253 replies to this topic

[LadyKate]

The white pine result is quite encouraging!? Was that Pinus radiata or strobus?

Pulverone is less dense so it will burn faster than dead-pressed and corned powder of similar particle size.? There is just more surface area for the same mass.? Not sure about moderately high densities like 1.7 g/cc, the optimum density might be a function of the charcoal's initial density or cellular structure.

I'm not sure of the exact species of pine since I bought the pine as cured lumber. The label was white pine and when we looked it up on the original order from the supplier it just said white pine or spruce. I asked the lumber yard to look it up since the actual label on the pallet was not informative. This pretty much followed what Kyle did on Passfire. His results for his charcoal seemed positive (nothing was measured but he did say that the charcoal made good lift powder).

EDIT: In the US, lumber called 'white pine' is sometimes harvested from the Western White Pine (Pinus monticola) or any of the other species of soft pines. The pine you don't want is any of the species of 'hard' pine known as 'yellow' pine. Yellow pine is used in larger size construction lumber (bigger than 2x4) and should be avoided because of the resin problems.

Your observation about pulverone coincides with other's opinions, too. However, most authors, including Perigrin and Malttiz have cited sources and also stated that pressing is needed to get optimum speed and (of course) durability of the grain. I have noticed that some mixes improve in speed after pressing and some don't. Which leads to the 'optimum density' question.

The 'optimum density' question seems intriguing. Some charcoals, after being made into BP, can be pressed to 1.7 grams/cc quite easily. Others require considerable pressure to get to that density. Is it possible that there would be optimum densities given different kinds of charcoal? Wow... that made the number of variables a bazillion and one.

I'm currently re-mixing some of the pine BP that was left over in the test sample with +10 dextrin. It will be made into pulverone. It would be nice to find an easy-to-make and durable lift powder formula.

EDIT: Dextrin decreased the speed of the pulverone a bit more than I expected.

Elephant 2fg 6.172
Pine with +10 Malto Dextrin 3.604
Pine with +10 Yellow Dextrin 5.872
Pine (same batch as 27 Aug shoot) 7.040

Edited by LadyKate, 31 August 2005 - 01:48 PM.

[LadyKate]

I just tested some Balsa wood charcoal. I was able to get enough together to make it worth while cooking some up.

There is no doubt that Balsa is the hottest of the charcoals that I've tested so far. In small quantity burn tests, BP made from Balsa charcoal burned almost like flash powder. It is quite scary for BP!

In my film can mortar tests, it had hang times of 9 to 10 seconds consistently - that on 2 grams of powder. The burn rate tests (time to burn along a 2.5' trough) were as follows:

Elephant 2Fg burn rate = .934 seconds (avg)
Pine Pulverone burn rate = .768 seconds
Balsa Pulverone burn rate = .434 seconds!

Did I mention that it was a bit scary working wth the Balsa BP? I think that it is the fastest BP I've ever seen and I don't think I want to make a lot of it. Pine, willow and maple are much tamer and still very servicable - they are much more to my liking.

[Yugen-biki]

I have some balsa, but have never thought about makeing coal with it. Maby now I'll make a small batch to confirm your results...
It could be interesting.

[karlfoxman]

Balsa wood gives fast BP, that speed is scary less than half a second and its gone! It would be good for lifting charge i guess and you wont have to use as much either due to the power. Might have to try some balsa charcoal but to buy it may be expensive as i can only see model shops selling it really.

[Rhodri]

Hi

I posted some information a while ago regarding bramble charcoal.

This is the time of year to harvest it. Strip it down, dry it then 'cook' as you would any normal wood for charcoal.

Try it, you'll be surprised and the smell is wonderful!

[karlfoxman]

Well being such a nice day (i hope) i might go look for some, even though i have 2kg of willow charcoal and 1kg of pine charcoal both already in powder form coming. Its going to be a BIG box i think!

[LadyKate]

I have some balsa, but have never thought about makeing coal with it. Maby now I'll make a small batch to confirm your results...
It could be interesting.

Please do! I was able to pick some up cheaply but it still cost about $9.00 for 100 grams of finished BP - it takes more of it to make enough for a batch of BP since it is fluffy. I would love to get some independent confirmation of this reactivity. Maltitz states in his book that the reactivity of Balsa charcoal is unknown but rumored to be the strongest of all wood charcoals. Perhaps we could support that claim a bit.

If you can, compare your finished product with a commercial BP in some sort of time test or mortar launch test. That gives a relative measurement of speed/power using consistent apparatus. That still may not be scientific, but it does communicate better.

You mentioned that you liked to mill your charcoal and BP until the charcoal is shiny when pressed down. You won't have a problem making shiny charcoal with balsa - that stuff is like fluffy grease when it is finished to airfloat!

[JamesH]

I may as well add a video clip of my BP here. In the clip there is 1 teaspoon of my 2Fg that was pressed and corned to 16 - 28 mesh. I use willow charcoal and the comp is milled for 24hrs.

http://media.putfile.../1-Teaspoon-2Fg

[ProfHawking]

thats very impressive compared to mine
however is that an ematch you are ignighting it with? Wouldnt the pyrogen have given it a bit of extra omph?

(my ball mill is still clogging up for some reason and making lumps of hard bp that i dont think are mixed very well:angry: any ideas?)

[JamesH]

I used my homemade igniters for ignition. I only used a very thin layer of bp bound with NC lacquer on this one so it wouldn't give a false indication.

[RegimentalPyro]

(my ball mill is still clogging up for some reason and making lumps of hard bp that i dont think are mixed very well:angry: any ideas?)

Could it be that your KNO3 is too well milled to begin with? If you mill KNO3 long enough it exhibits this "clumping" problem.

My BP (in it's Polvorone form factor) is quite well respected as "frisky" amongst the cognoscenti, The milling cycle is *only* 5 hours as follows...

First Mill the Sulphur and the WillowCharcoal together for 2 hours to ensure both are as fine as can be.
Add the bog standard G-direct KNO3, and dextrin if making Polvorone and mill for a further 3 hours
Transfer out of the mill, and moisten prior to pushing through a 10 mesh screen.

The advantages of this method is that the milling cycle is potentially dangerous for only 60% of the time, and I only have to handle really fine airfloat powders once, (when I empty the mill)

[ProfHawking]

Cool i will try it out, thanks!
Thing is charcoal i think. i have run out of commercial airfloat (dunno what type of wood(s)) and i'm using lumpwood that is ground up into the full dust-1cm lump. the mill bashes everything into powder, but i wonder if this is the cause.
I'll try doing it seperate next time, at least will then know if its the kno3 or not.

[Frozentech]

Empirical test of latest batch of milled and corned BP. This was from a 200 gram batch, milled 3 hours in a home built 'Sponenmill' from Lloyd Sponenburgh's plans. Media was 4 foot of brass 3/4" hex rod cut into .75 inch pieces, standard 75:15:10 BP with 4% dextrin, pressed at 4,000 lb in a press and corned. 1 gram each of corning dust ( meal ) on the left, and 10-20 mesh corned powder on the right.

corned BP tests

I've got a stop watch modified to trigger and stop externally, 3 microswitches, angle iron and materials to build a BP burn timer as described by Dan Williams at: Dan Williams' web page I just need to get it done, then I can start to do more scientific quality testing, like Lady Kate and others have been.

Edited by Frozentech, 23 November 2005 - 06:37 AM.

[ProfHawking]

Yep my BP sucks. Hmm
You can see from the pattern left on the paper that the corned one burn mutch quicker, it spread out further and burnt the paper less.
Do you have a corning machine frozen? or do you just bash in a pan or somrthing?

[karlfoxman]

I am thinking of building a bp speed tester, instead of using a stopwatch and microswitches i will design a digital counter. I am hoping to start and stop the timer using photodiodes that detect either the orange light from burning bp or the IR given off. This will be very accurate and will last and last. Any thoughts? It could be used as 'the' tester when the BPS is up and running.