6 replies to this topic

[maxman]

As its as quiet as the grave on here, I thought I'd take the opportunity to ask a few questions.
I have been trying to get in one place as many old comps as possible from Standard, Astra, Rainbow etc so as to be in a position to recreate if and when I get my explosive certificate which  by the way is now fast approaching a year with no word whatsoever!!
 
Anyway, whilst looking a  few comps questions came to mind so I am asking here.
 
I know chlorate add mixtures were banned (quite rightly) a long time ago but I can't say I know the answer to the question, are chlorates still used in consumer fireworks? cat2/3 or even cat4 for that matter? I know they used to be as in the example below.
 
I came across this comp

Astra size E Crackling Pearl
Tube size 4" x 3/8" ID
Potassium Chlorate 9lbs
Cryolite 12 oz
Accaroid 1lb 8oz
Magnalium 2lb
 

Not ever having used chlorates, I thought metal powders were also a no no with chlorate but here we have magnalium. Was this common place? and how safe is this?As no other details are given, would you think the magnalium might be mixed or coarse 100#? I suppose fine mgal would be a fuel and coarse used for crackle so is the fuel here just the acaroid resin?
 
With regards to recreating this, would potassium perchlorate instead of the chlorate work just as well? substituting like for like?
 
Would a comp like this be loaded dry or dampened with meths maybe? Not rammed obviously but lightly tamped? or pressed hard?
 
 Would there be a choke in the tube or not?
 
I understand that cryolite helps in someway the crackle effect so thought I might add this one to the list to try sometime.

 

Off to do more contemplating now.
 
Rod

[Deano 1]

You're probably just as well asking that tumbleweed that just past by. lol

[rocketpro]

Eh! even the tumbleweed has given up visiting!!!

[Arthur Brown]

The problem with that formula is that it makes no mention of particle size or method, both of which are critical to device function. 20 mesh MgAl would be very different from 200mesh. Also the method is critical -likely they were filled with funnel and wire, but is that certain?

[spectrum]

These fireworks were bump filled with mallet and drift final stemming (unbelievably). The presence of Chlorate is explained by the use of imperial measures - these were very old formulations like many of the other Astra mixes. There was even a flash composition which was 50:50 Potassium Chlorate and either Magnesium or Aluminium (I seem to recall Aluminium), although I don't recall it being produced.

 

The Magnalium was quite coarse in this mixture and again, from memory, was blended gently in as the last ingredient...no doubt with a sigh of reluctance by any mixer with an understanding of his job.

 

I believe the final fill was woodmeal and a squirt of PVA glue from a plastic sauce dispenser, these items were filled in large hexagonal bundles containing a gross of tubes, they were labelled, touchpapered and bundled with string off site by outworkers, brought in and filled from the base.

[maxman]

Hi Spectrum, that's very interesting information. So just to get this right, they would load the tube with a dry mix?, shaking it down? then finish off with a mallet and drift with a couple of blows to consolidate?  sounds very risky considering chlorate and coarse magnalium!  Then the end plug sawdust and PVA?
 
Do you have any info on the manufacture of the very small Astra red floodlight?

Red Floodlight ( Tube size: 1.5" x 1/2"x 3/4"(OD)

Pot Perc 3lb

Pot Chlorate 9lbs

Strontium Carbonate 2lb

Wood flour 9oz (used to cheapen the mix)

Accaroid 2lb

and are chlorates not used at all today in consumer fireworks?

Rod

Edited by maxman, 12 July 2015 - 03:43 PM.

[spectrum]

Each building / compartment would be dedicated to a specific firework as an all year round job, some would change throughout the season.

 

The tubes came into the factory in bundles as I said, they would have powder heaped on them by hand and then be bumped down to consolidate the contents. The bundle would then be thumped by mallet and drift to firm up the mix, then closed with a woodmeal dose followed by PVA glue. The powder was always dry - this process was employed across the range for all stemmed fireworks including the Floodlight