18 replies to this topic

[StarScream]

Please forgive me if this issue has been discussed before... I looked.

I bought some 4oz packages of KNO3 recently from a local oriental food store, but this stuff DOES NOT BURN AT ALL! I can hold my pocket torch to a small pile of milled powder and it just gets hard and crusty... doesn't burn. This is food-grade KNO3 so I would assume that it's very pure.

I'm wondering if the factory screwed up with the labeling or something. Maybe it's not really KNO3? Maybe it's KNO3 coated with something to inhibit burning?

I've never tried lighting KNO3 on it's own like this before, so maybe it's not supposed to ignite. All I know is the BP I made with this stuff doesn't light.

Help!

[bobconan]

No kno3 can not burn on its own. it is an oxidixer and needs a fuel to burn. i suggest you start reading some more. Almost afraid to ask how you made your bp. Burn some charcoal and once its red hot put some of the kno3 on it. It should flare up.

[Richard H]

Oh come on! You do know how to make bp, don't you?

[StarScream]

Guess I should have supplied more info instead of thinking aloud too much!

I've made meal powder numerous times with no problems, and this time the only ingredient that was changed is the brand of KNO3. I grabbed a few small packages from a near-by supermarket to try out, milled some down and used it in a small test batch of meal powder... which doesn't ignite no matter what you do to it.

I guess my question was is there a way to test KNO3 to see if it is the real thing? I just thought maybe it would burn easily.

[chemicalwazi]

Guess I should have supplied more info instead of thinking aloud too much! 

I've made meal powder numerous times with no problems, and this time the only ingredient that was changed is the brand of KNO3. I grabbed a few small packages from a near-by supermarket to try out, milled some down and used it in a small test batch of meal powder... which doesn't ignite no matter what you do to it.

I guess my question was is there a way to test KNO3 to see if it is the real thing? I just thought maybe it would burn easily.

Hi StarScream

This may help, i was testing some Potassium salts with help from Stuart back in July
Only i was identifying Perchlorate. This is the post from Stuart

Mix some with sugar and ignite. It should produce a pall purple flame. This tells you that it is a Potassium Salt.

You could then see how much dissolves in water. Potassium Perchlorate seems to be pretty insoluble at 10*C while Potassium Chlorate is slightly soluble and Potassium Nitrate is very. I only give these solubilities as they are the most likely salts that they could be.

Potassium Perchlorate: 1.05g
Potassium Chlorate: 5g
Potassium Nitrate: 20.9g

Get 100ml of water and get it to about 10*C. Add 1.05g of one sample and stir. If only a tiny amount does not dissolve, then you may have Potassium Perchlorate. If it all dissolves, then add another gram. If this dissolves, then it ain't looking good. Then add 2g and see if this dissolves, if so, add 10g. If this dissolves, then it is pretty likely to be Potassium Nitrate. If it does not dissolve, then it is probably Potassium Chlorate.

Repeat the test with the other sample.

This is not the best way to test as there maybe impurities but it will give you an idea if it is Potassium Perchlorate or not. Also, even if it is Potassium Perchlorate, don't expect all of the 1.05g to dissolve.

Stuart

As you can see there is a Nitrate test here. (20.9g in 100ml @ 10*C)

Also if you take a Nitrate solution and dip some thin coloured tissue paper in it (the kind you get in sheets from a craft shop) Then leave to dry. This will give you ignitible 'touch paper'.

Hope this helps

Cheers

[seymour]

I grabbed a few small packages from a near-by supermarket to try out, milled some down and used it in a small test batch of meal powder...

you can buy kno3 at the supermarket in canadia( i just like saying it that way)! that would be cool! bet it costs lots though. hear in nz u can get it for under $2 a kilo. but it is agracultural grade so not that pure.

[Andrew]

Meal does not really go with a normal lighter. A blowtorch type tends to set it off quite well, if you are using a normal lighter you may as well change tactics. Lighting a piece of paper or thickish string, blowing out the flames and applying the embers to the powder will set it off. If this does not work, you have not got meal powder!

[Pretty green flames]

You are saying that meal will not light with a lighter. This i can not belive. Decent Bp should ignite from sparks.
I really see no reason for using a blow torch.

I ignite my Bp with a burning bamboo stick, it needs just a touch to set it off

[adamw]

GOOD meal WILL ignite with a common lighter. You should not need a blowtorch to get it lit.

[alany]

He's probably refering to the effect where a pile of meal is so smooth it is somewhat resistant to ignition from a cool orange gas flame. The calm orange flame convects most of its heat upwards so it isn't very good at lighting anything flat on a surface. A splint or torch pokes into it and ignites it instantly because the heat transfer is much more efficient.

Granulated BP is easier to light with a lighter because it is sharp. If you are crazy enough to try lighting anything with a lighter that is! IMO it just puts your fingers *way* to close to the action. Even a 6" long splint is too close for firing grained BP. One of the animated pictures in my avatar picker is of me doing that, I held the splint too vertical and singed the hairs off my nuckles, narrowly avoiding getting a powder tatoo.

If you are testing compositions use a stick of blackmatch for $deity's sake! Especially for 'unknown' comps. It costs virtually nothing, and you probably already have metres of it laying around, just cut off a few inches. Same goes for stars, they can do nasty self-propelled tricks and shoot up your sleve or down your pants!

[StarScream]

you can buy kno3 at the supermarket in canadia( i just like saying it that way)! that would be cool! bet it costs lots though. hear in nz u can get it for under $2 a kilo. but it is agracultural grade so not that pure.

It's a Asian supermarket that imports most of their products from China. They sell 4oz packages of potassium nitrate for $0.98 CDN each, so about $4.00/lb. That's still considerably cheaper than buying stump remover at a garden centre for $12.00/500g. Believe me seymour... It's harder to find here than you think!

I'm now pretty much convinced that what I have here is not KNO3. I made some touch paper with it last night and it doesn't work. The paper just burns as it normally would.

[alany]

Got a picture of the package?

I used to use food grade KNO3 of Asian origin, it came in very similar sounding packaging. Sugary moist crystals in a plastic heat sealed package. Only 2 oz IIRC, red or blue printing most of it Chinese.

[adamw]

If you are testing enough of anything to singe your hairs I'd say you were testing too much!

[alany]

A half-teaspoon of 10-20 mesh BP IIRC.

The problem was the hot gasses rose around my fingers before I really knew what happened. If I had approached from the side rather than the top nothing much would have happened.

[miniskinny]

If your Potassium nitrate isn't performing, recrystalize it. If it still doesn't work, check your methods, and make sure you aren't making any critical errors. If all of these are done, and it still baffles you, it's not Potassium Nitrate.