flash burst

[pyrochris732]

Hey guys,

 

Would a small amount of flash, maybe half a gram be ok to burst a 2inch can shell? Maybe surround the flash with bp coated rice ? Ive been using meal powder but im not getting the burst that i want.

 

Thanks,

 

 

Chris

[dagabu]

Dust the break with a full gram. Don't consolidate it in one place. Try that and back off a little if it is too much.

 

D

[pyrochris732]

thanks a lot. Do you think I need to worry about the flash coming into contact with the sulfur in the BP hulls? I know it can make the flash more sensitive.

[Ventsi]

Are you using PERchlorate flash? If so you're in the clear. Worst case scenario is that the shell's time fuse doesn't light and it explodes once it hits the ground. Still with such small shells that is VERY unlikely.

[pyrochris732]

gotcha, yea its perchlorate... im pretty particular about making my time fuse, cross matched and all.. So you think I can just put my stars around the perimeter, have my meal hulls in the center, and then dust them with the flash? Can I give the plastic shell a few taps to integrate the flash through the hulls you think? Im wary about flash as it is so i dont want to set it off. How about if flash powder comes directly into contact with meal powder? Edited April 23, 2010 by pyrochris732

[Ventsi]

Yes, they can come in contact. But a heads up , don't use meal powder as booster or in a shell. There really is no use for it in there, I see you are using BP on hulls so just stick to that. What are you using the mill dust for anyway? And mixing flash with the hulls and mixing the two all homogeneous is fairly common practice.

[pyrochris732]

thanks a lot.. well the reason i threw the meal powder in there was because when i made my meal hulls, i didnt use enough meal and they burn a little on the slow side. So, I added a tablespoon or so extra meal to the dried hulls in the shell to made give it some oomph. I made five that way.

 

Will that screw up the break now? Would you say that fffg would be suitable instead of the meal?

 

Again, many thanks.

[Ralph]

mabey try using granulated bp instead of meal granulated bp will be much faster than re-asses weather or not you need a booster

[gordohigh]

In a 2in shell there isn't a lot of extra room sometimes, depending on what all you put in. I generally use granulated BP just because of the small cavity left after filling with stars. The meal would be more of a star prime than anything else in this situation but unless the stars are in their own part of the shell the meal is likely to just spread around the shell so it is really a waste in most instantances.

Which flash are you planning on using as many use a slower nitrate based flash with good results. As was mentioned, chlorates and sulpher are of concernn, a perchlorate with alu doesn't have that incompatibility issue but still requires great care. Be sure to mix very small quanitys if you decide to go that route. There are a lot of videos on mixing flash on the net, not all are safe.

[dagabu]

I break ALL of my small shells with a booster, mostly its whistle, up to 5 grams depending on the contents.

 

A few things I have seen on this thread that I would like to address first.

 

-Meal is not good for break because of the lack of air spaces allowing the fire to propagate amongst all the burst.

-If your rice hulls are not performing the way you want, you can add another layer of BP or you can add a light coating of whistle or KP.

-Dust the hulls, granular BP, with your booster. You do that by measuring out your break and add the increment of booster in the same container and mix thoroughly.

 

The Chinese use Perchlorate coated hulls for break in their small shells and it works well.

 

D

[pyrochris732]

wow, great responses guys thanks..

 

I have components for KNO3 flash. I will try that instead of the dark aluminum flash. I've used the latter and dont like mixing KCLO4 with dark Al so the KNO3,sulfur,al will suffice. One question though: i Just got 400 mesh atomized Al. Can i use that with the KNo3 and sulfur for slow flash in stead of dark indian?

 

Thanks,

 

Chris

[Ventsi]

Unfortunately , no you can't. That mixture will barely burn and will be incredibly hard to ignite because of the spherical shape. Think of it as lighting a ordinary 8.5x12 piece of paper, it lights easily and burns fast. Now take a stack of papers and try and light that, hard to ignite and takes forever to burn. Its the same with the aluminum powder, just a really small scale. And I like using Nitrate flash because I feel its less brisant and gives the contents of the shell more of a "push" making them go out further.

[pyrochris732]

thanks a lot man, this is very helpful info. Do you think i can make a 100 gram batch to store or is that a no no? Is slow flash like KNO3 about as fast as whistle mix? I would do the whistle but i dont have any Na benzoate. Also, should I diaper mix it too like you would with very dangerous flash powder?

 

Sorry for all the questions, i just want to do everything the right way.

 

Chris

[dagabu]

Sensitivity of flash from greatest to least not including the ones that spontaneously detonate and only using the three oxidizers:

 

-*Chlorate, sulfur, finely divided Magnesium

-*Chlorate, sulfur, finely divided Aluminum

-*Chlorate, finely divided Magnesium

-*Chlorate, finely divided Aluminum

-*Perchlorate, sulfur, finely divided Magnesium

-*Perchlorate, sulfur, finely divided Aluminum

-*Perchlorate, finely divided Magnesium

-Perchlorate, finely divided Aluminum

-KNO3, sulfur, finely divided Magnesium

-KNO3, sulfur, finely divided Aluminum

 

*Not suggested due to extreme friction and static sensitivity.

 

Anyone, feel free to correct my list, you are welcome to do so.

 

D

[Ventsi]

thanks a lot man, this is very helpful info. Do you think i can make a 100 gram batch to store or is that a no no? Is slow flash like KNO3 about as fast as whistle mix? I would do the whistle but i dont have any Na benzoate. Also, should I diaper mix it too like you would with very dangerous flash powder?

 

 

Yes you can make a 100g batch, I personally like making one big batch rather than five little ones. Slow nitrate flash is MUCH slower than perch. flash. I use bright aluminum for all flash since its cheaper and while my KP flash goes away in a "whooomp" the nitrate flash burns slow and bright like a flare. But confine it and it goes bananas... Also whistle would probably be more violent than nitrate flash, even if its made with a dark aluminum.

 

As far as mixing, I have done it three ways, well four actually. Normal "diaper" mixing on a large sheet of paper. Using a 40mesh non-sparking screen. Putting the components in a SAFE anti-static plastic bag and mixing them by hand. Also I take a small amount of the aluminum before hand and ix it with Perch./KNO3 to make it more free-flowing and then proceed to the mixing method.

 

Please note that you should be wearing heavy PPE equipment during any of these methods. This is what I use but not limited to: Safety glasses, Face Shield, dust mask/respirator. Long sleeve cotton sweatshirt, gloves. And don't forget to spray everything with anti-static spray.

 

Guys I'm sure there's more, and if I got something wrong, please don't hold back.

[dagabu]

I make what I am going to use so if I am making reports, I make them all at the same time. I do not store loose flash.

 

D

[Ralph]

you should never aim to store lose flash

 

dagabu I think your list has some issues

 

I don't see nitrate sulfur magnesium flash as less sensitive than 70/30 try mixing magnesium with a solution of KNO3 using 80mesh mg i same minor effervescence using a differnt nitrate like ammonium nitrate results in a rapid heating and much effervescence though with KNO3 the reaction is considered to be small enough by many to be ignored I certainly would not say it is less sensative than 70/30

[dagabu]

Its all based on an impact test done on all of the above with a drop tool. Which height was 1:10 gram of a composition ignited by a dropped weight from a determined height.

 

Not my test and I dont know how fine the materials were. Go ahead and copy/paste the list and make changes.