20 replies to this topic

[takuma]

Hello Everyone,

Today I got my kno3 from GD, I dont have any sulfur but yeah! I thought id test it with just charcoal see if it was the real deal...

So I weighed 7.5g of kno3 and 2.5g of charcoal, and it sucks!

My question is, is sulfur needed to produce a fast burning bp, or is my kno3 naff?

My kno3 is from chempak and the label on the bag reads:

"POTASSIUM NITRATE
Nitrogen(N) 13%
Potassium Oxide(K2O)
Soluble in water 46%(K38.2%)"

Any help?

Thanks guys.

[pyromaniac303]

What type of charcoal did you use? If you bought from Garden Direct its definately not your potassium nitrate thats at fault. Can you tell us how you processed it?

And to answer your question, sulfur makes it burn more consistently, hotter, and slightly faster, but sulfurless BP is still perfectly usable.

[takuma]

Quick reply, thanks!

Well, I cant tell you what charcoal it is, I can tell you that it's been stored for yonks in a powdered milk tub.

heh, I used to mess around with it when i was younger, so didnt pay much attention.

The charcoal was ground up in a coffee grinder years ago, and I ground the KNO3 tonight aswell. Mixed it by sieving.

The charcoal worked perfectly a few years back, is it possible it could have reacted with anything?

Ill get some charcoal and sulfur tomorrow, what charcoal do you suggest?

Thanks in advance.

[Arthur Brown]

GD nitrate is Commercial purity, so it is OK. Possibly better than in the days when gunpowder was commercially used.


Do please get a respected text on black powder! COPAE is one and has a chapter on the development and formulation of BP in different grades for different purposes.

Any powder made from just mixed charcoal and nitrate will be very weak as the grain incorporation will be very poor.

If your bag from GD says potassium nitrate then it IS. BUT the grain size is unsuited for BP and even the milled ingredient with charcoal will be poor.
Good BP is an art worth researching.

[pyromaniac303]

Its possible the container wasnt airtight, and the charcoal contains a small percentage of moisture, you can try spreading a small amount on a tray and leaving it in a warm place for a day or 2, then trying it again. Also as its only fertiliser grade KNO3, could have been stored just about anywhere, so it may help to do the same with this too.

If you remember whether it was lumpwood or briquettes that would be useful though, if the source is briquettes, you have no hope of getting a usable product.

It depends what your after producing as to what charcoal you want, to start with normal lumpwood charcoal will be fine for relatively slow BP for making fountains and stars, but for lift go for willow, alder, balsa, and maybe others, everyone has their own preference but I think willow is the most common.

Another thing is, you don't know the particle size of either ingredient, so a ball mill would be a good investment if your after really fine powders for fast mixtures, but fountains, stars and fuel for small rockets can be hand made with a mortar and pestle, sieve and a coffee grinder.

[takuma]

Im thinking ill start out with a little fountain, Im fairly certain it was lumpwood charcoal.

I am going to invest in a ball mill, and was planning on getting it from here. Is anyone familiar with this site? know if they're any good? Any recomendations on other places to get ball mills? Also what media should I use? I was going to melt down some lead, but what other options are there?

Arthur said:

the grain size is unsuited for BP and even the milled ingredient with charcoal will be poor.

Do you agree with this pyro? If so should i consider getting KNO3 else where? May i ask where you get yours from?

Thanks a lot.

[pyromaniac303]

I have the exact same mill as that, and have problems with the barrel slipping, and its underpowered. I recently bought one from America and I'm waiting for it to arrive (note that if you buy an american mill, you will need a voltage converter).

I think what Arthur means is that the 2 ingredients need to be ball milled together to make a useful powder, rather than the ingredients themselves are poor.

I use 12mm lead media, seem to be good quality, I bought them from Cooperman435 on this forum who makes them himself. Previously I used lead fishing weights, but they were 'pear shaped' and started to wear unevenly, they were never intended to be a permanent solution anyway, just a cheap temporary one.

I use chempak KNO3, from the local garden centre, which is the same stuff you bought from garden direct, though I have some more expensive 99.8% pure KNO3 if I ever need higher purity.

[Arthur Brown]

A mixture of even the finest (grade and particle size) ingredients will perform less well than the same ingredients properly incorporated, milled, pressed and corned.

The sulphurless compound is of some significance but is less sensitive to ignition than the "normal" mix with sulphur.

That mill is underpowered but it will be fine as a starter mill

Edited by Arthur Brown, 07 March 2008 - 10:09 PM.

[takuma]

Ahh I get you now Arthur!

Thanks for the help guys, I'll let you know how i get on!

[Arthur Brown]

Remember that BP is a 2 or 3 part mix of solids! The particle fineness and the close incorporation of all the particles is critical to the performance of the final product

[takuma]

Heyo!

So today I went out and bought:

Big K Lumpwood Charcoal (made from residue wood?)
Yellow Sulfur

Anygood? Couldn't find any other charcoal anywhere!

On the upside i bought myself a new car aswell! woo

[xXPyroJoeXx]

Sorry I cant answer you question, as I have little knowledge of the process of BP at the mo....however I would like to ask you a question: Is the stuff from GD any good? Also do they accept paypal??
Thanks

[and7barton]

I only use soft airfloat willow charcoal....... it's as fine as the finest talc. I mix up the complete formula, then pour in enough hot water to make a soup like a watery porridge - add a couple of drops of washing-up liquid as a surfactant. Then ball-mill it for around six hours. Then spread it on a drying plate to dry out, occasionally moving it around. When dried to a damp condition I've been pressing it in a 2-ton press, but I'm trying to omit the pressing process as it's messy and takes time. Anyway, when it's dry break it up or rub it through a coarse plastic sieve. DO NOT ball mill a DRY mix !

[knackers]

g`day mate,.... Do not mill a dry mix, are you talking about Bp, ( you mentioned willow so i am assuming you are ) why not ? i only mill my bp dry, then rice it, as it illieviates all the mess, as for a surfactant, i`ve never used washing up liquid and never thought too, as a solution of alcohol and water would suffice, breaking down any surface tension and leaving no residue, .. does your mill soap up ? how does your bp burn ?

Edited by phill 63, 15 August 2008 - 09:23 AM.

[dr thrust]

hi!, well it certainly looks like an interesting method, ball milling a watery soup like bp, how does it compare in burn rate to dry milled bp? it looks messy but there's no i guess chance of a spark, and how did you come about this method your own? at the end of the day its about what method best suits you, and what your comfortable with, ho how noisy is the watery milling method? and does it aid noise reduction.