Environmental impact of frame materials

[winjim]

Does anyone know the environmental impact of the various frame materials out there? Can carbon fibre be recycled? I have chosen a Ti frame thinking that it is probably easier to recycle than CF at the end of its life, but I understand that Ti is pretty difficult stuff to get out of the ground in the first place so am I barking up the wrong tree?

Obviously second hand is better for the environment, which my new frame is.

 

[Drago]

Ali takes a phenomenal amount of power to extract and refine.

 

[AndyRM]

Recycling CF is doable, but a pain in the arse due to all the different compositions and resins used.

Bike Radar had a good article about the issue a few years ago, don't recall reading anything more recently.

 

[Yellow Saddle]

According to JE Brown's absolutely brilliant Structures and Why Things Down Fall down, carbon fibre requires about 100 times (IIRC) the energy to create than the equivalent-in-strength piece of steel. And it is not recycled, although probably recycleable if you can find an innovative way of re-using an inseparable matrix of resin and carbon.

The book was written many years ago so things may have changed. I think a google search will bring up a table of the energy requirements of many manufacturing materials, but it is worth getting the book in anyway. Any serious arm-chair engineer/mechanic should read this one.

Titanium oxide is plentiful, probably one of the most plentiful minerals we have. However separating the metal from the oxide requires a lot of megawatts. Once it is extracted, re-melting it is no more of an issue than steel or aluminium. The problem is that titanium is not separated for recycling and just falls into the aluminium bin, I guess.

 

[raleighnut]

When melting scrap aluminium anything that doesn't melt is scraped off the surface or out of the bottom of the pot (crucible) and the dross (technical foundry term, that's where the word comes from) is just normally chucked in the skip. I've melted hundreds of tons of the stuff when I worked in non-ferrous foundries.
Aluminium and Iron (steel) can be re-cycled indefinitely.

 

[Yellow Saddle]

When melting scrap aluminium anything that doesn't melt is scraped off the surface or out of the bottom of the pot (crucible) and the dross (technical foundry term, that's where the word comes from) is just normally chucked in the skip. I've melted hundreds of tons of the stuff when I worked in non-ferrous foundries.
Aluminium and Iron (steel) can be re-cycled indefinitely.

I've often wondered about the melting pot at recycling foundries. What happens to the steel or titanium or copper in the aluminium pot? Can the metallurgist separate it for re-use or is it all chucked? Oh yes, and you say alu can me reused indefinitely but I've heard otherwise. Is there a rider to "indefinitely"?

 

[raleighnut]

I've often wondered about the melting pot at recycling foundries. What happens to the steel or titanium or copper in the aluminium pot? Can the metallurgist separate it for re-use or is it all chucked? Oh yes, and you say alu can me reused indefinitely but I've heard otherwise. Is there a rider to "indefinitely"?

No there is no 'rider' to aluminium being recycled however precision components must be made of the specified alloy (e.g LM 25 is a general casting alloy and 6061/7005 are alloys used for frame construction none of these are 'pure' Aluminium)
Each of these alloys (of Aluminium) must be mixed with the correct amount of other metals to achieve the correct properties for their intended use, that's where the metallurgist comes in.
Most of the scrap Aluminium I used was for making working patterns from the wooden 'Master Pattern' (very expensive and liable to damage in daily use) but I also made engineering components mainly in LM's 4, 6, 10 and 25 each of which has different characteristics.
Scrap metal is broken up (pulverised) and sorted by magnetism, Aluminium does a very strange thing when passed over a magnetic coil, it flies away. (I'll see if I can find owt on Google.)
EDIT this explains the process.
http://www.google.co.uk/url?sa=t&rc...PF0lIWn5caOttvmgUDnT-ow&bvm=bv.96783405,d.d24

 

[winjim]

Seems like my pre-owned Ti is the way to go, then . Do they site Ti extraction plants near hydroelectric dams, same as with bauxite?

 

[Yellow Saddle]

No there is no 'rider' to aluminium being recycled however precision components must be made of the specified alloy (e.g LM 25 is a general casting alloy and 6061/7005 are alloys used for frame construction none of these are 'pure' Aluminium)
Each of these alloys (of Aluminium) must be mixed with the correct amount of other metals to achieve the correct properties for their intended use, that's where the metallurgist comes in.
Most of the scrap Aluminium I used was for making working patterns from the wooden 'Master Pattern' (very expensive and liable to damage in daily use) but I also made engineering components mainly in LM's 4, 6, 10 and 25 each of which has different characteristics.
Scrap metal is broken up (pulverised) and sorted by magnetism, Aluminium does a very strange thing when passed over a magnetic coil, it flies away. (I'll see if I can find owt on Google.)
EDIT this explains the process.
http://www.google.co.uk/url?sa=t&rct=j&q=&esrc=s&source=web&cd=5&cad=rja&uact=8&ved=0CEMQFjAE&url=http://www.aluminiumindustry.org/en/sorting-aluminium-alloy.html&ei=Vl6RVZG3L4qyUcLSqsgG&usg=AFQjCNHXUEbPF0lIWn5caOttvmgUDnT-ow&bvm=bv.96783405,d.d24

Thanks for the link. I think I now understand the problem with re-re-recycling aluminium. Eventually it is so contaminated with silicon that it can no longer be used for wrought aluminium (cans and the like) but only for casting aluminium (your moulds). Therefore virgin aluminium goes to cans and contaminated alu to cast products.

From the article linked above: "In recycling of aluminium, the problem arises that more often than not so called cast alloys of high silicon content are inevitably remelted together with wrought alloys. The mixture obtained in this way can only be used as base material for cast alloys."

It appears as if the recycled alu is continually downgraded.

 

[raleighnut]

Thanks for the link. I think I now understand the problem with re-re-recycling aluminium. Eventually it is so contaminated with silicon that it can no longer be used for wrought aluminium (cans and the like) but only for casting aluminium (your moulds). Therefore virgin aluminium goes to cans and contaminated alu to cast products.

From the article linked above: "In recycling of aluminium, the problem arises that more often than not so called cast alloys of high silicon content are inevitably remelted together with wrought alloys. The mixture obtained in this way can only be used as base material for cast alloys."

It appears as if the recycled alu is continually downgraded.

Far more Aluminium is used in castings these days (whether traditionally sand cast or increasingly die-cast) so it makes sense to re-use it as opposed to using freshly mined Bauxite as the raw ingredient even though it is the 3rd most common element on Earth.
http://www.google.co.uk/url?sa=t&rc...qxmWe3Wd7mQPymbXCpRzu8Q&bvm=bv.96783405,d.bGQ

 

[Yellow Saddle]

Seems like my pre-owned Ti is the way to go, then . Do they site Ti extraction plants near hydroelectric dams, same as with bauxite?

You really want that Ti frame, don't you?

OK then, Ti extraction plants are always located near hydro generators and the process is so green that they have a hard time keeping the undergrowth at bay in those factories.

If I insert real smileys I'll ruin my reputation but please consider this as a friendly comment. I like it when people are enthusiastic about stuff. I wish I was like that.

I just don't get the Ti-mania thing though. It started, as far as I can see, back in the 1980s with Gasnost. Remember Gorbachov and Reagan? They agreed to melt down the missiles and then symbolically played a round of golf using drivers supposedly made from recycled missiles. That launched Ti mania. It also heralded the metal's entry into the consumer realm, previously it was a kinda strategic metal consumed (or horded, depending on your conspiracy outlook) by the military and us civilians weren't supposed to have it. The Japanese watch company Citizen made a diving watch from Ti and it was an instant hit. The bicycle industry took a cue from golf and for a while, every high end frame manufacturer had a Ti model. Colnago was so obsessed, it created a frame with a double down-tube made from the precious stuff. It developed a fierce reputation as a military grade, super duper metal and in consumer goods it was always presented naked, never painted. But paint could be Ti-coloured though and suddenly silver paint was passé, it was Titanium. Even Platinum stood back.
Doctors liked it because it didn't rust and bone would fuse into the porous metal. They used it in structural implants and of course, as screw-in bases for false teeth.
Hydroformed aluminium came along and blew Ti out of the water with looks, weight and durability. There was no single good reason for spec'ing a bike with Ti, yet consumers would have none of it. Ti it had to be.
Ti is difficult to weld (reliably) and machine and to the untrained eye, looks like aluminium.

I do admit that Ti welding is beautiful. But I cannot fathom why anyone would specify jewellery made from the stuff. It is so boring and dull.

I do hope you like your ozone-friendly low-carb frame though. Post a pic.

 

[winjim]

You really want that Ti frame, don't you?

OK then, Ti extraction plants are always located near hydro generators and the process is so green that they have a hard time keeping the undergrowth at bay in those factories.

If I insert real smileys I'll ruin my reputation but please consider this as a friendly comment. I like it when people are enthusiastic about stuff. I wish I was like that.

I just don't get the Ti-mania thing though. It started, as far as I can see, back in the 1980s with Gasnost. Remember Gorbachov and Reagan? They agreed to melt down the missiles and then symbolically played a round of golf using drivers supposedly made from recycled missiles. That launched Ti mania. It also heralded the metal's entry into the consumer realm, previously it was a kinda strategic metal consumed (or horded, depending on your conspiracy outlook) by the military and us civilians weren't supposed to have it. The Japanese watch company Citizen made a diving watch from Ti and it was an instant hit. The bicycle industry took a cue from golf and for a while, every high end frame manufacturer had a Ti model. Colnago was so obsessed, it created a frame with a double down-tube made from the precious stuff. It developed a fierce reputation as a military grade, super duper metal and in consumer goods it was always presented naked, never painted. But paint could be Ti-coloured though and suddenly silver paint was passé, it was Titanium. Even Platinum stood back.
Doctors liked it because it didn't rust and bone would fuse into the porous metal. They used it in structural implants and of course, as screw-in bases for false teeth.
Hydroformed aluminium came along and blew Ti out of the water with looks, weight and durability. There was no single good reason for spec'ing a bike with Ti, yet consumers would have none of it. Ti it had to be.
Ti is difficult to weld (reliably) and machine and to the untrained eye, looks like aluminium.

I do admit that Ti welding is beautiful. But I cannot fathom why anyone would specify jewellery made from the stuff. It is so boring and dull.

I do hope you like your ozone-friendly low-carb frame though. Post a pic.

I am genuinely interested, not just trying to justify a purchasing decision. I had a little cash to spend and this was my last chance to buy something for myself before the baby arrives and all my money has to go into the university fund. How better to react to impending fatherhood than to build a sick racing bike? I wanted something a bit special and exotic, and something I could build myself. Second hand frameset means I don't feel too guilty about buying something I want rather than need. If I can pretend it's made out of cold war missiles that's even better.

There's a pic of the frame over in the Show Us Your... thread. I'll post more once I've built it up but deity knows when I'll get the time.

Keep the environmental / metallurgical discussion going though, I am interested.

 

[Yellow Saddle]

I am genuinely interested, not just trying to justify a purchasing decision. I had a little cash to spend and this was my last chance to buy something for myself before the baby arrives and all my money has to go into the university fund. How better to react to impending fatherhood than to build a sick racing bike? I wanted something a bit special and exotic, and something I could build myself. Second hand frameset means I don't feel too guilty about buying something I want rather than need. If I can pretend it's made out of cold war missiles that's even better.

There's a pic of the frame over in the Show Us Your... thread. I'll post more once I've built it up but deity knows when I'll get the time.

Keep the environmental / metallurgical discussion going though, I am interested.

You forgot about the ultimate justification. The frame will last long enough to be inherited by the incumbent winjim. It is an investment, therefore.

 

[winjim]

You forgot about the ultimate justification. The frame will last long enough to be inherited by the incumbent winjim. It is an investment, therefore.

Indeed, I am hoping that all I've read about the longevity of Ti frames turns out to be true.

 

[PhilDawson8270]

I cannot fathom why anyone would specify jewellery made from the stuff. It is so boring and dull.

I have a Ti ring.

Not through beauty of aesthetics, but as an Engineer. Titanium is beautiful as an engineering material, which has more interest to me than generic gold.