Anyone around here with experience with magnesium flashlights?
The upcoming (somewhere May) Fenix HM65R appears to be made of magnesium.
I could only find the Surefire Maximus headlamp as an example of a portable light source made of magnesium.
Magnesium seems to be a potentially promising and innovative material for flashlights/headlamps.
So I was wondering why are there no other examples?
High production costs?
Lack of knowledge/skills/tools/experience working with magnesium?
Corrosion problems?
Low heat conductivity?
I’ve been wondering about Magnesium in flashlights before. Overall - it seems workable. Heat conductivity is good. Toughness is low but good enough. Costs are a problem. Corrosion was worrying me but I don’t know if it’s a problem really.
I thought it can start a fire during machining. Mechanical properties of magnesium is sufficiently interesting to be superior to aluminium under certain conditions, but I hardly see machined magnesium products. If a product is made from magnesium, then it’s often injection molded or die cast.
Historical footnote, according to CPF in 2008 the Muyshondt Aeon CR2 was (also) available in magnesium, under the caveat that “Be aware that although magnesium is very light, it is not an inert metal and is capable of corroding over the course of many years.”
So this makes we wonder why Surefire and Fenix in these particular headlamp cases decided to choose magnesium over aluminum. I wonder if in these cases the die casting is an additional advantage for specific designs, in addition to weight saving.
I consider weight saving not so interesting with small flashlights as a large contributor to total weight is the battery itself.
Of course, a company can always promote how the magnesium light is x% lighter than the aluminium variant, or generally how much less dense magnesium is…
My son, a machinist, tells me that magnesium can be machined but has many hazards as it can be ignited so easily. So many shops will not even touch the stuff. Magnesium has the unique ability to react with things around it such as CO2 (Carbon Dioxide) or H2O (water) to extract Oxygen for burning. It cannot burn in an atmosphere of pure nitrogen though. So they have a special enclosed 5 axis machine for machining magnesiumand a few other dangerous metals.
In the form of a finished light it is not so dangerous. It is the machines spiral strips that ignite very easily and powder that explodes. The deck of my old lawn mower was magnesium and it was never considered a hazrd even with a hot gas enine bolted to it . FYI, magnesium is used as the igniter in thermite.
I disagree here. In all but few cases flashlight weighs more than battery. Even the lightest lights could be reduced by 10% (cell included) if they had mg shells, most would be close to 15-20%. Overall not a killer kind of feature but definitely nice to have.
Overall - I’m reading through the topic now.
The toughest Mg alloys (f.e. Elektron 675) are way tougher than 6061 and close to 7075, have adequate thermal properties and are much lighter. There are some advanced surface finishes available (like Plasma Electrolytic Oxidation) though I’m unsure how do they compare to anodized alu. Cost….is surely a factor but I believe a high end light could be very good when done with Mg.
I'm thinking Mg lights will have to start in the realm of expensive lights like Muyshondt. If they were popular, we might see them sometimes as we do Ti lights, but I don't really expect it. I don't even really see any fuss being made over the choice of aluminum alloys for lights. I didn't get my D25C Ti because I need titanium, but because titanium is cool. But maybe that's the point, here, too. A magnesium light would be pretty cool.
P.S. Doubles as a road flare in case of emergency. Just put your battery into thermal runaway and the light goes too!
Nah. It melts before it burns and that’s 650 Celsius. You won’t set it alight without external heat source.
So….tactical - maybe no, maybe a direct hit with a bullet could cause local heatup leading to ignition. But firefighters should be fine and regular users even more so.
cliff notes:
a 28 gram flashlight made of solid aluminium, would weight 18 grams if made of magnesium alloy, a savings about 1/3 the weight of the body.
magnesium alloy oxidizes, because it contains aluminium
magnesium burns:
it is used in firestarters
I can see it now… LiIon vents with fire, the magnesium flashlight body joins the thermal runaway
I guess Fenix knows what they are doing, and would not manufacture and sell a light that is inherently unsafe; especially in combination with an 18650.