Looking for the best fire extinguisher

My latest purchase has bits of magnesium under the hood which has my wife nervous. I know it takes quite a bit of heat to light the stuff, and once it ignites I would need a class D extinguisher to put it out. Class D fire extinguishers are a lot of dollars. My thinking is a good "normal" extinguisher (class a,b,c) would be enough to put out anything that might go up in time to save the magnesium bits.... My only experience with car fires had me wishing that I had something other than a liter of Dr. Pepper to put it out with.

Looking for a relatively small QUALITY extinguisher that I can keep in this car ('84 corvette) for a little peace of mind. I have zero experience with extinguishers and thought I'd ask the hive mind for advice before spending money. 

Thanks

The way to put out a magnesium fire is to cut off the oxygen that allows the fire to burn.  Sand is what is commonly used. That being said  a whole piece of mag does not just burst into flames it takes some other hot fire to set it off. If you put out that fire quickly enough then the mag won't be an issue. Most mag fires occur when the metal is abbraided is some way. Like dragging on the pavement. The small bits that get scraped off can light off and that can get the rest of it going.  Machining mag can be iffy as under the right conditions the cuttings can start to combust.

A dry chemical exting. seems like the best option as far as cost.  Their messy when used but they will do a better job then a CO2 or other liquid or gas exting.

In reply to jimbbski :

That was pretty much my thoughts. The magnesium bits are valve covers and air cleaner cover and they'll take quite a lot of heat to ignite. Basic thinking is to put out any fires before the mag. catches. Thanks. I may also be able to delay the mag. burning more by painting them with some high heat paint like bbq paint or a ceramic header paint. Appearance is of little concern... I just don't want to be like my neighbor who tried putting out his c4 fire with the hose and now he has two less c4s.

I'd make sure my fire insurance was up to date and not worry about it. 

I wouldn't spend a minute worrying about it.  Volkswagen made about 21 million air-cooled Beetles with a magnesium crankcase.  You didn't hear about them burning very often.

The last time I tried to burn magnesium, it took concentrated heat from a torch, for a fair amount of time, to get it to light. By the time a fire gets hot enough to light off the magnesium bits, the fire department will be there and the car will already be totaled. You should have time to get to the local bar and cry in your beer. Tell the wife not to worry. 

I use a Kiddie marine fire extinguisher in most of my cars. Durable, small, will put out most fires. There is also a available metal mount for about $10. 

With almost any car fire if you extiguish it quickly and turn off electrical and fuel then it's not a big deal.  If you don't then it's a really big deal.  The big thing is to have any B,C extiguisher and use it quickly.   If you don't get the fire out right away then go find a safe place to sit and cry while you wait for the fire company.

In the aviation world if you discharge a dry chemical type it requires an extensive teardown and thoruogh cleaning due to the corrosive nature of the dry chemical.

In reply to 1988RedT2 :

That was something I had considered, being a VW guy in a former life. I've lit those cases on fire a time or two, but it was only after tossing them in an open fire and waiting a little that they would burn.

Funnily enough, my only personal experience with a car self igniting was in an acvw, and that only damaged rubber and warped the carb flange a little.

In reply to pilotbraden :

I had not considered that. Good to know. Bears some research as to what materials might be at risk... off to google

You ride around in a vehicle that runs on highly flammable fuel under pressure, but you're worried about magnesium catching fire? I think your priorities are out of line. That gasoline is more of a threat than any other single thing on that car, and you're probably carrying anywhere from 15 to 20 gallons of the stuff.

In reply to barefootskater :

For aviation they're all Halon charged which you likely want to stay away from as there's serious disposal concerns when the pressure vessels age out as well as health concerns. It's heavier than air and binds to oxygen in your lungs if you inhale it, seriously bad news. Hurts like hell too if you discharge one in an enclosed space and breath it in. (Somtimes I wonder if I'm going to live past 40 everytime I say that on this board.)

I wouldn't worry much about the magnesium bits either, everyone points to those magnesium firestarters my counter point is that flour is explosive under the right conditions too. Outside of grain silos exploding you don't have to worry about the 5lb bag of flour if it isn't aerosolized, same with magnesium as I highly doubt you have large piles of drilled or scraped magnesium near a heat source the car.

In reply to ncjay :

You are correct, the mag. is not even remotely the most dangerous part of this car. I will also be the first to admit that my priorities are rarely in the order they should be in. Those things aside, when my wife allows me to buy a completely unnessisary car, and then goes "Wait, those parts are magnesium? Isn't that stuff flammable? You need to get a fire extinguisher in there before you drive it." I'm not going to argue. Especially after watching two burn down when one would have been saved had an extinguisher been handy... long stupid story...

Anyway. A little peace of mind and a happy wife for the price of a fire extinguisher? Sign me up. I just would rather buy a good one than whatever is cheapest, just in case.

Edit:  I rarely have anything near 15 gallons in my tank. But thats a different story

In reply to The0retical :

The only thing that ever hurt after I accidentally inhaled a bit was from a hole I drilled in an old billiards ball making it into a shifter handle. No idea what that resin was.

Anything is combustible in the right environment. I seem to recall hearing that solid rocket fuel is in large part aluminum, and thats what pistons and modern engines are made of.... Good point

And I have to give respect to your signature... Class act sir.

My next (running) fiberglass car will have a foam system.  Watching them burn to the ground is not a good experience.

Dry chem will ruin the engine as well. Halon is being phased out by means of production limitations and price increases. Halotron is your answer.