[BALLOKNET]

Hi all.
I'm a videoartist, I just want to know if exists a combustion that is invisible for the eyes.
It's to make a video with things burning but any flame shown.
Is that posible?
Thanks in advance

[hmx9123]

Sure.  Hydrogen burns with an invisible flame, for example.  It's gotta be pure, though.  If you're burning paper, etc., you could always use steam.  That's kind of neat.  Once you start burning carbon-rich materials, though, you'll get the nasty yellow flame from the sodium line in the spectrum.

[BALLOKNET]

Cool,
Then...Is possibe tu buy Hydrogen easyly? or someone have to make it in the lab?
What materials do you recommend to burn and avoid sodium flames or other flames (also invisible smoke)?
Thanks again.
Joan.

[Borek]

Cool

I don't think so, you are too optimistic IMHO.

I think you are making very basic mistake in your approach.

If I understand correctly you want to make film of something that burns, but in such a way that only changes of burnt material are visible, not the flames and the smoke, am I correct?

The problem is, once this material starts to burn - it burns. Doesn't matter how you started the fire - it will be always the same process. As Polish saying goes where there is fire - there is smoke (well, it goes "there is no smoke without a fire" but let me reverse it for a better effect ).

Hydrogen flame is almost invisible, but once it will touch a piece of paper, there will be no difference in a way the paper burns - it will react with oxygen, there will be flames and some smoke. It is unavoidable.

When it comes to burning organic substances (let's assume they contain mostly carbon, hydrogen and oxygen), there are two types of flames (that's my classification, nothing official, and it is definitely not a thing I will die for, it is based on loose observations of pyromaniac ). Some flames are yellow, some are faint blue. Blue color is that of hydrogen reacting with air oxygen, yellow one is that of carbon - stripped of hydrogen, heated up but not converted to CO₂ yet. Some compunds contain less carbon (in terms of percentage) and these have tendency to burn almost invisibly (faint blue - but that can be filtered out). Such is methanol for example - but it is liquid. Paraformaldehyde will be better as it is white solid. But even these may have some traces of yellow in the flame.

The problem is - if you want to burn something that looks like book and behaves - when burning - like book, just there are no flames visible, you should probably start thinking about other idea. Every substance behaves differently when burning, changing its appearance, shape, size and so on. If you burn a book - flames will be yellow, and it will be obvious it is made of paper, as pages will shrink and get black in a characteristic way. If you make model of the book from the paraformaldehyde or something similar - there will be no flames, but it will be obvious that what burns is a model made from some other substance.

OK, so what do you want to burn?

[jdurg]

Methanol is notorious for having a very faint, if even visible at all, flame.  I'm sure it can be found on the net, but in one of my OSHA classes I took in college they had a video of a tanker truck overturned on the side of the road.  They showed firemen in their fire suits walking towards the truck and suddenly catching on fire.  The video then showed the same truck but through an infrared filter to show the heat.  It was amazing how the fire was clear as day through the infrared filter, but absolutely invisible on the normal film.  You could only see the waviness of the different air densities where the flame was.

[mike]

Don't forget that safety proecautions will be paramount in this venture. You should probably have some kind of "expert" there with you at the video shoot as it is very dangerous to work with these types of flammable reagents.