Sodium Azide and Blackpowder

[jaysgoh]

I know it's a uncommon questions for pyrotechnic , but i would like to know about airbag more , their technology make me salute to them .

Usually Sodium Azide found in car airbag in older days, a mini seat belt air bag inflator 17mm X 36MM can produces up to 4Litre of gas in less than 3ms where commercial driver seats airbag can produce 36.4Litre of gasses . I got it from a friend who work in car parts shop . He also mentioned that 17x36mm seat belt inflator use less than 6g of explosive propellant ( he did not want to reveal what is it inside ) can easily inflate a seat belt airbag .

 

i believe that Sodium Azide decompose at 300C and form a violence decomposition of Na and N2 gases . How do this NaN3 decompose look like ? Deflagaration ? Explode ? I didn't get to access to NaN3 as it too costly for it , but i did actually ignite a car airbag with under profession supervision .

Can anyone eaxplain to me that how do we determine the amount of gases produce by blackpowder. So , why they dont use blackpowder for the airbag ? Is speed is the main factor in airbag or gas produces is the main factor ?

 

Thank you in advance , if i violating this forums rules by asking uncommon pyrotechnic questions , please do remove this post .

Edited November 7, 2014 by gohjiejing

[modelrocket]

I think this is HE and therefore not allowed? :S

[BurritoBandito]

I think it's because there is no flame involved with NaN3, just the rapid liberation of nitrogen.

[Arthur]

1/ No-one specifies what is in air bag inflation charges. The web might guess the content but if your airbag goes off while you are opening it you have 2 milliseconds to get out of the way.

2/ If it is an azide then remember how toxic they are.

[taiwanluthiers]

I never worked on or been near airbag devices so I can't say what's in them, however from googling about sodium azide it does say that some airbags have also used nitroguanidine based explosives because they are not as sensitive or toxic as azides. Blackpowder is a poor choice of explosives for airbags. For one thing it can degrade due to moisture, which means it could lose performance simply because the car has been exposed to rain or whatever (which it often does). Also blackpowder does not produce much gas at all, and also the combustion product of black powder is corrosive, so it could damage components if it's not cleaned very well. Furthermore blackpowder is simply too slow. Sodium azide is a high explosive so it produces gas fast enough to inflate the airbag in the event of a crash. Black powder can burn at 600 m/s in the best case scenario, while sodium azide is over 5000 m/s. Big difference.

 

Don't go messing with airbags... in addition to being very sensitive sodium azide is also a contact poison. It is as bad as cyanide in fact.

[smokeytech]

Thats one hardcore and complicated airsoft grenade, I would worry about my fingers

 

http://www.mypixshare.net/files/img/user_uploads/displayimage.php?id=8wsbi8cbm2o06065456.gif

[Arthur]

In an improperly designed airbag, in an incident, the bag goes off and spreads azide into the bag and onto the driver, -and he dies, because no-one thinks azide poisoning before it's too late. 1/beware of copy airbags, 2/ DONT mess with azides unless you have ebola grade PPE. Most chemical destruction methods are poor so almost all airbags are fired remotely to destroy them when the vehicle is decommissioned.

[jaysgoh]

I never worked on or been near airbag devices so I can't say what's in them, however from googling about sodium azide it does say that some airbags have also used nitroguanidine based explosives because they are not as sensitive or toxic as azides. Blackpowder is a poor choice of explosives for airbags. For one thing it can degrade due to moisture, which means it could lose performance simply because the car has been exposed to rain or whatever (which it often does). Also blackpowder does not produce much gas at all, and also the combustion product of black powder is corrosive, so it could damage components if it's not cleaned very well. Furthermore blackpowder is simply too slow. Sodium azide is a high explosive so it produces gas fast enough to inflate the airbag in the event of a crash. Black powder can burn at 600 m/s in the best case scenario, while sodium azide is over 5000 m/s. Big difference.

 

Don't go messing with airbags... in addition to being very sensitive sodium azide is also a contact poison. It is as bad as cyanide in fact.

Thank you for this message ,

i didnt meant to make them or what , i would just want to know something more about airbag more .

Sodium Azide is quite uncommon chemicals , googles has not much information about them .

 

Anyway thank you .

[pyrojig]

AS stated above SA is a very toxic compound/. When initiated in a airbag, there is other chems mixed in to complete combustion so that there is only nitrogen as a bi--product. If done right there is little to no toxic remains in the gasses of a initiated bag. Although if S-azide is handled by hand expect to get very sick. It is a LD50 chem.,PPEs are a must ./ ] I dont think SA is 5000 m/s . maybe 1/2 that .but still huge amount more than bp.

 

As stated by taiwanluthiers,bp is a very poor choice for a bag. Low burn speeds and lack of gas production, make it no good for these tasks .

[Arthur]

The issue with BP is;

1/ it produces 51% solids (the smoke)

2/ it produces a temperature in excess of 2000K so anything would ignite from a tank of fuel to the driver's face and clothes.

3/ it is too slow you'd have hit the steering wheel before it worked.

4/ it doesn't store too well, properties would change after 10 years and several cars last ten plus years.

 

Don't mess with azides, and don't fit airbags of dubious supply source.

[jaysgoh]

Thank you, there sell sodium azide 100g for 50Usd and available to public. What does analytical research means?

I will send a email to the seller and of course with a msds to them.

[taiwanluthiers]

don't mess with azides, even if you can buy them. They are used for various analytical chemistry but if you don't know how it works, don't mess with it. LD is .7 grams and it absorbs through your skin. MSDS will probably say something like fatal if swallowed or something. Not to mention the stuff decomposes at 300 degrees, and forms sodium in the process (which is also in itself hazardous). Commercial airbag devices mixes other chemicals such as kno3 to make sure any leftover azide is completely consumed, and that any reaction products are converted to harmless chemicals. I won't say more about what to do with it because that's bordering on HE...

 

There are far safer ways to make things go bang.

[jaysgoh]

I just send a emailed to them and ask them to take down or be more specific about this chemicals . they seems don't really know this chemical well and they said they might consider to take down .

Azides salts are very toxic . I won't risk my life and my money with it .

 

Thank you for the information as i learned a lot something new today .

[Zyklon39]

don't mess with azides, even if you can buy them. They are used for various analytical chemistry but if you don't know how it works, don't mess with it. LD is .7 grams and it absorbs through your skin. MSDS will probably say something like fatal if swallowed or something. Not to mention the stuff decomposes at 300 degrees, and forms sodium in the process (which is also in itself hazardous). Commercial airbag devices mixes other chemicals such as kno3 to make sure any leftover azide is completely consumed, and that any reaction products are converted to harmless chemicals. I won't say more about what to do with it because that's bordering on HE...

 

There are far safer ways to make things go bang.

You're talking about hazards?Well...we're on a forum called "amateurpyro".Seriously...

[Zyklon39]

I just send a emailed to them and ask them to take down or be more specific about this chemicals . they seems don't really know this chemical well and they said they might consider to take down .

Azides salts are very toxic . I won't risk my life and my money with it .

 

Thank you for the information as i learned a lot something new today .

People who don't have any connections with explosives usually don't know too much about them.They can be also toxic,and this is more dangerous if you don't know it.

I don't really see any problem in using it.Wet it a little to prevent it from getting all around,wear a dust mask and cover your skin and head with something like a raincoat.It is also very easy to make a little...I don't know how to call it...maybe a box.A box with a frame made out of wood or metal.At the top and in front of you/it use glass.On the sides use something like cellophane.You put your hands(gloves on) inside the box through the sides and manipulate x powder without spreading it all around.I hope you understand what I try to describe here...

Now,black powder needs to be confined in order to explode.If you do that,you may provoke a shrapnel which can break the bag or worse hurt the drive or other persons.It also burns too slow for this purpose.

Now...black powder is a mixture,it's somehow complicated to calculate how much gas you will get after burning it.You need to know how much combustible "material" you have.After that,you must write down the reaction(s)(this is what you should do first.).After that see how much oxidizer you have.After this,calculate the amount of gas.I wouldn't even bother to do this.It's pointless.I think you can find it on the internet.

[BurritoBandito]

People who don't have any connections with explosives usually don't know too much about them.They can be also toxic,and this is more dangerous if you don't know it.

I don't really see any problem in using it.Wet it a little to prevent it from getting all around,wear a dust mask and cover your skin and head with something like a raincoat.It is also very easy to make a little...I don't know how to call it...maybe a box.A box with a frame made out of wood or metal.At the top and in front of you/it use glass.On the sides use something like cellophane.You put your hands(gloves on) inside the box through the sides and manipulate x powder without spreading it all around.I hope you understand what I try to describe here...

Now,black powder needs to be confined in order to explode.If you do that,you may provoke a shrapnel which can break the bag or worse hurt the drive or other persons.It also burns too slow for this purpose.

Now...black powder is a mixture,it's somehow complicated to calculate how much gas you will get after burning it.You need to know how much combustible "material" you have.After that,you must write down the reaction(s)(this is what you should do first.).After that see how much oxidizer you have.After this,calculate the amount of gas.I wouldn't even bother to do this.It's pointless.I think you can find it on the internet.

Are you serious? I hope you don't ever get your hands on any NaN3.

 

Edit: fixed typo

Edited November 8, 2014 by BurritoBandito

[taiwanluthiers]

.... until Sodium Azide explodes, showering you with glass shards. Would be better to use 1" lexan shield. I read it doesn't take much to cause Sodium Azide to explode either. The chemical has no use for pyro, and it's used in airbags simply because it produces a lot of gas.

[Zyklon39]

.... until Sodium Azide explodes, showering you with glass shards. Would be better to use 1" lexan shield. I read it doesn't take much to cause Sodium Azide to explode either. The chemical has no use for pyro, and it's used in airbags simply because it produces a lot of gas.

If you take it like that he shouldn't make any explosive because it can explode.No...the shock shouldn't shatter the glass since 2 parts of the

"box" doesn't even stop the shockwave like the glass does.I think I've already said something about "common sense" in the last answer.The quantity of explosive shouldn't destroy that box.If it does,it's too much explosive.The objective was to manipulate small amounts of NaN3.

By the way...I wasn't talking about that kind of glass which is easy to break.

Edited November 8, 2014 by Zyklon39

[Zyklon39]

Are you serious? I hope you don't ever get your on any NaN3.

 

Why not?

[pyroman2498]

you guys are making such a big deal about the azide xD, I used sodium azide solution in Earth and environmental science class for the DO test , don't open an airbag and you will be fine ...

Edited November 8, 2014 by pyroman2498

[BurritoBandito]

Why not?

Because I'm inclined to believe you'll kill yourself.

 

you guys are making such a big deal about the azide xD, I used sodium azide solution in Earth and environmental science class for the DO test , don't open an airbag and you will be fine ...

...And some people take nitroglycerin for heart conditions.

[MrB]

I'd prefer working with nitroglycerin over azides any day. Both can be nasty, both can cause some havoc, but the family of azides just tick a box i don't like. It's unreliable stuff, that really needs real lab conditions.

B!

 

Edit

BTW, Why are we on this topic anyway? Azides have very little, to no place in pyro.

/Edit

Edited November 8, 2014 by MrB

[pyroman2498]

its in the chemistry part of the forum , so im guessing we are just discussing azide its self ... I just saw it and thought I would read it xD

[Jakenbake]

Zyklon39 for President!

[pyroman2498]

^ LMAO xD