarbon materials that you could print with finally get released to the public. Like the Nano-Carbon composite filament that prints at 200°C and then continues to harden over the next 48 hours to become as hard as steel and lighter then aluinum.

So why is it an engineering problem and not a chemist or functional materials problem?

Cause the engineer never forgets... Its the ride... Its all about the ride... Ha

zandoval 

Yikes... Bat Man!

nomadmax 

The top tube snapped a nano second after the down tube went. To say I'm not a fan of only xxx of them have failed is an understatement. For me, it was 100%.

rollagain

Sure, and I forgot about that, but my torch (Ace Hardware brand, IIRC) burns either one, and I have it on a MAPP cylinder now. Ultimately, both fuels do the job equally well; the MAPP will just save you a little time.