Is Magnesium ok?

[Mark Holschuh]

I once proposed to make some small engine parts out of magnesium alloy. Our company's insurance company threatened to cancel our policy immediately if we machined them in house. (They didn't work very well.)

[PAR_WIG1350]

Originally Posted by Mark Holschuh

I once proposed to make some small engine parts out of magnesium alloy. Our company's insurance company threatened to cancel our policy immediately if we machined them in house. (They didn't work very well.)

The engine parts, or the insurance company?

[Mechvet]

Originally Posted by DonRotolo

As many have noted, Magnesium in typical form is no more dangerous than any other metal - even underwater. However, smaller chips or particles are able to be ignited, and then become extremely difficult to extinguish.

Yes a class D extinguisher has a chance, but hav limited effectiveness and are costly.

If you use the metal and don't need to machine it, you'll be fine. But if it needs to be machined, you are better off avoiding it. The risk is small but the consequences very large.

This is a line of reasoning that's excellent. Risk v. reward is always an excellent comparison to run before selecting something outside the "norm."

Originally Posted by Mark Holschuh

I once proposed to make some small engine parts out of magnesium alloy. Our company's insurance company threatened to cancel our policy immediately if we machined them in house. (They didn't work very well.)

Seems like a rather uninformed reaction for an insurance company. Magnesium has applications all over, and can be machined and used quite safely.

Just get a Bromotrifluoromethane extinguisher (Halon 1301) for areas where swarf and chips can gather, and all will be well. I've personally used a CBrF3 extinguisher on several fully ignited systems (one jet engine, two transmissions, and one interior cabin fire involving vaporized JP5) with great success.

[ctt956]

Originally Posted by Mechvet

Seems like a rather uninformed reaction for an insurance company. Magnesium has applications all over, and can be machined and used quite safely.

Just get a Bromotrifluoromethane extinguisher (Halon 1301) for areas where swarf and chips can gather, and all will be well. I've personally used a CBrF3 extinguisher on several fully ignited systems (one jet engine, two transmissions, and one interior cabin fire involving vaporized JP5) with great success.

Wow, that's a lot of fires! Halon hasn't been produced in over 20 years, but it's still legal to use if you can find some; end of first section here.

[techhelpbb]

Fine silicon sand works but not instantly and you need enough sand to bury the fire and cut off the oxygen.

The sand will also take heat from the magnesium helping to bring the mass below ignition.

Be very careful: you need to keep adding sand for some time while eliminating other things that can ignite and this means you need to be close to a hot fire. The sand itself can be fuel in small quantites mixed into the magnesium dust. You need to bury and not mix.

There are several YouTube videos that show mixtures of magnesium dust and sand flaring up: in these cases the sand to magnesium ratio is too low and the 2 are mixed.

[adciv]

Originally Posted by Mechvet

Just get a Bromotrifluoromethane extinguisher (Halon 1301) for areas where swarf and chips can gather, and all will be well. I've personally used a CBrF3 extinguisher on several fully ignited systems (one jet engine, two transmissions, and one interior cabin fire involving vaporized JP5) with great success.

USAF?

[Dan_Karol]

Alloys of various metals can have hugely differing properties in certain areas. throwing blanket statements about classes of materials isn't always appropriate. Please see the link below for some testing performed by the FAA in related to this very topic of conversation.

https://www.fire.tc.faa.gov/pdf/AR11-13.pdf

Knowing how badly it can go if not handled properly, I highly caution inexperienced users form considering magnesium in FIRST. That said, from experience, I can say that there is at least one Magnesium alloy that can withstand some impressively high temperatures after being machined into fine chips without burning

[Dan_Karol]

The alloy from my previous post is AZ91D

[Mechvet]

Originally Posted by ctt956

Wow, that's a lot of fires! Halon hasn't been produced in over 20 years, but it's still legal to use if you can find some; end of first section here.

The supply system that I worked inside of had enough Halon to last for quite a long time, so acquisition was never a problem.

Also of note are some of the AFFF agents used in fighting large (and very hot) fires, but these are utterly impractical and too expensive for an FRC team.

The principle of operation is the same: Remove the access to oxygen as rapidly and thoroughly as possible.

Originally Posted by adciv

USAF?

USMC.