Red Gum BP

[Wiley]

By red gum BP, I am referring to the tutorial by Ned Gorski, in which he uses a 100 mesh screen to mix the BP chems, wets the greenmix with 1% red gum dissolved alcohol, and granulates it through a 4 mesh screen. The charcoal used is commercial airfloat.

 

People talk about the grains being crumbly, but I would like to know just how crumbly. The NC bound pulverone I'm making now, when granulated through the small side of a cheese grater (little larger than 1/16" holes) makes little worms and mouse turds that are VERY easy to crush between thumb and forefinger. Rub thumb and forefinger together for a bit, and a granule can be reduced back to nearly dust without any trouble at all. The BP made in Ned's article has to be a bit better than that.

 

Has anyone tried granulating this red gum BP through a smaller, 15ish mesh screen, or in my case, a cheese grater? The powder should be faster, but the grains will be weaker. I want to use it for lift and break in 1.75" nominal shells fired from consumer mortars, so I think the smaller/ faster powder should do better in that case.

 

Lastly, and kind of related to the subject as a whole, how are people getting true airfloat charcoal? I have good wood and all the apparatus for making charcoal, but I don't have anything that will make it truly fine. A coffee grinder takes a long time with its small batches, and yeilds a very inferior result, filled with particles about 20 mesh in size that refuse to grind any smaller. Milling the C and S together in a the coffee grinder helped cut the dust a bit, but that was about it. I'd like to use my cedar charcoal, but until I can actually grind the stuff, I'll be stuck using commercial airfloat.

Edited March 17, 2014 by Wiley

[Bobosan]

I use dextrin most of the time. You're going to have fines no matter what methods used to bind, including dextrin.

 

Ball mill is your answer to producing airfloat charcoal.

[Wiley]

Fines aren't the problem; the problem is the super weak grains that my current process creates.

 

That's kind of what I thought about the airfloat. Somehow I'm going to have to get a ball mill.

[Bobosan]

Never had much success granulating with just water and haven't tried the red gum binding at all. With water alone, the granules do stay together but easily break down from a lot of handling, crush easily and end up with a lot of fines anyway. I just ram rockets using meal and O-rings on my rammers to minimize dust puffing.

 

Have you tried using distilled hot water with the dissolved red gum?

[Wiley]

I don't have my chems in yet, but I do know that hot water does not solvate red gum. That's what the alcohol is for.

 

2%-5% dextrin activated with hot water is supposed to make very firm granules.

[Bobosan]

I've not used dissolved red gum for binding. Could you not dissolve the RG into a portion of alcohol first, then add to the hot water?

 

You may have seen this thread before -

http://www.amateurpyro.com/forums/topic/8178-hard-grained-bp/?hl=%2Bdissolving+%2Bred+%2Bgum&do=findComment&comment=107499

Edited March 17, 2014 by Bobosan

[Col]

The grains are not as strong as dextrin bound but plenty sturdy enough. I dissolve the red gum in methylated spirits (purple stuff).

[Wiley]

Col, how does it do as lift powder, particularly on small, consumer sized shells?

[Col]

works fine for lift but not much good for lift in traditional candles as the grains get crushed when you compact the delay comp

[Wiley]

Are you referring to the screen mixed version? I know some people bind ball milled meal powder with red gum, and that's really fast, but it's not what I have in mind.

[marks265]

Fines aren't the problem; the problem is the super weak grains that my current process creates.

 

Wiley,

 

You should be able to use dextrin as a binder and get as hard as a grain that you would need for any application. I use absolutely no alcohol in my HOT water when making my BP. If you're not happy, there has got to be something wrong with your dextrin or your process. Otherwise the next step would be to corn the powder. I am almost wondering if the problem is simply because you are trying to make such a fine grain.

 

I get it that people like to play with stuff. But red gum and/or alcohol in BP is just plain ridiculous IMO. I have heard people complain about the non-binding problem in the past. I think Ned was off his rocker on that one. I have also had some commercial 2FA that was much more dusty than others and it worked well enough to use.

[pyrokid]

Keep it simple.

 

NC binding and red gum/alcohol are both much more expensive and complicated than dextrin and water.

 

+/-5% dextrin and room temperature water has never failed me.

 

It is correct that in the context of BP smaller grains will have a faster burn rate to an extent, but if you have weak unmilled powder to begin with, the maximum potential speed of the powder will be rather limited.

 

My advice is to invest in a mill.

[Wiley]

So mark, does screen mixed BP work as lift/break if bound with dex and hot water?

 

I'd rather avoid using a ball mill if I can help it.

[Col]

Wiley,

Red gum wont make up for the speed difference of using non milled bp. I only use it when i need a batch of lift in a hurry as it dries much faster than water/dex.

[Wiley]

Huh, I'd always heard the common consensus was that the red gum added a tiny bit more "spice" the mix, particularly if using commercial airfloat. But dextrin is by far the better binder, so I'll try 2% of it in my first batch.

 

Worst case scenario, I'll just have to keep putting it in spiked, Maltese-style "lift maroons" to get the pressure I need. Even the NC bound crap works fine that way. On a side note, do the Maltese use real, green mixed pulverone in their lift maroons? I know that on the big shells they also use a newspaper or cloth sabot that expands to fit the bore when the maroon fires, but do they ever use just the maroon, minus the sabot? It looks like most of their ball shells are this way. What do they use for lift on their small shells? Do they ever ball mill their BP? If not, how do they make quickmatch and spolettes?

Edited March 18, 2014 by Wiley

[nater]

Why do you want to avoid a ball mill?

 

If you truly must avoid a ball mill, then lift your shells on a rocket and use a booster for breaks.

[Wiley]

I would only be able to afford a HF rock tumbler, and folks say that they can be a bit of a pain to use, that the bearings and belts wear out pretty quickly, and that they can take a really long time to make quality BP.

[marks265]

So mark, does screen mixed BP work as lift/break if bound with dex and hot water?

 

I'd rather avoid using a ball mill if I can help it.

 

Wiley,

 

I know a guy that does make screen mixed powder but he mills individual components and then screens them together. Even with that he uses maple for charcoal. With that said the powder is slightly slower than good milled powder with good charcoal. I tested his powder in a BP rocket vs my powder in a black powder rocket. There was a noticeable difference but the maple powder flew fairly decent. Had the guy used good charcoal it would be that much more closer.

 

There is pretty much no way to get around good milled bp for lift and break. Even air float charcoal is still coarse compared to milling. If you were to play with it long enough it would be easy to add extra powder to a lift charge. For break charge you would have your work cut out for you. Boosters will help but it will mess you up when talking to others in the future about other problems because you won't be in the normal realm of pyro. By avoiding the mill you start to avoid the full benefit of the hobby. I would find a way to reduce the chems as much as possible individually if you cannot afford a proper mill. Then screen them together 3-4 times with the dextrin added. Then granulate the powder through the screen of you're liking 3-4 more times after wetting. Use hot water and no alcohol (take the alcohol back to the store and get some good stuff for medicinal purposes). Save red gum for stars. Use enough water to make a dough ball or several of them and force each one through the screen. When I squeeze the dough balls I will see the sheen on the surface of the ball change from squeezing water in and out of the ball... almost microscopic not as drops of water.

 

For me if you over wet slightly you will get a harder grain, but you will need to granulate the batch several more times on occasion to keep the grains from mushing back together on the paper for a final grain.

 

Yep my 2 cents again!

 

 

Mark

[nater]

I use one of those for small batches. If you take the time to properly align the motor and tension the belt, you will not have those issues. If you add some tubing to increase the diameter of the drive roller, like Ned's article on Skylighter and properly load the jar, you can mill a batch in 2-3 hours. Last, like any machine, make sure the moving parts are properly lubricated.

 

You don't always need the fanciest tools for this hobby, but you need the right ones for the job. Cutting corners to make do will do you more harm than good.

[Wiley]

If I do go that route, I'd like to use some kind of milling media other than lead, since it wears out, and not ceramic because its too pricy for the right stuff. 360 brass is non-sparking, and should last quite a long time. A 96" long stick of 1/2" round costs $35 and, if cut into 1/2" long slugs, would make almost 200 pieces. That is what I need to half fill a HF mill jar, correct?

[nater]

I use .45 lead balls, so I do not know how much brass you would need. I do know that a guy who posts on fireworking.com claims good results milling with it. Most use lead, so it is easier to get help from their experience by trying to follow their same methods.

[Wiley]

Are you using lead balls intended for use in muzzleloaders? I think Hornady is a common brand (comes in a red box: https://www.poewolfsportinggoods.com/catalog/productInfo/spid/H154/sprid/3491?gclid=CLiQxJKLm70CFTBgMgods3wAOg). Those say they're pure lead.

[nater]

I don't recall the brand name, I have been using them for several years. Yes, they are plain lead balls for shooting.

[Wiley]

So, pure lead? They haven't gotten smaller over the years?

[nater]

I have not measured them with calipers, but there is no significant wear. According to Lloyd Spoenenburgh's book on milling, using the media that is the same size, with the proper amount of media and mill charge prevents wear. If you don't have his book, it is a good one. You can get it for a reasonable price from American Fireworks News.