Binded bp vs no binder and alc or water

[PyroGnome]

I like the pine resin theory on why some people can get a hard grain with high alcohol...  since an alternate name for one form of it is colophony, and apparently vinsol is made by oxidizing one of the types...  although in charcoal it's probably closer to "pine pitch" since it's been burned in low oxygen conditions or something even dryer than that (and harder when it's dissolved and the solvent evaporated).    The stuff is insoluble in water and used for waterproofing paper wrappings outside of pyro as well as with some flares.    There's a thread on these forums about it and another on the rec.pyrotechnics archive

 

I don't see why pine charcoal wouldn't still contain enough of this to act as a binder...  attempting an ethanol extraction and filtering off the charcoal then evaporating it down would probably give at least enough residue to see whether anything is there even on a small scale, and on a slightly larger scale you'd have some idea of how solid the stuff was when dry.  🙂

 

https://rec.pyrotechnics.narkive.com/I9UB1rQl/experiments-with-rosin-warning-ramble

 

[All10Fingers]

You know... I have a jar of pibe charcoal I made from the same tree I got that big blob of resin from in the above picture. I've only used it for stars and therefore with plenty of binder. But could totally mix something up sans binder and see what happens. If you internet people really want   however there's another product called pine "tar" which is a made by heating pine wood in a kiln and it sweats out and collects in the bottom. 

Basically the same as the resin. If it comes straight from the tree, it's resin. If you process and filter the resin, you have pitch, or rosin dep on the method used. Pine tar is made from wood or wood pulp and is slightly different but I don't know the specifics of how it's different.

That said, the fact pine tar is a real thing indicates the there is resin in the wood. But the process of heating the wood to make charcoal will cook the resin out. If you use distillation methods, your left with turpentine. Still has uses but not very sticky 

[DavidF]

Wow, it's cool that so many folks are interested enough to ponder different theories about BP

As Mumbles suggested, there is a possibility for confusion when using the term 'straight' for the alcohol. You folks in the USA have different standard strengths for isopropyl alcohol than we do in Canada. Here we have 99% and 70%. Rubbing alcohol is now more commonly made using ethanol, and is usually 50% (here). The alcohol Ned was using when he made his fastest powder with no binder was SLX brand denatured alcohol, made by Klean strip I believe. It's a mixture of ethanol and methanol. My attempts to duplicate his method with straight (no water) alcohol failed with ethanol, failed with methanol, and failed with isopropyl alcohol. I did many experiments in good faith, but eventually came to the conclusion that the reason this D.A. powder was so fast is because of lack of consolidation and lack of binder.

As far as the resin binding goes, I agree with the others that charring of the charcoal would ruin any chance of the resins binding. The remaining volatiles in black powder have also been alleged to be the cause of binding, because (perish the thought) it can't be the water  It's the water. Scientists have studied bP for a long time, and just about any idea any of us could ever have has been thought of and tested by somebody at some time. The resins theory has been debunked by scientists. The plastic flow of sulfur under pressure has also been said to having binding ability. Again, it's easy to show it has limited if any binding ability. That leaves the potassium nitrate. Call me crazy, but I consider the potassium nitrate to be the binding agent in black powder, and it is activated by being slightly dissolved in water and then re-crystallizing on a microscopic level in the mixture. Potassium nitrate that has gotten damp will often harden into a very solid mass. Black powder is mostly potassium nitrate.

I did some tests where I suspended weighed filter paper sachets of greenhouse grade potassium nitrate in various liquids. The sachets were dipped (25 times?) in the liquids and hung to dry. Then the texture of the potassium nitrate was evaluated. It was weighed to see how much, if any was lost by being dissolved. The potassium nitrate crumbled right back to powder with the different alcohols and with acetone, and didn't lose any weight. Then the tests were repeated with 50/50 w/w solutions of the original liquids and water. Again, the sachets were dried and re-weighed. All of the potassium nitrate had hardened to a solid piece that was broken with a small hammer. As I recall, the acetone chunk was the hardest, and the amount of potassium nitrate dissolved was the most. It should be noted there was only natural settling done ie. weighing, dipping, drying, weighing, no compaction of any kind.

I'm sure the alcohol is a really valuable aid if you make sure not to use it straight, unless maybe for rockets like SW said. Once I tried to press a puck of black powder dampened with 99% isopropyl alcohol instead of water. The powder would not consolidate into a puck, even at 3 times the force normally used to make a puck. It broke apart coming out of the die.

Good to see you back here too cmjlab

 

 

[cmjlab]

In the U.S. (where I live)....

- straight or 100% implies denatured alcohol (as that is the closest you can get to 100% off the shelf.  You can buy anything online and would typically specify that)

- Isopropyl Alcohol (IPA) can mean several strengths available of the shelf, but primarily whats available is 50% IPA to 50% water, 70% IPA to 30% water, or 90% IPA to 10% water, but in the U.S, (AFAIK) IPA is still IPA and has a distinctly different odor and taste.

- However I'd expect that if someone said I used 50%IPA, then I can either buy it at 50% IPA to water (as labeled) or mix water with any of the other two options off the shelf to make it so I then have 50% IPA amd 50% water.  

- I've also used 50% Denatured Alcohol to 50% water which I WILL admit could cause confusion since it likely is NOT 100% alcohol (having absorbed some water over time). 

For B.P. grains that are rock hard, I've used all the alcohols described above to make it so I have a solution of 50% IPA or denatured alcohol to 50% water (based on the label being taken as a accurate description of the alcohol content.  

I hope that clarifies what I meant in my posts when describing what produces rock hard grains in B.P. granulated with no binders.  I also hope that clarifies my original post to show that most people agree that you can NOT get rock hard grains with 100% denatured or IPA.

Edited August 18 by cmjlab

[DavidF]

I understood the 50/50 thing and it makes perfect sense. I think Mumbles was talking about 'other' people, not us  I referred to the experiment with the sachets to add support to the statement that 50/50 alcohol water makes hard grains.

Just a thought, but anybody could take some ERC charcoal, or whatever other kind, soak it in some alcohol, filter the liquid off, and evaporate it to dryness. The ability to bind will be left on the dish. I think I'll try it.

I did read in Pyrotechnica once that they dissolved the volatiles out of a fast charcoal with acetone, and re-deposited them on another (activated?) charcoal and got improved performance. Shimizu says the best BP charcoals are 70-80% carbon. That leaves room for a lot of other stuff.

I get on a bit of a ramble when water and BP comes up because all our different understandings of how to use water judiciously with black powder is a topic that has been hotly contested over the years. I still can't believe that the 'standard' way to press BP rockets is with dry powder and lots of pressure when it could easily be done at around half the pressure. The roles of water in pyro should be at the very core of our knowledge of it, in my opinion, especially with black powder stuff.

 

[cmjlab]

I certainly don't claim to understand the science behind how hard grains are obtained with no binder.

I've always kind of preferred your water theory, acting with the KNO3 to bind, as my damp KNO3 always seems to turn back into pretty hard chunks just sitting around if it hadn't been dried and kept in a air tight container. 

However, just water doesn't seem to make as hard if grains either.  So beats me!

[cmjlab]

I also like to ramble! 🙂 some of the best conversations I've had are with myself!

[Mumbles]

I've never bothered to check, but I wouldn't be shocked if the majority of denatured alcohol sold at hardware stores is the azeotropic stuff with 5% water in it. SDS are generally intentionally vague, and water isn't a hazardous chemical so it's content doesn't need to be disclosed. I deal on and off with denatured ethanol at work, and almost everything comes in 190 proof and 200 proof grades.  The 200 proof grade is often more expensive, and will absorb water much more strongly.  It seems like something a company selling denatured alcohol to consumers wouldn't waste time, energy, or money on.  You'd need to track down a specific Certificate of analysis to know for sure.