Gum arabic binder for black match (and CMC)

[oldfella]

Yes, sorry, it is indeed another thread about black match.

I made my last batch a lot of time ago and I am about to make another one.

I was very happy about that last batch for which I used gum arabic and cmc; I am quite sure that the cmc was 1%, the problem is that I don't remember how much binder I used.

All the answers I find only make me doubtful: is it 1%, 5%, 3%?

Maybe between 3% and 5% does not make much of a difference but if the good amount is only 1% gum arabic and I use 5% I won't get the match I am going for.

And if I rise the cmc to 2% will I get more flex or just ruin everything?

The one I have now is nice and stiff but also quite flexible, even after three years (that last batch was a big one) and I'm hoping to get more or less the same result.

 

My other question is about the hot water everybody uses. Doesn't potassium nitrate recrystallizes with all that hot water?

If there is something I remember of the process I followed to make that old black match is that I used hot water too but I really wonder why.

 

Seeing how black match behaves unconfined and then inside just a thin paper tube is what many years ago got my pyro passion started; I know it is stupid and simple but black match for me remains something special

Edited January 22, 2021 by oldfella

[SharkWhisperer]

Yes, sorry, it is indeed another thread about black match.

I made my last batch a lot of time ago and I am about to make another one.

I was very happy about that last batch for which I used gum arabic and cmc; I am quite sure that the cmc was 1%, the problem is that I don't remember how much binder I used.

All the answers I find only make me doubtful: is it 1%, 5%, 3%?

Maybe between 3% and 5% does not make much of a difference but if the good amount is only 1% gum arabic and I use 5% I won't get the match I am going for.

And if I rise the cmc to 2% will I get more flex or just ruin everything?

The one I have now is nice and stiff but also quite flexible, even after three years (that last batch was a big one) and I'm hoping to get more or less the same result.

 

My other question is about the hot water everybody uses. Doesn't potassium nitrate recrystallizes with all that hot water?

If there is something I remember of the process I followed to make that old black match is that I used hot water too but I really wonder why.

 

Seeing how black match behaves unconfined and then inside just a thin paper tube is what many years ago got my pyro passion started; I know it is stupid and simple but black match for me remains something special

Not sure exactly what your concern is, or where you are now having problems. You detailed your experiences with various concentrations of gum arabic and also CMC, so it's difficult to dissect out exactly where your concerns arise.

 

Gum arabic, CMC, dextrin...available inexpensively and freely worldwide. You mention that your BM works well. Great. So where's the problem? It's a little confusing because you state that the "one I have now is nice and stiff but also quite flexible," Which is it? Flexible or stiff? They are polar opposites of one another. What do you want it to be in terms of flexibility?

 

With due respect, it seems like you're searching for an answer to a problem that doesn't exist. Your years-old BM works the way you want it to,right? Still lights. Still reliable. So what do you need to change, and why?

 

Any of those binders---CMC, dextrin, and I'm guessing gum arabic (guessing because I've never used it) will expectedly slow burn rate a bit if you up it from 1% to 5%, but why is that troubling you? Why not just use whatever you've used before? If your BP is decent, the little bit of binder addition won't really be any issue. As you mention, even slowish (if slow) BM speeds up pretty quickly in confinement in a tube to QM speed. Do you need 10 meters/second or 50 meters/second? Would you even be able to tell the difference?

 

Go with the usual...1-5% binder, regardless of the binder, depending on how fast you want your BM to burn and how flexible it needs to be. BM is usually pretty stiff. CMC vs dextrin makes in a little more flexible typically. How important is this? Even with stiff BM, we usually just add an extra strand or two around corners/bends to ensure fire transfer. They'll all burn super fast when enclosed as QM. Sorry, but it seems to me that you're creating an issue out of a non-issue. Especially knowing you have some hot BP made with vine charcoal....

 

Hot water? Please look at the KNO₃ vs temperature solubility curves that are widely available. Even making a slurry, the majority of nitrate is not going to dissolve. For BM, most folks don't really obsess over nitrate crystal size due to water temps. With BM, the water is there to act as a solvent but more importantly to activate dextrin binding/polymerization (because dextrin is arguably the most widely used binder these days) that's faster at higher vs lower water temps. That's also why it's a good idea to wait 20-30 minutes after water addition when wetting dextrin-bound BP or star compositions--it gives the dextrin enough time to fully meet the water and "activate" vs using immediately after wetting. In those instances, I mix water and give the dextrin a little time to work better. The water volume is low enough that its temperature probably will not have any appreciable effect on the final product or the composition behavior during handling. And the water volumes used, even to make a slurry, are not going to dissolve all that much nitrate--most will remain in a slurry/suspension status.

 

I've used CMC, too, but also never really worried about the water temp, and have no knowledge of temperature-dependency like with dextrin. And yes, CMC, at the same % as dextrin, makes (slightly) more flexible BM. Not much more, but it bends (slightly) instead of being completely stiff, at the same binder %.

 

BP is cheap. So is cotton string. Perhaps make a few batches with different water temps and different binder %s, and see if the product behaves any differently from one another. Quick (apart from waiting for it to dry--many BM issues are from people's impatience and having damp BM--and see what you like. They'll probably ALL work just fine for basic BM needs, but if one's flexibility or burn speed appeals to you more than the others, well, there's your huckleberry!!!

 

Appreciate your desire to fine-tune your BM, but it seems to me that you can easily solve this "problem/concern" in a single afternoon with minimal effort or time/$ expenditure.

 

Kinda like improving on a proven mouse-trap design...

 

 

Edited to reflect response to: "I used gum arabic and cmc; I am quite sure that the cmc was 1%, the problem is that I don't remember how much binder I used.

All the answers I find only make me doubtful: is it 1%, 5%, 3%?"

 

Having dedicated notes, and learning to take detailed notes of your experimenting, will save you time in the long haul. It's easy to forget the little tweak that you did that worked so well (or didn't--don't want to repeat!) without a documented written reminders. Many times I've made a familiar composition that I'd forgotten the little procedural details that make things easy and never appear in the textbooks or protocols, that save time and money. Notebooks are useful for keeping track of all the small things you change when you're learning (and then making--each batch can be slightly different) to make great BP, simple, all the way to complex pyro device constructions with unique compostions. It's difficult to remember all you did before to get things working right--so much easier if it's written down for your to review and remember. Can save a lot of frustration, and makes a good personal library. Keep a notebook!!

Edited January 22, 2021 by SharkWhisperer

[Baybird]

Hey, this is somewhat off topic but, what recipe did you use for your purely gum Arabic binder? Like what amount per unit water, what temp, and how much per unit black powder? I havent been able to find a recipe for gum Arabic black powder so I figured Id ask here. Im also a new member so I cant make a new topic yet.