thexman

This is probably old news to many of you, but I recently learned that Lotus apparently glues their frames together, instead of welding:

https://www.autofieldguide.com/articles/040408.html

It's supposed to increase strength/save material by not significantly heating up the metal. The article also says gluing spreads out the stress more than welding.

Have any of you tried this for bike frames? It seems like it would have interesting results.

vinfix

I don't usually visit this sub-forum, but this caught my attention. Alan frames were "screwed and glued", they were doing that 30 years ago. I had one for 25 years, no problems, though I've heard frames that worked hard might de-bond. Vitus is another one- I ride one now.

Bianchigirll 

"back in the day" (as they say) almost everyone who made Aluminum frames (at least the ones not rebranding Alans) were as the previous poster says glued and screwed. also most of all the early carbon bike were made this way as well. cannondale was welding but that was partly because of the diameter of the tubes they used were not compatible with luggs available.

the term 'glued and screwed' did not exactly mean that the tube were "screwed" together but (atleast as I was told) that the tube had a few grooves around it's circumfrence to help retain adhesive while being pressed into the lugg.

one evening while out on a ride in the early '90s a customer of mine had the seat tube of his Geurcrotti pop out of the BB shell.

jgedwa

Some screwed and glued Al frames are actually screwed though. Miyata Elevation MTB's, for example have the tubes glued into lugs and then a bolt through the whole for good measure.

jim

NoReg

Not that i have anything against epoxy, spent most of the last month bonding stuff in my boat with it. But whatever someone says about a process, you have to check the fine print:

"Realizing that no mass-production operation can afford the Elise's 50-minute curing time (nor would it wish to incur the expense of multiple ovens), Lotus is replacing the heat-cured single part epoxy adhesive used on the sports car, which required temperatures of 180ºC, with one that will cure in the lower heat of the paint oven."

Those are some pretty pathetic limitations to asume in your process. I build stuff in my garage and have a curring oven that heats to 180F (3 x 100 watt lightbulbs), and the cure takes 4 hours. Now at their level they probably don't have a problem curing in their paint oven. But spare me if I don't get all goose pimply over what they are doing. This is a classic pros against joes issue. I would never want to go into the ring with a pro boxer, but often in the crafts there can be an edge for an amateur with a lot of time to waste, though no hope against Lotus. One comon example is when pros can't source materials at the scale of their production, while a Joe can get just about anything on a small scale.

cs1

Once the glue cures can it be reheated? I ask because I wanted to powder coat an old Raleigh Technium frame. I'm a little leary of the 375 deg heat though. So, I passed on doing it.