Air2gxs From , joined Dec 1969, posts, RR:
Reply 1, posted (8 years 9 months 4 weeks 1 hour ago) and read 2058 times:
Chances are that all the usable components have already been taken off and sent to be overhauled or checked out. All that would be left is structure, skin, tubing and wiring.
Why would coke cans be a myth? The metal is recycled and may in fact be used in the production of other machines. Is it used to manufacture other aircraft? I don't know, but the stuff is recycled.
Using the scrap as material, without processing, to build other airplanes? I doubt it. Remember this metal, and I'm talking skin, has holes in it, probably has some kind of curve to it, and may be damaged. Too much risk and rework involved.
The structural components (beams, spars, ribs, stringers, etc.) are designed for the aircraft. You would have to design an aircraft around the existing dimensions and then pray that enough aircraft are scrapped to meet your production needs. Or you can build your own unique aircraft.
MrChips From Canada, joined Mar 2005, 926 posts, RR: 0
Reply 2, posted (8 years 9 months 4 weeks ago) and read 2052 times:
Quoting Leezyjet (Thread starter): Surely it could be x-rayed or ultra sound scanned or what ever to check for any stress fractures or other weaknesses before it is re-used.
I just thought that it seemed such a waste that all this a/c grade metal is junked and then new metal produced - it must be a huge waste of the earth's resources.
It would be nice to reuse metal like that, but unfortunately it is not possible. You see, a piece of metal is made up of many small crystals...over time, these crystals of metal degrade - corrosion. No matter how hard you try and prevent corrosion, it will happen eventually.
By melting and reprocessing the metal, you renew these crystalline structures. Theoretically, the metal should be useable for just about anything, as long as the final alloy is suitable for the application.
As for the second paragraph, creating "new" aluminum from bauxite (aluminium ore) is many orders of magnitude more costly, in terms of both money and energy, than simply reprocessing scrap aluminum.
DALMD88 From United States of America, joined Jul 2000, 2507 posts, RR: 14
Reply 3, posted (8 years 9 months 3 weeks 5 days 8 hours ago) and read 1961 times:
Why is the coke can thing a myth? Soda and beer cans only use virgin AL. I also think it is almost pure with no alloy elements. All aircraft AL is alloy. When the plane gets scrapped the metal does get recycled.
Jetstar From United States of America, joined May 2003, 1616 posts, RR: 10
Reply 4, posted (8 years 9 months 3 weeks 5 days 5 hours ago) and read 1926 times:
Scrapped aircraft aluminum cannot be used in the manufacture of new aircraft. The FAA requires that only virgin aluminum be used.
This is because when recycling the aluminum at the smelter, it can be contaminated with other metals or chemicals that can affect the strength or corrosion properties of aluminum.
When aircraft are scrapped, all the aircraft parts go into a smelter furnace, aluminum melts at around 1200 degrees and all the paint, chemicals and plastic parts are burned up, but some traces can be left in the aluminum. Metal or steel parts melt at a higher temperature and they remain intact and are caught in a filter as the molten aluminum passes through.
Scrapped aircraft aluminum is recycled into other items. FYI, aluminum cans are the highest value of all the items placed in the residential recycling bins.
VSIVARIES From United Kingdom, joined Aug 2004, 108 posts, RR: 4
Reply 6, posted (8 years 9 months 3 weeks 5 days 3 hours ago) and read 1918 times:
Recycling has it place and purpose and hats off to all of those 'green' people.
If you were making a rubbish bin or some other non performance item then fair enough, but hell, even if I manufactured fishing rods (as an engineering designer) I would still insist upon the very finest raw materials - assuming you want to make a first class product.
I cannot see the rationale for any sane aircraft designer to wish to use second rate raw ingredients to their design given all the uncertainties that surround re-smelted Al.
Considering that 10's of 1000's of souls will trust their lives in the design of your AC the designer should have the right and choice to pick the very finest materials. - Never mind any of this recycled crap - why take the risk for and few dollars on construction. Sorry - stupid post in my opinion.
And before you go to guns on me yes I am head of a department that does mass volume product design - (and materials technology) for a living. We make about half a million consumer appliances per year and are not in the business of taking risks.
For every action there is always an unequal but mostly similar reaction.
MD11Engineer From Germany, joined Oct 2003, 13815 posts, RR: 63
Reply 9, posted (8 years 9 months 3 weeks 4 days 10 hours ago) and read 1827 times:
Even for use in beer cans the aluminium has to be smelted and refined. Aluminium for food applications has to be pure, the alloys used in aircraft contain copper and zinc. Duraluminium contains cadmium, also not permissible in food containers.
The scrap aluminium gets molten down together with fresh aluminium, purified and then realloyed for the specific use. So it is quite likely that e.g. a new Airbus contains aluminium from a WW2 plane. During WW2 both Britain and Germany salvaged shot down enemy planes for recycling in the aluminium factories. Talking about virgin aluminium is cr@p. If a piece of sheetmetal from the factory fulfills the specifications for it's particular alloy (composition, strength), it doesn't matter if it came straight out of bauxite or out of scrap.
MD11Engineer From Germany, joined Oct 2003, 13815 posts, RR: 63
Reply 11, posted (8 years 9 months 3 weeks 4 days 6 hours ago) and read 1800 times:
Hawk, I´m not talking about taking a piece of sheetmetal from an old plane and to bash it into shape to nail it on another plane. I'm talking about shredding the metal and sending it back to an aluminium factory, where it will be molten in a furnace with fresh aluminium. Then, after having been alloyed to specs, it wil be cast into bars and rolled to factory new sheet metal. Do you really think all aircraft aluminium is fresh metal just made out of bauxite?
HAWK21M From India, joined Jan 2001, 31580 posts, RR: 57
Reply 14, posted (8 years 9 months 3 weeks 3 days 10 hours ago) and read 1733 times:
Quoting Leezyjet (Reply 13): So not really a stupid post after all. The only way people can learn is to ask questions, surely you have asked loads in your lifetime - does that make you stupid too
Like my Old Professor once said.If you have a question which may seem the most foolish,go ahead & ask it.And the End you'd now the Answer which many may not
Go Ahead and Ask questions.I know I've learnt a lot out here.
If it were not for questions there would never be a Discussion forum.
In A net you'd encounter the odd person,who would remind you that you said the same thing differently or asked a stupid question or this was discussed before.Just dont give it a thought.
Lightsaber From United States of America, joined Jan 2005, 12444 posts, RR: 100
Reply 15, posted (8 years 9 months 3 weeks 3 days 1 hour ago) and read 1705 times:
Quoting Leezyjet (Thread starter): Surely it could be x-rayed or ultra sound scanned or what ever to check for any stress fractures or other weaknesses before it is re-used
The pieces have to be rebent from an odd selection of part sizes. What if there is a rivet hole where one needs a solid piece of metal? Also, new alloys of aluminum have better fatigue life, etc. So that the airframe could be lighter and possibly cheaper with virgin material.
Overall, one needs a very detailed pedigree on any flying part. By law one needs to have the following documentation on a part:
1. The "heat" batch from the foundry when the raw stock was made.
2. Chemical analysis of that heat.
3. Tensile strength test of that heat
It would cost more in paper to reform an existing part than to make virgin material. Recall that when an airframe is scrapped so are 2 or 3 18-wheelers full of paperwork!
Nope. The #1 use of aluminum is beverage containers. The joke is old airframes become beer cans at end of life.
Quoting Jetstar (Reply 4): Scrapped aircraft aluminum cannot be used in the manufacture of new aircraft. The FAA requires that only virgin aluminum be used.
True. Every piece of aluminum has a cycle life. Also note the need for pedigree.
Quoting Leezyjet (Reply 13): I just though that the metal could be cut down into sections that could be re-worked to make new a/c, but thanks to the replies here, then I realize it wouldn't be possible.
Any non-experimental aircraft requires the pedigree on the materials. And experimental aircraft cannot carry passengers for hire.
Quoting HAWK21M (Reply 14): If it were not for questions there would never be a Discussion forum.
here here. Good question. Its a fair question to ask.