Source of fairly pure magnesium tube 1/4" to 3/8" diameter.
For arrow shafts....
Source of fairly pure magnesium tube 1/4" to 3/8" diameter.
For arrow shafts....
Richard fired this volley in news:C56dnRba1OlqQZvOnZ2dnUVZ snipped-for-privacy@earthlink.com:
I don't believe pure magnesium is strong enough for that sort of duty. It's light, yes, but also brittle and fragile.
Any 'magnesium' you find in that kind of service is more likely an Mg/Al alloy, like the German Elektron Alloy used in old Karman Ghia and Porshe blocks.
Those are still _almost_ as low in density as pure Mg, but worlds stronger. FWIW, they still burn almost as well as pure magnesium, too. When I was in a volunteer FD, I saw a fatality accident where a guy was trapped in his Karman Ghia and the block caught fire. Went quick...
Lloyd
LLoyd
Same stuff in Beetle and Hippie-van blocks. (and transmissions)
Yeah, I've heard that too. But... Back when I was building VWs to fly I actually tried to light some of the shavings from the case. Couldn't get them started with an OA torch.
This application would prefer purer magnesium. They are intended to be "special" arrows. :)
But perhaps this approach isn't practical? A carbon fiber shaft might be a better starting point?
IIRC only the earlier blocks contained significant magnesium the later ones were straight aluminium.
Without letting us know what's special about it, how can we say?
If you're looking for light/stiff/strong, carbon fiber will probably get you there a lot quicker than some fancy magnesium alloy, and be easier to find, to boot.
The metal they use in arrows is actually pretty impressive stuff. It's notable how stiff they are and then once you cut or break one open how thin the walls actually are.
Yeahbut... There are other properties besides mechanical. And light can have other meanings as well. Like the high temperature part?
Well doggies! My favorite metal supply actually has something close. Roto Metals has 1/2" diameter rods @ $4 a foot. Now the silly problem is I have no way of machining magnesium solid rod. It would need a pocket at least 6 inches long (?) at the head end. FeO2 and Al should work, shouldn't it?
Richard fired this volley in news:QqOdnTUmlp1IXprOnZ2dnUVZ snipped-for-privacy@earthlink.com:
Richard, being in a business that uses a lot of pure magnesium powder, I can tell you that solid Mg, despite its flammable nature, is hard to ignite 'on the fly' (as it were), and difficult to keep lit unless it's allowed to burn quietly in fairly still air. LARGE masses of it are difficult to extinguish because of the heat envelope and mass, but small masses of it are almost impossible to keep lit.
If you're having trouble locating magnesium in form you wish, I would suggest that it isn't even the _beginning_ of your endeavors.
Lloyd
Thanks, Lloyd. Actually I'm kind of following part of the story line in the last book of the Hunger Games. Wondering if it's possible.
I knew solig Mg is hard to light, but didn't know that it had to be allowed to burn calmly (if that makes sense).
Which probably leaves the only other possibility as a Therm. mix?
Richard fired this volley in news:7rydnbGFg4BZVZrOnZ2dnUVZ snipped-for-privacy@earthlink.com:
You do know, Richard, that projectile incendiaries are illegal at the Federal level, unless licensed for specific purposes like Forestry Service back-fire starters, and the like?
You could be launching into a trajectory you really don't want to explore.
Lloyd
A guy I used to know worked for a magnesium alloy race wheel maker and he was always popular on Guy Faulks night as he would bring along magnesium wheel turnings. They could be tossed into the bonfire and wouldn't flare up or burn until water was tossed onto them then you got a blinding white flare as it burned. I presume the heat made it oxidise and prevented burning initially but with added water the hot magnesium would react readily. They did have the odd fire in the factory, troublesome to put out apparently.
The later beetle engines (Mexican and Brazillian) are aluminum
Can anyone say "flaming arrows"???
A large surface to mass ratio is required. A thin magnesium ribbon will burn VERY well - and blowing on it does NOT put it out (from experience in the science lab years ago) Sodium is worse. So is white Phosphourous
David Billington fired this volley in news:5307cc6f$0$1135$ snipped-for-privacy@news.zen.co.uk:
Actually, magnesium is electrochemically active enough to decompose water, leaving oxygen to burn the Mg, and hydrogen to burn in air.
Lloyd
Nope! Couldn't say anything like that!
snipped-for-privacy@snyder.on.ca fired this volley in news: snipped-for-privacy@4ax.com:
Clare, your high school experiences aside, I do this for a living. A large thermal mass contributes to keeping it lit under adverse conditions. True enough, a large volume of high surface area will cause vigorous-enough burning so that it's difficult to put out.
But a small surface like an Mg ribbon will only keep burning under strong air flow if it's inverted so that the heat climbs UP the ribbon. Stand it upright, and you can blow it out with a simple puff from your mouth. 'Done it many times for demos.
The same is true for "never put water on a magnesium fire". If the thermal mass is small, a tiny bit of water will cool it below the combustion temperature. With a large mass, or very high surface area, water then decomposes and promotes combustion.
Lloyd
I thought that carbon fiber was now the basis of super-duper arrows.
But the last argument about arrow shafts I remember was "is birch really better then willow?"
In a more serious vein, what sort of supper arrows are you making?
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