Nitrocellulose Lacquer--easy dissolving smokeless powder

[SharkWhisperer]

For those who make their NC lacquer by dissolving smokeless powder in acetone...I've repeatedly come across threads (here and elsewhere) and other written pyro tips/protocols for getting good dissolving. It seems that many commercial smokeless powders, whether to formulation or extreme compression, can be difficult to get to dissolve, and sometimes require repeated stirring with wait times in between stir sessions. No longer.

 

Recently, when out at Cabella's buying smokeless powder and some new shore fishing lures, I impulsively bought an extra bottle of shotshell double-base powder because it was on sale. Turns out to be the best ever for making NC lacquer. It is Hodgdon's "International" shotshell smokeless double-base powder. No fancy name; no formula number The Hodgdon's International appears as thin round wafers approximately 1.5 mm in width/diameter and very thin, with separate and distinct burnt orange and green particles. It's specs show it to be a fast-burning formula because it's made for shotguns that require high-speed smokeless. Anyways, the stuff is an absolute dream for rapidly making top-notch beige-colored NC lacquer! It will dissolve to a syrup-like 10% solution in acetone with perhaps 2 minutes (!!) of decent shaking. No waiting. No clumping (as always, add while mixing to prevent clumps). None of that stir, stir, and stir again. The stuff is great and has performed excellently for tested uses (dragon eggs--it's the bomb!!; topping the ends of visco with a BP slurry to assist ignition, pyrogen component/adhesive with homemade e-igniters...). It's as messy as any NC solution to work with, but super simple to get to dissolve. The best smokeless powder for quickly making cheap & easy high-quality NC lacquer, in my experience.

 

I also bought slower burning IMR 3031 single-base powder (NC only, for when I pretend to be a purist). Incidentally, "IMR" is a 100-year-old designation that means "Improved Military Rifle". The IMR grains are short, dense, black extruded rods, approximately 2 mm long x 0.5 mm on the cross-section. Similar to a small grain of black rice but without the tapered ends. Graphite-coated & buffed shiny. It's more like the "typical" smokeless powder, with regards to getting it into an acetone solution and the dark black slime that results. This requires, as many before have reported, long dissolving times with extra stirring/babysitting. Final NC made with the IMR is high-quality, but slow to make lacquer with if you need it in a hurry.

 

Both powders described here are manufactured in Canada, so thanks Canucks!

 

Hodgdon's International is the best/easiest smokeless powder that I've ever found for quickly making NC lacquer. No hassle. No (visible) residue or precipitate. Stores well warm or cold. No NG separation. Pretty beige lacquer color is a nice change from the usual jet-black. And it makes absolutely dynamite Dragon Eggs!

Edited February 20, 2020 by SharkWhisperer

[Bigmark]

Good to know thanks for sharing this bit of info.

[nordicwolf]

Sorry to revive this old topic, too...

 

What are the ratios of Hodgdons International to Acetone to create a slurry suitable for good dragon eggs? I'm not clear on what the "10% solution" mentioned above refers to.

 

Thank you!

[stix]

Sorry to revive this old topic, too...

 

What are the ratios of Hodgdons International to Acetone to create a slurry suitable for good dragon eggs? I'm not clear on what the "10% solution" mentioned above refers to.

 

Thank you!

.

And dragging it up again...

 

I think SW means 10% by weight. That is, 90 units smokeless powder + 10 units of Acetone to dissolve it.

 

I've often wondered when making NC for DE's, what difference (apart from the safety factor), should it make using too much Acetone?

It may start off as a thin slurry, then when you add the other chems and mix it, the acetone is going to evaporate quickly enough to the right consistency for rolling and cutting.

 

Just a thought.

 

[EDIT] Correction as per SW below. I should have said: 10 units smokeless/90 units solvent/acetone

Edited June 9, 2021 by stix

[Richtee]

.

And dragging it up again...

 

I think SW means 10% by weight. That is, 90 units smokeless powder + 10 units of Acetone to dissolve it.

 

I've often wondered when making NC for DE's, what difference (apart from the safety factor), should it make using too much Acetone?

It may start off as a thin slurry, then when you add the other chems and mix it, the acetone is going to evaporate quickly enough to the right consistency for rolling and cutting.

 

Just a thought.

Yep, exactly what happens. to the point you get a block of NC. And it’ll collapse a glass jar. This- I know

 

On Edit: Ah, I see the point. Kinda depends if the mix yer binding is A solvent to a big degree. Might “leach out” some of the ingredients, causing a poor mix?

Edited June 8, 2021 by Richtee

[SharkWhisperer]

.

And dragging it up again...

 

I think SW means 10% by weight.

 

I've often wondered when making NC for DE's, what difference (apart from the safety factor), should it make using too much Acetone?

It may start off as a thin slurry, then when you add the other chems and mix it, the acetone is going to evaporate quickly enough to the right consistency for rolling and cutting.

 

Just a thought.

Yeah, I go weight/weight. Most folks prefer to use weight/volume, but acetone's less dense than water so 1 mL is not 1 gram as with water. Either way should work--you know how much NC per mL lacquer. The key is getting enough NC into your comp. Get a syrupy suspension/solution that pours slowly but reliably. A 10% w/v solution is just a little thicker, and works fine. Personal preference.

 

And I like the stabilizers in smokeless. Just used a last few drops from a solution made a year ago for rocket motor igniters and set aside and worked as well as the day I made it. I have pure NC too, but that's been in the freezer for 2 years now. No stabilizer and I'm probably not buying diphenylamine to stabilize it unless I'm going to use it all in a short time. I have no other use for diphenylamine (common stabilizer in smokeless and commercial lacquers; there are others but this one I see most often). And I don't mind the NG content in double-base, though I have single-base powders, too. Others subjectively report better results with DEs using NG from double-base; I can't tell a difference.

 

Acetone's specific gravity is 0.791 g/mL at 25C (77F). I round it off to 0.8 g/mL for "room temp" work, and call it good. For 100 mL of a 10% NC/acetone solution, that would be dissolving 10g of smokeless into 90g (112.5 mL; 90/0.8) acetone. This is accurate w/w, but is actually a little more dilute than w/v NC lacquer with 10g smokeless/NC dissolved in 90 mL acetone. I aim for 5% NC final in DEs/crackle, but you can give or take a decent margin without worry. When using double-base smokeless, I just lump the NG mass in with the NC calculations (I weigh total smokeless as "NC"). Added to the DE mix this makes a thick syrup that needs to have solvent evaporated off to leave residual NC. Acetone won't leach out any components--nothing else in DE comp is acetone soluble, and shouldn't really matter.

 

The trick is that the stuff is a lot more sticky when damp, and it goes from pain-in-the-ass sticky to workable within a minute or two, so you need to be attentive. Once it's ready to go (easily separates from the walls of your container with a wooden stick without leaving strands/residue is my gauge), you need to work quick to roll it out on prime, top prime, and cut. It's pretty much mandatory for me to have a spray bottle of acetone at hand to keep the top surface pliable and adhesive to prime, but if you let it dry too much before cutting you're going to have issues. I have tried screen cutting, but hand cutting gives me better control over the dough ball and provides a few extra valuable minutes for work before it dries up. Hard edges on cut DEs will round out when primed with an acetone-based prime, but I get more rounding if I do the next prime step right away instead of waiting. Still, many believe that rough edges on your DEs, even if coated with a round (eventually) prime layer helps them take fire. I've never had an issue with ignition with a hot/cold acetone-red gum based double-prime. Still wonder how the Chicoms get those tiny round crackle stars primed up; their starting stars must be tiny.

 

Also, I don't use the (expensive) Bi-heavy formulas. Typically I use about 35% Bi/40% CuO/15% MgAl (-200+325 or similar)/5% Al -325 (around 44 micron)/5% (by weight) NC from the lacquer. Works well. Could possibly reduce the Bi ratio even more, but haven't tried. If you're just starting out with crackle, I'd suggest keeping batches between 150-200g so you get a single decent handful of dough (the stuff's super dense) and get the feel of the details. Took me a couple of tries to get things right (for me). Taking notes at any hands-off break will probably prove useful in getting your technique right. Have your primes ready and have enough at hand.

 

Though I've never tried it, you can slow solvent evaporation rate in many instances (for example, when dipping igniters) by adding a fraction of methyl ethyl ketone (MEK), available for $7/quart (same as acetone) from HD, etc. This dissolves NC just fine, and slows the evaporation rate. I'm already waiting a half hour for acetone to evaporate to begin with in my DE mix, so if I wanted to add some it would probably only be at the very end, towards when I was getting ready to roll the eggs, so I had more working time.

 

Commercial NC lacquers for guitar finishing etc usually have a mixture of various solvents and don't go for the fastest drying with acetone only so you don't get an "orange peel" paint surface effect. Can't see why this wouldn't work for your DEs, but they might take a little extra time to cure and have the remnant solvent evaporate (overnight probably fine...). I get my acetone from the Chicom dollar store, but it's getting to be less and less of a bargain. Used to be 10 oz fingernail polish remover for a buck. Then the trade wars began and they shrank it to 8 and then 6 oz/container for a buck. And you need to read the label to make sure it says 100% acetone, not "Acetone, water...". At a buck for 6 oz, besides saving $1.50/quart vs HD (less if you buy it by the gallon for around $20), I appreciate having individual 6 oz containers (wish they were 10 oz still) that remain sealed until use. Keep in mind that acetone is very hygroscopic, so keep lids closed when not actively using it. Your "100%" acetone probably contains 0.5-1% water anyways (rough guess) but you really don't want to add more water into the mix or you risk trapping it inside your DEs (or any stars you make with it), which I'd rather avoid. If you're real anal, you can get molecular sieves, beads to absorb water from your acetone, but I don't bother... No idea of the hygroscopicity of MEK; would need to look that up. Ok, I looked it up--yes, like acetone, MEK loves water. Keep it sealed. MSDS available at: https://www.pure-chemical.com/msds/Methyl ethyl ketone.pdf

 

 

**Edited to make shorter paragraphs so I can keep our pal Stix alert and awake (long diatribes were making him sleepy :+] ). He also suggested I cut text length, but i disagree--info requires space sometimes, tsk tsk. You still awake, Stix?? Sheesh, it's pushing "winter" in Australia; maybe he's hibernating like a drop bear? "Drop Bear"? Hylarctos plummetus. Look it up, gringos. It's some serious shit.

 

Here's a typical Aussie Drop Bear:

Edited June 10, 2021 by SharkWhisperer

[stix]

. . . I think that was a typo above that said "90 units smokeless and 10 units acetone". . .

.

Yeah thanks SW , I've made a correction to my original post.

It should be the other way around: 10 units smokeless/90 units solvent/acetone.

Edited June 9, 2021 by stix

[Piccaso]

Fireworks cook book has started stock pure NC for less than current powder prices.