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KNO3 and KClO3 incompatibilities


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Posted

Good day pyros

i made a lift charge using 40%kclo3 30%kno3 and 30%charcoal. I want to ask if there are incompatibilities with this mixture mainly kno3 and kclo3 together as i cannot find any article regarding this. My goal with this mixture is to make good lift without using ball mill. 

Posted

No issues. Just be aware that adding perchlorate to the mix increases the burn exponentially based on pressure. It'll become too spicy to use as lift pretty quickly as you increase the weight of the shell.

Posted
13 hours ago, FrankRizzo said:

No issues. Just be aware that adding perchlorate to the mix increases the burn exponentially based on pressure. It'll become too spicy to use as lift pretty quickly as you increase the weight of the shell.

Thanks! Just to make sure, it was potassium chlorate that im using. I havent read any books containing kno3/kclo3 incompatibilities. Im using this composition because i cannot make a good bp without milling forever. 

Posted
7 hours ago, Pyrophoric30 said:

Thanks! Just to make sure, it was potassium chlorate that im using. I havent read any books containing kno3/kclo3 incompatibilities. Im using this composition because i cannot make a good bp without milling forever. 

You can eliminate all the kno3 and use only chlorate, i would add also a bit of sulfur but if it Is acidic could be a big problem, i found the 93% Is the One used for agricultural had inside carbonate and sulfate like anti acidic so if used with the due Precautions can be suitable

Posted (edited)
16 hours ago, Pyrophoric30 said:

Thanks! Just to make sure, it was potassium chlorate that im using. I havent read any books containing kno3/kclo3 incompatibilities. Im using this composition because i cannot make a good bp without milling forever. 

Thanks for pointing that out, I did miss it. My post still applies; both chlorate and perchlorate have a pretty severe pressure exponent and you'll want to be aware of that when scaling up.

Chlorate and charcoal compositions like H3 do have safety considerations though. Be aware that your comp will be friction and impact sensitive. Absolutely do not ball mill the entire mix. I would also make a small 10g batch, and then take sub-gram samples from that to abuse on the cement with a hammer face and get acquainted with the sensitivity.

Edited by FrankRizzo
Posted (edited)

Chlorate / charcoal likely has a higher probability of exploding with minimal confinement (like a shell sitting on top of it) than black powder which pretty much won't do that.  I'd probably attempt something less sensitive that generates more gas like guanidine nitrate before using a chlorate for that.  FAST lists charcoal / chlorate as 1 (lowest sensitivity) but it still does sensitize things and 70% chlorate / 30% charcoal is nearly the worst ratio as far as that combo goes, with the hammer drop test @ 65cm (compared to 116cm for KClO4, 95cm for KNO3, and 91cm for NH4ClO4)...  Technically it's the third worst ratio, since pure KClO3 was measured at 64cm max before it exploded and 60/40 was 62cm making it the only ratio more impact sensitive than a plain old bag of potassium chlorate.   So congratulations, you've made the chemical marginally safer by adding to it...  until it gets loaded up with acidic sulfur residues from the tube it's loaded in as lift anyway. 

Friction of chlorate wasn't affected at all by the hemp charcoal he was using (the maximal 75kg weight didn't set it off). H3 is usually considered to have friction issues because it's inside of a shell where stars are usually primed with something containing sulfur and there's a sulfur containing fuse and crossmatch going into it.  If isolated from the rest of the shell and the charcoal isn't somehow loaded with sulfur or some other acid all information indicates there won't be any friction problems.  Of course your fuse leading into it probably contains sulfur...  Charcoal doesn't have much effect on ignition temperature so aside from the part where it's going to explode if you try to lift anything bigger than maybe 1.5" with it...

I'd consider, unless you're retired, to start figuring your time as money though.  A mill running isn't "your time", it's just sitting there drawing very little power.  If it's taking so long that it's actually an issue it's probably just not a good mill for the purpose, or the media isn't good for the purpose, and you should look into replacing it instead of looking for solutions to problems that shouldn't exist (and that people would be using if they were functional in general;  obviously you could use far less of a chlorate based powder, so why is literally nobody doing that?) I use benzolift for star guns / 1.25" crossette firing specifically because it's far too "sharp" a lift powder and it simulates a hard break better than just poofing it up in the air with regular BP.  If things reliably ignite and stay lit when lifted at that speed, they'll probably tolerate a boosted break easily.  If shell inserts survive and ignite, they're good too.  I wouldn't use it for an actual shell over maybe 2" and I let the consumer fireworks companies make those small ones for me because it's a pain to work on that scale and they're very good at the miniaturization these days.  Between the two sizes of tubes I generally use benzolift in (1/2" and 1.25" IDs), benzolift is weird and ill-behaved.  Roughly ~75g crosettes only need ~35% more of the stuff than a couple of 5g stars fired from a narrower tube to reach full height, even with an inner cardboard disk & wadding and taped tops on both.

If you don't think the mill is the issue, get better chemicals.   Use the ones you have to make slower BP or prime or whatever.  I can mix powder good enough for 3lb stingers and hummers out of the KNO3 / C / S I have without ever touching a ball mill or using the idiotic CIA process.  The extent of my labor is a couple of screenings, 10 minutes in a giant granite mortar and pestle, spray it with 30mL or so of 75/25 water / alcohol, screen it again, and let it dry.  If it's fast enough for 3lb stingers it'll be fast enough for 1lb rockets too, although I haven't fired any yet.  I haven't had the need to do anything but screen mix for primes and glitters.   I haven't granulated any to try for lift because I'm getting a mill for that and it doesn't seem like pressing pucks is worth my time until I have a very consistent powder that I can base my lift calculations on.  I'm not about to start throwing together 4" multibreaks without knowing how high I'm putting them;  there are already too many other variables. 

 

Edited by PyroGnome
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