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Working with molybdenum

Strostkovy

Titanium
Joined
Oct 29, 2017
My parents have a wood stove that they light with one of those waxy fire bricks every cold morning. It's always a bit of a balancing act trying to get one corner of the starter up off of the base to have a surface to light with a match.

I was thinking that for a late father's day gift I would try and make a small stand out of a refractory metal that could hold these bricks while exposing the lower surface for easy lighting.

I understand that there are much easier ways to do this, and honestly it's such a minor problem we've never bothered trying to solve it, but I have an interest in these types of metals and it would be a neat gift regardless.

So my question is, how difficult is molybdenum to work with? I would likely be using 0.047" thick pure Mo sheet and would like to form it into a sort of box if possible. I would be using a 1/4" radius punch and probably 7/8" V die, with urethane die film, to a 135 degree obtuse angle. I am having a hard time finding a description of the brittleness of this metal.

Also, is this possible to plasma cut or shear, or what? I will be ordering a square of material large enough to do a few tests, but I would like to have some idea of what I am getting into if anybody has worked with this stuff.
 
According to this doc: http://www.molybdenum.com/wp-content/uploads/2015/02/Moly-Machining.pdf

"Bending - When properly heated, molybdenum can be formed into intricate shapes. Moly sheets less than 0.020” thick can usually be bent at a 180° angle during normal room temperature conditions."

And later in the same doc, under "Welding":

"Note that if you weld the pure molybdenum in the open atmosphere, the material is at risk of absorbing the nitrogen and oxygen, thus causing oxidation and causing brittleness."

So one gets the idea you should use a shielding gas if heating it significantly.

I've only machined moly, not formed it. Good luck.
 
nichrome and inconel are metals engineered for high temp. service, but even these, when subjected to the alternate reducing/oxidizing atmosphere of a wood stove hearth won't do well in thin sections.
its hard to beat cast iron, time proven and cheap. seriously doubt pure moly would be remotely cost effective.
 
Nah.

MAPP gas, here.

It's PM.

We have higher standards to uphold than the average redneck!

Using a "Red Dragon" (100% US-made, despite the Chinese-sounding name) don' need no steenkin' pinecones,..

...but is serious cheating!


:)

It's not serious until LOX get's involved.......
 
I would just get some stainless tube or rod. Drill a few holes in a firebrick and bend the rod to make a elevated grill. Or just drill some cross holes connecting in the firebrick. Perhaps a old cast iron gas stove burner or grate.
Bil lD
 
Thank you for all of the alternatives, which I will probably pursue when this doesn't work.

The goal here is to place two logs and a fire starter brick, light it, and then let it do its thing. My family is also less industrial in their antics than most folks here.

To be honest there are a lot of solutions I skipped straight past on my way to molybdenum. Pretty sure I just like molybdenum.
 
Ignoring all of the much more practical solutions, Mo is a really bad choice for this application. In inert atmospheres it is super capable of high-temperature use. In air, however, it oxidizes pretty readily, even at the temperatures in wood fires. Lots of "regular" metals would perform better.
 
Ignoring all of the much more practical solutions, Mo is a really bad choice for this application. In inert atmospheres it is super capable of high-temperature use. In air, however, it oxidizes pretty readily, even at the temperatures in wood fires. Lots of "regular" metals would perform better.

So would a hunk of rock .... or a brickbat.... but "It's PM".

Why trifle with "the ordinary" when failing at doing things the hard way is so much more interesting!?
 
Yeah, it seems like at the very least I need to choose a different metal.

Too easy by half.

Use a Moly laser-optics disk OUTSIDE the firebox ....aimed at the kindling.
Bounce a sore-powerful laser beam off it, and .....

Or go retro-tech, pre-Columbian Amazonian-Indigenous agro-plantation style:
Light a naked Brazil nut "meat" and flick it in. No platform required.
There's a reason their other name is "candlenut".

Many others among the oilier nuts can be either food or fuel.
You can literally get this job done for peanuts, even if you have to eat your mistakes.
 








 
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