10 replies to this topic

[Yugen-biki]

Is it OK to have this changeing relay with this read star?:

Lancaster red:
KClO3 70
SrCO3 15
Red gum 10
Dextrin 4
C 150mesh 1

Shimizu changeing relay:
KNO3 35
KClO4 35
C 24
Dextrin 6

As long as there is no sulfur and/or metal like Al or Mg everything is OK...?
I cant see why it should not be OK but i like to be "on the safe side".

[Richard H]

Don't worry, The above two should be compatible with one-another. The danger occurs when you start mixing chlorates with the following:

sulfur and sulphides
ammonium salts
phosphorous
pitch or asphalt
picric acid and picrates
fine metal powders

(Source: Fireworks principles & practice, 3rd edition, Lancaster)

Lancaster also advises that the following should be avoided with perchlorates:

sulfur and sulphides
phosphorous
picric acid and picrates

[lord_dranack]

So fine metal powders means you shouldn't make chlorate flash? (not that I do or will do, I have just seen lots of formulae for it)

[BurlHorse]

Yugen-Biki,

Looks Ok To me, The Nitrate will keep the Relay from being ( Technically) H-3 but will impart a slight , very slight blue/yellowness to the flame tips which will be undetectable in the air.

Only 2 things I would humbly suggest:

1) For the lancaster red, use no nore than 15% to 20% alcohol/water to bind, else the red gum gunks everything up (Assuming you are rolling them, if your cutting them use up to 30%alcohol/water, they'll dry alittle faster (any more alcohol affects the binding properties of Dextrin)), let the cores dry completely before rolling more red comp or the Relay Comp.on the relay comp.

2) Reduce the amount of dextrin to 4% up the charcoal to 6% and use 33% alcohol and water mix for wetting/rolling onto the cut stars or cores, that particular relay comp will not be truly "Dark" if you use 6% dextrin as the dextrin will impart a yellowish tinge and relay comps are supposed to be "dark" passing fire to next color, in this case your lancaster's red. If the Charcoal is fine enough, I.E; Airfloat or milled to dust, you won't notice much of the charcoal addition from a ground to air perspective.

one more thing, I personally prefer another one of Lancasters reds,

Lancaster red#3
----------------------------
Potassium Chlorate - 64
Red Gum - 13
Strontium Carbonate - 19
Dextrin - 4

He lists this as a pill box star, but I have found it works great as a core for color changers as the star will have slowed down a bit by the time the relay comp hits the core, a 3/8" star will burn just barely over 1 second with a very intense red while in the air. When viewed up close on the ground, you will see a slight tinge of orange at the tips of the flame, the red gum is responsible for this I am sure, again, use no more than 15% alcohol/water ( Isopropyl 70% 16 oz or 473 ML from the drug store is easy enough, empty 1 bottle into a suitable container and add 4 bottles distilled/deionized water, will = out to about 16%alcohol/water (If the Bottles are different sizes over there, no matter, the ratio is still the same, 1 bottle at 70%/30% + 4 Bottles of distilled/de-ionized water)) to bind this comp when rolling. Do not force dry, don't roll too thick and dry at room temperature for a week or two should be fine.

Just some thoughts,

Regards, Stay Green,

Bear

[fusion121]

picric acid and picrates

Why would you ever mix anything with picric acid? that stuff is seriously unpleasant.

[Richard H]

Picrates were used in whistles.

[Phoenix]

And to deepen colours. (Why does this work; does picric acid contain a halogen?)

[Yugen-biki]

Thanks a bunch every one!!

Richard H
Thanks for the info! I have Lancasters book but I really like to be safe! Thanks :-)

BurlHorse
Interesting! I picked this red formura because Lancaster says this is one off the fastest and gives a large flame. I am searshing for a really large flame and strong intensity combined with fast burning. That is why I fell for this one with chlorate and the more economical carbonate in stead off nitrate.
I had in mind to cut them and maby roll some in the future. To save time and money I only take a few formulas and try them. Now I am searching for a new faster red. And most important the changeing relay. This one has to be as dark ass possible.

/John

Edited by Yugen-biki, 18 January 2004 - 04:18 PM.

[adamw]

Picrates (were) also used in indoor / 'table' fireworks. The thought of picrate whistles made with KClO3 makes me shudder... ughhh....

[lord_dranack]

I think I remember reading somewhere that they were prepared on the site of use

[ash]

does picric acid contain a halogen?

No it doesn't contain a halogen, picric acids systematic name is 2,4,6-trinitrophenol