Best Lift BP For Small Shells (1-2 in.)?

[lloyd]

You're right! I missed that, but it might have just been a typo.

 

Lloyd

[Wiley]

As for TLUDing coal, head to Walmart and get yourself a bale of eastern red cedar pet bedding. A gallon of it will cook down to about 30-40g of delicate, flaky coal. I run it through a meat grinder to crush it up, but it could be rubbed through an 8 mesh screen to accomplish about the same thing. Make powder with that and I'm sure you'll be pleased with the results (assuming the milling operation is optimized).

[thepyrotextbook]

 

why do I think too much charcoal is the issue ? I expected your formula to be the issue . As in 15% charcoal ! Do others use this much charcoal with good results ?

I can't believe I didn't see that error! I meant to say 15%, as Lloyd had commented. I'm so sorry for not proofing that post... I'll edit that right away!

 

EDIT: Unfortunately, I can't edit this comment as the time period for editing has expired, I guess. Sorry 'bout that.

Edited February 13, 2017 by thepyrotextbook

[thepyrotextbook]

 

As for TLUDing coal, head to Walmart and get yourself a bale of eastern red cedar pet bedding. A gallon of it will cook down to about 30-40g of delicate, flaky coal. I run it through a meat grinder to crush it up, but it could be rubbed through an 8 mesh screen to accomplish about the same thing. Make powder with that and I'm sure you'll be pleased with the results (assuming the milling operation is optimized).

I checked out the prices, did some conversions, and I should be able to make some red cedar charcoal for $3 a pound or under, depending on the brand or whether it is bough online or not! Since I'm also waiting for my milling media, I might as well run out and make some better charcoal in the meantime. Thanks for the suggestion!

[Arthur]

Charcoal is the major reason why mixes of BP go wrong.

Use a recommended wood,

charcoal it carefully

keep it dry -it absorbs moisture then you weigh the water calling it charcoal.

[lloyd]

To clarify Arthur's slightly obscure comment: When he said "...then you weigh the water...", he meant, the absorbed water becomes part of the weight you THINK is charcoal, so you actually have less coal in the mix than you believed.

 

He's completely correct. Keep your charcoal DRY from the moment it's cool-enough to package after cooking.

 

Lloyd

[FlaMtnBkr]

You are on the right path for sure. Good charcoal is very important. If you are using the ERC pet bedding that is great but you can also use white pine/fir untreated lumber. If you can get scraps for free, great, but if not a couple 2x4 aren't very expensive. Go thru the stack and look for boards that weigh the least. It also should be really white looking and not yellow.

 

Once you have your good charcoal then mill away. Many people with the rock tumblers let them run a full 24 hours but that's your call. Once made, I find about the minimum water I can get away is 18% and have gone up around 25% before. I think the type of charcoal has a big factor on this. I like to get my BP about like modeling clay. Once you get close with the amount of water, stop and get a squirt bottle and add 1 squirt at a time, mixing and checking it well each time. Once you get to the clay like consistency it's time to screen. You can use window screen and push it thru or you can get bigger 1/4" hardware cloth and scrape/grate for bigger granules.

 

I put the granulated BP on plastic trays in about 1/4" to maybe 3/8" layers and place in the sun on a hot sunny day. If it's not real sunny I will add a fan blowing across the trays. After an hour or so I gently stir everything and get the bottom wet stuff up towards the top. I usually stir it 2 or maybe 3 times and in the sun it's usually nice and crunchy dry in 2-3 hours. I believe this is an important aspect that many people over look. Drying quickly will make the absolute hottest BP when using water as a solvent as the longer it stays wet, the more the nitrate that gets dissolved will have crystals that grow in size. Some use alcohol to get around this but that is expensive and not necessary if you dry quickly. I can notice that hot BP becomes just good if allowed to take around a day to dry. If you aren't sure if it's dry yet, throw some in a ziploc bag and seal it with a little air inside so it's like a pillow and let it sit in the sun. If there is still any water left, you will see condensation steaming up the bag after 20-30 min.

 

Do these things as well as the previous info and you will have some nice hot BP.

 

Good luck, stay safe, and have fun!

[braddsn]

Book, I will add 1 more thing that you may try, and it may also expedite your process. Personally, I lift all of my shells (3" up to 8") with bp coated rice hulls. I do this for a couple reasons... 1) Coated hulls are easier and quicker to make than granulating bp, and 2) Hulls dry quicker. I make shells in bulk so I try to be as efficient as possible. In addition to this advantage, I have also noticed that coated hulls seem to be slightly more powerful than granulated powder, using the same amount (weight) of lift. Obviously, this is a personal preference... but it's something you might try while you are testing, since the hulls dry so much faster. Lloyd "literally" wrote the book on ball mills, so I suggest doing exactly what he says. And some of the best fireworking advice I ever got was from Mumbles when I first started, "use what works for you". In other words, most people will say that you need to use 10% of your shell weight to lift your shell. Don't get hung up on those numbers, it's a reference point, BUT use what works for you. For me, I use 13%. I make my bp exactly the same every time, thus, 13% works perfectly every time. No surprises. I don't care that it's not 10%. Some guys can use 8%. A lot of variables can change that number. Good luck!

[memo]

brad are you using mill dust or reground granulated bp ? what is you ratio ?

 

memo

[Sulphurstan]

I first make sure all the ingredients pass through a 40-mesh screen, and screen mix the Potassium Nitrate (75%) , Charcoal (25%), and Sulfur (10%) together 3-4 times. I then put the ingredients in the ball mill for anywhere from 4-6 hours, and then screen mix in Dextrin (3%). From there, I wet the meal powder with straight water (about 15% of the total weight of the meal powder) and then screen through a 10-mesh screen. I let the granulated meal powder then dry in an about-room-temperature place for anywhere from 1-2 weeks, making sure all the moisture is gone. Lastly, when using the completed powder, I use 10% of the total weight of my shells in BP to lift them. I would have specified this in my initial post, but it was already lengthy to begin with. Sorry 'bout that.

Textbook,

From your posts i might understand that you damp your milled bp with water, screen / granulate it, and let it dry. That is what i did before, and hum... it burns, sure, but maybe not fast enough to get over the 60 feet limit you mentionned. Then, very recently, i made the szme, BUT precipitated the bp dough with ice cold iso propanol, mixed it pretty strongly (goal is the isopropanol sucks up most of water, and being cold, kno3 crystals have no time to grow), let the stuff separate at the bottom ("decant" is that english ??), and then granulate it. Have you try that? it is the cia method if I dont make mistake... regarding my bp, the burn rate was almost doubled in 30 cm linear burn tests.

 

Another point is of course charcoal, i was relunctant to make my own charcoal, so as OM suggested, a TLUD is an easy-to-build tool, odorless.... I was previously using commercial pine charcoal, and then made some batches with homemade willow charcoal. The difference is just hard to believe the first time you run a burnrate test, thats all i can say for today!

[FlaMtnBkr]

S-stan: Why add water to the BP at all if you are going to add it to the alcohol? At least that's the way I read that part. Adding enough alcohol to actually decant the extra seems like an expensive proposition. Do you plan on reusing the decanted alcohol? If so, first adding water to the BP is just adding water to your alcohol.

 

Did you not mill it well before doing this to get such a jump in burn speed? I think you will find that if you dry your granulated BP quickly and try to get it crunchy dry in 2-3 hours as I detailed above, you will notice a similar increase in speed though maybe not quite as much. Presumably the increase is from the alcohol not being a solvent for the KNO3 so that it does not dissolve and then recrystallize in bigger particles as it dries. The longer it stays wet with water the bigger the crystals will grow so if you dry it quickly this is minimized.

 

Also, temperature has a big impact on the amount of KNO3 that will dissolve in water and significantly less dissolves in 32 deg ice water than will dissolve in room temp water. So using ice water minus the ice and keeping the BP near freezing if you allow your BP to sit and 'temper' and as cold as possible while manipulating it, the minimum amount of nitrate will dissolve and probably be even closer to alcohol processed BP.

 

But I would say milling makes the biggest difference, hot charcoal a close second, and quick drying or alcohol processing to minimize crystal growth would be the 3 biggest factors to making hot/fast BP. If you do those 3 things you will be making really hot BP. It's hard to do without a mill and since BP is the 'flour' of the pyro 'bakery' so a good mill is a good and almost necessary investment if you plan on becoming heavily involved in hobby pyro. There are lots of tools needed so it's best if you are handy and have the means to make a lot of your own stuff. Though we all need to buy some of it and when you do you normally get handmade metal works of art.

 

Stay safe and have fun!

[lloyd]

Some folks here should be listening to Dave Forster.

 

Lloyd

[Sulphurstan]

S-stan: Why add water to the BP at all if you are going to add it to the alcohol? At least that's the way I read that part. Adding enough alcohol to actually decant the extra seems like an expensive proposition. Do you plan on reusing the decanted alcohol? If so, first adding water to the BP is just adding water to your alcohol.

 

FlaM

 

I always mix my 15-20% of water prior to isopropanol, to make sure my dextrin dissolves in order to have a binder which is well diffused everywhere. Maybe this is not ncecessary... if someone has an explaination about this, I would appreciate

[lloyd]

If you'd avoid the isopropanol entirely, and follow DavidF's recommendations, you'd have better powder at a much lower cost.

 

Lloyd

[Sulphurstan]

If you'd avoid the isopropanol entirely, and follow DavidF's recommendations, you'd have better powder at a much lower cost.

 

Lloyd

Lloyd,

You mean, with the 2% wax?

[lloyd]

The wax is specifically for rockets. So, if you're making rockets, yes, that too.

 

But I was talking about his 'general' advice about making good, fast BP. He's really 'nailed' the process to make it without milling the full mixture.

 

Lloyd

[Sulphurstan]

Yep just seen your other post in the thread about "what did you do in pyro today"

[...Properly done, ball milling is a "relatively safe" procedure, even on the full mixture.

Now... that said, David Forster has done extensive experiments with ball milling non-explosive mixtures, then combining them after milling. He's had VERY good success with the method, obtaining powders stronger and faster than stock Goex powders.

You do yourself a great disservice if you do not read his posts. I believe he goes by "DavidF" here.]

Thanx for the advice :-) I'll investigate that.

Edited February 17, 2017 by Sulphurstan

[Mumbles]

If you add alcohol to a wetted BP composition you're going to deactivate the dextrin by precipitating it before it can harden the grains. Water and alcohol alone will do some binding on their own due to other components of BP. The dextrin may still be activated somewhat by residual water as well.