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> “The problem is that glue is not a mechanical fastener, [and it] can deteriorate over time,” he tells CityLab. Current materials can rust or rot over time. W

> “The problem is that glue is not a mechanical fastener, [and it] can deteriorate over time,” he tells CityLab. Current materials can rust or rot over time. Water can get in places and cause failures[1]. The problem, in my uneducated-on-the-topic mind, is that glue seems more likely to fail all at once or exhibit a cascade failure than mechanical fasteners. [1] - http://www.mercurynews.com/bay-area-news/ci_28329832/berkeley-deck-collapse-irish-consulate-prepares-arrival-grieving http://www.mercurynews.com/bay-area-news/ci_28329832/berkele...

bufordsharkley 11y ago
Yes, glue (at least current glues) are brittle. Failures with ductile materials are preferable (which is why we see rebar inside concrete, for instance)
- monk_e_boy 11y ago
  You can put carbon fibre into glue. We make epoxy kiteboards and hydrofoils. Very very light, very strange shapes.
  - kazinator 11y ago
    Some glues are flexible. Certain epoxies can be mixed in a range from 2:1 to 1:1, giving a range of flexibilities. Epoxy can also be combined with rubber.
- jdietrich 11y ago
  Many adhesives are extremely ductile, the obvious example being silicones.
msandford 11y ago
There's a lot to be said for a mechanical interference that prevents two things from moving relative to one another. Like say a bolt, in shear (or a pin). Better still is a bolt that exerts clamp force, thus leaving it far, far less in shear. Bolts are amazing and I can't see why people think glue is better. Welding is better, sure, but it's also a lot more permanent. EDIT: I get why people like glue for things like carbon fiber bikes, etc because weight is an issue and you can't really bolt it. But for buildings? That's a different use case.
- monk_e_boy 11y ago
  > I can't see why people think glue is better It's cheaper. And you can glue wibbly shaped bits together easier than bolting.
- JoBrad 11y ago
  I can't speak for other materials, but for wood, a properly glued joint is far superior to fasteners. The glue combines the wood at the molecular level, so that the two pieces are one. There are similar glues for plastics, too. I don't know about metal and mortar, but if such a thing exists, using it would be much better than bolts or screws. The one drawback is that, if you have to replace a portion of a structure that is glued, the process is necessarily destructive. You can limit the destruction, but you still have to cut the old piece out. It doesn't seem like this would generally be a problem with buildings, though, as almost every type of renovation is destructive.
  - Tyr42 11y ago
    Welding?
- WalterBright 11y ago
  Mechanical fasteners are easily inspected. Welded and glued joints, not so much.
- Scuds 11y ago
  Modern cars use structural adhesive to eliminate excess weight. http://www.repairerdrivennews.com/2015/10/23/gm-spotlights-structural-adhesives-for-collision-repairers-gives-sample-joining-how-to/ http://www.repairerdrivennews.com/2015/10/23/gm-spotlights-s...
ethagknight 11y ago
We already use glue extensively in glue lam products, basically huge beams that are a bunch of small wooden beams glued together. No reason that we couldn't glue the connections together as well.
DrScump 11y ago
A far more costly (and frightening) example is the Eastern Span of the SF Bay Bridge, e.g. http://www.latimes.com/local/lanow/la-me-ln-bay-bridge-report-20140123-story.html http://www.latimes.com/local/lanow/la-me-ln-bay-bridge-repor... http://www.nbcbayarea.com/news/local/Caltrans-Allowed-Bad-Welds-in-New-Bay-Bridge-Report-Says-241598471.html http://www.nbcbayarea.com/news/local/Caltrans-Allowed-Bad-We... And things are known to be even worse than these older stories imply. I couldn't find a good, concise summary of the problems, costs, and long-term effects.

bufordsharkley 11y ago

Yes, glue (at least current glues) are brittle. Failures with ductile materials are preferable (which is why we see rebar inside concrete, for instance)

monk_e_boy 11y ago
You can put carbon fibre into glue. We make epoxy kiteboards and hydrofoils. Very very light, very strange shapes.
- kazinator 11y ago
  Some glues are flexible. Certain epoxies can be mixed in a range from 2:1 to 1:1, giving a range of flexibilities. Epoxy can also be combined with rubber.
jdietrich 11y ago
Many adhesives are extremely ductile, the obvious example being silicones.

msandford 11y ago

There's a lot to be said for a mechanical interference that prevents two things from moving relative to one another. Like say a bolt, in shear (or a pin). Better still is a bolt that exerts clamp force, thus leaving it far, far less in shear. Bolts are amazing and I can't see why people think glue is better. Welding is better, sure, but it's also a lot more permanent. EDIT: I get why people like glue for things like carbon fiber bikes, etc because weight is an issue and you can't really bolt it. But for buildings? That's a different use case.

monk_e_boy 11y ago
> I can't see why people think glue is better It's cheaper. And you can glue wibbly shaped bits together easier than bolting.
JoBrad 11y ago
I can't speak for other materials, but for wood, a properly glued joint is far superior to fasteners. The glue combines the wood at the molecular level, so that the two pieces are one. There are similar glues for plastics, too. I don't know about metal and mortar, but if such a thing exists, using it would be much better than bolts or screws. The one drawback is that, if you have to replace a portion of a structure that is glued, the process is necessarily destructive. You can limit the destruction, but you still have to cut the old piece out. It doesn't seem like this would generally be a problem with buildings, though, as almost every type of renovation is destructive.
- Tyr42 11y ago
  Welding?
WalterBright 11y ago
Mechanical fasteners are easily inspected. Welded and glued joints, not so much.
Scuds 11y ago
Modern cars use structural adhesive to eliminate excess weight. http://www.repairerdrivennews.com/2015/10/23/gm-spotlights-structural-adhesives-for-collision-repairers-gives-sample-joining-how-to/ http://www.repairerdrivennews.com/2015/10/23/gm-spotlights-s...

ethagknight 11y ago

We already use glue extensively in glue lam products, basically huge beams that are a bunch of small wooden beams glued together. No reason that we couldn't glue the connections together as well.

DrScump 11y ago

A far more costly (and frightening) example is the Eastern Span of the SF Bay Bridge, e.g. http://www.latimes.com/local/lanow/la-me-ln-bay-bridge-report-20140123-story.html http://www.latimes.com/local/lanow/la-me-ln-bay-bridge-repor... http://www.nbcbayarea.com/news/local/Caltrans-Allowed-Bad-Welds-in-New-Bay-Bridge-Report-Says-241598471.html http://www.nbcbayarea.com/news/local/Caltrans-Allowed-Bad-We... And things are known to be even worse than these older stories imply. I couldn't find a good, concise summary of the problems, costs, and long-term effects.