False advertising thread

Y'ever see ads claiming "aircraft grade" aluminum? Cars, motorcycles, guitar bridges, etc. BULL{censored}! There is no such thing as aircraft grade aluminum. Metal is metal. I do aircraft sheetmetal work for a living. Parts on aircraft have to meet FAA standards, but the aluminum we get is the same thing anyone can get at the local metal supplier. So next time you see that claim in an ad, remember that they're tugging your chain.

so you do regular metalwork for a living then. haha. ive always wondered about that. thanks for clearing the air about that.

Well, there's definitely a lot of BS floating around when people make impressive sounding claims like "aircraft grade aluminum". However, there definitely are different types of aluminum, and some of them would not be suitable for aircraft structural components or skin. For example, the magnesium and silicon alloys (the 6xxx series) are easy to extrude, so they're great for window frames and such, but they crack easily when flexed so you wouldn't want to make a bulkhead out of it.

The copper alloys (2xxx series) and zinc alloys (7xxx series) are often quoted as "aircraft grade". However, I've never seen anyone use the term "aircraft grade", and then back it up by telling you which particular alloy they used. I disregard all of that marketing hype. If a manufacturer has to tell an electrical engineer what kind of aluminum his capacitors are made from, it makes me wonder if it's not because the electrical characteristics of his capacitors are nothing to brag about.

6061 is widely used for construction of aircraft structures, such as wings and fuselages, more commonly in homebuilt aircraft than commercial or military aircraft

http://en.wikipedia.org/wiki/6061_aluminum

In the environmental test world of shock simulation we regularly use 6061 aluminum for it's dynamic properties. Test fixtures made of 6061 have a good ringing quality in the acoustic frequency range. While it's ringing property is particularly useful in designing shock fixtures it's a problem for vibration test fixtures. If I was looking for a metal to use for a guitar bridge or tailpiece I'd probably go with 6061.

I recently read about a pilot who did some kind of acrobatic maneuver in a 747 (I think) and they mentioned that the wings were bent up about 3 inches after the stunt. Supposedly that aluminum will take a lot of abuse.

As for false advertising, I honestly don't understand why companies are allowed to lie everyday and get away with. Maybe no one cares here in the US. I saw where BofA lied to that guy when his mother died, telling him he was responsible for her credit card. He was smart enough not to fall for it. If I stood on the corner and tried to sell drugs to kids, I would be jailed and in big trouble. It wouldn't matter if no one bought the drugs. Merely the attempt should be punished. And the bigger the company, the bigger the punishment has to be, else it is not punishment.

6xxx is used in aircraft for extruded spars & such. 2xxx aka 2024 T3 or T3 for short is used alot as is 7075 ak T6. About the only aluminum you won't see in aircraft is 1XXX or damn near pure. But it does get used on some stuff. Glad to see some knowledgeable souls around here. BTW I just bent up a piece of .050" T3 "aircraft grade" aluminum for a new footswitch. I'll try to post pics when finished.

Question:

Can aluminum be annealed. Not sure that I would want to use aluminum on a guitar bridge and don't know much about metallurgy. So school me.

Here is a quick Aluminum tutorial:

http://www.tinmantech.com/html/aluminum_alloys_article.php

I just bought a 1/4 inch square aluminum tube from Lowes. I'm going to use it as a truss rod replacement in a prototype 6 string guitar neck. It seemed really strong, and doesn't require an access port to adjust (the neck is headleess) which simplifies construction. We'll see how it goes.

I am not a metallurgist by any means. My take is based on the properties of aluminum wire in electrical components. When aluminum heats it expands much more than other metals, when it cools it contracts back to its original size. This expansion coefficient caused many house fires when the aluminum expanded and because of its malleability the connecting point was loosened; and was eventually the cause of aluminum being outlawed for house wiring.

If you were to use it for a truss rod, then you run a chance of the metal expanding enough to separate the fretboard or crack the back of the neck because there is little to no clearance in a non adjustable torsion rod.

The AP types here may be able to shed more light on this.

Good info. Thanks!

As far as a pickguard you could use anything. Annealed, aka "O'' would be fine. I'd be tempted to use whatever is cost effective. Powder coat clear would keep the scratches away. No bending or structural issues with a guard, so 1xxx would work. Good idea! I have an alodine tank at work to etch the aluminum.

It turns the metal a nice gold color. Now I have to reconsider the final color for my next build!

Travis Bean guitars with Al necks were notorious for going detuned with temp changes, Vigier uses a big piece of CF and no truss rod; it is closer to wood in thermal expansion I believe. Decent CF pieces at LMII and Dragonplate.

Metal is metal unless its hardened steel and not typical "pot metal" and somewhere around here theres some guy cutting ruskie Ti into trem blocks for ~$300...unless his business model expired...

For a bridge I'd use some 6061 as it can be welded. Then you could weld a thick piece to a thin piece to make a fender hardtail clone. Or you could use some 7075-0 in about .080. Bend it & get it heat treated & age hardened to T-6.