Sciencemadness Discussion Board

big fast smoke screen

smokeup - 28-11-2014 at 23:32

I want to make a smoke screen device that actually works. All the commercial stuff I've seen does not get the job done its all cute toy stuff. I want something that nearly instantly blocks out the sun over a 50ft diameter area.

Any thoughts?

I thought about a glass bottle of the sugar and saltpeter stuff and dissolving it in a light oil to make it liquid and either adding something that would ignite on contact with air or another glass bottle inside full of a strong acid. But if it works at all it sounds like it might be too hot and just send all that glass flying at me.

What do you guys think?

Metacelsus - 29-11-2014 at 07:53

White phosphorous is a very effective smoke agent, but it's also extremely nasty. You could also try something like titanium tetrachloride (again, be careful).

TheAlchemistPirate - 29-11-2014 at 10:09

An idea for a smoke grenade I've been considering for paintball-
1. A strong 2 1/2 inch diameter paper tube is made using this method. http://www.skylighter.com/fireworks/how-to-make/Fireworks-tu...
2. One end of the tube is plugged with bentonite clay, and another plug (with a fuse hole) is made (as the normal method of making salutes).
3. The normal smoke mixture of 60/40 KNO3/Sugar is made and broken into pebble-sized pieces.
4. The pieces are mixed with a small amount of black powder or pyrodex and poured into the salute tube.
5. The other plug is tapped into the open end of the grenade. (still unsure of the safety of this part...I would use a wooden mallet of course)
6. A fuse is inserted and connected to a party popper to make an actual pull-ring device (cant find the link but look it up).

In theory this would make a low power salute that shoots little smoke bomblets everywhere, without being very dangerous to any paintball players (except for the flying/burning pieces)
EDIT: This thread might be more fit for the amateurpyro site, unless you want to discuss compositions.

[Edited on 29-11-2014 by TheAlchemistPirate]

Oscilllator - 29-11-2014 at 18:30

TheAlchemistPirate, I have had some experience with these compositions, so I feel I can weigh in on this issue.
The first thing to say is that if you use granules of KNO3/sugar as you describe in conjunction with a well-sealed tube, the tube WILL explode with enough force that you don't want to be holding it.
Secondly, you don't need to worry about igniting the mixture by hitting it. I have whacked this stuff as hard as I can on an anvil and it just won't go off, so no problems there.


For an effective smoke bomb that had no chance of explosion I recommend that you break up the mix into small pieces while it is still hot and sticky, then compress it into a ball. The pieces will stick together but there will still be lots of air spaces, so the ball will combust within about 3 seconds. Glad wrap or similar can be used to prevent the absorption of air, and will burn away upon ignition.
The problem this design has (and that is common to almost all designs) is that the smoke formed is quite hot, and as such tends to rise up into the air fairly quickly.

Chemosynthesis - 29-11-2014 at 18:33

I've seen ABS or similar tubing used for a case. If you try this, make sure the ends are unsealed, and remember that scale up may increase deflagration risks. Lots of smoke mixtures out there. Used motor oil, while not environmentally friendly, can add some smoke.

Bert - 29-11-2014 at 23:35

Anyone care to consider the science of "screening" smoke generation and what is actually used in military applications? It is NOT sugar/nitrate.

White Phosphorus works- If you do not inhabit or care too much about the area where it is deployed.

careysub - 30-11-2014 at 00:36

Quote: Originally posted by Bert  
Anyone care to consider the science of "screening" smoke generation and what is actually used in military applications? It is NOT sugar/nitrate.
...


Yeah, I posted here recently about the zinc and titanium smoke compositions used by the military.

As they say: UTFSE.

Fulmen - 30-11-2014 at 12:45

I agree. You want to research zinc or titanium chloride forming compositions, these can be highly effective. Zinc oxide shouldn't be hard to synthesize if you can't get it, you also need a suitable chlorine donor like PVC, saran or parlon.