NEMO-Chemistry
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Colured smoke
What can i use to make a fairly dense coloured smoke, ideally i want 3 colours, the actual colour dosnt matter but the smoke should be thick.
it should also be pretty safe and able to be passed through a glass tube in a stream (that might be asking too much).
All its for is testing some adapted rotors on a drone, We are trying to see the air patterns created by variously altered props and enclosures, the
idea is to find good lift but with as little air disturbance as possible.
one test is simply a 20 foot shed and we will fill it with smoke, then from the outside via a window film it taking off and landing.
We have some other tests but its the smoke i cant figure out! I can make it but its choking!!
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aga
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Heat glycerol.
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Vomaturge
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On the energetic materials side of things, you can use an incense, cigarette, fireworks lighting stick, or other smoldering material for small amounts
of smoke, and of course there are pyrotechnic mixes to make bigger clouds of smoke. This one didn't make very much color, and begun flaming at the
end. Maybe he could have used less oxidizer?:
https://www.youtube.com/watch?v=4cHJbAIIdQ8
These did better, although it might be hard to replicate the exact ratio of ingredients used, since they were not weighed carefully:
https://www.youtube.com/watch?v=1I2SuS2Z1JM
It seems that some crayons have dyes which evaporate easily, and others don't:
https://www.youtube.com/watch?v=SJe5THzGBZI
In all these cases, I think you could probably take the pan off the heat before adding the potassium nitrate. That might make the process safer. Other
than fire hazards, I see two big drawbacks to these homemade smoke generators. For one, you need KNO3. Also, as you have already found out: you can
breathe the smoke about as well as you can breathe a crayon.
For an indoor test, you might do better with some type of fog machine/vaporizer. I seem to recall that fog fluid is propylene glycol or glycerol mixed
with water, and heated with an electric element. Or, if you're willing to spend the money, you can buy one:
https://www.amazon.com/dp/B01MDNTD7A/ref=sspa_dk_detail_0?ps...
But what's the fun in that?
Edit: Of course you can also create a wisp of ammonium chloride particles by combining ammonia and hydrochloric acid vapors. Again, not great to
inhale, but okay for producing a little trail of smoke to track airflow. I also wonder if you should really fill the whole shed with smoke, or if just
a stream would work better? If the whole thing is smoky, it might be hard to see the air moving once it becomes a homongenous cloud of smoke.
[Edited on 12-3-2018 by Vomaturge]
[Edited on 12-3-2018 by Vomaturge]
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Sulaiman
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https://www.ebay.co.uk/itm/6Colors-Smoke-Cake-Effect-Show-Ro...
CAUTION : Hobby Chemist, not Professional or even Amateur
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NEMO-Chemistry
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Thanks. those smoke pellets Sulaiman posted look like they will do one the jobs! HCl and electronics not a great mix .
Some of the smoke will be pushed as a small stream into the blade enclosure the take off test in the shed is just to see how disrupted the air is, the
only way i could think of doing it was several coloured smokes and then taking off and seeing how they mixed.
might not work yet, but worth a try. I still honestly think drones lack decent props, might be wasted effort or might be a way to get better lift from
less power.
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Bert
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Smoke Cookie Recipe-
There are not a lot of possibilities for COLORED smoke you would want to breathe.
White is fairly benign done with vaporized "fogger fluid", as is used in concert venues. Lots of other ways to do white, but they all are bad to
breathe, varying only in HOW BAD: Like Titanium tetrachloride, Posphorus pentoxide, Zinc chloride... For an amateur without a theatdical fog machine
or a lot of chemicals available, a reasonable alternative is:
Smoke Cookies!
For OUTDOOR USE, a cheap long burning white smoke is made by mixing 50:50 by weight of Pottasium nitrate and non dairy coffee creamer powder (yes, the
same powder as is used for the 5 gallon bucket sized "Cremora fireballs").
Mix the dry ingredients well, then damp with the minimum ammount of water to make it into something like a stiff cookie dough or Playdough modeling
compound. Roll it out into a slab about like you were making biscotti, around 1" thick has worked for me. Cut the slab into "biscotti" about as wide
as they are tall, more or less a 1" X 1" cross section, and as long as you made the loaf of cookie dough. With experience, you will know how long
these burn, and hopefully tailor the length to your needs. If you want MORE smoke output, you can cut the slabs WIDER. Or just use a whole loaf of
dough-
Bake the slabs on a cookie sheet at around 250 F. until completely dry, this takes a while. If you don't get them dry in the center, you may not be
able to get them to stay lit, and they will all get damp if kept in a sealed container as that last bit of water wicks out to what FELT like a
crunchy dry outer surface. So a long drying time, ideally overnight.
I cook these to dryness in one of those cheap little countertop convection ovens, and OUTDOORS. The fairly low temperature, just enough to boil away
the water is to keep the cookies from going off in the oven, but you really don't want to take any chances on these catching fire inside your kitchen.
When you smell the smoke, you WILL understand why.
To use, hold a lighter to one end of the cookie, or use a propane torch to get it going faster. Set the cookie on a non flammable surface you do not
care about ruining, I like to use leftover ceramic tiles. These need atmospheric O2 to keep burning, don't completely enclose them. They burn a much
long time but with a lower smoke output compared to chlorate/lactose/dye smokes the same size.
[Edited on 12-3-2018 by Bert]
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NEMO-Chemistry
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Cheers Bert, might be able to do that outside. I will try and grab some pics when i try it at the weekend, might make sense what i am trying to do.
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Bert
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| Quote: | | might be a way to get better lift from less power. |
Not chemistry, but-
How about DUCTED fans?
| Quote: | | In some cases, a shrouded rotor can be 94% more efficient than an open rotor. The improved performance is mainly because the outward flow is less
contracted and thus carries more kinetic energy. |
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Twospoons
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If you are trying to see air currents you will want thin streams of smoke, not a room full. If it were me doing this I'd be using the commercial fog-
juice, or the home-made equivalent of gylcerol+water, in a tube with a reasonably powerful heater, and a nozzle to create a stream. That would give
you good control over the smoke stream.
examples
Helicopter: "helico" -> spiral, "pter" -> with wings
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NEMO-Chemistry
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Quote: Originally posted by Bert  | | Quote: | | might be a way to get better lift from less power. |
Not chemistry, but-
How about DUCTED fans?
| Quote: | | In some cases, a shrouded rotor can be 94% more efficient than an open rotor. The improved performance is mainly because the outward flow is less
contracted and thus carries more kinetic energy. |
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Ducted fans is exactly what I am looking at, I couldnt think of the word! Mine are made with DELL pc fan ducts, I notice the distance at the top etc
seems to make a big difference.
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