16 replies to this topic

[Techohead]

Hello to all,
i hate to have to bring up something i'm sure has been done to death, but finding certain bits of information on this forum is proving difficult at times. for the last 6 months i have been using tech grade to make all my pyrotechnics compositions, and have been getting excellent performance out of everything.
recently my supplier went out of business due to false declaration of dangerous goods in the national postage system. i have recently been looking all around the internet for another AUSTRALIAN supplier, but have not been able to find anyone who sells tech grade KNO3 in less than 1 tonne quantities. i have however found a source for farm/agriculture grade KNO3 in 25Kg bags. this KNO3 is much more affordable but price was never an issue anyway. i would like to know what the typical percentage purity would be for this type of KNO3, and will i still be able to get the same sort of performance from my black powder and other compositions? any information anyone can give me on the subject is much appreciated,'
thanks in advanced,
techohead.

[bigtonyicu]

Hello to all,
i hate to have to bring up something i'm sure has been done to death, but finding certain bits of information on this forum is proving difficult at times. for the last 6 months i have been using tech grade to make all my pyrotechnics compositions, and have been getting excellent performance out of everything.
recently my supplier went out of business due to false declaration of dangerous goods in the national postage system. i have recently been looking all around the internet for another AUSTRALIAN supplier, but have not been able to find anyone who sells tech grade KNO3 in less than 1 tonne quantities. i have however found a source for farm/agriculture grade KNO3 in 25Kg bags. this KNO3 is much more affordable but price was never an issue anyway. i would like to know what the typical percentage purity would be for this type of KNO3, and will i still be able to get the same sort of performance from my black powder and other compositions? any information anyone can give me on the subject is much appreciated,'
thanks in advanced,
techohead.

the short answer is it depends, I personnaly have been using the stuff for several years with great results, but not all brands are of the same purity. If you can see it before you buy it you'll now the biggest contaminent tends to be clay the brands that aren't pure (or very close to it) tend to be beige or tan in colour. take a look at www.nakka-rocketry.net. my friend Richard Resently covered the subject, he also covers how to purify it if it isn't good enought to use in pyrotechnic devices... in his case High power Rocket motors. hope this helps a little.

[marble]

It will be fine, just buy it.

[Arthur Brown]

Buy it and try it! As you say suppliers may falsely declare things for easy postage.

KNO3 should be a white crystaline powder looking similar to granulated sugar, but not for eating!

If it is tainted then a simple recrystalisation from water with filtering the solution through a fine paper should help.

In the days when BP was an industrial essential then the Saltpetre was of uncertain quality but BP was still made and still worked for cannons guns blasting and fireworks.

[Night Owl]

I have to dissagree all the unpure KN03 Ive bought has never bin any good for BP and i got it from different suppliers, the only KN03 thats bin usable for me is 99% pure.

[phildunford]

Don't know what you've used SS Man, but I think you must have been very unlucky.

I've use Garden Direct 'fertiliser grade' KNO3 for everything for years and it's perfect (and cheap as chips). It's a white powder and (I guess, never analysed it) pretty pure.

I've tested it up against AR grade laboratory stuff in identical batches of BP and find no discernable difference in the end result...

[Night Owl]

When Iv'e bought KN03 from pyro suppliers it just doesnt mill down or mix very well even after 30 hours milling, ive tried 3 differnt suppliers all with the same result so Iv'e started using 99%+ reagent which works great, very fast bp but expensive

Iv'e jus purified 1k of poor grade KN03 today so we'll see wot results that has

Edited by shell shooter man, 21 September 2008 - 08:05 PM.

[Arthur Brown]

I doubt that the Chinese use AnalaR grade in all their BP maybe if buying form some places a propper analysis is needed but KNO3 is so simple a chemical that the imurities should be in the ppm range and not interfere with the normal uses.

[Night Owl]

Well Arthur please tell me whats wrong here???? I use sulphur marked on the jar as "98% sulphur", Willow charcoal made by me, these milled with 99% reagent KN03 from a chemist supplier, I get purfec BP:) then I mill with KN03 from 3 different pyro suppliers and the BP is but a fizzle, Wots wrong????

Please put me out of my missery:(

[Bonny]

I only use garden grade KNO3 and homemade willow and even pine charcoal and have no problems with my BP...

[Arthur Brown]

Every problem I have rotates around particle size! Trying to make good mixes from coarse granules means longer mill times, Also if the mill is too full it will mill very slowly (but more quietly!)

Pre milling things in a kitchen blender reduces the time to mill tremendously. It's likely that agricultural KNO3 is coarser than AnalaR powder to start with so it really just needs more mill time.

[Night Owl]

The KN03 from pyro supplies comes in a powder form, the KN03 I use from chemist supplier comes in prill form which I grind up in a pestal and mortar, this then takes about 12 hours milling for purfec BP, my pyro supply batch which has been milling so far for 50 hours and is still milling time of writing this, lights about six seconds after a flame is put to it then burns very slowly (it did this after 12 hrs milling) for some reason low grade KN03 is not grinding down and mixing,

I have purified it now so hope this solves things but I cant figure out what is wrong..................

Edited by shell shooter man, 23 September 2008 - 10:27 PM.

[pyrotrev]

The problem with using agricultural grade or any other type that is not of guaranteed purity is that it CAN vary. It may be very good for a long period but if the supplier changes their source or manufacturing method then you could be stuck with dodgy stuff all of a sudden. I've used GD KNO3 for a while and it's excellent for most purposes apart from a little sodium contamination, but what I've got is only probably from one or two batches. However very pure it is not, I was quite horrified at the murky liquor I decanted when recrystallizing some for a white glitter mix.

[Night Owl]

The problem with using agricultural grade or any other type that is not of guaranteed purity is that it CAN vary. It may be very good for a long period but if the supplier changes their source or manufacturing method then you could be stuck with dodgy stuff all of a sudden. I've used GD KNO3 for a while and it's excellent for most purposes apart from a little sodium contamination, but what I've got is only probably from one or two batches. However very pure it is not, I was quite horrified at the murky liquor I decanted when recrystallizing some for a white glitter mix.

Hi Pyrotrev

After you recrystalized it was it much more pure?? and did your BP improve? I'm still waiting for my KN03 to dry its taking ages:(

[pyrotrev]

Yes, recrystallizing made it a) visibly whiter as a powder, and got rid of a yellowy tinge in the glitter compo I was working on. I didn't have any problems with basic BP in its raw state though so can't really comment on that. I dried mine in the oven at about 70 deg C, just made sure there was nothing combustible available to fall into the dish! Good luck. BTW, the secret to recystallising KNO3 is to get a saturated solution in boiling water, then cool right down - it's fairly insoluble in cold water, whereas NaNO3 varies much less with temperature.

Edited by pyrotrev, 24 September 2008 - 01:12 PM.