Using water in making red gum / alc BP?

[jwitt]

After reading von Malitz' book on BP, I see that he claims that

 

1) the theory that S and KNO3 are "pounded" into charcoal pores is false and

 

2) that since KNO3 is water soluble, addition of water during granulation should help distribute KNO3 in the black powder, thus yielding faster powder.

 

Since KNO3 is not water soluble, a strict red gum & denatured alcohol binding system won't distribute KNO3 in the microscopic charcoal particles.

 

Before I mess up a batch of BP in experimentation, I would like to know if the addition of water would prevent red gum from doing its binding job. Red gum granules sure aren't rock-hard in the first place, at least at the 2% of batch weight I've used.

 

Red gum is incorporated into the BP by first dissolving in denatured alcohol a.k.a. methylated spirit.

 

Could one pre-wet the mill dust with, for starters, 25% of total liquid to be incorporated as water, then add the remaining 75% red gum/alcohol solution? If this would do the job of further incorporating KNO3 into the charcoal, and still allow the red gum to function, it might increase the resulting granulated powder's speed. However, it might prevent red gum from functioning properly.

 

Thoughts and/or experiences?

[Mumbles]

So, one way you could do it is to wet the powder first with water, kneed it, and granulate it to speed up drying. Once dry it could be screened or re-ball milled to repowder yet retain most of the benefits of water addition. The addition of water and kneeding has been shown many times to increase the performance of powder. Commercial Goex powder is a glorified green meal with lots of kneeding if you think about it.

 

I still don't know about the redgum addition. I agree that over wetting can cause issues, but it you keep it reasonable the powder comes out just fine with water addition.

 

Hmmmmmmmmm, I wonder if the rising usage of heated drying boxes could cause the apparent decrease in performance. If you got the powder/granules hot, it could dissolve a significantly larger amount of KNO3, thus re-precipitating more of it.

[jwitt]

Well, I am conducting my first highly un-scientific experiment.

 

I graded my granulated (riced) red gum/alc powder yesterday evening into 2FA, 4FA, little stuff retained on a...uh...little stuff, and fines/dust.

 

I put my fines/dust into a little pyrex pan (didn't have much since I captured and re-processed fines a couple times prior to this).

 

I moistened the ~70g with enough 75/25 water/denatured alc to make a dough ball as if I were going to rice it. Kneaded it a bit and pushed through a small kitchen colander to incorporate the water. It's drying now...high humidity, so this might take a while.

 

What I hope to learn-

 

1) does the 75/25 liquid activate the red gum? I don't think it will.

 

2) how easily will these "sorta-granules" and lumps go back into putty mode with the addition of denatured alcohol? I think it will do so easily.

 

3) after ricing and re-grading, is there a noticeable change in burn characteristics between this powder and it's "ancestor" batch? I hypothesize there will be a slight difference.

 

However, a silly "burn a gram of 4FA" test doesn't yield very good evidence. but who knows? I could suddenly see kno3 slag in the new batch, or more/less ash, or an obvious difference in the way it burns. Ultimately, testing will need to be done in a quantitative manner, because BP explodes when confined, and it's doing a specific job as a propellant. Baseball shootin' time cometh...

 

 

~~~~~~~~~~~~~~~~

 

Forgive the rambling nature of the following. I'm just shooting from the hip, but I think it's getting somewhere. (Surely someone else has gone down this road in the last few centuries...but nonetheless...)

 

Long story short, for folks that don't want to read the brainstorm of a raving lunatic, maybe a solution that activates the red gum and soaks up a little KNO3, thus depositing same in charcoal as the BP dries, would be the "ultimate" red gum BP ricing solution. The solution could be tailored to the solubility of KNO3 at a reasonable temperature (say 70-80°F) for optimum results.

 

~~~~~~~~~~~~~~~~

 

 

I think I'm going to continue down this line of research, and hopefully get a bit more "scientific" about it in the future. I'm thinking about, as an example, a 75/25 wetting mixture of alcohol and water (opposite of normal) and thorough kneading of the dough ball for a future test, compared to a control from the same batch of mill dust processed in the standard red gum/alc manner, plus equal amount of kneading. (I knead the dough ball pretty well anyway, but am gonna increase/standardize)

 

First, of course, I need to check the solubility of red gum in 75/25 alc/water. Ooh, then I could check solubility of KNO3 in same. I'm not sure how the presence of the two different solvents (one protic and one aprotic polar solvent) would effect solubility of different materials in a solution. Waaaay over my pay grade.

 

Another consideration- say KNO3 is "slightly soluble" in the alc/water solution...moreso than in straight denatured alc, less (obviously) than in pure water. The solution should be able to put 1/4 the amount of KNO3 in solution that straight water would.

 

What I'm thinking is that recrystallization of KNO3 and other potential problems with using straight water would be nullified because of the small amount of total KNO3 that's put into solution. (750g of KNO3 in 1kg BP mix...depending on how much KNO3 can be crammed into a given amount of water...)

 

A quick internet search tells me that KNO3 solubility in water is 36g/100ml at 25°C. Aww crap, math...time to talk to the engineer roommate when I get home.

Edited May 13, 2010 by jwitt

[dagabu]

Jwitt,

 

While I understand that you want to see for yourself what these do, Danny Creagan did this a long time ago and posted it online for all of us to see.

 

LINK

 

 

 

Edited May 13, 2010 by dagabu

[Mumbles]

Two things. Firstly, both water and alcohol are protic solvents. Secondly, solubility isn't linear. IE a 50:50 water:alcohol mix wont dissolve only 50% the amount of KNO3.

[swervedriver]

2% red gum added works. Don't add the binder before milling the BP until it's fast, especially with red gum. Adding it to the mill when the BP milling time is finished just to mix it in works well. A solution of 70% alcohol/30% water works good with RG, but you have to add quite a bit of the solution to really activate the RG and get the nice hard grains. A consistency like sticky playdoh, then let some of the alcohol evaporate a bit before granulating if necessary. Adding over 2% RG does slow the speed down some, adding 5% of binder will noticeably reduce lift performance... IME

[jwitt]

D-

 

The relevant information on D.C.'s site seems to be "Cheap Trick #1" and, below that, a comment on wetting improving BP speed. So, we know that wetting (below the point of causing crystallization problems) is a good thing.

 

But what I'm either not seeing, or what isn't there, is if I can combine the fast drying time of alcohol/red gum and the KNO3 soaking into charcoal provided by water, through a process that's relatively painless. (I'd be down with time consuming "special" processing for making sporting powder, but that's down the road a piece).

 

So I think this line of experimentation is relevant...although I'd sure be happy if someone has already done the work.

 

 

 

M- Oh...I thought they were different. But I'm no student of chemistry, and can barely remember how each type of solvent functions, so go figure

 

As to solubility being non-linear, I knew that solubility describes a curve in relation to temperature, but not volume (or would mass be a more appropriate measurement here?)

 

Say 1 gram of chemical X is soluble in 100ml of water at 20°C. I'm having trouble wrapping my mind around the thought that .5g would not be soluble in 50ml water, or that 2g wouldn't be soluble in 200ml water. Or you could replace "less" with "more" in that sentence, get my drift?

 

Or is that where you're headed with that statement, or are you referring to something else?

 

Man...I was gonna stick to alchemy, now I'm delving into chemistry.

[Mumbles]

Oh yeah, it's linear like that. .5g would be soluble in 50mL of water. But .5g would not be soluble in 100mL of a 50:50 mixture of water and ethanol, despite having the same amount of water in it.

[homebrewed77]

After reading von Malitz' book on BP, I see that he claims that

 

1) the theory that S and KNO3 are "pounded" into charcoal pores is false and

 

2) that since KNO3 is water soluble, addition of water during granulation should help distribute KNO3 in the black powder, thus yielding faster powder.

 

Since KNO3 is not water soluble, a strict red gum & denatured alcohol binding system won't distribute KNO3 in the microscopic charcoal particles.

 

Before I mess up a batch of BP in experimentation, I would like to know if the addition of water would prevent red gum from doing its binding job. Red gum granules sure aren't rock-hard in the first place, at least at the 2% of batch weight I've used.

 

Red gum is incorporated into the BP by first dissolving in denatured alcohol a.k.a. methylated spirit.

 

Could one pre-wet the mill dust with, for starters, 25% of total liquid to be incorporated as water, then add the remaining 75% red gum/alcohol solution? If this would do the job of further incorporating KNO3 into the charcoal, and still allow the red gum to function, it might increase the resulting granulated powder's speed. However, it might prevent red gum from functioning properly.

 

Thoughts and/or experiences?

Been down this road many a time..Straight ALC with red gum will yield

the faster BP..But the grains will be kinda wimpy..That's the 

problem with that..But then again..In pyro..The fastest BP is not all

way's the best..In fact..There's really no need to have a hell ripping

fast BP..What we do need though is consistent

BP...When you add water to the meal..The kn03 dissolves then

re-crystallizes  forming larger's particle's..Voiding the whole

reason you milled it in the first place...But like I said..We are

looking for consistent BP..Just my two penny's worth..Witch aint worth

spit now day's lol!<img class="bbc_emoticon" alt=""

src="http://www.amateurpyro.com/forums/public/style_emoticons/default/blush.gif">&nbsp;

<br>

Edited May 14, 2010 by homebrewed77

[jwitt]

OK, Mumbles, I read you L&C now.

 

Would you mind explaining that phenomenon? I'm guessing that it has to do with how the solvent molecules are arranged in the solution.

 

 

 

Homebrew- good to know that I'm not doing something wrong with my 2% red gum...the grains are hard enough to work with, but they sure do crush easily. (That actually worked to my benefit- got lots of nice looking 4FA from a pile of big lumps by gently pressing the hard grains through the top 10# of nested 10/20/30 mesh screens)

 

I'm hoping I can make reasonably consistent batches...my thought with the slight water addition was that it may help achieve this goal (with consistent processing methods of course)

 

But yeah, I don't need to make the hottest BP ever and start flowerpotting shells.

 

 

 

 

 

By the way, my first little experiment involved wetting some leftover red gum/alc bound BP fines with my spray bottle of 75/25 (for stars) and letting it dry. I haven't re-granulated it yet, but the resulting product showed that the red gum was "more or less activated" and the product burns like crap! I'm going to crush it and granulate by re-wetting with alcohol and see what happens, but I'm expecting the same slaggy, sparking burn I'm getting now.

 

I'm gonna do a proper experiment with part the batch of mill dust I'll make on the 22nd.

[jwitt]

I'm not totally satisfied with my BP's performance yet- 40g shot a 158g 3" shell to a very respectable height- not measured, but the shell broke at about 3.1 seconds, and it appeared to break just as it began falling back to earth. 25% of shell weight- not bad, but I'd like to get this down to 10%-15%. It might be mill charge volume issues, breaking up the clump that forms after about 6 hours, or something similar. This experiment interests me though, and the techniques might be able to be applied to powder produced after I learn the finer points of my ball milling setup. Man, there are so many variables.

 

 

~~~

 

 

Well, I spoke too soon with regard to the sloppy-experimental batch I talked about above. It's been pretty rainy lately, and though the RH was supposedly low during much of that, the little pile must have taken a week to dry. Last night I burned a couple grams, and the burn was, roughly speaking, "very energetic." The burn was obviously different than a comparable pile of 2FA red gum/alc, the "father" of the experimental stuff.

 

Of course, open burn "tests" barely even qualify as tests since 1) nothing's measured and 2) the reaction is somewhat different when used as a propellant.

 

So, having observed the blatantly obvious difference in appearance of the burning of riced red gum/alc and rough, similarly sized chunks of the stuff wetted with a bit of water, I'm going to continue down this thread with my next batch of mill dust.

 

Forthwith, prepare materials for investigation thusly:

 

1. Dry all mill feed ingredients before milling.
2. Pull 133.3g mill dust from each of 3 kilos made to total 400g, a nice round number.
3. Mix the three samples for a presumably more consistent product.
4. Divide into 4 100g batches.

Then I need to figure out what to do with 'em.

 

Batch #1 - control - Standard Red Gum BP.

• Process as normal. 2% red gum and denatured alcohol. Weigh alcohol required to bring to granulation dampness. Rice through 10 mesh.

Batch #2 - Kneaded Red Gum BP.

• Same as #1, except kneaded thoroughly...time TBD depending on how quickly I get tired of kneading and adding small amounts of alcohol to replace evaporated liquid before ricing.

Batch #3 - "Water Processed" Red Gum BP.

• Add a small amount of water to mill dust, maybe an amount similar to pumped star comp, incorporate by pushing through 20# screen. Dry. Then process as in #1.

Batch #4 - "2 Solution" Red Gum BP.

• Based on liquid requirements, calculate how much liquid is needed to wet 100g batch. Split this into increments- one increment with red gum, which is incorporated into the mill dust, followed by an alcohol & water solution, bringing totals to 75/25 alcohol/water. Process as in #1.

Now...the only thing I'm missing in those test batches is kneading. I'm not doing this because I think results will show how water addition changes the BP's properties. A further experiment could be performed on a control group plus the best performing of batches 3&4 ("best" being a function of performance and work involved)

 

So, this weekend I make my mill dust, then process the samples, and shoot some baseballs with the resulting powders as soon as possible after.

 

QUESTIONS:

 

1. Binder "activation." In this case, does this simply mean the binder is in solution? If so, I wonder if the red gum could just be dissolved in a 75/25 alc/water solution and still do its work?
2. Holes in the experiment? Do yall see any?
3. I still haven't found anything on the internet or the published material I have access to regarding this specific question (red gum, alc, and water).

[Seymour]

Binder "activation." In this case, does this simply mean the binder is in solution? If so, I wonder if the red gum could just be dissolved in a 75/25 alc/water solution and still do its work?

 

Yep, when I binder is activated, that means that it is in solution, at least to the extent neccisary.

 

As for one part water with three parts alcohol working as a solvent for Red gum, I'd expect that the water will seriously reduce the alcohol's ability to dissolve the red gum... and to an even greater extent the alcohol will stop the water from dissolving the Potassium nitrate.

 

Since you want those two to dissolve, using that mixture seems counterproductive to me.

 

It is an experiment however, so don't let me discourige you from testing it!

[Mumbles]

70% alcohol (isopropyl) still activates the red gum in some stars I tried making. They were kind of crumbly while working with them, but they still dried hard as a rock. Now, these also had significantly more than 2% RG in them. Only one way to find out. You don't have to manipulate the grains nearly as much when making BP as with making stars.

[50AE]

My opinion is that alcohol also increases the performance of BP, not only water.

[dagabu]

When Ned was pushing this really hard last year I bought a trough for BP so I could measure the burn and made some golf ball shaped shells (OK, they were golf balls...) and tried all of the methods that he suggested and found that as long as the red gum activated, the BP had the same power.

 

I used the four alcohols I had and they all activated the red gum but made no difference how much I used (percentage wise). I found the fastest BP by diluting 100% of the red gum in a jar with a small amount of alcohol and filtering out the granules, adding the rest of the water I needed and whetting the BP with the fluid with a spray bottle, rice and dry.

[jwitt]

I found the fastest BP by diluting 100% of the red gum in a jar with a small amount of alcohol and filtering out the granules, adding the rest of the water I needed and whetting the BP with the fluid with a spray bottle, rice and dry.

 

 

You said "water" and I assume you mean water, not alcohol? Asking because Ned's standard approach is to use only alcohol.

 

My latest method has been to dissolve the gum in a small amount of alcohol, incorporate that solution into the mill dust, then bring it up to proper wetness with more alcohol. It sounds like you're using water to bring it up to wetness, which sounds like what I'm interested in.

Edited May 24, 2010 by jwitt

[dagabu]

Yup, I meant water. Alcohol does not whet the KNO3 into the charcoal, water does not activate Red Gum, Red gum first with alcohol to dissolve it, water second to dissolve the KNO3.

 

Many ways to skin a cat.

[jwitt]

Gotcha!

 

Gonna experiment with this stuff tonight, pending enough time after visiting with my mom who's in town.

 

2kg mill dust just beggin' to be turned into something useful. Nice to have met that quota...but I have a feeling I'll soon be milling BP just for fun