BP base - use dextrin or not

[MWJ]

Hi everyone, I downloaded the awesome book, turbopyro and have learned a lot from it but in the book when he makes bp base mix he doesn't use dextrin, this is making bp without a ball mill, in another video I watched he does use it (with a ball mill). I want to make a good bp base mix for rockets but I'm not sure if I should use dextrin or not. Any advise?

 

Thanks, Mike (AKA- MWJ)

[schroedinger]

That always depends on what you want to do with you BP. Dextrin is a binder, you only need if you are going to bind the BP in any way. Also i often read that you also need it if you are pressing the BP witout granulation, as it stay better together.

But you won't need it if acetone would be the solvent.

[dan999ification]

You don't need it, but I find it makes better fuel

Grains. I don't bind it (yet) the same meal is used for bp, endburner fuel and delay.

Just for convenience, though I'm coming round to the idea of binding and granulating with just a few % when upping the power in core burners.

 

Dan.

[Bobosan]

I mill my powder with a ball mill and normally add 2-3% dextrin and use the same powder for both rockets and granulation. This way I don't have several different BP mixes to deal with. Tried 60/30/10 (no dextrin) for endburner rockets and was not impressed. 6/3/1 would be ok for a driver or fountain. That being said, I also use a hot charcoal (Paulownia) and ram rockets with the BP meal just as it comes from the mill jar. It's a bit messy to use that way though.

 

You may want to try screen mixing with a good hot charcoal in an end burner until you acquire a ball mill. It would be a relatively inexpensive way to learn BP making combined with rockets.

[pyrokid]

For my coreburner fuel I don't use any dextrin. You don't want the granules to retain any character when compressed into a fuel grain. For 6-3-1 I find this to be especially true. The granules reduce dust and ease consolidation.

 

 

I've had catos with 75-15-10 without a binder, which I attribute to the greater KNO3 percentage.

[MWJ]

would the rocket fuel pack better and work better (in rockets) with a binder or is it even necessary to use. ( I haven't made any rockets yet) but Like Bobosan said "This way I don't have several different BP mixes to deal with." It would be easier to not goof up.

[Col]

I dont use dex in rocket fuel, i just granulate it with water to keep the dust down. I use 75/15/10 without cato`s

[dan999ification]

Try fling a rammed one:)

I granulate 6/3/1 with water and no binder, the meal that has a binder is not granulated for my rockets. I read somewhere (here) that harder grains compact better, my pine will NOT compress enough to not Cato, why i use willow. 1or 2% dextrin should change its springy nature, I believe it will help (me) the higher the charcoal the bigger the problem, high nitrate fuel compacts well for me, maybe it's the dex?

Dextrin will not affect bp performance that much, it is convienient to use the same bp for a few jobs.

 

I hear ya bob, I also ram meal powder... I can put up with one black hand have you tried an "o" ring? To keep the dust in.

 

Dan.

[Bobosan]

Yeah, bought a few O rings to put on the rammers. Works real good but still get the black hand if I don't wear gloves, which isn't very often.

 

Col, I also use 75/15/10 in rockets and the dextrin doesn't seem to affect it much at all. A hot charcoal may very well overcome any slowdown due to dextrin.

 

I've granulated my 6/3/1 with water only just to see if there was a dust reduction...and there is. However, the BP easily breaks down due to handling and end up with a quarter tub of meal anyway.

[dan999ification]

That's another reason I wanted to try granulating with dex, my 6/3/1 is the same if you look at it too long.

The dust and granules mixed make a fuel grain that is not uniform, the unit volume changes. 1% dextrin Should help keep

The charcoal together long enough to load the tube, I don't see any problem consolidating it as I can easily crush my bp in a pestle and mortar, there is a lot more direct force and weight available when I'm ramming

 

75/15/10 may bind harder than 6/3/1 with the same amount of dextrin, there is more soft porous material that can be crushed and packed down with 6/3/1.

 

After milling bp there is always some dust left in the jar, the batch of fuel I mill directly

After always stays together better and rams nicer after granulating, I can get more weight in the tube ( about 4g 8%) It's gotta be the dextrin left in the jar.

 

I'll try 1% on the next one and report back.

 

Dan.

[Blaster5337]

Newbie here, haven't attempted anything yet just doing lots of reading and coming up with probably stupid questions that are probably answered somewhere else in this forum, so forgive me but here is my question. In the process of making BP I see dextrin is utilized as a binder, can that be replaced with nitrocellulose lacquer as a binder? Would there be any benefit?

Blaster

[MWJ]

I'm not sure where to begin with this but no it wouldn't. Are you making black powder or something like quick match or MCRH's or what?. Either way if you want to use water as a solvent then use Dextrin if you want to use Alcohol as a solvent then use CMC. Do more reading on making black powder. There is a lot of great info. here and a lot of very knowledgeable people.

I use NC Laq. for priming fuses, or making crackle micro stars . There are more uses but not binding bp.

Edited November 19, 2014 by MWJ

[Jakenbake]

I'm not sure where to begin with this but no it wouldn't. Are you making black powder or something like quick match or MCRH's or what?. Either way if you want to use water as a solvent then use Dextrin if you want to use Alcohol as a solvent then use CMC. Do more reading on making black powder. There is a lot of great info. here and a lot of very knowledgeable people.

I use NC Laq. for priming fuses, or making crackle micro stars . There are more uses but not binding bp.

FWIW CMC's solvent is water.

[schroedinger]

Not if you intend to use the bp for lift and similar.

For those use dextrin, gum arabic or sgrs

[Mumbles]

Yes, it can be used to bind BP. It probably wont be as resilient as dextrin bound grains, but they'll hold together. One person I know who has tried it claimed that it's faster, but he's well known to me to rather biased and over exaggerate things. It tends not to be economical however. Any increase in performance is more than balanced out by the increased cost.

[Blaster5337]

Thank you to everyone for your comments, and sharing the knowledge! Like I said in my original post, I havn't made anything yet, but I fully intend to. I need more intel before I'm comfortable messing around with some things.

 

Blaster

[Blaster5337]

Anyone ever utilize or make "BP" with sodium nitrate instead of potassium nitrate for your fireworks?

If so, did you find it beneficial? In what way/s?

 

Lammot du Pont developed this mix known as "soda powder" and it began to be used at about the time of the US Civil war.

Edited November 29, 2014 by Blaster5337

[Mumbles]

It's generally used as a slower powder. BP based on both potassium and sodium nitrates are available for the blasting industry. Potassium nitrate versions are the A type blasting powders we're most familiar with (2FA, 4FA, etc). Sodium based powders are B type blasting powders (2FB, 4FB, etc.). Sodium versions are across the board generally slower and offer a softer heave. I don't know if it's necessarily an intrinsic property, or just a formulation/processing factor.

[Blaster5337]

OK, so what I was reading was more of a history lesson than a chemistry lesson, but it said that sodium nitrate "soda powder" was more powerful than potassium nitrate "BP", to my knowledge that would go along with what Mumbles is saying about it deflagrating slower and offering a softer heave, but is it a more powerful heave? Therefore offering a higher lift? It would seem to me very beneficial to be able to push a shell harder and higher?

 

Correct me if I'm wrong, but the faster the deflagration, the more brisance, the more cutting or shattering power?

The slower the deflagration, the less brisance, the more pushing power?

[marks265]

I'm thinking there is a something about gas production that comes into play with this. Sodium may be much slower or less gas, than when the shell leaves the muzzle which may be less productive for lift.

[ChemMork]

Sodiumnitrate BP should be faster because: The molar mass of Sodium is lower than Potassium so Sodiumnitrate contains more % Oxygen. I hope you know what i mean

Sorry for my bad english

[Blaster5337]

Sodiumnitrate BP should be faster because: The molar mass of Sodium is lower than Potassium so Sodiumnitrate contains more % Oxygen. I hope you know what i mean

Sorry for my bad english

 

 

Actually, you have me confused! Sodium is Sodium it doesn't contain any oxygen, to my knowledge? The oxygen is contained within the nitrate (NO3), is it not? Therefore, wouldn't the oxygen content be the same for both compounds (KNO3) / (NaNO3)? That would be 3 oxygen atoms per molecule! To my knowledge the molar mass being lower is due to the mass of sodium and has nothing to do with oxygen content. Feel free to correct my Chemisty if I'm wrong!

Edited December 1, 2014 by Blaster5337

[schroedinger]

What he is talking about is the ratio of moloar weight to contained oxigen.

But this isn't the only factor wich affects the burn rate. You still need energy to free the oxigen from the the nitrate ion and this energy is not independent of the cation (e.g. you get different dissociation energy and other internal forces).

 

Also don't forget sodium is quite hydroscopic, so bp made with sodium will always contain more water then a pottasium one.

[Blaster5337]

The greater hygroscopy of sodium would explain a greater oxygen content as well as an increased molar mass, provided it was wet.

[Mumbles]

It's probably best to just ignore ChemMork since he's incorrect. Schroedinger pointed out some of the reasons. By that logic ammonpulver should be even faster, but anyone who has worked with it will confidently tell you the opposite.

 

Molecule for molecule both sodium and potassium nitrates contain the same amount of oxygen. On a mass comparison, sodium nitrate will have more oxygen weight for weight than potassium nitrate. The molecular mass of NaNO3 is 85g/mol, while KNO3 is 101.1g/mol. So 85g of NaNO3 has the same amount of oxygen as 101.1g KNO3, but 100g of NaNO3 will have more oxygen than 100g of KNO3, since there are more molecules of NaNO3.

 

While sodium nitrate is relatively hygroscopic, the oxygen contained in the water really isn't available as combustible oxygen. The initial heat of the reaction will be used to drive it off as water, which will slow the rate of actual combustion.