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What did you do today in pyro?


dagabu

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  • 2 weeks later...

Sondre, sed..."...it was the powder right from the mill..".

 

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Ah! A LOT of folks think that's "Meal powder". It's 'mill dust'. As before, Meal Powder is a specific thing; precisely, the fines from pressed and corned black powder.

 

So... mill dust I can appreciate, because I've been known to have some interest in ball milling! <grin>

 

Lloyd

"I'd agree with it entirely if the initial sentence began "Commercial meal is and only is..."
See the 1947 edition of Weingart's Pyrotechnics, s.v. "Meal Powder" (pp. 13-14). There he writes:
"... a fairly good meal powder can be prepared in the following manner:
"Mount a 50-gallon wood barrel on two uprights so that it can revolve freely on centers fastened to the heads. To one center attach a crank. Cut a hole in the side for putting in and removing the necessary ingredients, this hole should be closed by a suitable plug. Place in the barrel from 300 to 500 lead balls about 1 inch in diameter. Then add a thoroughly mixed composition as follows:
Saltpeter, double refined........ 15 lb.
Willow charcoal...........................3 lb.
Sulfur flour...................................2 lb.
"The barrel is now revolved for about 500 turns. The longer it is turned the stronger the powder will be. (...)"
To sum up, in his usage, a material described as meal powder tout court may mean ball-milled powder.
Domenico Antoni gives very similar directions in his Trattato teorico-pratico di pirotecnia civile (1893) s.v. "Polvere pirica," and also describes and illustrates a stamp mill.
I have examined quite a number of old formularies, mainly compiled by Italian-American pyrotechnists in the period ca. 1920-60. All of them mention home-made powder, describing it variously as "meal dust," "mill powder" or "home powder" in English or as "polvere al barile" in Italian. Commercial meal is inevitably described as "A dust," "regular powder," or "machine powder,"and so specified in a formula when it is to be used.
Here's an example quoted as it is written:
"Wheel turning for lift Girandolas.
Meal dust.............................10 lbs.
Regular Powder....................5 lbs.
limatura..................................1 lb. 14 oz.
White Aluminum................... 1/2 oz.
"Also for wheels. no aluminum."
Note here that "meal dust" means ball-milled powder, and "regular powder" means the commercial product. Remember, these were poor people, and they wanted where possible to extend their supply of commercial powder - regular powder - which they had to buy, with the cheaper "meal dust" which they made themselves. N. B. - The word "limatura" means filings - presumably iron.
Here's another calling for "meal dust" -
"White Gerb (Fondanone)
Meal Dust......................................... 20 lb.
White Alu.......................................... 2-1/2 lbs."
The three grades, Meal D, Fine Meal and Extra Fine Meal, appear not to have come into use until after World War II. My 1934 edition of DuPont's Blaster's Handbook illustrates and lists only the granulations of C, FF, FFFF, FFFFF, and FFFFFFF, plus A Dust.
It is my observation that commercial meal is absolutely essential for only one thing, and that's making spolettes. Meal dust, mill powder, home powder, poussier de tonneau, polvere al barile, or whatever you call it, can replace it in tremalon compositions, rockets, wheel pushers, gerbes, etc., unless extreme vivacity of burning is for some reason a necessity.
There is one more very rare use that probably requires commercial meal, and that's the following:
"Stop powder (morto)
Carbonate strontium............................... 1 lb.
Regular powder (machine)...................... 1-1/4 lb."
This is the "dead lance" composition used in transformation lancework pieces. For lance to be made to appear halfway through the piece, the tubes are filled so as to begin with this composition, and at the halfway point of filling, the regular color is filled so as to follow it. All the lance, both those that appear at the start, and the transformation lance, are matched to light at the same time. The "morto" composition burns with very low light output at about the same rate as an ordinary colored lance, and is not seen to be burning by the spectators. Then when the flame front advances to the colored lance composition below the dead lance composition, it ignites, and the hidden portion of the design becomes visible.
The carbonate serves as a heat sink, both slowing combustion of the meal, and almost smothering the flame. I'd want to use commercial meal for this application because I wouldn't want to alter the burning rate or in any way to compromise the continuity of burning."
Some relevant scripture, from a respected member of another forum.
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Last I checked, we were not living in the 1900's.

 

If the term has gone from a nebulous to a specific meaning, I am all for the clarity that adds.

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I've started experimenting with various scrap cardboard tubes from a local store. They all go into the bin otherwise! I made a shell casing from a shrink wrap tube, and another from a different tube that is a similar diameter but with walls just over 1/4" thick. (They are quite sturdy, and I've already successfully made a 3" mortar with one using Gilliam's tutorial on skylighter.) The ends are constructed of scrap 1/4" chipboard from pallets (free!) cut with a harbor freight circle cutter in drill press. It is my hope that I can use these to create a super loud report using milled bp with minimal (if any) booster type powders or spiking. I've got a bunch of large Ti flake to toss in for effect. Also considering dragon eggs. I'd love any feedback.

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You can make them sound like a cannon for sure with hot bp.

Check out the lift on these babies.

a 3in. double voice cracker.. the lift sounds like a cannon going off. :) Just 2 discs on the bottom glued in.

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I burned a little zirconium powder

it burns with beautiful very bright white sparks

 

Edited by pirotek
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Why not, it's popular and keeps everyone motivated with new ideas.
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You can make them sound like a cannon for sure with hot bp.

Check out the lift on these babies.

a 3in. double voice cracker.. the lift sounds like a cannon going off. :) Just 2 discs on the bottom glued in.

Sweet! That's what I'm hoping for.

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I think the weight of the stuff on top makes them loud on the lift.

That tube was probably 7in. long. 1in. clay in the middle. full of hot bp on the bottom and flash on top with a fuse through the clay.

 

:)

I sell those ya know. :) :)

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  • 2 weeks later...

I made a mix of Lloyd Sponenburgh's "Buttered Popcorn Glitter".

 

Naughty me, I've complicated the mix by using my home-made SGRS (never tested). Normally I would just use Dextrin as the binder. What a revelation using SGRS is - much easier to make a dough and cut 1/4" stars from a patty.

 

So I probably should not have used two variables, ie. a new composition with an un-tested binder. However, some preliminary tests from some dry crumbs is looking very very good - already getting some nice looking spritzels. :) :)

 

The proof will be when fully dry - around 5-7 days I reckon.

Edited by stix
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Stix,

I believe I remember others who've made it with SGRS with good success. In the small amount either binder is used, it probably would not make any difference.

 

Lloyd

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Thanks Lloyd. Nice to have a comment from the person that actually created the original composition. :)

 

My concern is if my home-made sgrs will foul the composition. At this point it looks good.

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  • 2 weeks later...

Made some copper benzoate, rolled some small 6mm ID tubes for small reports, + got my 15mm and 22mm comet molds and rods from the shop.

 

Nice pyro work ahead. Yeepee.

Edited by Sulphurstan
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  • 3 months later...

That gives new meaning to really getting in there and breaking up the cores.

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But Mumbles, how else would you test the torque of your star roller and get a real feeling of how it to turns?
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Related... Making and assembling pulleys to get a reasonable speed in the rolling machine from a sewing machine motor. Two stages reduction since I can´t make a big enough pulley.

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Made what for me is good sized bunch of 3/8" and 1/4" stars using the tabletop roller. Yankie's Purple using phenolic. Went very well once I got the cores right.

 

post-20116-0-21441100-1527366285_thumb.jpg

Edited by OldMarine
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  • 2 weeks later...

A little carpentry. Made an small drying cabinet, 30x30x90 cm, and an small 9V dehumidifier. Exhausted my existences of scrap wood.

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today was drudge work day, totally cleaned the shop. washed all the tables and swept the floor and watered it down, swept it again. (dirt floor) then ball milled 2 5 gal. buckets of charcoal . finished product. got chlorate cell up and running again that's all for today

Edited by memo
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