Lance troubleshooting

[p00rs4pp]

First off, hi all -- new to the forum, but not pyrotechnics. I believe I used to have an account here many years ago, but have long since forgotten the login.

 

To the point --

 

I'm trying to make a lance set piece to propose to my girlfriend. I know better than to go too over-the-top as an amateur, so my main goal is just to be able to spell out 'marry me?'. Unlike a professional piece, I only need it to burn for 10-30 seconds (enough to get down on one knee and present my offering :-D )

 

I had some mixed success years ago making lances from 1 cent coin roller tubes & the pyrotechnic composition found in road flares (a cheap and easy source of Sr(NO3)2 + slow-burning fuel). The composition in flares is already ideal -- low smoke, burns slow & bright with a deep red flame, and easy enough to find.

 

I discovered even back then, that the composition in road flares can be somewhat difficult to ignite and get going -- it seems to need to get _really_ hot before it becomes self-sustaining. I managed to solve this previously by layering a bit of 50/50 blend of BP + flare composition on top of the main unadulterated flare charge, and an additional thin layer of pure BP on top of that. While visco fuse could light the pure flare comp + 50/50 blend, a top thin layer of pure BP was necessary to reliably get it going via homemade sticky match.

 

This time around though, I'm really struggling to get the flare comp going, and my previous trick of layering gradiants of BP on top isn't working. The top layer of pure BP ignites, and it seems the blended mixture of flare comp + BP is burning, but the pure flare comp just won't catch.

 

There's a chance my flare powder is just wet -- I live in an area known for its humidity, and I've come to understand Sr(NO3)2 is very hygroscopic. I've cooked it in an oven @ ~235 for 2 hours, it certainly feels drier than it was initially (very clumpy before), but is it possible it wasn't long / hot enough?

 

The other thing that's different this time around is instead of penny rollers, I'm using hand-made 1/4" diameter paper tubes from kraft paper and wood glue. I'm thinking that maybe being so narrow, exhaust and debris is quickly smothering / insulating it, and the heat just isn't transferring well.

 

Any thoughts?

 

Some ideas I've had:

• Adding a sensitizer to the main flare comp charge -- but what's a good (non-perchlorate) sensitizer? (something mild that won't just cause the whole lance to burn up in < 10 seconds)
• "core-ing' the main flare comp charge -- i.e. carving out a central hole in the main charge so that the BP + flare blend extends down into a ring of pure flare comp for better heat transfer. Similar as one would do to a rocket, except instead of leaving the core open / hollow for gasses, filling it w/ BP + flare blend.
• Abandon the 1/4" tubes and opt for a larger diameter. I know 1/4" is on the smaller end of traditional lance diameters, but I've only got a limited amount of supplies, and at a bare minimum I'd need at least 87 lances to spell out 'marry me?' legibly.

 

Love and much appreciation for any help or suggestions y'all pyros can throw my way.

 

EDIT -- I forgot to mention; the flares are 'Orion' brand -- the MSDS is available here: https://www.orionsignals.com/wp-content/uploads/2018/06/750.pdf

It doesn't list the exact ratios, but roughly:

• Sr(NO3)2: '< 75%'
• Sulfur: < 25%
• KNO3: < 25%
• Paraffinic Oil: < 10%
• Potassium Chlorate: < 5%
• Waxy Sawdust: < 5%
• Polyvinyl Chloride: < 5%
• Shellac: < 1%
• Charcoal: < 1%

Edited June 15, 2021 by p00rs4pp

[pyrokid]

Harvesting the composition out of road flares would not be my first choice, but a constraint is a constraint. One possible explanation for the ignition failures with the new tubes is their smaller diameter: it could be that your prime does not transfer enough heat into the smaller area of flare comp. To that point, I think adding some geometry to the interface to increase surface contact would be a step in the right direction. A central conical core could be added with an appropriately shaped drift. An easier approach might be to modify your prime formula with the addition of some metals such as magnalium, silicon, or aluminum in order to heat it up. Are you assured that the flare composition at your disposal burns properly?

[SharkWhisperer]

 

First off, hi all -- new to the forum, but not pyrotechnics. I believe I used to have an account here many years ago, but have long since forgotten the login.

 

To the point --

 

I'm trying to make a lance set piece to propose to my girlfriend. I know better than to go too over-the-top as an amateur, so my main goal is just to be able to spell out 'marry me?'. Unlike a professional piece, I only need it to burn for 10-30 seconds (enough to get down on one knee and present my offering :-D )

 

I had some mixed success years ago making lances from 1 cent coin roller tubes & the pyrotechnic composition found in road flares (a cheap and easy source of Sr(NO3)2 + slow-burning fuel). The composition in flares is already ideal -- low smoke, burns slow & bright with a deep red flame, and easy enough to find.

 

I discovered even back then, that the composition in road flares can be somewhat difficult to ignite and get going -- it seems to need to get _really_ hot before it becomes self-sustaining. I managed to solve this previously by layering a bit of 50/50 blend of BP + flare composition on top of the main unadulterated flare charge, and an additional thin layer of pure BP on top of that. While visco fuse could light the pure flare comp + 50/50 blend, a top thin layer of pure BP was necessary to reliably get it going via homemade sticky match.

 

This time around though, I'm really struggling to get the flare comp going, and my previous trick of layering gradiants of BP on top isn't working. The top layer of pure BP ignites, and it seems the blended mixture of flare comp + BP is burning, but the pure flare comp just won't catch.

 

There's a chance my flare powder is just wet -- I live in an area known for its humidity, and I've come to understand Sr(NO3)2 is very hygroscopic. I've cooked it in an oven @ ~235 for 2 hours, it certainly feels drier than it was initially (very clumpy before), but is it possible it wasn't long / hot enough?

 

The other thing that's different this time around is instead of penny rollers, I'm using hand-made 1/4" diameter paper tubes from kraft paper and wood glue. I'm thinking that maybe being so narrow, exhaust and debris is quickly smothering / insulating it, and the heat just isn't transferring well.

 

Any thoughts?

 

Some ideas I've had:

• Adding a sensitizer to the main flare comp charge -- but what's a good (non-perchlorate) sensitizer? (something mild that won't just cause the whole lance to burn up in < 10 seconds)
• "core-ing' the main flare comp charge -- i.e. carving out a central hole in the main charge so that the BP + flare blend extends down into a ring of pure flare comp for better heat transfer. Similar as one would do to a rocket, except instead of leaving the core open / hollow for gasses, filling it w/ BP + flare blend.
• Abandon the 1/4" tubes and opt for a larger diameter. I know 1/4" is on the smaller end of traditional lance diameters, but I've only got a limited amount of supplies, and at a bare minimum I'd need at least 87 lances to spell out 'marry me?' legibly.

 

Love and much appreciation for any help or suggestions y'all pyros can throw my way.

 

EDIT -- I forgot to mention; the flares are 'Orion' brand -- the MSDS is available here: https://www.orionsignals.com/wp-content/uploads/2018/06/750.pdf

It doesn't list the exact ratios, but roughly:

• Sr(NO3)2: '< 75%'
• Sulfur: < 25%
• KNO3: < 25%
• Paraffinic Oil: < 10%
• Potassium Chlorate: < 5%
• Waxy Sawdust: < 5%
• Polyvinyl Chloride: < 5%
• Shellac: < 1%
• Charcoal: < 1%

 

Dude sounds like a troll.

 

If he were not "rusty" in pyrotechnics (here years ago but forgot his login--ping an admin), he would immediately know how to address his issue. One generally does not get forgetful or "rusty" (my words) in fireworking.

 

I call bullshit. Dude knows the basics of fire. If you cooked the flare comp in your oven at 235 (was that F or C?) then try turning up the heat some, maybe.

Edited June 15, 2021 by SharkWhisperer

[pyrokid]

Sharkwhisper, please refrain from posting on the forum again until you can get a handle on your severe psychological disturbances. I think you spending some time in an institution away from the dangers of the internet would be good for you, and the rest of us.

[SharkWhisperer]

Sharkwhisper, please refrain from posting on the forum again until you can get a handle on your severe psychological disturbances. I think you spending some time in an institution away from the dangers of the internet would be good for you, and the rest of us.

Oh piss off, kid.

 

You're imaginative as a stocked trout.

 

But thanks for the combined lesson on flare chem and geometry.

 

ffs

Edited June 15, 2021 by SharkWhisperer

[Carbon796]

Troll, bullshit, "your an asshole", and douche.

 

You called that one perfectly, that self introspection is really paying off for you.

Edited June 15, 2021 by Carbon796

[Carbon796]

 

You're imaginative as a stocked trout.

 

 

ffs

You may want to spend more time looking in the mirror.

 

Your about as boring and predictable as a sloth.

[SharkWhisperer]

You may want to spend more time looking in the mirror.

 

Your about as boring and predictable as a sloth.

Ohhh, my geriatric friend!! I missed you! And your humor, you're so funny!!!

 

Love your knowledge, not so much your personality.

 

Stay crabby. It's your trademark!!!

 

 

 

p.s. uhhh, it's "you're" an asshole; not "your"

Edited June 15, 2021 by SharkWhisperer

[Carbon796]

Your going to have to do better than that. Same whining, different temper tantrum.

[SharkWhisperer]

Your going to have to do better than that. Same whining, different temper tantrum.

I love you, too!

 

 

_{are we done yet?}

[SharkWhisperer]

Your going to have to do better than that. Same whining, different temper tantrum.

Carbon. Repetition is key. It's "you're" as a contraction of "you are", not "your", you absolute cretin!

 

You really are a bit of a ham-fisted simpleton, aren't you? You're so silly!

 

Now teach our troll how to say "Marry Me?" on the ground in red pyro, Wizard.

Edited June 15, 2021 by SharkWhisperer

[pyrokid]

Snakewhispers, you are really out of control. Did you have a bad day? Did something trigger you IRL? You should speak to your doctor about how you aren't taking your medicine. It really shows. I would tell you that you're letting down people who care about you, but I wouldn't want to mislead you. You need to stop with pyrotechnics before you hurt yourself.

[p00rs4pp]

Dude sounds like a troll.

 

If he were not "rusty" in pyrotechnics (here years ago but forgot his login--ping an admin), he would immediately know how to address his issue. One generally does not get forgetful or "rusty" (my words) in fireworking.

 

I call bullshit. Dude knows the basics of fire. If you cooked the flare comp in your oven at 235 (was that F or C?) then try turning up the heat some, maybe.

 

I'll skip over the inflammatory bits as they're not productive, though I'd have to say, my post would be pretty shitty as far as troll posting goes.

 

I was reluctant to cook the flare comp at too high of temperature -- I read in another reference that 275*F @ 2 hours was the recommended procedure for dehydrating similar compounds, but given I did not have my infrared thermometer to verify the accuracy of my oven (in addition to my flare comp being somewhat different from the one in the reference), I erred on the side of giving a wide berth for margin of error. I did actually give an extra 30 minutes in the oven once I was confident it wasn't going to grossly overshoot the target temperature, but I didn't want too verbose in an already long post.

 

I'll try giving it another pass in the oven for 2 hours @ 250*F, thanks for the suggestion. It's hard to be certain how dry it actually gets, as the small amount of paraffinic oil in it leaves a residue and always leaves it feeling a bit moist / greasy.

[p00rs4pp]

Harvesting the composition out of road flares would not be my first choice, but a constraint is a constraint. One possible explanation for the ignition failures with the new tubes is their smaller diameter: it could be that your prime does not transfer enough heat into the smaller area of flare comp. To that point, I think adding some geometry to the interface to increase surface contact would be a step in the right direction. A central conical core could be added with an appropriately shaped drift. An easier approach might be to modify your prime formula with the addition of some metals such as magnalium, silicon, or aluminum in order to heat it up. Are you assured that the flare composition at your disposal burns properly?

 

I agree that ideally one would create the lance composition from components themselves, but in my case, the time it would take to obtain the components would jeopardize being able to complete this project in what little time I have. Using off-the-shelf flare composition definitely puts me at a disadvantage, but as you said, a constraint is a constraint.

 

I definitely think you're on to something regarding the geometry of the interface between the primer and main flare comp charge. Towards the end of my original post I did propose that maybe I needed to core-out the main charge a bit to increase surface area with the primer, but I like your idea of simply creating a conical section; that'd be easy enough to accomplish by whittling down the tip of one of my ramrods into a blunt point.

 

Re: if I'm sure my starting flare comp even burns properly -- that's one thing I've planned to test but haven't actually verified yet. I tried a new intermediate primer last night (4:1 flare comp to BP this time, compared to 1:1 flare to BP I had been using) that showed some promise -- I got some brief wisps of bright red before it extinguished itself. Not quite a success, but progress none-the-less. As far as testing the flare comp directly, I plan to just dump a spoonful of the raw powder onto asphalt and hitting it with a blow torch -- if it burns and stays lit on its own in an unconfined space, that should be a good indicator the flare comp is workable, right?

 

Re: adding some metals -- I hadn't considered this yet, so thank you for the idea; it's definitely worth trying. I'm not sure I'll be able to find a proper source for magnalium or silicon in the time I have available, but aluminum flakes might be possible. I'll check the local craft store for some as a paint additive, if that fails I can resort to filing away at some aluminum stock to gather enough for a small test. Any suggestions on the proportion to add to my flare-comp / BP priming mixture?

[davidh]

Smaller diameter lances are harder to keep burning. For "normal" lance comps I recommend a tube no smaller than 5/16" id.

Second, you really need a good lance comp. Road flare comp is great - for road flares. There are a crap-ton of red lance comp formulas made with many different chemicals. If you are so short on supplies that you can't make any of them, then making lances might not be the best endeavor for you.

[p00rs4pp]

Smaller diameter lances are harder to keep burning. For "normal" lance comps I recommend a tube no smaller than 5/16" id.

 

Second, you really need a good lance comp. Road flare comp is great - for road flares. There are a crap-ton of red lance comp formulas made with many different chemicals. If you are so short on supplies that you can't make any of them, then making lances might not be the best endeavor for you.

 

I'm actually open to any color lance, red is just the default for road flares (from the Sr(NO3)2). I'll take a look through the comp database, but from what I recall most of them require one or more somewhat 'exotic' components, and by that I mean something I can't easily find (or make from) local sources. The shipping times from online pyro stores makes depending on anything from them a real risk; otherwise I would just order ready-made lances from a site like ACE pyro. Also peak season around 4th of July makes it even more of a gamble. The upside of independence day coming up though is that firework stands are already starting to pop up everywhere. I may be able to cannibalize consumer fireworks for supplies, but starting with an unknown composition may be more difficult than starting with a re-purposed one.

 

Unfortunately, while lances themselves are only 1.3g (articles pyrotechnic, legal for consumers), I've never seen them kept in stock at a consumer fireworks store / stand.

 

If you know of any local pyro component suppliers here in Florida (or a place that sells lances), I'd love any info you have on them -- if I can shortcut shipping by driving a few hours, it'll make up for whatever lead time is necessary.

 

I bought an array of different size dowels to make into ramrods / tube formers, including 5/16", so I'll definitely give that a go in addition to the other suggestions I've received so far.

 

Much thanks and appreciation for all the help so far!

[Carbon796]

What you want is, 1.4 class C.

 

1.3 is class B and not available to consumers.

 

If you can make a reliable hot prime. It would probably be easier, to reconfigure the fuzee's, as color pots. Since typical lance timing isn't needed.

[SharkWhisperer]

What you want is, 1.4 class C.

 

1.3 is class B and not available to consumers.

 

If you can make a reliable hot prime. It would probably be easier, to reconfigure the fuzee's, as color pots. Since typical lance timing isn't needed.

My good buddy Carbon's probably right on this last suggestion. That said, how big of a display are you considering? I ask because of the price of road flares. I checked Amazon, Ebay, HD, Tractor Supply, Auto Zone, and Advance Auto, and they're all ridiculous--like $10 for 3 x 15-minute flares. Surprisingly, I just bought a pack of 3 x 20-minute flares from a local Walmart for $6, which might be your cheapest option. All are Orion brand. orionsignals.com . They don't list prices online so maybe don't sell direct. No idea who their generic competition is.

 

Maybe you could stretch them if you had some type of reflector to guide the light. Perhaps something made out of Al foil or shiny metal gutters? Just winging it here.

 

These are friction ignition, and the very top of the main unit is coated with a match-like chorate-based comp (the button) that probably will fire up pretty easily with visco fuse, but I'd test one first. Might have to rough it up some but be careful--friction sensitive. The idea to soup them up with some hot prime is not a bad one just to be sure--this isn't an event that you want to take chances with. It's possible that you could fire them all up near simultaneously with either well-anchored silver/grey fast fuse or quickmatch with openings to slow the burn momentarily over each flare.

 

Going the powder extraction route, maybe you could perc up the ignition rate a bit with some, uh...perc? I've attached the Orion MSDS. Components are not hard to guess. Neither are the percentages (only ranges given). May or may not be useful...

 

I live in FL half the year & there's plenty of fireworks stores open all across FL, but you already know this. Gotta sign that waver that you can only use them for farm and agricultural purposes, like scaring off predators or crop destroyers. Yeah, my tomato garden qualifies in my eyes. Also, FireworksCookbook.com is based out of Georgia, so next door. Kind of. He's just south of Macon, which is pretty much dead center GA. Chris is a decent dude and will probably prioritize a chem shipment if you let him know your situation. His phone's posted on his website. Good prices, too.

 

If it doesn't work out with the flares or homemade red comps, perhaps LED strips are a viable option?

 

Good luck.

Orion Flare MSDS.pdf

Edited June 16, 2021 by SharkWhisperer

[Piccaso]

Heres some lance tubes I am sure some one would spilt an order with you. Heck I would.

 

https://www.woodysrocks.com/store/p331/Lance_Tubes_.html#/

Edited June 17, 2021 by Piccaso

[p00rs4pp]

FIgured I'd post an update:

 

Assembled another test run tonight w/ the following tweaks (taking into consideration all the advice y'all have graciously offered thus far):

 

• Wider tubes -- 3/8"
  • Previously was using 1/4" ID tubes; turns out I do not have a 5/16" dowel for forming & ramming... but I did have 3/8" (6/16"), so I went w/ that. 1/16" wider than suggested
• Conical interface between main charge (flare comp) and primer charge (4:1 flare comp + BP)
  • Whittled one end of a wood ramrod to a point, total depth of conical point is ~3/8"
• Extra dry main charge
  • Took the flare comp for another pass in the oven for 1 hour @ 250.
• Small pinch of Al powder added to primer
  • Filing down aluminum stock by hand with a rat-tail file is slow work. After about an hour of filing, I had maybe a few grams at best. Didn't really know how much to add, but in all scooped up as tiny a sliver of Al powder as one can w/ a teaspoon, and mixed into about 1-2g of primer before charging.

End result - another dud :-(

 

I think all the advice so far has been good, and in this case, I simply did not leave enough room for an ample amount of primer. I only had about 1/4" (packed) of primer, not counting the conical section between layers.

 

Unfortunately it started raining right after, so I lost my chance to recover, clean out the debris, re-pack fresh primer and try again, but I'll try it with more like 1/2" of primer next time.

 

I also vaguely recollect that when I had some success making lances like this before (besides the obvious wider 3/4" ID tubes that aren't too practical to make a whole set piece with) is that I don't think I made pre-mixed primer, but instead just did the layer of flare comp, charged it, plopped in a scoop of BP and shallowly stirred it a bit with a piece of thick wire before filling up the rest of the tube with pure BP. I think I might give that a try in the next test as well... it should create more surface area between the primer and main charge if not overdone.

[davidh]

Unless you are using a lance machine, make your own lance tubes. Use a 5/16 hollow mandrel (Ace hardware sells 5/16" brass tubes that are perfect) and 4"x4-3-16" 24lb white printer paper (grain doesn't seem to matter). I recommend paper with no recycled content. use wheat paste for glue, with a 3/16" line on the trailing edge of the roll-up, and an 1/8" line on the bottom. Roll the tube up, slide 3/16" of the tube past the end of the mandrel, pinch and twist. This will close the end of the lance, and the hollow mandrel will not suck the twist apart when removing the tube from the mandrel. If you use used paper and make wheat paste with flour, these tubes cost nothing and can be made very quickly after a bit of practice.

Edited June 17, 2021 by davidh