27 replies to this topic

[SharkWhisperer]

"Shaking" a pyro comp "as hard as you can" to test stability/safety is just plain dumb. No way to state it otherwise.

 

You seem like an inquisitive experimenter, and that's great.

 

You'll probably get away with it, but more concerning is what else you won't get away with in the future.

 

Not a fan.

[JTO]

Thanks! Unfortunately the publication seems to be pretty hard to find, too esoteric I guess.

Pressed stars have edges and the prime doesn't cover them completely and evenly like it does with rolled stars. I would be nervous adding black powder burst and closing a shell with those kind of stars too. I'll let others that know more than me advise you on that, but you might look into rolling your stars instead of pressing or cutting in the future. 

 

A retired fireworks manufacturer named Bill Ofca wrote a series of pamphlets called 'Technique in Fire'. One volume was specifically devoted to working with chlorates. I don't have it any more, but it was a good read.

Edited by JTO, 23 September 2021 - 05:31 AM.

[JTO]

My true and tried white composition is very simple :-)

50% KClO3

40% aluminum (very fine, airfloat, don't know the particle size because I milled it myself, but it is so fine that one batch turned out pyrophoric)
10% shellac (already dissolved in ethanol) (shellac is cheap at Aliexpress!)
For me, the shellac-ethanol solution alone is adequate to moisten the mixture, no water or ethanol needs to be added. I am using a ready-made shellac-ethanol solution with 50g shellac and 200ml ethanol. I used a syringe to estimate the quantity of shellac, assuming 5ml of solution = 1g of shellac.

These stars are pretty fast and very bright.

I pumped them on a glass plate using a syringe with the end cut off to form 1g stars. Afterwards dipped then in H3 primer with some dextrin as binder.

I also tried a version with dextrin as binder, it was inferior (burned at least as fast but was not as bright).

Mind sharing your white formula? I haven't made any chlorate based stars containing metallic fuel. I don't think chlorate + metal is so much unpredictable (like chlorate + sulfur) as it is friction sensitive. All things pyrotechnic have the ability to go up, that is their purpose. We just want to have say so when they do. I'll deal with a predictably sensitive composition before I would an unpredictably "moderately" stable one. I may do some chlorate / metal (no magnesium... thats really unnecessary) composition tests in the future, but for now I'm leaving the metal with perchlorate.

 

[JTO]

Isn't BP worse because in my experiments it seems to burn *far* less aggressively that H3, which would suggest that the chance of a blowout or failure to ignite would be greater with a BP primer than with a H3 primer?

 

Most people I'm familiar with would probably suggest to prime your stars with BP instead of H3.

 

[JTO]

Thanks, I'll try to be extra careful with everything I do, always wear protection, and only work with small batches in the range of a few tens of grams at a time. My biggest problem probably is that I am stuck with potassium chlorate because I live in the EU, I would like to use percholarate but it cannot be purchased here (neither can chlorate but I make it myself). Thanks once more for your valuable feedback.

 

You'll probably get away with it, but more concerning is what else you won't get away with in the future.

 

 

[Arthur]

Sadly chlorate comps behave differently from perc comps -you will have to get used to it.

 

Sulphurless powder is available for making transitions from chlorate to sulphur comps. So use a BP spollette with one increment of sulphurless powder on the end to transition into H3 could be a useful practice. Chlorate stars could be coated in sulphurless powder or in NC lacquer as a barrier for sulphur/chlorates. 

 

Ebay has had some lead dioxide electrodes from an Australian supplier recently (likely made in China) If you are OK with MMO then you could soon be Ok with lead dioxide. Having a supply of DIY perc would help a lot.

[JTO]

The second clip looks pretty good, the burn rate looks pretty close to ideal. The visible difference between that and my BP spolettes (5mm inner diameter, BP + 5% dextrin, rammed in wet) is that mine produce easily over a meter long trail of sparks :-)

 

 

I can't say really. Depends on too many things. Though I kind of lean on the assumption that "its probably going to break harder than I think" and go from there. Not great advice, I know. Really for me it has been trial and error, and making changes to correct those errors.

 

Edited by JTO, 23 September 2021 - 06:59 AM.

[mabuse00]

I'd think JTO's projects have to be viewed certain perspective.

A few premises for most Europeans:

-To fly under the radar is not an option, it's mandatory. "Getting legal" is not possible.
-Apart from (per-)chlorates: Nitrates and metal powders are under surveillance or might not be available to private individuals at all.
-The effort to produce your own perchlorate, in a good chlorate-free quality increases your efforts at least threefold or more compared to just chlorate. For special applications that might be OK, for the bulk - no way.

So if you are such an unreasonable character and still try to pursue this hobby, developing a full chlorate system is an interesting challange worth taking. Especially if you only do small scale stuff and development is done for the sake of itself.

If magnalium is at hand, something like this

https://www.skylight...ow-rubber-stars

tuned for chlorate might be an option.

I remember trying the reds and blues once and it seemed to work nicely, but I didnt make proper notes back then.

 

 

Considering spolettes:

That's an application where imho H3 is very well suited, maybe in combination with a similar blackmatch formula.

The fast burn is not a problem, but a benefit, because it makes timing more precise. Try to make multi breaks or a ring of reports and use a slow burning delay, then you know what i mean.

(Extreme example - burning speed is 1mm/sec and your working accuracy is maybe 0,5mm - the reports will be totally scattered!

crackcrackcrack--crack--crackcrack------crack)

 

The rocket rules also apply, you want good consistent compaction, dont want wrinkled tubes (no wonder why it burns so fast... ), waxing helps.

Edited by mabuse00, 26 September 2021 - 04:36 AM.