displayfireworks1
01-06-2012, 06:47 PM
Here is one of the first updates I have received about the Blue Aluminum as featured in my video. As suspected, you are going to need a stronger ignition with a spolette. In case you missed my video on the Blue Aluminum, I will include it here.
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http://www.youtube.com/watch?v=DbjbwzGIsaA
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Blue Aluminum Brochure Language Dec 2011
Blue Aluminum, a novel aluminum powder designed for the commercial salute industry and other pyrotechnic applications, is a domestically sourced new product now offered for sale.
We claim novelty of application on the following basis:
1) Salute powder made with a binary mixture of 70% potassium perchlorate and 30% Blue Aluminum will not ignite when exposed to direct flame. Tests have been conducted using up to 30 gram masses of binary formulations. This is a unique feature of the binary mixture of potassium perchlorate and Blue Aluminum when used for salutes, in comparison to the other types of aluminum powders most often used in salute manufacture. Salute powders containing potassium perchlorate-7parts by weight, Blue Aluminum-3 parts by weight, and sulfur-1 part by weight are more energetic. Though small quantities on the order of one gram cannot be made to ignite unconfined, steady application of propane torch flame for 20 seconds or longer, in some instances, to a larger mass of ten grams will, in some but not all instances, produce a slow burning ignition that is self-sustaining unconfined. The function of Blue Aluminum salute powder formulations is based upon the different behaviors of pyrotechnic compositions under varying pressures. This phenomenon is well known, for example, with the widely varying behavior of black powder rocket motor grains when burned under different pressures. Our design represents the first commercial application of this phenomenon to commercially useful salute powders. The slower (if any) open burning rate of the variegated particle size and particle shape powder accelerates exponentially under increasing pressure. This results, in a salute casing, in a slightly delayed rise in the pressure production curve compared to standard fine flake aluminum salute powders, bursting the casing at a slightly higher pressures, with a resultant equivalent or louder noise, to that obtained with more brisant salute formulations whose sharp pressure curve rise breaks the salute casing more rapidly but at a lower pressure. It should be noted that the time differences are a few milliseconds. No perceptible difference in time to function is noted by an unaided observer, though the difference in noise output may be quite noticeable. These features are summarized in our formal testing data, obtained for us by Pyro Labs/ Dr. Ken Kosanke, as copied below.
2) No other commercial salute manufacturing process takes advantage of the characteristics of a mixture of ultra-fine up to the much larger particle sizes in Blue Aluminum powder, which offers greater ease in manufacturing as the aluminum powder does not adhere to open surfaces to the degree that standard salute powder flake aluminum powders do. It is much easier for the operator to work with.
3) The Blue Aluminum product produces consistently equivalent or louder reports at equivalent weights and in equivalent size salutes than do either standard blackhead flake, German Dark, or Chinese or American bright flake aluminum powders.
4) Ignition methods for the confined Blue Aluminum salute powder are of critical importance, though easy to accomplish. Both flame and gas production to increase pressure are required. The preferred formulae use a standard 7:3:1 (potassium perchlorate/aluminum/sulfur) formula. Preferred ignition methods are:
a) Spolettes with the inner ends stuffed full of hot-burning black match.
b) Cross-matched time fuse dipped in a slurry of Meal D and then dipped in coarse grain black powder, such as 2-3Fa to provide a hot, sustained ignition source.
c) Time fuse cross matched with an eight to ten-inch length of cross match, the excess being wrapped around the end of the time fuse.
d) Use of a one-teaspoon of Meal D in a burst bag
e) Charging the salute casing with a pre-weighed bag of flash, inserting a 5-6 inch piece of black match, the finishing with insertion of the cross-matched time fuse/top disc, to ignite the black match and then discharge the salute.
f) Alternatively, using a 7:3:1 formulation where the aluminum is 80% blue aluminum and 20% standard fine flake aluminum such as German Dark or Indian Blackhead
Blue Aluminum will discharge reliably (100 out of 100 tested) using a standard cross-matched piece of time fuse.
The use of Blue Aluminum in fireworks salutes, in both sole-use and blended aluminum powders, is patent and trademark pending. Use of ultra-fine (one to three micron) to large (in excess of 200 micron) particle size and using three distinct types of particle shape, aluminum powder (as opposed to solely using very fine flake aluminum powder) as described below, in fireworks salutes, is a novel application/method in commercial salute manufacture. The manufacturing process/application/method for doing so is patent pending.
5) No increase in confinement is required in salute assembly. Standard, well-constructed salutes will function with equivalent or increased noise production when Blue Aluminum based salute powders are used.
Blue Aluminum:
Physical description:
On microscopy, BA consists of ultra-fine flakes, spheres, and irregularly shaped particles.
Whereas most GD/blackhead/bright type salute aluminum powders have particles of 5 to 8 micron size, BA has a particle size distribution ranging from ultra-fine 1-3 micron to +200 micron size particles.
This aluminum powder is free flowing, non-stearin coated, and less dust producing than ultra-fine aluminum powders.
It is supplied in 100 pound drums, to ATF licensed entities only.
The price is $5.93 per pound plus shipping for 100 to 1000 pounds, $5.41 for 1000 to 20,000 pounds, and $4.94 for quantities in excess of 20,000 pounds. Please contact us at:xxxxxxxxxxxx
*This material is shipped, as reflected in our MSDS, as a non-hazardous material. This, too, affords the user substantive savings in shipping costs and eliminates storage requirements for HazMat materials for this product*
Use in salutes:
Blue Aluminum, a novel formulation of aluminum powder designed for the commercial salute industry and other pyrotechnic applications, is a domestically sourced new product offered for sale. Sales are restricted to ATF license holders who must provide a copy of a current license with any orders for this material.
Other applications for which Blue Aluminum has potential uses are in exploding targets and pest control devices.
Testing:
Use of Blue Aluminum in salutes requires actual assembly of salutes for proper function and evaluation. As noted, open burning of salute formulae and salute powder compositions using Blue Aluminum may not even produce ignition. Indeed, this is how the product was designed to function: the explosive yield should ONLY be possible when the powder is confined in salute casings. This aluminum powder is manufactured with characteristics that, when incorporated into flash powder formulae, may reduce risk to the manufacturer, though no guarantee of such risk reduction or safety is expressed or implied. Each manufacturer must determine the applicability of the properties of Blue Aluminum in his or her own manufacturing processes. Unconfined, binary mixtures of Blue Aluminum will not burn in our testing and triple component mixtures containing sulfur burn slowly and only after sustained application of flame to masses exceeding five grams.
Using the principal of magnum powders in firearms, we have designed an aluminum powder formulation, controlling particle shape and size range, that, when incorporated into flash powder formulations, retards the rate of pressure development slightly, allowing higher pressures to be obtained before the casing bursts, thus producing significantly louder reports.
These characteristics and the lack of heavy stearin coating also make the material much easier for the manufacturer to work with.
Little Big Shots testing:
Thanks to Little Big Shots of Addison, Pa. for conducting the following tests:
First tests: Ground Salutes:
Six canister salutes were constructed in a consistent manner, which can be seen on the LBS web site.
Each casing was 2.5 inches OD, 1 and 5/16 ID, and are the standard 3-inch salute casings used by LBS.
Each salute was loaded with 56 grams of salute composition, consisting of aluminum, potassium perchlorate, and sulfur.
Two salutes were constructed with a formula using blackhead aluminum powder.
These served as controls.
Four salutes were constructed using Blue Aluminum in a flash powder formulation.
Four observers were placed 100 yards away.
The salutes were fired on the ground, sequentially.
The firing order was: blackhead flash aluminum, then blue aluminum, in a series of three: black/blue/blue, and then repeated.
Each observer scored them as follows:
Blue aluminum salutes were each substantially louder than blackhead flash aluminum.
Each series of salutes was judged using ground salutes. Distances to observers and positions were kept constant.
Second test: aerial large salutes:
At a permitted and licensed range, in May of 2011,, further testing was conducted.
The following comparators were used:
Five-inch canister salutes with either 2.5 pounds of Blackhead Aluminum based flash, 2.5 pounds of Blue Aluminum based flash, and 1.4 pounds of Blue Aluminum based flash.
Several successive comparison tests were fired before a panel of observers.
In each instance, BOTH of the Blue Aluminum salutes were significantly louder than the standard Blackhead flake aluminum comparator.
Four-inch canister salutes with either one pound, ten to fourteen ounces of Blackhead Aluminum based flash, a similar weight of Blue Aluminum based flash, and, as before, a one-half weight charge of Blue Aluminum flash
Several successive comparison tests were fired before a panel of observers.
Once again, ALL of the Blue Aluminum salutes were significantly louder than the standard Blackhead flake aluminum comparator.
All of these large 4 and 5 inch salutes were ignited using the spolette method with the open end stuffed with black match. All functioned at exactly the proper burst height.
Aerial Salute Testing: (three-inch cylindrical salutes)
100 3-inch aerial salutes were made. The formula used was 7:3:1 with the aluminum powder being used a blend of 80% blue aluminum and 20% indian blackhead aluminum. Ignition was achieved using a two-inch piece of cross match and standard time fuse. 100% functioned as intended for 100 salutes fired.
Given that all series of salutes resulted in exactly the same observations and that Blue Aluminum powder produced a subjectively significantly louder salute than blackhead flash aluminum; given that Little Big Shots’ proprietor finds this aluminum formulation cleaner and easier to work with, we are proud to announce that we have permission to use the following endorsement of Little Big Shots, a leading manufacturer of domestically produced salutes, for our product as follows:
Endorsement:
"Blue Aluminum is a fine aluminum powder that I find easier and cleaner to work with than readily available blackhead flash aluminum. Salutes made with Blue Aluminum formulations in two, well-controlled dual series of comparative tests are significantly louder than similar salutes manufactured with blackhead flash aluminum. Provided a sufficient ignition method is used, Blue Aluminum produces superior salutes at equivalent weights compared to fine flake aluminum formulations.” (LBS currently uses a blend of 70% Blue Aluminum and 30% Indian Blackhead Aluminum.)
Albert Knoblach, Little Big Shots"
Critical Mass testing:
At the May 2011 testing, three series of salutes were assembled as follows, using a 7:3:1 formula:
Three-gram, seven-gram, and ten-gram salutes. Due to the less dense nature of some formulations, weights were not exactly identical in the mid-range salute testing, but were within one gram of each other.
In order to conduct an unbiased evaluation, a panel of six fireworks observers were assembled and asked to judge the salutes, labeled as “A”, “B”, “C”, and “D”. Only after the testing and judging were concluded were the panelists appraised of the identities of the salute formulas.
All salute powder formulations were binary, 70:30 potassium perchlorate:aluminum compositions.
A: German Dark aluminum
B: Chinese Bright Aluminum
C: Blue Aluminum
D: Blue Aluminum
Three-gram salute results:
B loudest, D second loudest, A third loudest, C did not explode
Seven-gram results:
C loudest, D second loudest, B tied for second, A fourth loudest
Ten-gram salute results:
D loudest, C second loudest, B third loudest, A fourth loudest
Overall, the judges found C and D to be clearly superior to the comparators. They were considerably surprised to learn that German Dark was their least highly rated formulation.
All salutes were constructed using parallel wound tubes and paper end caps/water-based glue. No other confinement methods were employed.
Conclusion: the critical mass required for ignition and function in salutes is likely above three grams and less than seven grams. Different means of ignition and using aluminum powder blended with 80% Blue Aluminum and 20% fine flake aluminum may yield functional salutes at lower critical masses than those established for formulae using pure Blue Aluminum.
Summary Blue Aluminum Sensitiveness Testing
Sample Description Ignition Temperature
[Notes 1-5] Friction Sensitiveness Rating
[Note 6] 50% Impact Sensitiveness
[Note 7] 50% ESD Sensitiveness
[Note 8]
7:3 (Obron GD) 675 °C Mildly Sensitive 25 inches 0.5 J
7:3 (2011-01) > 775 °C Relatively Insensitive 38 inches 3.5 J
7:3 (2011-01 + Obron GD) > 775 °C Relatively Insensitive 27 inches 2.5 J
7:3:1 (Obron GD) 425 °C Sensitive 7 inches 0.2 J
7:3:1 (2011-01) 650 °C Relatively Insensitive 9 inches 2.5 J
7:3:1 (2011-01 + Obron GD) 625 °C Relatively Insensitive 7 inches 1.5 J
Notes:
1) Temperature to the nearest 25 °C in which at least one of three trials produced an ignition within 10 seconds.
2) Sulfur has a boiling point of 445 °C. In all trials above this temperature, when sulfur was present and did not result in an ignition, the sulfur vaporized on contact with the ignition surface. In at least one case, the sulfur ignited and burned in air without igniting the flash powder.
3) Potassium perchlorate has a decomposition temperature of approximately 610 °C. In all trials above this temperature that did not produce an ignition, the potassium perchlorate decomposed, leaving a residue of potassium chloride.
4) Aluminum has a melting point of 660 °C. In all trials above this temperature and did not result in an ignition, the aluminum melted on contact with the ignition surface. In several cases, a number of aluminum particles did ignite and burn in air as sparks, but without igniting the flash powder.
5) The reported ignition temperatures are accurate to approximately ± 25 °C. A temperature of 775 °C is the maximum temperature of the apparatus.
6) A series of 10 friction sensitivity trials were performed for each test sample, using methods we have previously published.
7) A series of at least 30 trials were performed for each test sample, using a 5 kg drop-hammer. Results are reported to the nearest inch of impact height, the approximate level of precision in the results.
8) A series of at least 30 trials were performed for each test sample, using a 10 ohm series resistance and the deep well sample tray. Results are reported to the nearest 0.5 joule or one significant figure, the approximate level of precision in the results.
Blue Aluminum Friction Sensitiveness Testing
Sample Description Number of Ignitions in Ten Trials Sensitiveness Rating
Steel on Steel Wood on Steel Wood on Wood
7:3 (Obron GD) 2 0 --- Mildly Sensitive
7:3 (2011-01) 0 --- --- Relatively Insensitive
7:3 (2011-01 + Obron GD) 0 --- --- Relatively Insensitive
7:3:1 (Obron GD) 6 2 0 Sensitive
7:3:1 (2011-01) 0 --- --- Relatively Insensitive
7:3:1 (2011-01 + Obron GD) 0 --- --- Relatively Insensitive
Blue Aluminum Sound Output Testing
Sample Description Peak Overpressure
[Note 1] Duration of Positive Phase
[Note 2] Sound Pressure Level
[Note 3]
7:3 (Obron GD) 5.83 psi 0.82 ms 186.1 dB
7:3 (2011-01) 5.79 psi 0.82 ms 186.1 dB
7:3 (2011-01 + Obron GD) 5.89 psi 0.82 ms 186.2 dB
7:3:1 (Obron GD) 6.02 psi 0.83 ms 186.4 dB
7:3:1 (2011-01) 6.14 psi 0.80 ms 186.6 dB
7:3:1 (2011-01 + Obron GD) 6.17 psi 0.81 ms 186.6 dB
Notes:
1) The average of 3 trials using the previously published method (weak confinement, fired with an inverted and shrouded electric match at the bottom of the powder charge, using a free-field piezoelectric blast gauge, at a distance of 4 feet suspended in a blast chamber).
2) The average of 3 trials. It is thought that the duration of positive phase affects the perceived tonal quality of the sound of the explosion, with longer versus shorter durations corresponding to more mellow and more sharp impulse sounds, respectively.
3) Based on the average peak over-pressure using the relationship for peak –linear sound pressure level, of dB = 170.8 + 20 log P.
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.
.
http://www.youtube.com/watch?v=DbjbwzGIsaA
.
.
.
Blue Aluminum Brochure Language Dec 2011
Blue Aluminum, a novel aluminum powder designed for the commercial salute industry and other pyrotechnic applications, is a domestically sourced new product now offered for sale.
We claim novelty of application on the following basis:
1) Salute powder made with a binary mixture of 70% potassium perchlorate and 30% Blue Aluminum will not ignite when exposed to direct flame. Tests have been conducted using up to 30 gram masses of binary formulations. This is a unique feature of the binary mixture of potassium perchlorate and Blue Aluminum when used for salutes, in comparison to the other types of aluminum powders most often used in salute manufacture. Salute powders containing potassium perchlorate-7parts by weight, Blue Aluminum-3 parts by weight, and sulfur-1 part by weight are more energetic. Though small quantities on the order of one gram cannot be made to ignite unconfined, steady application of propane torch flame for 20 seconds or longer, in some instances, to a larger mass of ten grams will, in some but not all instances, produce a slow burning ignition that is self-sustaining unconfined. The function of Blue Aluminum salute powder formulations is based upon the different behaviors of pyrotechnic compositions under varying pressures. This phenomenon is well known, for example, with the widely varying behavior of black powder rocket motor grains when burned under different pressures. Our design represents the first commercial application of this phenomenon to commercially useful salute powders. The slower (if any) open burning rate of the variegated particle size and particle shape powder accelerates exponentially under increasing pressure. This results, in a salute casing, in a slightly delayed rise in the pressure production curve compared to standard fine flake aluminum salute powders, bursting the casing at a slightly higher pressures, with a resultant equivalent or louder noise, to that obtained with more brisant salute formulations whose sharp pressure curve rise breaks the salute casing more rapidly but at a lower pressure. It should be noted that the time differences are a few milliseconds. No perceptible difference in time to function is noted by an unaided observer, though the difference in noise output may be quite noticeable. These features are summarized in our formal testing data, obtained for us by Pyro Labs/ Dr. Ken Kosanke, as copied below.
2) No other commercial salute manufacturing process takes advantage of the characteristics of a mixture of ultra-fine up to the much larger particle sizes in Blue Aluminum powder, which offers greater ease in manufacturing as the aluminum powder does not adhere to open surfaces to the degree that standard salute powder flake aluminum powders do. It is much easier for the operator to work with.
3) The Blue Aluminum product produces consistently equivalent or louder reports at equivalent weights and in equivalent size salutes than do either standard blackhead flake, German Dark, or Chinese or American bright flake aluminum powders.
4) Ignition methods for the confined Blue Aluminum salute powder are of critical importance, though easy to accomplish. Both flame and gas production to increase pressure are required. The preferred formulae use a standard 7:3:1 (potassium perchlorate/aluminum/sulfur) formula. Preferred ignition methods are:
a) Spolettes with the inner ends stuffed full of hot-burning black match.
b) Cross-matched time fuse dipped in a slurry of Meal D and then dipped in coarse grain black powder, such as 2-3Fa to provide a hot, sustained ignition source.
c) Time fuse cross matched with an eight to ten-inch length of cross match, the excess being wrapped around the end of the time fuse.
d) Use of a one-teaspoon of Meal D in a burst bag
e) Charging the salute casing with a pre-weighed bag of flash, inserting a 5-6 inch piece of black match, the finishing with insertion of the cross-matched time fuse/top disc, to ignite the black match and then discharge the salute.
f) Alternatively, using a 7:3:1 formulation where the aluminum is 80% blue aluminum and 20% standard fine flake aluminum such as German Dark or Indian Blackhead
Blue Aluminum will discharge reliably (100 out of 100 tested) using a standard cross-matched piece of time fuse.
The use of Blue Aluminum in fireworks salutes, in both sole-use and blended aluminum powders, is patent and trademark pending. Use of ultra-fine (one to three micron) to large (in excess of 200 micron) particle size and using three distinct types of particle shape, aluminum powder (as opposed to solely using very fine flake aluminum powder) as described below, in fireworks salutes, is a novel application/method in commercial salute manufacture. The manufacturing process/application/method for doing so is patent pending.
5) No increase in confinement is required in salute assembly. Standard, well-constructed salutes will function with equivalent or increased noise production when Blue Aluminum based salute powders are used.
Blue Aluminum:
Physical description:
On microscopy, BA consists of ultra-fine flakes, spheres, and irregularly shaped particles.
Whereas most GD/blackhead/bright type salute aluminum powders have particles of 5 to 8 micron size, BA has a particle size distribution ranging from ultra-fine 1-3 micron to +200 micron size particles.
This aluminum powder is free flowing, non-stearin coated, and less dust producing than ultra-fine aluminum powders.
It is supplied in 100 pound drums, to ATF licensed entities only.
The price is $5.93 per pound plus shipping for 100 to 1000 pounds, $5.41 for 1000 to 20,000 pounds, and $4.94 for quantities in excess of 20,000 pounds. Please contact us at:xxxxxxxxxxxx
*This material is shipped, as reflected in our MSDS, as a non-hazardous material. This, too, affords the user substantive savings in shipping costs and eliminates storage requirements for HazMat materials for this product*
Use in salutes:
Blue Aluminum, a novel formulation of aluminum powder designed for the commercial salute industry and other pyrotechnic applications, is a domestically sourced new product offered for sale. Sales are restricted to ATF license holders who must provide a copy of a current license with any orders for this material.
Other applications for which Blue Aluminum has potential uses are in exploding targets and pest control devices.
Testing:
Use of Blue Aluminum in salutes requires actual assembly of salutes for proper function and evaluation. As noted, open burning of salute formulae and salute powder compositions using Blue Aluminum may not even produce ignition. Indeed, this is how the product was designed to function: the explosive yield should ONLY be possible when the powder is confined in salute casings. This aluminum powder is manufactured with characteristics that, when incorporated into flash powder formulae, may reduce risk to the manufacturer, though no guarantee of such risk reduction or safety is expressed or implied. Each manufacturer must determine the applicability of the properties of Blue Aluminum in his or her own manufacturing processes. Unconfined, binary mixtures of Blue Aluminum will not burn in our testing and triple component mixtures containing sulfur burn slowly and only after sustained application of flame to masses exceeding five grams.
Using the principal of magnum powders in firearms, we have designed an aluminum powder formulation, controlling particle shape and size range, that, when incorporated into flash powder formulations, retards the rate of pressure development slightly, allowing higher pressures to be obtained before the casing bursts, thus producing significantly louder reports.
These characteristics and the lack of heavy stearin coating also make the material much easier for the manufacturer to work with.
Little Big Shots testing:
Thanks to Little Big Shots of Addison, Pa. for conducting the following tests:
First tests: Ground Salutes:
Six canister salutes were constructed in a consistent manner, which can be seen on the LBS web site.
Each casing was 2.5 inches OD, 1 and 5/16 ID, and are the standard 3-inch salute casings used by LBS.
Each salute was loaded with 56 grams of salute composition, consisting of aluminum, potassium perchlorate, and sulfur.
Two salutes were constructed with a formula using blackhead aluminum powder.
These served as controls.
Four salutes were constructed using Blue Aluminum in a flash powder formulation.
Four observers were placed 100 yards away.
The salutes were fired on the ground, sequentially.
The firing order was: blackhead flash aluminum, then blue aluminum, in a series of three: black/blue/blue, and then repeated.
Each observer scored them as follows:
Blue aluminum salutes were each substantially louder than blackhead flash aluminum.
Each series of salutes was judged using ground salutes. Distances to observers and positions were kept constant.
Second test: aerial large salutes:
At a permitted and licensed range, in May of 2011,, further testing was conducted.
The following comparators were used:
Five-inch canister salutes with either 2.5 pounds of Blackhead Aluminum based flash, 2.5 pounds of Blue Aluminum based flash, and 1.4 pounds of Blue Aluminum based flash.
Several successive comparison tests were fired before a panel of observers.
In each instance, BOTH of the Blue Aluminum salutes were significantly louder than the standard Blackhead flake aluminum comparator.
Four-inch canister salutes with either one pound, ten to fourteen ounces of Blackhead Aluminum based flash, a similar weight of Blue Aluminum based flash, and, as before, a one-half weight charge of Blue Aluminum flash
Several successive comparison tests were fired before a panel of observers.
Once again, ALL of the Blue Aluminum salutes were significantly louder than the standard Blackhead flake aluminum comparator.
All of these large 4 and 5 inch salutes were ignited using the spolette method with the open end stuffed with black match. All functioned at exactly the proper burst height.
Aerial Salute Testing: (three-inch cylindrical salutes)
100 3-inch aerial salutes were made. The formula used was 7:3:1 with the aluminum powder being used a blend of 80% blue aluminum and 20% indian blackhead aluminum. Ignition was achieved using a two-inch piece of cross match and standard time fuse. 100% functioned as intended for 100 salutes fired.
Given that all series of salutes resulted in exactly the same observations and that Blue Aluminum powder produced a subjectively significantly louder salute than blackhead flash aluminum; given that Little Big Shots’ proprietor finds this aluminum formulation cleaner and easier to work with, we are proud to announce that we have permission to use the following endorsement of Little Big Shots, a leading manufacturer of domestically produced salutes, for our product as follows:
Endorsement:
"Blue Aluminum is a fine aluminum powder that I find easier and cleaner to work with than readily available blackhead flash aluminum. Salutes made with Blue Aluminum formulations in two, well-controlled dual series of comparative tests are significantly louder than similar salutes manufactured with blackhead flash aluminum. Provided a sufficient ignition method is used, Blue Aluminum produces superior salutes at equivalent weights compared to fine flake aluminum formulations.” (LBS currently uses a blend of 70% Blue Aluminum and 30% Indian Blackhead Aluminum.)
Albert Knoblach, Little Big Shots"
Critical Mass testing:
At the May 2011 testing, three series of salutes were assembled as follows, using a 7:3:1 formula:
Three-gram, seven-gram, and ten-gram salutes. Due to the less dense nature of some formulations, weights were not exactly identical in the mid-range salute testing, but were within one gram of each other.
In order to conduct an unbiased evaluation, a panel of six fireworks observers were assembled and asked to judge the salutes, labeled as “A”, “B”, “C”, and “D”. Only after the testing and judging were concluded were the panelists appraised of the identities of the salute formulas.
All salute powder formulations were binary, 70:30 potassium perchlorate:aluminum compositions.
A: German Dark aluminum
B: Chinese Bright Aluminum
C: Blue Aluminum
D: Blue Aluminum
Three-gram salute results:
B loudest, D second loudest, A third loudest, C did not explode
Seven-gram results:
C loudest, D second loudest, B tied for second, A fourth loudest
Ten-gram salute results:
D loudest, C second loudest, B third loudest, A fourth loudest
Overall, the judges found C and D to be clearly superior to the comparators. They were considerably surprised to learn that German Dark was their least highly rated formulation.
All salutes were constructed using parallel wound tubes and paper end caps/water-based glue. No other confinement methods were employed.
Conclusion: the critical mass required for ignition and function in salutes is likely above three grams and less than seven grams. Different means of ignition and using aluminum powder blended with 80% Blue Aluminum and 20% fine flake aluminum may yield functional salutes at lower critical masses than those established for formulae using pure Blue Aluminum.
Summary Blue Aluminum Sensitiveness Testing
Sample Description Ignition Temperature
[Notes 1-5] Friction Sensitiveness Rating
[Note 6] 50% Impact Sensitiveness
[Note 7] 50% ESD Sensitiveness
[Note 8]
7:3 (Obron GD) 675 °C Mildly Sensitive 25 inches 0.5 J
7:3 (2011-01) > 775 °C Relatively Insensitive 38 inches 3.5 J
7:3 (2011-01 + Obron GD) > 775 °C Relatively Insensitive 27 inches 2.5 J
7:3:1 (Obron GD) 425 °C Sensitive 7 inches 0.2 J
7:3:1 (2011-01) 650 °C Relatively Insensitive 9 inches 2.5 J
7:3:1 (2011-01 + Obron GD) 625 °C Relatively Insensitive 7 inches 1.5 J
Notes:
1) Temperature to the nearest 25 °C in which at least one of three trials produced an ignition within 10 seconds.
2) Sulfur has a boiling point of 445 °C. In all trials above this temperature, when sulfur was present and did not result in an ignition, the sulfur vaporized on contact with the ignition surface. In at least one case, the sulfur ignited and burned in air without igniting the flash powder.
3) Potassium perchlorate has a decomposition temperature of approximately 610 °C. In all trials above this temperature that did not produce an ignition, the potassium perchlorate decomposed, leaving a residue of potassium chloride.
4) Aluminum has a melting point of 660 °C. In all trials above this temperature and did not result in an ignition, the aluminum melted on contact with the ignition surface. In several cases, a number of aluminum particles did ignite and burn in air as sparks, but without igniting the flash powder.
5) The reported ignition temperatures are accurate to approximately ± 25 °C. A temperature of 775 °C is the maximum temperature of the apparatus.
6) A series of 10 friction sensitivity trials were performed for each test sample, using methods we have previously published.
7) A series of at least 30 trials were performed for each test sample, using a 5 kg drop-hammer. Results are reported to the nearest inch of impact height, the approximate level of precision in the results.
8) A series of at least 30 trials were performed for each test sample, using a 10 ohm series resistance and the deep well sample tray. Results are reported to the nearest 0.5 joule or one significant figure, the approximate level of precision in the results.
Blue Aluminum Friction Sensitiveness Testing
Sample Description Number of Ignitions in Ten Trials Sensitiveness Rating
Steel on Steel Wood on Steel Wood on Wood
7:3 (Obron GD) 2 0 --- Mildly Sensitive
7:3 (2011-01) 0 --- --- Relatively Insensitive
7:3 (2011-01 + Obron GD) 0 --- --- Relatively Insensitive
7:3:1 (Obron GD) 6 2 0 Sensitive
7:3:1 (2011-01) 0 --- --- Relatively Insensitive
7:3:1 (2011-01 + Obron GD) 0 --- --- Relatively Insensitive
Blue Aluminum Sound Output Testing
Sample Description Peak Overpressure
[Note 1] Duration of Positive Phase
[Note 2] Sound Pressure Level
[Note 3]
7:3 (Obron GD) 5.83 psi 0.82 ms 186.1 dB
7:3 (2011-01) 5.79 psi 0.82 ms 186.1 dB
7:3 (2011-01 + Obron GD) 5.89 psi 0.82 ms 186.2 dB
7:3:1 (Obron GD) 6.02 psi 0.83 ms 186.4 dB
7:3:1 (2011-01) 6.14 psi 0.80 ms 186.6 dB
7:3:1 (2011-01 + Obron GD) 6.17 psi 0.81 ms 186.6 dB
Notes:
1) The average of 3 trials using the previously published method (weak confinement, fired with an inverted and shrouded electric match at the bottom of the powder charge, using a free-field piezoelectric blast gauge, at a distance of 4 feet suspended in a blast chamber).
2) The average of 3 trials. It is thought that the duration of positive phase affects the perceived tonal quality of the sound of the explosion, with longer versus shorter durations corresponding to more mellow and more sharp impulse sounds, respectively.
3) Based on the average peak over-pressure using the relationship for peak –linear sound pressure level, of dB = 170.8 + 20 log P.