Would the fact that aluminum is lighter possibly be detrimental? While I’m sure it’d make it easier to swing, it seems like you’d have to build up a bit of momentum if you were planning on tearing through platemail, or knocking an opponents shield out of your way.
Would lightweight aluminum make for better seige weapons, like trebuchets or catapults, i.e. getting into the larger items?
I expect it would also be useful for small skiffs and possibly barges.
Tripler: Yes, because we all know that the English were fighting Communists at the battle of Poiters.
Damned Commies.
[hijack]
I’m not sure if you’re agreeing with me, or poking fun at me.
It’s a distinct possibility you’re doing both at the same time. 
[/hijack]
Tripler
Damned commies.
Wow. Okay, first off, as I recall, aluminum was first refined in the mid-late 1600s, but only in very small quantities. It was considered extremely valuable at the time.
It’s also rather difficult to properly smelt, requiring evacuated furnaces and other later technology. Even if some aliens gave large ingots to a mideval blacksmith, he would have considerable difficulty actually doing anything with it.
It cannot be “forge welded” (like heating two bars of steel to bright red, then hammering them together, the usual technique for, say, making Japanese swords of the time) and it cannot be “wrought” (heated to a state of soft ductility and hammered into shape.)
Aluminum retains much of its strength until just before it turns to liquid, and it gives no visible sign- IE, turning red as steel does- to tell a smith when than will happen.
At best, if the aliens gave the 'smith some premade sheets, he might be able to rivet them together to make certain items. Unless he used iron rivets, which would eventually lead to galvanic corrosion (dissimilar metals) and eventually to a total failure of the assembled part.
With a decent alloy- including some silicon, perhaps some zinc- it can be easily cast by any competent blacksmith, but that’s about the extent of it’s usefulness to a mideval sort. Cast parts are also not the strongest by any means- the resulting piece would be light, but soft, and being cast, would tend to crack from any heavy blow, rather than bend (which would absorb some of the energy.)
Basically, it would have done little or no good whatsoever- not even as seige ladders.
Aluminum arrowheads: Perthaps, yes. Decent against wood, more than adequate against flesh, mediocre against iron mail, possibly wholly worthless against good plate armor.
Going with the “more range” error, the arrow has to have some mass in order for it to carry any energy. Like throwing a golf ball vs. throwing a ping-pong ball; if both are thrown with identical starting velocities, the heavier/denser golf ball will fly considerably further.
A bow provides a fixed amount of energy, so yes, a lighter arrow will indeed travel further, since the bow can accellerate it to a higher initial velocity. But that additional range does no good if the arrow doesn’t have enough energy at range to do any damage.
And again, being softer than the armor it’s trying to defeat, it will tend to spend that reduced impact energy simply deforming it’s own point, rather than penetrating.
Aluminum Cannon: Quite right. A very thick, forged aluminum barrel would resist the pressure just fine, but a cast aluminum barrel would be a bomb. And yes, erosion of the bore, both from the harder steel of the ball and the hot powder gasses, would be a considerable problem. A very few shots indeed would have “burnt out” the barrel in short order.
"Aircraft grade": That’s basically a marketing term. Nearly any alloy you can think of, from 2021 to 7075-T6, whether cast, extruded, rolled or forged, has been used in aircraft. Any aluminum is “aircraft grade” one way or another.
Hardnesses and tensile strengths do vary, of course- 2021 is quite soft, and is typically found in thin sheets. Old Ferrari bodymen would form racers from hand-hammered sheets, and oxyacetelene-weld them together, both nearly a lost art.
On the other hand, the BattleBots guys will armor their 'bots with 7075-T6 (the T6 being a reference to temper, how the alloy was heat-treated) which, while still being softer than Titanium or most steels, is lighter than both, and considerably cheaper than the former.
It’s interesting to note that the actors in the movie Zorro (Hopkins/Bandera, et al) used aluminum blades. I did know the alloy at one time, but it was essentially the same material, tempered to the same spec, as Cessna landing-gear struts. Both very rigid (for aluminum) and springy (it would return to shape rather than permanently deform.)
Aluminum mail: As noted, probably no better than decorative. A true sword blow, from a steel edge, would simply have to part several small sections of aluminum- basically a distributed mesh of soft wires- rather than a single homogenous plate.
Mail in general is poor against bludgeoning weapons (maces, clubs) and aluminum mail would be little better than leather against swords and spears, and probably almost worthless against steel-tipped arrows.
Long story short, if they had it, they wouldn’t have been able to do much with it. If they were able to do anything with it, it wouldn’t have done them much good anyway.
I’m not so sure a lughtweight arrow is the best way to go.
Wouldn’t a lightweight arrow be more succeptible to wind resistance?
Valgard:
Ask your sister if she has indeed study medieval martial arts. My guess is she will say “no”.
I don’t doubt they go after each other with intent at SCA matches (as I’ve mentioned, I’ve seen them), but going at each other with swords does not necessarily mean you have to know what you are doing.
It’s still a lot of fun just trying to nail one another without any sense of technique or fencing skill.
So again, the SCA does not practice actual historicla fencing. They play fight.
A historical fencer would have them for lunch. Or maybe a snack 
Mm – arrowheads were not necessarily “fire and forget.” It was common to collect them after a battle. After all, they were reusable, and cost money.
Unfortunately, the difference in weight of a steel arrowhead and the weight of an aluminum one is pretty negligible. Why bother? Particularly considering that after one or two shots, the aluminum one will be unusable, and it won’t penetrate armored targets.
I agree that durn near any aluminum GUN would be, at best, usable a few times. And that’s assuming you had a VERY experienced gunner who knew the limitations of the piece. Given the malleability of most aluminum alloys, it seems to me that a gun or cannon or field gun would likely burst or simply explode on the first shot, under most circumstances. Hell, quite a few medieval guns exploded or burst under the BEST of circumstances – medieval gunsmithy was not the most refined of arts; highly skilled and very exact, sure, but a joke by modern standards.
Kinthalis, I hope you don’t mind me linking to the fascinating discussion you and Una had on the subject of swords and modern metallurgy in godzillatemple’s thread [Are there any known “lost arts”?](http://boards.straightdope.com/sdmb/showthread.php?
s=&threadid=219126)
I was looking for that link, but I didn’t recall the title of the thread.
did aliminum get mentioned there? (looking through it now).
IIRC one of the important criteria for aerodynamic stability of a projectile is sectional density - mass divided by cross-sectional area. This is why things like discarding sabot DU tank rounds are good at long rang - very high mass with fairly small diameter. So all other things being equal a heavier arrow will “wobble” less in flight. On the other hand machined aluminum will give you more uniform arrows and they’ll fly faster.
As far as my sister goes, no argument there as she was an archer (and quite a good one). However I still stand by my assertion that a lot (not everyone, but not 0%) of the fighters are not engaging in either stage fighting or just random fiddling around with a stick in their hands. I had more than a few friends in the SCA who did in fact study medieval fighting techniques - and not just fencing. Like I said a lot of those people are very seriously into what they do and they go to great lengths to be accurate about it, including how they fight. Survive enough fights and you have good technique!
In regards to who would actually win some of those fights, no argument that in a fencing match I’d lose against somebody who knows fencing. I don’t think that that means a fencer would automatically fare well against a fighter who learned the hard way, regardless of how historically accurate the moves are. This is the old “which martial art is better” debate, no?
IIRC one of the important criteria for aerodynamic stability of a projectile is sectional density - mass divided by cross-sectional area. This is why things like discarding sabot DU tank rounds are good at long rang - very high mass with fairly small diameter. So all other things being equal a heavier arrow will “wobble” less in flight. On the other hand machined aluminum will give you more uniform arrows and they’ll fly faster.
As far as my sister goes, no argument there as she was an archer (and quite a good one). However I still stand by my assertion that a lot (not everyone, but not 0%) of the fighters are not engaging in either stage fighting or just random fiddling around with a stick in their hands. I had more than a few friends in the SCA who did in fact study medieval fighting techniques - and not just fencing. Like I said a lot of those people are very seriously into what they do and they go to great lengths to be accurate about it, including how they fight. Even somebody who doesn’t study old techniques will develop good ones after enough combat - let’s face it, that’s how every combat art was developed, trial and error and live testing.
In regards to who would actually win some of those fights, no argument that in a fencing match I’d lose against somebody who knows fencing. I don’t think that that means a fencer would automatically fare well against a fighter who learned the hard way, regardless of how historically accurate the moves are. This is the old “which martial art is better” debate, no?
Doc Nickle: your post was quite informative (I am especially glad that you mentioned galvanic corrosion, which I meant to note) However, I do have a few minor quibbles. Mostly they are clarifications of points that might be misinterpreted. I know how hard it is to reduce a technical subject to lay language - or even to figure out how a layman might interpret a statement.
While I’ve seen dates as early as 1808 claimed, Hans Christian Oersted is usually acknowledged as the first to isolate aluminum in 1825 in Copenhagen. Friedrich Wöhler is usually considered the first to make a pure sample of aluminum by chemical reduction in 1827.
While I completely agree that forge-welding aluminum is extremely difficult, and usually requires equipment and techniques completely out of the reach of a medieval metalsmith, wrought aluminum is not uncommon. While the current processes, like rotary degassing, date to the 1970s, hand-wrought aluminum pieces from the 1930s (not long after aluminum became affordable) are not uncommon. I know someone who specifically collects them.
You are quite correct that it is tricky. It is not, however, impossible Farriers rework aluminum horse shoes using some care and fairly standard techniques. It isn’t like working with iron, but there are small smithies in Florida and Hawaii that work in nothing else.
I’m so-o-o glad you raised this. In our consumer markets, the term “aircraft grade aluminum” is basically meaningless, and AFAIK the newer version “aerospace grade” is no better. Certainly, the AIA (Aerospace Industries Association) doesn’t list a standard.
-
-
- Aluminum is just more difficult to make and work with than steel is. Aluminum is an artificial suspension in that it doesn’t want to stay alloyed–if it is melted, the alloying ingredients will tend to separate out into layers according to their different densities. This is one of the two big reasons that aluminum is profitable to recycle–the other being that under normal atmospheric conditions, it will not oxidize the way steel does. A steel vegetable can will rust into a handful of brown flakes in a few years in a mid-lattitude humid locale, but an aluminum soda can left submerged in water will live for centuries.
-
- Present-day re-enactors use it because it doesn’t rust ugly-brown like regular steel would. To that end, the guy I know who has been into re-enacting used stainless steel wire for making chainmail and aluminum for making armor. Stainless steel sheet could be used also of course, but cutting it by mechanical means is a royal b!tch and it requires different equipment to weld than regular steel or aluminum–so many of the people who do manage to cut pieces of it end up riveting it together.
- Also: when someplace sells “aircraft grade” aluminum, usually what that means is that the material contains no recycled material and is inspected more closely. In the case of smaller pieces and welding rod, it also may be wrapped in plastic to prevent oil and dirt from impregnating it during shipping.
-Um, well, it does kinda turn light brown. The bigger problems (for middle-age metalsmiths) with working it are that it needs flux to join and that it spreads heat over a wide area–steel needs neither of these things and so is much easier to work with.
~
Ok this does make sense.
Yes, I know some who do the same as well. But the SCA does NOT teach medieval martial arts in any way shape or form.
Their bouts have a lot of rules and regulations that have no place in a study of martial arts (where every part of the body is a legal target and where contact -body on body- maneuvers are also studies).
No it isn’t. And the answer why is very simple.
The SCA bouts are NOT martial arts. They are based on staged combat with rules and regulations which make it into a sort of sport (much like modern fencing).
A historical fencer would have studied manuscripts from the ancient masters of swordplay, dagger and wrestling combat, as well as other weapons.
He would have researched with and trained with modern practioners of the art as well.
Comparing the two fighters would be like comparing your average off the street driver with a tournament champion formula 1 driver.
Or better yet a modern fencer and a historical fencer.
But of course the primary reason why the SCA and their usage of aluminium is useless in discussion of the OP is that they do not attack each other with hard edged weapons ie the particular area in which SCA fighting is not realistic, is the particular area which would otherwise reveal the flaw in aluminium in armour or weaponry (its softness).
Aluminum would make fantastic flesh piercing arrows, which would work excellent against light calvary.
Aluminum plate would be a joke, as with mail. A aluminum helm might be effective but only slightly more so than leather. I can see aluminum being effective for any troops that would normally wear leather. Blunt aluminum weapons wouldn’t be even slightly effective.
It is a combination of small aluminum granules and Fe2O3 (iron oxide) called Thermit. It burns fast producing red hot molten iron in the process.
It is used in demolition work and as a welding agent for heavy iron/steel pieces.
Aluminum wasn’t known at the time. It is only good for it’s light weight and ease of fabrication of replica armour and weapons.
Even then it should be colored to look authentic.
“Beware of the Cog”
Napoleon Bonaparte wished he could make aluminum cannon and was kind of pissed off that the technology for obtaining affordable aluminum from ore hadn’t been invented yet in 1812. When invading Russia, he kept getting his cannons bogged down in mud. He figured that aluminum would be light enough to make cannon transportation more feasible. Whether he fully considered the question of aluminum being strong enough to withstand artillery use, I don’t know.
Sorry if I’m repeating someone elses arguement that I missed, if someone was using an aluminum sword against someone using a steel sword, they would die very quickly. A sharp piece of steel would make short work of a sharp piece of aluminum. Aluminum clubs on the other hand might work.
Aluminum armor would be destroyed by steel tipped arrows and weapons. Same goes for chainmail. Steel would go right through it.
Cannons as other have said would explode. Bronze and brass are far better materials for the job.
As for arrows, they wouldn’t pierce steel armor but would be good on lightly armed opponents. However, aluminum would be of more use for the shaft than the head. They still are making arrow shafts from aluminum because it holds up better than wood. A steel headed arrow with an aluminum shaft would be a definate advantage on the battle field.
The only other use for aluminum I can think of is for the little things. Sword handles, decorations, accents on armor, utensils and cups. Steel still beats it in other respects.
OK Kinthalis, I see what you mean. I took “stage combat” to mean predetermined motions & outcome. Modern fencing has very specific rules about what is and is not allowed but a fencing match is still “real combat” within that context. Obviously two people trying to kill each other for real will probably discard one or two of the stylistic conventions of the time (“You don’t have rules in a knife fight!”)…
Still haven’t thought of any big advantage of aluminum for battles of the day. Perhaps this is because they didn’t move large objects made of solid metal around, where the weight advantage of aluminum would start to tell. Aluminum horseshoes don’t make a big difference compared to iron ones, whereas a tank with cast-iron armor will be considerably slower than one with aluminum armor. Jomo’s mention of Napoleon wishing for lightweight field artillery seems closer to the mark.
Perhaps aluminum assault ladders for climbing walls, battering rams with aluminum plate shields to protect the operators?