KP on Hulls

[xBangergoosEx]

Does anyone have any experience with KP on rice hulls? if so, how does it perform in shells as a burst charge? also, how does it compare to BP?

[fredhappy]

I am currently only using KP on hulls as break. It has a couple of big benefits as opposed to mcrh.

 

1: easy to make.

The ingredients can be screened to get an intimate mix. I've heard people ballmill the sulphur and charcoal before screening the KCLO4, but I just screen the ingredients and it works fine.

 

2; no ballmill required.

No ballmilling, just screening the ingredients together gives a very potent KP.

 

3: Kind of charcoal used is not as important as it is with blackpowder.

I use grape charcoal, which works fine. I ve got hemp charcoal , but there is no need to use it, KP is powerfull enough for my needs with ordinary grape charcoal.

 

4; ELIMINATES THE NEED FOR A BOOSTER

The main reason for me to experiment with KP is not having to go through the hassle of making 70/30 everytime I make a shell. I have no problems with using/making 70/30, but being able to ommit the need for a booster is a big plus for me.

 

5: More gentle breaks as opposed to mcrh boosted with some kind of flash( also depends on pasting) . KP also burns hotter then MCRH, thus enabling better ignition rates for stars.

 

downsides:

 

1: use of a more expensive oxidiser (KCLO4) as opposed to KNO3 , which is a lot cheaper for me.

2: friction sensitivity. KP is actually more sensitive to friction then H3 is. When you work responsible, there is no problem whatsoever with it.

3: need for a bit more pasting. ( not that much in comparison with mcrh/hotflash breaks.)

 

Just check my last shells for examples , I ve used KP with good results, even for 3 inch shells. It is especially good for double petals. See my 4 inch double petal, it was broken with KP on hulls in a 7/1 ratio. It gave a huge round break.

 

I hope this helps.

Edited June 9, 2011 by fredhappy

[xBangergoosEx]

Thanks that was really helpful! ill try this out.

[usapyro]

Anyone here ever used sulfurless KP granulated?

[Mumbles]

Sulfurless KP is mentioned in Shimizu as burst No. 5. I've had it recommended to me in shells no smaller than 10", and even then only in single petal peony form. I've never tried it for lift, but I also personally wouldn't.

[redandblue]

Does anyone have any experience with KP on rice hulls? if so, how does it perform in shells as a burst charge? also, how does it compare to BP?

This is a topic close to my heart. I have tested and found that KP as a lift and break is equivalent, up to a point. In confinement, and in large quantities it's power increases rapidly. IE- for lifting up to 3" shells, I find KP granules to be the same as commercial 2 FA BP. For 4" shells, I mix 60% KP and 40% BP for lift. If I use all KP for 4" ers it would be too much bang and not enough gas.

I just mixed a batch of 50/50 BP and KP on hulls for break charge on 4" shells. I did this after reading once again, Shimuzu's data on both comps. I want the speed of BP, but the temp of KP. I have been using DB's whistle on BP hulls, but wanted a one step process. Shimuzu says that BP burns 2X faster than KP, but KP burns 2X hotter. Not sure why no one has mentioned this that I can find on the web, but my hypothesis is that I should get the best of both.

I am trying this as I have some silver comet and AM Perc Blue stars rolled that are brittle and are breaking apart in 4" shells. So I want a soft burst, but a hot one to ignite all the stars. (and yes the AM perc stars are coated with an K perc prime).

I use the KP with sulfer 90% of the time, but for chlorate stars, either prime or burst, I omit the sulfer, just in case.

For very small shells, (1.5" or 2") BP on hulls with flash or whistle has worked very well. But I am doing mostly 3" and 4" shells now. The 3" have been pretty much perfected, but the 4" are fairly new, hence the experimentation. They take more of everything and the dynamics seem to be quite different.

For reference, I use round paper shells with gummed tape and string spiking, this cuts down on the number of layers of tape. So, gummed tape, stringing, more gummed tape. I don't like the mess of packing tape which I used to use.

 

I'd love to hear any comments on my rambling. I also have a question about -325 mesh Mg or -100 to -200 Mg for Mg stars, but that's another topic!

[Mumbles]

The burn speed is in the open. Under pressure it burns much faster than BP. By adding black powder, you're simply diluting the burst speed and temperature. I suppose BP may help to get it up to pressure easier though. Something to keep in mind is that just because it burns hotter, doesn't mean it has better ignition properties. Harder breaks give poorer ignition in general. There is typically less exposure to the flame, and the stars are ejected faster so they are more likely to blow out.

 

BTW, if your stars are being shattered by the break, you may want to look into your manufacturing method. They're clearly not bound well enough.

[redandblue]

Thanks mumbles.

My hope is that the BP KP mix will be slower than the whistle on BP hulls, therefore reducing the shock but providing the necessary force. It's an experiment I know.

And yes, the stars were rolled in a hurry, we had 6 days of rain ahead of the 4th, so I ended up rolling in 98% humidity, and in the rain under a tent, and could not follow my usual pattern of rolling, drying some, rolling, etc. So I have a large batch of stars I'm trying to save. I've tried putting a coat of NC lacquer with BP, etc, but they still seem brittle. But I am not surprised they are having trouble due to the non-standard process I had to use. Usually my stars are hard as rocks and don't fracture.

I should be able to test the break this weekend, I'll post results. I'll see how it compares to whistle/BP hulls. I have enough of both to make identical shells and compare.

[redandblue]

Did a lot of testing. The humidity was the cause of the star problems. Rolled the same comp outside, and inside with a filter/fan and mask. Couldn't roll the ones outside for crap. Always stayed too wet.

Also, just tested KP vs BP in the star tester. Used some indoor rolled perc blues and reds, hard as rocks, like they should be. No shattering.

Star tester- 1/2" ID aluminum tube, welded solid base.

 

Used very accurate scale,( for reloading gun cartridges). Used 2, 1/4" perc based stars with BP prime for each test. Both BP and KP granules were screened through a household strainer, not the fine one, with ~3% dextrin, KP was with sulfer.

 

1st- 18 grains BP, put in 2 stars, then added 3.5 grains BP. Both stars ignited, good height, but could have had more.

2nd- 18 grains KP, put in 2 stars, then added 3.5 grains KP. One star ignited, much louder. Too much bang, heard the other star hit the ground though, sounded intact. Went higher too.

3rd- 12 grains KP, put in two stars, then added 2 grains KP. Both stars ignited, good height. Acted just like BP #1 test.

 

Not sure this answers the original question, but confirms to me that KP is very similar to commercial BP. Now the question of confinement... If you use KP like commercial BP, at some point it is bound to become too harsh. Just like my lift, I use some granulated KP, some granulated BP. All KP lift is too harsh, all BP and you have to use a BUNCH of it. A bit of both works just like the weights given for commercial BP. I found many years ago a formula for Pyrodex, commercial black powder for firearms that claims to be "smokeless BP". It is almost identical to KP, but yes, less residue due to more total combustion. So they tuned it to act like commercial BP in the same quantities.

Next test will be to use the BP+KP on hulls in a real shell. It is dry now, moooore rain has slowed everything down the past week. So 2 shells, one with BP on hulls and whistle, one with BP and KP 50/50 on hulls, no whistle. Same stars. We will see....

[PersonGuyDude]

Can anyone with a good amount of experience comment on the possible dangers of working with KP?

I was planning on bursting 2" plastic canister, and 3" plastic ball shells with pulverone (I do not have a ball mill capable of producing enough burst for the rockets headers ill be making at a 3-day long club meet) and quite a bit of slow flash or whistle.

After reading up a bit, it seems KP will do a better job.

I realize that it will be quite difficult to make good breaks with the limitations of plastic AND un-milled powder, but since this is my first club meet, I'm just trying to get the best out of it.

Should I worry about friction with KP more than BP/slow flash?

The area where the club is meeting is in a desert environment in Nevada, heat will be high and humidity likely very low, so I'm not too worried about static.

Thanks

[Seymour]

Star tester- 1/2" ID aluminum tube, welded solid base.

 

While star guns are commonly made from metal, I would never put KP mixes in them for lift. While you can feel comfortable with the fact that BP cannot go "high order", I do not have the same trust with KP mixes. KP burst is much more pressure dependent than BP, and if the pressure decides to spike, you may be on your way to hospital. Obviously I do not know the wall thickness of this tube of yours, but I'd want it to be at least as thick as the tubes ID before I'd feel like it's not pushing your luck with KP burst.

 

Personguydude, the sensitivity of KP burst depends somewhat on the composition. Where I work we have a mix using only Potassium perchlorate, Potassium nitrate and charcoal, and it will be quite insensitive for a perchlorate mix.

 

Shimizu's Sulfur containing KP burst on the other hand, is really quite sensitive. I don't think it would take that hard a whack with a hammer to set a little bit off on concrete. However, the same would apply to many Potassium perchlorate coloured star mixes. Quite sensitive compared to BP, but I'm very comfortable working with it.

 

The sensitivity of the slow flash depends on the formula, but I would guess that a KP burst with sulfur will be more sensitive, and one without sulfur less sensitive than your average slow flash (nitrate/Al/Sulfur is what I'm guessing).

 

 

As for the talk about sulfurless KP burst, and what size shells you need to use it in, this all seems quite contrary to my experience. The sulfurless KP burst I mentioned earlier works very nicely in small shells, and I would be wary of using it in a ten inch shells due to it's power. Perhaps it is due to the well ball milled charcoal from a reactive wood that we use?

[redandblue]

As for the tester, thin walled, but I've been using it for 8 years, worst that happens is that with a few stars in the tube, they can once in a while get jammed, and they are then obliterated. Still not much sound produced. It's behind a concrete step when lit, so I would not be in the line of fire in any case.

 

The sensitivity to friction and shock is listed in Shimizu's book. I test any new comp I use with a steel hammer on concrete just for my own knowledge-

From Shimizu-

KP- 2Kg drop hammer 62cm, 10 tries, no explosion. friction test- 87.5 Kg 10 tries= no explosion.

BP- " " 85cm, 10 tries," "= never an explosion.

H3- " 79cm, 50 tries," "=75Kg 10 tries= no explosion.

 

I just tried my hammer test with a couple of pinches of KP with sulfer, I thought I would break the concrete slab I was hitting it so hard, no reaction. Sliding the hammer head around with pressure, no reaction.

In the past I found that whistle when dry will pop with a pretty good blow, once the humidty sets in, no reaction.

And JUST Pot Chlorate takes a small hit to go off, add sulfur, and it gets loud!

 

In a dry climate, with the danger of static, flash would be scary to me. Not only is it VERY sensitive, but the metal makes it more likely to take a static spark.

Since Pot chlor by itself will go off with a hit, the charcoal in H3 must be desensitizing it quite a bit. I suspect the same is true of KP. 2Kg from 62 cm is a hard hit!

 

I looked through my notes from a few years ago for small shells with KP burst. Here are some results.

2 1/4" plastic shell- KP granules with 1/4 tsp flash, packing tape added, Too hard break, no stars.

2 1/4" plastic shell- KP granules with 1/4 tsp flash, no packing tape. Too hard break, no star ignition.

2 1/4" plastic shell- " ", with packing tape, but very hard mag stars. "HUGE break! Really large spread!"

3" plastic shell- KP granules 1/2 tsp flash, no tape. It was a salute!

3" plastic shell- BP on rice hulls with 3/8 tsp flash, with tape. Notes said"out$&)^@#@standing!" Large tigertail stars, so they were probably more fragile than some other comps too.

 

* 3" plastic shell- KP granules NO FLASH, no tape. "need longer time fuse, but very good. Very nice bouquet effect"

So at least one test with just KP granules worked well. Just leave out the flash..... I assume the bouquet was due to the too short time fuse. These were 10mm tiger tail stars, so there probably wasn't much room for the KP either.

 

I guess the one success with KP granules and flash was due to the mag stars being very hard and withstanding the force. Otherwise, KP granules appeared to be too harsh with flash. I went to BP on hulls after that with flash. I now use BP on hulls with whistle for 3 and 4" paper shells. And am testing the BP/KP on hulls currently.

 

So I believe that no matter what you are using, or where you get the data, the ONLY reliable way to make all the factors work is to test, test, test.

 

And for 3" shells, the KP with flash was a salute, so I wouldn't use KP in ANY larger shell, unless maybe on hulls. But I haven't tested that.

Good luck!

[Mumbles]

I see you've rediscovered on your own the pressure gradient for burn rate of KP. It really does not take kindly to boosters.

 

I too have never been able to set off KP with a hammer or mortar and pestle. Doing potassium perchlorate and sulfur together is really no feat for either test. I really can't say how it'd work for plastic canisters or ball shells. I haven't made either in years. Back when I was playing around with them, they were burst with BP on hulls and whistle.

 

Seymour brings up a good point, if you have any hot charcoal, you can certainly make some fairly powerful bursts without milling (besides the charcoal). I made up a KP mix designed for 5 and 6" shells, and was regularly blowing 3" shells of charcoal streamers blind when I used milled willow. Even a green mix BP with good charcoal will probably get okay bursts on it's own, much better with a gram of booster in there.

[PersonGuyDude]

Wow, you all have my thanks. That is exactly the information I was looking for.

I think I will either try KP(w/ sulfur) with commercial charcoal, or perhaps pulverone with balsa charcoal using Mike Swishers method of granulating with boiling water.

I can't believe how misinformed I was about static, I was under the impression that humidity was bad and a dry climate was ideal....

Thank you to alerting me to that, I think ill stick with KP or BP+whistle in that desert, and some anti-static spray won't hurt.

[Mumbles]

Humidity is not desirable for drying things and comfort, but good for keeping down static.

[vladou]

I made a large batch of KP coated rice hulls 1:5 as burst charge for my 4" shells. Since I can't use my ball mill to make BP, I will try to use KP as lift charge but I don't know if 10% of shell's wheight is too much and can blow up the mortar? Maybe I should use 8%? I have not ball milled anything but the grapewine charcoal is airfloat. Any suggestions?

[fredhappy]

I made a large batch of KP coated rice hulls 1:5 as burst charge for my 4" shells. Since I can't use my ball mill to make BP, I will try to use KP as lift charge but I don't know if 10% of shell's wheight is too much and can blow up the mortar? Maybe I should use 8%? I have not ball milled anything but the grapewine charcoal is airfloat. Any suggestions?

 

Your ratio is very strange to begin with. 1: 5 ??. KP is not usable as lift, for all the reasons outlined so clearly in this thread. Read this thread carefully, and you'll understand. Like KP being pressure dependent and so forth, this should make it crystal clear for you that it has no use as a lift powder!

 

Since you can't use your ballmill, you simply can't lift anything at the moment. Fix your ballmill, and you can make some lift. Don't dabble with KP as a alternative for granulated BP lift , it really is NOT an alternative for this purpose.

 

Have the courtesy to read the whole thread, before you ask a question/suggestion . All the pro's and con's have been outlined and are being spoonfed very clearly in my opinion , and still these questions pop up about using KP as lift or other uses.

[Seymour]

Your ratio is very strange to begin with. 1: 5 ??. KP is not usable as lift, for all the reasons outlined so clearly in this thread. Read this thread carefully, and you'll understand. Like KP being pressure dependent and so forth, this should make it crystal clear for you that it has no use as a lift powder!

 

Since you can't use your ballmill, you simply can't lift anything at the moment. Fix your ballmill, and you can make some lift. Don't dabble with KP as a alternative for granulated BP lift , it really is NOT an alternative for this purpose.

 

Have the courtesy to read the whole thread, before you ask a question/suggestion . All the pro's and con's have been outlined and are being spoonfed very clearly in my opinion , and still these questions pop up about using KP as lift or other uses.

 

 

While I agree with most of this post, I disagree with the statement "you simply can't lift anything at the moment."

 

While it's a seriously disadvantageous situation, for almost all firework building, and especially lift, screened together components CAN work as lift if the confinement is sufficient. I'd never dare relying on the shell's fit for this confinement, and would suggest loading the granulated greenmix in a plastic baggie, then pasting with several layers of pasted paper. More layers for crappier greenmix. after being pasted and dried, you can punch a hole in it for the timefuse to "mate with", amd another punch for inserting Quick match. This, along with using more of the stuff will allow lifting, if at a large labour cost.

 

Spiking canister type lft charges is just as effective.

 

However, I recommend the ball mill method for the long run!

Edited July 26, 2011 by Seymour

[fredhappy]

While I agree with most of this post, I disagree with the statement "you simply can't lift anything at the moment."

 

While it's a seriously disadvantageous situation, for almost all firework building, and especially lift, screened together components CAN work as lift if the confinement is sufficient. I'd never dare relying on the shell's fit for this confinement, and would suggest loading the granulated greenmix in a plastic baggie, then pasting with several layers of pasted paper. More layers for crappier greenmix. after being pasted and dried, you can punch a hole in it for the timefuse to "mate with", amd another punch for inserting Quick match. This, along with using more of the stuff will allow lifting, if at a large labour cost.

 

Spiking canister type lft charges is just as effective.

 

However, I recommend the ball mill method for the long run!

 

O darn Seymour, that one hadn't crossed my mind! ...Screening a greenmix is a possibility too I guess. I would never dare using it for lift myself , but with sufficient spiking it might work fine.

[redandblue]

The results are in on my test of KP and BP powder on hulls for burst. I finally had good weather to get the tests in.

 

I made 2 3" paper shells. I tried to make them as similar as possible.

In common-

bottom of shell- ~31 blue K perc stars, top ~44 red Sr N mg stars.

1 layer of wet gummed tape, spiking spaced about 1/2 to 3/4", two more layers of gummed tape. 2 3/4" lengths of 1/4"chinese time fuse with NC lacq./BP on fuse ends.

Both sent up via 19g KP granules mixed with 6g BP granules. I know, I know, you can't do this, but I have been using KP for SMALL shells for years for lift. It takes half as much as home milled BP.

 

1St shell- Used 50/50 BP/KP powder on hulls 4 to 1. KP had sulfur, used about 2.5% dextrin. Burst was very good, although not very symmetrical. Star ignition was >90% based on video counting. (red mag stars ROCK!).

 

2nd shell- Used BP on hulls 4 to 1, with ~1tsp whistle dumped in center. Burst was more symetrical, and somewhat larger. All red stars ignited, but only about 70% blue. (red mag stars still ROCKED!)

 

So, not sure if I did it again the results would be identical, but I'm thinking the KP/BP burst with one more wrap of tape would be perfect. Hopefully the star ignition will still be as good, and I can get a bit larger break. They both looked great for amateur shells, the neighbors were happy! So I will try some more and see what happens, but I can say for certain that it does work well. So hopefully I can just make whistles with whistle mix from now on.

 

So to the original question, I think yes, KP does have a use in breaking shells within certain parameters.

[psypuls]

have someone else tried the 50:50 BP:KP on hulls method? i'm interested in using this for my 4" shell that have previously blowed perfectly fine primed stars blind with kp only burst

[Guest]

I want to start making shells but I want to start small.less comp to make, cheaper, and less damage if it goes wrong. I was told small shells like 1" or 1 3/4" shells are harder to burst than 3+" shells. Would kp be better than bp for small plastic shells? Edited September 15, 2016 by tacticalnoodle

[OldMarine]

I haven't used plastic shells but for my 1.75" paper ball and cylinder shells I've had to dust some KP burst on my BP to get a decent burst.

[Mumbles]

KP is sort of a weird composition. It does burn faster than BP in some instances, but requires higher pressure to do so. Small shells like you describe would not be effectively burst by KP since they cannot generate sufficient pressure on their own. It really is in kind of the sweet spot between 4-6" shells, perhaps 3". Mixing it in with something like BP which burns well at ambient conditions might be a way around this or to stretch into other sizes. You in theory could try boosting it, but you're going to be dealing with a fine line. KP is best on it's own, and simply dialed in with pasting or ratios on your burst carrier. It goes from anemic burst, to great burst, to salute without a whole lot tuning.

 

I've also never had any luck with it using plastic shells. Flash bags and BP tend to be the easiest method for them.

[Merlin]

I don't worry about it since changing to cylinder shells but on these small ball shells why would benzolift not work for break? it's very reliable and more potent than BP. Since it is basically a type of whistle diluted with BP it would seem a version could be made diluted with more BP in the benzolift formula that would be just the right burst strength.