Lampblack in place of charcoal?

Yes, charcole is actually a better fuel for Black powder and the like, although I've never worked with lampblack befor. I would amagin charcole is alot cheaper too.

[Edited on 6-1-2004 by JDP]

I have tried

it SUCKS in most composition. I don't know why it is so inert to ignition. sulfurless black powder didn't burn at all! I heated some on bare flame the nitrate melted and started to bubble! but no ignition! . normal meal powder with charcol substituted with lampblack burns very slowly and veeeery smoky

Depends

.

It's carcinogenic..

Quite a while ago, I tried to use soot instead of charcoal. I had a bag full of soot after cleaning a metal chimney tube of a wood-burning furnace, and I wanted to see whether it would work. This would provide a free source of relatively pure and finely divided carbon, suitable for the purpose (or so I thought). Unfortunately, I must report a lack of success.

The major problem when working with soot was that I couldn't get it wet before blending. This is easily seen if You deposit some soot on a test tube, e.g. by using a candle flame, and when it cools down, immerse it in a glass of water: some soot falls off and floats on the surface, some remains on the tube, but none gets wet. It was difficult enough to admix finely pulverized sulfur, but soot..... A "fair success" was ultimately achieved by admixing some flour-based gel, obtained by boiling some flour in water, and later vigorously shaking this in a bottle with lots of soot. When this mixture was blended, it was poured out and left to dry, and later re-pulverized in a mortar, in a similar fashion as with the charcoal. However, this fuel could never be completely dried, and consequently, could not burn very fast. I didn't find any other suitable wetting agent, though I tried many. Working with this was painstaking though, as the soot is very light and easily flies, is difficult to measure, gets things messy etc.

The "flour-bound fuel" could be used in a furnace as a very good fuel, but that's all it was good for. Later I learned lampblack is used in fireworks for making bright, finely dispersed "stars" that burn bright but slow.

I speculated on why the results were so poor, but I couldn't be sure my speculation was correct. I didn't encounter this topic in the literature, so if someone else did, I'd appreciate the input. I tried to identify the main differences between the soot I used and standard charcoal. The two most obvious were the chemical composition and mixing properties. The fact that the soot could not be wetted by itself, led to the conclusion that it couldn't be intimately blended with other ingredients (chiefly the oxidizer) so the contact surface would be small. Second, the charring procedure retains catalytically active metal oxides in charcoal, whereas the soot is almost pure carbon (and perhaps some incomplete burning products): when lightly compressed and exposed to Bunsen heating in a ceramic dish, it ignites (shines) and almost completely burns leaving very little residue.

My conclusion at the time was that the lack of catalytic action of metal oxides that promote burning could be the cause of soot being such a slow burning fuel when compared to charcoal. I remember the old experiment of igniting sugar: it burns very well in contact with wood or cigarette ash, but only melts and carbonizes if ignited alone. Now that someone mentioned that, it appears logical that the high carbon content in soot would require more oxidizer, as well. As to the contact surfaces, charcoal is a good adsorbent owing to large contact surfaces its porous structure has, so these two might contribute to the observed results. I speculate the repelling of water might indicate the soot repelling the hot gases during combustion as well, which could hinder the process. Sulfur melts at elevated temp, so the analogy would not apply. Again, this is just my speculation and may not be true. If someone reported success with this fuel, please provide some input about the procedure they used. It would certainly be great to have access to a scanning electron microscope as the one described in the technical report above, to see what really happens in there, but...

Yes, I'm aware of that, but as I said, the goal was to obtain cheap fuel. I also tested it to see how much residue it would leave after burning all the carbon out, as I explained. It left almost none . . .

I didn't want to use pure lampblack because it was always too expensive compared to charcoal, and I thought my experience with chimney soot would apply to lampblack as well, at least in part . . .

And yes, I forgot, I've seen mentioning isopropyl-alcohol somewhere in the literature, which would be similar to EtOH You proposed for the purpose, but again, "reasons of economy..."


[Edited on 7-1-2004 by overseer]