clorate in fireworks

[memo]

i want to make some flash bags and i have no perclorate just how would it work using clorate and dark al in flash bags ? i know the clorate would come into contact with black powder in the spolette and the black match. is this doable ? or is there enough sulfur to cause a problem.

 

memo

[OldMarine]

Aren't you on FW as well? Mike Swisher has an article there that dispels most of the chlorate sulfur wives tale.

[schroedinger]

No, the problem with chlorate are acids. I recommend that you read about the problem in shimizu, somewhere around p.190 the discussion about thunder 1 and Hardt Pyrotechnics, where a good discussion is found and some analysis on accidents is evaluated. A real risk is posed by degrading paste. Edited June 5, 2016 by schroedinger

[OldMarine]

I'd not heard of the paste as a problem. Dagnabbit, more reading.

[schroedinger]

The Problem is that degrading paste or gummi arabicum solution, turns acidic during the degrading/moulding process. So always use fresh paste with chlorates, never paste that is on the edge of beiing o.k. It's cheap anyway.

That can alsk be a problem with ready made adhessive, if they use preservatives that rely on dropping the Ph.

Edited June 5, 2016 by schroedinger

[OldMarine]

I've not dealt with chlorates yet but want to be up to speed when i do. Thanks much.

[taiwanluthiers]

You can always put a thin piece of plastic between the flash burst and the spoolette or time fuse. The plastic would prevent contact but will burn through easily to ignite the charge.

[memo]

how can you prime a chlorate star with bp and not have a problem. what is the difference between black match nosing bp prime on stars ?

 

memo

[Mumbles]

The biggest issues with chlorate and sulfur is friction and impact. Acidic sulfur is much worse, though sulfur does sensitize mixtures. Being in contact is not the same as being intimately mixed. My feeling has always been a solidly adhered BP layer over a chlorate star is pretty safe. There will be minimal mixing of the star composition with the BP. Additionally you have sort of a protective coat over the top. This will prevent chlorate from rubbing on any abrasive burst particles or against one another.

 

If you still have concerns, and that would not be unreasonable, I'd use sulfurless black powder as the prime. It should help put your mind at ease, while also providing basically the same protections already mentioned.

 

I will admit that chlorate flash has still always left me uneasy. I've used it in a couple of select applications, like rosettes. Then again there is no issue with obtaining perchlorate in the US. I would ensure that the chlorate flash bag is well sealed, and take extra care, but otherwise it's probably fine. I build all of my shells "upside down" so the flash bag would be protected anyway until you fill the cannula. I wouldn't worry about blackmatch being in contact with the flash really.

[memo]

thanks mumbles, i was hoping you would give some input.

 

memo

[lloyd]

Yeah... but even chlorate flash is 'safe' inside a coupette fused with BP fuse.... Ehh... I think the issue is, if you coat chlorate stuff thickly-enough with BP to prevent direct friction issues, you don't have to worry.

 

I've been doing this for a while, and I've never had a mishap (with a firework) caused by chlorates in contact with sulfur-bearing compositions.

 

Lloyd

[OldMarine]

Mike Swisher wrote an excellent post on sulfur and chlorates. He stated that early fireworkers had to contend with impure sulfur which lead to problems in chlorate based comps. Since today's sulfur is purer he said the risk is overrated.

For any with a Fireworking.com membership, here's a link to the article:

https://fireworking.com/content/chlorates-and-sulfur

Edited June 7, 2016 by OldMarine

[memo]

thank pat and lloyd. its not like you can throw caution to the wind.

 

 

memo

[Arthur]

Purer chemicals may well reduce the risk but making interfaces with sulphurless BP is also a risk mitigation factor, so could be a good plan.