Setting up my beginner home chemistry workspace now. I can’t afford a fume hood, so I was wondering if using a table fan in front of a fuming
solution, in front of a window, would be an alternative to doing experiments outside? It’s a bit of a hassle to move equipment outside!
Thanks!Abromination - 17-6-2019 at 21:51
No, no no no!
If you are doing something that would require a fumehood, it needs to be done either in a hood or outside.
If it just smells, it is alright to use a fan.
Flammable fumes should not be pulled through a house fan and should also be avoided in general.
Here is a hood design that is alright for minimal fumes but is overloaded easily and should not be used with flammables, gasses like NOx or corrosive
gas like HCl.
I have used it for RT reactions that release irritating fumes or odors.
This is NOT A FUMEHOOD SUBSTITUTE!
It is much more of a hassle for your family to pay your funeral costs!Quantonium - 17-6-2019 at 23:14
Ok, outside it is then!
Thanks for the info.draculic acid69 - 18-6-2019 at 05:02
Depends what it is like cyanide needs to at least be done outside but if it's just something that smells bad or fumes bad like xylene or HCl then the
fan is fine.its all bout the danger rating.Quantonium - 18-6-2019 at 05:48
I definitely want to be safe, so I won’t be using anything crazy.
Is reading the datasheet, and following the precautions there, usually enough to stay on the safe side? condennnsa - 18-6-2019 at 06:54
I definitely want to be safe, so I won’t be using anything crazy.
Is reading the datasheet, and following the precautions there, usually enough to stay on the safe side?
kill yourselfSWIM - 18-6-2019 at 10:01
If you need a fume hood, you need a fume hood.
But it's not just a matter of flammable or not flammable; toxic or not toxic.
Concentrations matter a lot.
Flammable vapors are only flammable within certain limits, and careful technique and proper equipment can keep those toxic or flammable materials
largely in the glassware so the dangers are minimized.
Ive distilled ether without a hood. Efficient condensers and vapor traps, and a vent hose that leads out the window.
But a well installed window fan with sufficient power is much better than no fan at all.
Use a large box type window fan, and put filler material around it so the only open space for airflow is the fan itself.
Have an internal box structure that goes on the inside of the window so all the air sucked out the window is drawn from the end of the box, and if
possible fit some plexiglass, or even a curtain of thick plastic sheeting on the inner opening of the box so it just gives you room to work, and
ideally set that up so it can be nearly closed when you're not actually sticking your hands in there.
Sparks from the fan? Cover the vents of the fan motor with fine metal screen. This will allow the cooling airflow for the motor but limit the danger
of ignition (Like a Davy lamp, I think that's what they're called).
This will be NOWHERE near as good as a proper fume hood, but tremendously better than just putting a fan in the window and hoping for the best. I
wouldn't put a baking dish full of hexane in there to evaporate or anything like that, but evaporating solvents shouldn't be done like that anyway.
Use a still.
Such a setup, with a good airflow, will keep gasses released from building up to flammable concentrations in most situations.
However the most important part of working with flammable and toxic materials is that first line of defense: the glassware itself.
Ground glass joints or stoppered flasks can be set up with the venting limited to one or maybe a few tubes which can be led outside through hoses as I
did with the ether I mentioned earlier. For corrosive or toxic gases these tubes can be lead through gas washing bottles where they are neutralized or
collected with appropriate chemicals.
Ideally, there should be no troublesome materials released except when you open the apparatus for adding chems or for breaking it down when you're
done. For low boiling solvents, cool the flasks before opening that equipment up to further limit vapor release.
However this is only if nothing goes wrong. Broken glass, a fire, a runaway reaction, all these may result in stuff getting out of that glassware so
you still need ventilation, as you do for the final disassembly of your equipment.
One more word about corrosive vapors: These can't really be dealt with by just blowing them out the window anyway.
Even in very low concentrations they may eventually really fuck up the paint outside that window, and anything else nearby. If it's corrosive, lead it
through some sort of neutralization device.
For acids or bases a Dreschel bottle with an appropriate acid or base in it.
For other materials whatever will absorb or destroy it.
happyfooddance - 18-6-2019 at 14:18
That's good advice, SWIM, I want to add that you can avoid release of harmful chemicals when breaking down as well. Apparatus can be placed in a
large basin or bucket or tote, filled with water and/or a neutralizing agent, and opened under liquid.
Also, neutralizing in situ, either through an addition funnel or other, more creative means.
Also, removing by entrainment, a brisk stream of air is great (don't use an air compressor with glass), let it run through the system (and through
your venting tube and out the window) and forget about it.
There are many ways to deal with dangerous compounds safely, and the challenge in dealing with them is a big part of the fun, for some people.morganbw - 18-6-2019 at 14:55
Even if you work outside, common sense will still need to be used. The air is not always moving and the vapors can still be a problem.
I have had to use a fan on the outside a few times.Quantonium - 18-6-2019 at 21:29
Thanks for the great answers! I will likely stay away from most dangerous stuff for a while, until I have learned more of chemistry in general. That
said, I am thinking I might make a diy fume hood to have outside, with a long air duct going away from where I am. Double protection so to speak.
I definitely want to be safe, so I won’t be using anything crazy.
Is reading the datasheet, and following the precautions there, usually enough to stay on the safe side?
Well it depends.
MSDS are unnecessarily scary. No one would get into chemistry if they only read those files
I cant think of the name of the experimenter but there is a nice story around 1850 of a chemist who as many chemists read that copper reacts violently
with nitric acid and wondered what "violently" meant.
A lot of us have beliefs based on what we read but the truth can sometimes be different.lordcookies24 - 19-6-2019 at 14:14
