Drying 20mm Lancaster silver

[ivars21]

How are you priming your stars if you use H3 break? It sounds very loud break indeed. Edited November 26, 2012 by ivars21

[Potassiumchlorate]

I didn't prime them. They ignite fine anyway, being chlorate stars.

 

The first time I made silver stars, I only had German Dark and atomized aluminium, though. The atomized burns pretty slowly. Those I primed with magnalium/Fe₂O₃ thermite.

 

Yes, H3 gives powerful bursts indeed. I just pasted 12 layers of gummed tape on that one.

[ivars21]

Now I am thinking that I could make some H3 for salutes, as it is safer and I am out of KClO4. I think I could granulate them to make it a bit violent. Any suggestions? Have anyone tried which one is louder - whistle or H3?

P.S. Sorry for disturbing your topic.

[Potassiumchlorate]

It's OK

 

I use this composition:

 

Potassium chlorate 75

Willow charcoal, airfloat 23

SGRS 2

 

You can of course use dextrin instead of SGRS, but then you have to go up to 3 or 4%.

 

It works fine to granulate it. I have noticed that if you wet it repeatedly, the KClO₃ seems to get incorporated into the charcoal. Since just a small amount of KClO₃ dissolves in water, the risk of over wetting it isn't great.

Edited November 26, 2012 by Potassiumchlorate

[Mumbles]

I'm not sure what you mean by safer. H3 is still 20-50% more sensitive to impact than 70/30 flash made with Perchlorate and flake aluminum. There are tables in Shimizu and Shidlovskiy if you want to compare values.

[AirCowPeacock]

Yeah, but considerations of static sensitivity are a must, especially when talking about F. Is H3 static sensitive?

[ivars21]

I thought it is safer than 70:30, but obviously I am wrong. But it cannot be so sensitive as it can survive lift, so dropping it in the shell from ~1.5m shouldn't be a problem. (while handling etc.). What are the main risks of working with H3, considering I am not going to hammer/ram it?

Thank you for your answers.

Edited November 27, 2012 by ivars21

[Potassiumchlorate]

Yeah, but considerations of static sensitivity are a must, especially when talking about F. Is H3 static sensitive?

 

It doesn't feel that way. I feel quite comfortable with working with it, as opposed to flash, where I always feel a little bit nervous.

[Potassiumchlorate]

I thought it is safer than 70:30, but obviously I am wrong. But it cannot be so sensitive as it can survive lift, so dropping it in the shell from ~1.5m shouldn't be a problem. (while handling etc.). What are the main risks of working with H3, considering I am not going to hammer/ram it?

Thank you for your answers.

 

The main risks are spontaneous ignition, if it comes in contact with ammonium compounds or sulfur. The only sulfur that comes in contact with potassium chlorate in my shells is the delay fuse, and in this shell I covered the fuse with thin tape, so there wasn't any contact between them at all.

[pyrojig]

Shoot, that little contact would create little to no issue ever. You would have to have perfect conditions, and sheer bad luck to get a accident( spontaneous ignition) from sulfur in that time fuse. So much bad rap on kclo3 was due to unwashed sulfur, and bad manufacturing practice's in the past. Many formulas can be utilized that where a "dangerous mix" in the past, with the purity of the chems we have now. But this doesn't mean to not be cautious . Much research and time must be given to pyro to be a good( safe_) builder. This will save you the painful learning curve of "bad combinations " of chems .

[AirCowPeacock]

According to Shimizu H3 broken shells are known to explode on contact with ground if not ignited by lift--apparently because of the contact and friction between sulfur in timefuse. Certainly alot more force then you would probably be incontering under normal conditions, but to be noted.

[Potassiumchlorate]

Shoot, that little contact would create little to no issue ever. You would have to have perfect conditions, and sheer bad luck to get a accident( spontaneous ignition) from sulfur in that time fuse. So much bad rap on kclo3 was due to unwashed sulfur, and bad manufacturing practice's in the past. Many formulas can be utilized that where a "dangerous mix" in the past, with the purity of the chems we have now. But this doesn't mean to not be cautious . Much research and time must be given to pyro to be a good( safe_) builder. This will save you the painful learning curve of "bad combinations " of chems .

 

Yes. Ammonium compounds is a big no-no, but sulfur is very unlikely to cause any spontaneous reaction with KClO₃ with today's pure chemicals. The use of potassium perchlorate seems to be mainly to have a broad safety margin. Chlorate compositions are also more shock and friction sensitive, so the manufacturers of fireworks prefer to make blue and green with potassium perchlorate and potassium perchlorate+barium nitrate and throw in some magnalium for brightness rather than using the superior organic chlorate blues and greens.

[Potassiumchlorate]

According to Shimizu H3 broken shells are known to explode on contact with ground if not ignited by lift--apparently because of the contact and friction between sulfur in timefuse. Certainly alot more force then you would probably be incontering under normal conditions, but to be noted.

 

No, you can't say that for sure. Back then they just had BP and H3, and H3 is of course more impact sensitive than BP, but a potassium perchlorate burst composition with sulfur is actually more impact sensitive than a potassium chlorate burst composition with charcoal only.

[AirCowPeacock]

Hey, I didn't say it; Shimizu did. The sensitivity of KP may be why he thought the sulfur in the timefuse is the problem, because perhaps KP broken shells are not known to explode if they fail to ignite; then one could suggest that it cannot be the sensitivity of H3 alone, and thus must be something else, such as sulfur in timefuse--which would make sense.

[Potassiumchlorate]

Anyway, I just remembered another method to inhibit contact between sulfur and chlorate: I pour a small pile of perchlorate prime on the exposed end of the time fuse. It also has the benefit to enlarge the flame from the fuse, so that the burst is ignited well.

[Mumbles]

PotassiumChlorate, you might want to recheck your copy of F.A.S.T. before trying to put words in Shimizu's mouth. He actually says the exact opposite of what you just mentioned.

 

"The great advantage of this KP charge is that it causes less trouble in the manufacturing operation than that of the chlorate charge H3; i.e. the friction sensitivity of the KP charge in contact with black powder or other compositions which contain sulphur or it's compound is not so high as that of the chlorate charge H3. Therefore it can be said that the KP charge is safer than H3 during the loading of shells or to the shock on the ground in the event of a misfire."

[Potassiumchlorate]

 

Yes, I see that now. The impact sensitivity is lower, though. Page 212.

[AirCowPeacock]

I have heard of people doing that with sulfurless BP or a tiny peice of tissue paper covering the end of the timefuse.

[Mumbles]

That chart has always been a little suspect to me, especially in comparison with table 29 on page 319. Table 29 you can see values for a variety of mixes with a variety of fuels and oxidizers. A 75:25 mixture of chlorate and charcoal has a non-explosive height of 79cm, but a 70:30 mix (which is closer to what you have when including binders), has a non-explosive height of 62cm. Going from 70:30 to 65:35 the sensitivity decreases, and then to 60:40 it increases once more before starting another upward trend.

 

The entire chart shows some inconsistencies that make me wonder sometimes about the data. I've actually been considering building friction and impact sensitivity testers of my own.