crackle formula problems

[ronmoper76]

ANyone familiar with 68/30/8 formula? I originally made a more common 75/15/10 with lots of bismuth and a eyeballed a big glob of homemade nitrocellulose from smokeless powder. they worked beautifully my first try. The new recipe with only 8 parts bismuth i used store bought nitro and i weighed it out precisely at 10% of the weight of my crackle batch,it was about 70 grams if i remember dissolved in acetone. IT looked like ALOT but it was 10% This stuff didn't work at all!!! It was more like flash powder that was a bitch to light. When it did light it was hot and fast and gone in a flash with no crackling or noise.....So i suspected it had way to much nitrocellulose so i made several small batches minus the nitro and added to the original mix one at a time to dilute it,testing after each addition. Finally it started to crackle and pop some but still wanted to burn up all at once like flash powder..I was out of ideas,had a massive dough ball of i don't know what the fuck and about 75 grams of bismuth left......I made one last attempt and instead of making a new batch i added the rest of my bismuth straight to it,remixed and granulated again... Now they kinda function ok ... I mixed a bunch in a fountain like i normally do with the old formula and gave me the very first fountain cato i ever witnessed,lol It started out great cracking and popping and then,BOOM They are more like dragon bombs than eggs,WTF

 

Does any of this make sense? What do you think went wrong? Why did they go from shit to what i have now?.I ended up adding 600 more grams of complete mix with zero nitrocellulose in it to dilute the mix enough so it didn't burn like flash powder Is it to much nitrocell like i suspected? Do they mean use 10% by eyeballing it instead of actually weighing out dry nitrocellulose?

The first video is unprimed and the second primed with BP but still a bit damp so i had to keep lighting it ,but they are decent,I was mixing my old eggs in the delay of my whistle rockets but after i saw what they did to my fountain,im very leary.

My whole thing is i don't want to try this recipe again if i have to fuck with it to make it work,when i used the first formula heavy on bismuth it just worked but that crap is expensive,anybody else have problems with this formula?

Edited April 26, 2021 by ronmoper76

[BasedAndRocketpilled]

I have never actually made crackle but from what Ive read isnt the NC supposed to be weighed in lacquer form rather than solid? Also, what caused you to deviate from your previous method that worked? Edited April 26, 2021 by BasedAndRocketpilled

[ronmoper76]

I have never actually made crackle but from what Ive read isnt the NC supposed to be weighed in lacquer form rather than solid? Also, what caused you to deviate from your previous method that worked?

Bismuth trioxide is 25.00 a lb! The first formula is mostly bismuth,the second has hardly any bismuth in it. That's what i was trying to say earlier. Kinda hoped mumbles would reply,that guy is intelligent and explains

stuff so that an average person can understand what he is explaining. I started with 800 grams and almost ended up with 1400 grams of crap,im just glad i could correct it without losing anything. It seems to me the bismuth is either off in this formula "it doesn't add to 100 so i treated numbers as parts" or i used way to much nitrocellulose. The video doesn't do it justice,the stuff i made at first burned all at once,hot,and explosively,it was exactly like putting a gram of flash down and lighting it. A huge smoke cloud and flame that stained a part of the table,it was scary because i was thinking to myself,thank god i didn't try to light anymore than that at once,i might have burned a finger.

Edited April 26, 2021 by ronmoper76

[DALE]

I have a bigger problem , You may be able to help . I am using the same formula 75/15/10 . in a 50g batch I am adding 4.5 fl oz of n/c made from green dot . all chem's screened 3x with 40 mesh . The dough is pushed thru a #10 screen. The eggs come out looking like rice. After drying , They won't light, just smolder. the Magaluim is -200-325 mesh . I have tried 5 times, with the same results

[SharkWhisperer]

I have a bigger problem , You may be able to help . I am using the same formula 75/15/10 . in a 50g batch I am adding 4.5 fl oz of n/c made from green dot . all chem's screened 3x with 40 mesh . The dough is pushed thru a #10 screen. The eggs come out looking like rice. After drying , They won't light, just smolder. the Magaluim is -200-325 mesh . I have tried 5 times, with the same results

DEs, even the little mouse turds, require serious priming to get a uniform heat "shell" that makes them do their thing. I use a hot perc prime w/red gum acetone administered followed by moderate-burn red gum bound BP outer prime, 91% IPA administered, both with some Si (5%). Interesting that yours are only smouldering, a torch should make them pop after a short delay even unprimed.

 

To reduce Bi costs, I use Witchita Buggy's (DC's) recipe using equal amounts of Bi and CuO, with great results. Usually 37.5% BiO3, 37.5% CuO, 20% MgAl -60, and 5% Al -325 spherical. Bound with +10% NC (final NC weight). Zero problems. Same when I used 5% NC final, which takes less time. All worked and didn't note a real difference from 10% NC. The Al might help maintain the flame temp during the smoulder and the variety of MgAl sizes allows their use in 1/4" DEs or mouse turds.

 

Have also used 35/40 BiO3/CuO to good effect, too. Remaining comps the same. Haven't gone lower in bismuth than that--it replaces the lead tetraoxide of old and there's probably a critical minimum. All you're left with is something getting closer to a CuO thermite as you reduce the Bi much more... And CuO thermites are very energetic beasts...especially with -200 MgAl.

[DALE]

I tried lighting them with a propane torch, no luck ! I had a typo on the ncl , I used .45 fl oz . Is that enough for a 50 g batch ?

[SharkWhisperer]

I tried lighting them with a propane torch, no luck ! I had a typo on the ncl , I used .45 fl oz . Is that enough for a 50 g batch ?

About a half ounce of NC lacquer to wet 50g of comp??? That's 12.7 mL. It would contain, if 10% w/v NC, 1.3g NC. 1.3g/NC divided by 51.3g total solids = about 2.5% NC final. That's not a lot of binder (NC or other) for that dense comp. Did you even get adequate wetting of your comp to form stars? If not, the mixing of your NC into the powdered ingredients might not have been uniform. I'd have used twice that NC volume to get a soup that you know is intimately "wetting" all ingredients (the acetone evaporates pretty quickly).

 

I don't know. I use more total metal, 20% MgAl and always add 5% Al. Never a failure, even with much lowered Bismuth. 15% metal might not be enough. Where are your chems from. For DE comps, FWC's ingredients have never let me down.

 

Is it possible your acetone has absorbed an inordinate amount of atmospheric water? What's your acetone source? How stored? Even hardware store will happily absorb .5-1% water, which usually isn't enough to affect DEs. Any more, though? Might be an issue if a bunch of water's being trapped inside. Are you sure they're completely dry? Any acetone smell to them at all? Shouldn't be.

[DALE]

It could be fake/ bad chems. I could not find bi203 on line, so I bought it on e bay .who is Fwc ? You have been more than helpful, Thanks

[SharkWhisperer]

It could be fake/ bad chems. I could not find bi203 on line, so I bought it on e bay .who is Fwc ? You have been more than helpful, Thanks

My pleasure. Don't buy chems on ebay. Often you'll get ripped off. And you'll almost never save money. Other times it's reliable vendors who charge less when ordered direct (no Amazon/Ebay fees). FWC is fireworkscookbook.com. Out of Georgia. Never in many years have had a questionable batch of any chems I've received from him. Excellent service and quick. Cheapest MgAl (and others) at the pound levels. His BiO3 is proven quality and is $20/pound, cheaper than elsewhere. Pyrochemsource is also a favorite go-to, but his stuff's about a buck a pound more expensive for many items; sometimes he has items that FWC might temporarily be out of. There are other excellent vendors besides these two--I'm only mentioning these because they're super reliable and that's where much of my chem money goes. These guys have established a livelihood from selling high-quality chems at decent prices.

[DALE]

I checked out the 2 places, they look like pro's to me . I was looking over your comps and got thinking . I used -200-325 mag al.from Skylighter. Yours is 60 mesh . Would That stop my d e from igniting ? pyro chem has 30-60 if you think it will help

[Mumbles]

Normally too fine of metal usually has the opposite problem you're encountering. They start snapping or sizzling before the entire comp granule can be consumed. Dragon eggs are effectively a 2 part reaction. The first they'll heat up, glow red, and smoulder a bit. This is kind of the delay stage. Then they'll explode or snap or go off. This is the effect most people are used to seeing. The smoulder stage isn't always that long that you can easily identify it. Basically, finer metal often will get to the exploding stage faster. Sometimes so fast that it can start snapping before the entire granule is consumed. Each granule will produce a range from a few reports to an undistinguishable sizzle depending on how pronounced this is. This is fine for some effects, but when you want a single loud report, it's not ideal.

[SharkWhisperer]

Normally too fine of metal usually has the opposite problem you're encountering. They start snapping or sizzling before the entire comp granule can be consumed. Dragon eggs are effectively a 2 part reaction. The first they'll heat up, glow red, and smoulder a bit. This is kind of the delay stage. Then they'll explode or snap or go off. This is the effect most people are used to seeing. The smoulder stage isn't always that long that you can easily identify it. Basically, finer metal often will get to the exploding stage faster. Sometimes so fast that it can start snapping before the entire granule is consumed. Each granule will produce a range from a few reports to an undistinguishable sizzle depending on how pronounced this is. This is fine for some effects, but when you want a single loud report, it's not ideal.

 

 

I checked out the 2 places, they look like pro's to me . I was looking over your comps and got thinking . I used -200-325 mag al.from Skylighter. Yours is 60 mesh . Would That stop my d e from igniting ? pyro chem has 30-60 if you think it will help

Mine is -60 mesh, not pure 60 mesh. That means it has everything that goes through a 60-mesh sceen, so a pretty wide variety of sizes, including fines. If you poke around DE recipes and discussions, you'll read about using larger mesh MgAl for larger eggs and smaller mesh for smaller eggs/microstars. I've always used a range of sized MgAl and they always work, in 1/4" cubes or microstars. There may be optimization possible, but I'm happy enough using what I use. I don't recall ever hearing about somebody making DEs/crackle with MgAl larger than -60.

 

Not sure if you saw it but on the FWC MgAl page there's a drop-down list of the various mesh-size ranges he sells. All $14/pound. If you have a screen set, you can generate any specific metal mesh size or range that you might want to test.

 

Are your DEs rock solid with the estimated 2.5% NC binding them? At 5+ percent NC, they're like little heavy chunks of granite that are almost impossible to break up with your hands.

 

And I've never made DEs without a little supplemental fine spherical Al added, which may prove important to regulating the heat transfer during the smoulder phase Mumbles mentioned. I generally use 5% of -325 spherical but 5 micron atomized has worked in the past, too.

[SharkWhisperer]

It could be fake/ bad chems. I could not find bi203 on line, so I bought it on e bay .who is Fwc ? You have been more than helpful, Thanks

Where'd you get your other chems from? Bi2O3's often used as pottery glaze/colorant but no idea the quality from Ebay. What's the source of your MgAl and CuO?

 

NC from smokeless should be fine, but you might want to up it from around the 2.5% you tested.

[DALE]

I replenished my chems from Pyro source , They will not crackle, just smolder a few seconds & go out . Take a Look at my ncl and see if I am correct I add 10g of green dot to 100 ml of good acetone for my ncl mix.( viscosity of thin paint) . For a 50 g batchof d-e I mix in 1.6 fl oz. of the ncl . stirr until I have a dough that I can work into a paddy, then screen.What am I missing ?

[SharkWhisperer]

I replenished my chems from Pyro source , They will not crackle, just smolder a few seconds & go out . Take a Look at my ncl and see if I am correct I add 10g of green dot to 100 ml of good acetone for my ncl mix.( viscosity of thin paint) . For a 50 g batchof d-e I mix in 1.6 fl oz. of the ncl . stirr until I have a dough that I can work into a paddy, then screen.What am I missing ?

You went from about 2.5% NC final to almost 10% NC final. That's a big difference, but would be surprised if that's your primary problem.

 

Most likely issues are mixing/integration and chem quality, particularly your metal. Was that from Ebay, too? A known vendor? What about your CuO? Where from? How does your MgAl perform in other comps? CuO? You are screen mixing all of your chems together several times for good integration? Pretty important.

[DALE]

I will have all new chemicals delivered from cookbook this week . I will start from scratch with all fresh chems and will keep you advised. Btw the mouse turd sized crackle is hard and it can be detonated with a 5# hammer hammer ( testing done with 3 turds at a time, I may be old, but not stupid )

[SharkWhisperer]

I will have all new chemicals delivered from cookbook this week . I will start from scratch with all fresh chems and will keep you advised. Btw the mouse turd sized crackle is hard and it can be detonated with a 5# hammer hammer ( testing done with 3 turds at a time, I may be old, but not stupid )

Yup, you're getting closer. DEs/crackle is a bit sensitive, so don't get too complacent with it, even the batch that's not working quite the way you want it. You've seen that a hammer will set it off...

 

You'll get it working--all of my DE chems are from FWC, although I would have no reason not to trust PCS's chems. Ebay...maybe not so much.

 

Anyways, with proven chems, well mixed (screen mixed several times, not just by hand stirring), the right size of quality MgAl, and you'll never have to look back or troubleshoot your DEs again.

 

Crackle's a pretty simple comp except it can get messy cutting patties if it's too damp/sticky, and eggs/crackle really need a good thick hot prime coating followed by a layer of easy lighting BP meal or a slower prime to function reliably and light as stars. No priming needed if you're embedding crackle within a matrix comp like a charcoal star formulation for example, but many/most(?) uses require good priming.

 

Mentioned earlier that all of my DEs have about 5% Al in them. Something to consider, but not yet. Test your base formula with the new chems, get it working, and then make decisions on changing formulas (like equal amounts Bi/Cu to trim costs). Always best to only change one thing at a time when troubleshooting comps/devices.

 

What size MgAl are you planning to pick up from FWC?

[DALE]

I thought I would take your advice and do 60 mesh mgal . I screen all my chems thru 40 mesh , then mix together by hand, then screen mix with a 20 mesh .three times. I have not bothered with priming them yet. No need , If they won't light with a torch, I am wasting money

[SharkWhisperer]

I thought I would take your advice and do 60 mesh mgal . I screen all my chems thru 40 mesh , then mix together by hand, then screen mix with a 20 mesh .three times. I have not bothered with priming them yet. No need , If they won't light with a torch, I am wasting money

Great, you'll get them firing up. Confused about 60 mesh. I have been using -60, which would be different from "straight" 60-mesh (everything that's captured on a 60 screen and doesn't pass. The -60 in contrast is everything that passes a 60 screen, so 61 mesh and below, a wide range with some medium-sized and many smaller particle sizes. Also, FWC changed out their sifting options and now offers a -50 and a -50+200, both of which I'd substitute without concern. Did you mean one of these? That said, most people use finer Mg (200 or 225 mesh) for DEs, but for me those are only good for smaller crackle (mouse turds) and not the bigger louder larger star sizes (1/8-1/4"); my inclusion of both medium and small grains seems to be suited for both applications.

 

Anyways, if you have a large metal size range, it can be good because you can use your own screens to sub-segregate several different size ranges for different purposes.

 

I push my stuff through a 20 mesh screen 3 times, with a little shaking/stirring of the catch container after each pass. The Bi tends to go through in smallish clumps that benefit from knocking around a little bit to get decent distribution. Not difficult; if you see different shades of chems in your sifted pile it means it needs another pass or two.

 

I would probably go straight to the 20-mesh screen for all mixing instead of trying to push -60 (or -50 if that's the case) through a 40 mesh screen because a few stray large metal particles might do minor damage (push wires apart making bigger holes) if they were forced through. You really never want to force metals through screens, even if sparking isn't a big concern. Your screens will last a long time.

 

You'll get them popping!

[DALE]

shows how much I have to learn. I ordered mgal 30-60 mesh .Will the 30-60 work without screening ? I also ordered copper oxide black. Is it the same as copper (II ) oxide black ?

[SharkWhisperer]

shows how much I have to learn. I ordered mgal 30-60 mesh .Will the 30-60 work without screening ? I also ordered copper oxide black. Is it the same as copper (II ) oxide black ?

FWC black CuO is copper (II) oxide; you're fine there. My friend, you will spend a lot of money if you don't ask these questions before you hit the "purchase" button. On small orders, shipping costs will suck if you need to reorder.

 

Unfortunately, I wouldn't expect great results with that large of MgAl in crackle, especially without any supplemental Al to keep the flame envelope hot (never tried without it and it's cheap; what I use is detailed earlier in this thread). If your package hasn't gone out yet (Chris is fast) then I'd call him pronto and ask him to substitute or add in the smaller MgAl!

 

Are you sure you ordered -30+60 MgAl from FWC as you stated earlier? It for sure is not listed on his website! But that is listed on Pyrochemsource... He also sells an 80-200 mesh range for the same price, which is close to what I use.

 

Pyrochemsource is great and I use him often. But all of the items you ordered are a few bucks cheaper on FWC than PCS...unless you have an allegiance or shipping is significantly less, you might be spending a few bucks more than necessary on this particular purchase. Not a lot, but it all adds up.

 

I would keep any tests to very small batches to save on expensive Bi. All of these unprimed crackle test mixes you have can probably be redissolved in acetone and incorporated in part into your new proven crackle comp, once you get there.

 

However, your 30-60 MgAl will be great for an addition to charcoal stars/comets and fountains! I posted a C6/MgAl stargun test a few weeks ago somewhere on here, probably in Pyrotechnics, in which the white flashes are due to -20+30 MgAl. Here it is: https://www.amateurpyro.com/forums/topic/14081-c6-10-2030-mgal-minimine/ . A lot of other similar tests, including complete shells, are not difficult to locate. MgAl always has uses.

 

May I suggest you slow down a few mph, whether making comps or ordering chems...take your time and make sure you are on top of all of the details before proceeding. Saves headaches. And you cut corners when you're in a hurry and not thinking a few steps ahead. That's when accidents are most likely.

 

You'll get it sorted out.

Edited August 24, 2021 by SharkWhisperer

[DALE]

I really appreciate your help . I will order the correct agal-50+200 . When you do not know what you are doing it is hard to find your mistake without help.If you ever need to know anything about weapon systems or flying helicopters I can return the favor. Is the copper oxide going to work?

[SharkWhisperer]

I really appreciate your help . I will order the correct agal-50+200 . When you do not know what you are doing it is hard to find your mistake without help.If you ever need to know anything about weapon systems or flying helicopters I can return the favor. Is the copper oxide going to work?

I've never used PCS' CuO, but I have no reason to doubt its quality. I'm sure it's fine. I have never had a problem with any of his chems. "Black copper oxide" on pyro vendor websites is pretty much always going to be the one you're looking for, CuO (II), the cupric salt. The "cuprous" red copper oxide is Cu2O--different beast. Black good. Red not for crackle. Red has other uses I think, but I've never used it for anything.

 

Besides DEs/crackle, CuO is used as a colorant for blue/purple/violet/magenta stars, as a component in super energetic thermite comps (DEs are a regulated thermite reaction; careful with using it in the "regular" thermite applications--it will spray vaporized/molten copper all over--a lot more "explosive" than iron oxide/Al thermites), as a burn rate catalyst for some propellants like sugar-based rocket candy, and strobes (fuel, pots, stars).

 

CuO is good stuff. Can never have too much laying about. For me during chem orders it's always "aww might as well tack on a pound or two of CuO even though I know I've already got plenty...". But that's the same with a lot of chems that get common use.

[deepakpyro]

 

To reduce Bi costs, I use Witchita Buggy's (DC's) recipe using equal amounts of Bi and CuO, with great results. Usually 37.5% BiO3, 37.5% CuO, 20% MgAl -60, and 5% Al -325 spherical. Bound with +10% NC (final NC weight). Zero problems. Same when I used 5% NC final, which takes less time. All worked and didn't note a real difference from 10% NC.

SK, indeed it's a great formula. I made one small batch of DE with mentioned formula and crackling is good. No difference from original DE forumula visibly where it uses 75% Bismuth. Great one though.

[DALE]

Let me see if I have this. I have coming -50+200 mgal coming.I want to screen the mgal and use in my mix what stays on the top of a 60 mesh screen ?