Red gum BP vs. dextrine BP

[dangerousamateur]

I use redgum BP to lift shells, but the granules are broken to easy in my opinion. Otherwise it's very fast. Have you ever compared dextrine bound granules with redgum bound granules?

 

How much speed do i sacrifice when I move over to dextrine?

 

 

My process is wetting and rubbing through a screen. A press for pucks is not available.

[Nessalco]

DA,

 

I took to making BP with 4% redgum this year, and found it to be very useful. The grains are quite hard, and don't break down with handling. My standard to this point had been pucking and corning powder, so that is my baseline for durability.

 

Wet out with alcohol, and when granulating rub it through the screen with a 'push and twist' motion, not rubbing it across the screen like a cheese grater. Your grains will be quite durable.

 

Kevin

[FlaMtnBkr]

I don't use any binder and get fairly hard grains. Hard enough that it hurts your fingers trying to break them up. Just have to get enough water that it is like clay and I also push thru instead of grate.

 

Someone was just discussing the use of 70 percent rubbing alcohol with red gum powder. And the grains were much harder than with pure alcohol and nearly the same power using a rocket test stand.

 

With dextrin, someone showed a few years ago that using dextrin liquor resulted in around 20 percent faster powder when testing in a BP rifle and using a chronograph. 10% liquor is made and then around 20 percent is added to the BP resulting in 2 percent dextrin. This was found to be faster over the dextrin being milled into the powder.

 

In all of these the faster it dries, the faster the powder will be, IMO. But once you have a good mill and use good charcoal it's all a bit over kill because what you are making will all ready be substantially faster than Goex. And I find I don't need the most violent powder I can make for all but a few things.

Edited September 7, 2014 by FlaMtnBkr

[psyco_1322]

4-5% dextrin makes very hard granules, you won't have the issues that the red gum presents. Really, with hot charcoal, you don't really see any reduced speed with the dextrin. Just try the dextrin.

[dangerousamateur]

The BP is made from willow charcoal and I would say it is decent quality.

 

But I want to use this for rockets to. So the grains must be crushed when ramming or pressing. can this be done with dextrine BP?

[FlaMtnBkr]

Why not try not using any binder if being used for rockets? No one seems to believe me but I don't use any binder for any of my BP needs.

 

The key is to add enough water that it is a clay like consistency and dry as quick as possible. In the sun it should only take 2 or 3 hours. Plenty hard and perfect in hand rammed rockets.

[dangerousamateur]

Yes I know. But often I make a large batch of bp at once, because it is such a mess. And I don't know at that time, what someday I'm gonna make with it.

 

You know, I like to have some universal stuff, one for all

[FlaMtnBkr]

Well that's exactly what I use my binder-less BP for. Everything. It is surprisingly durable if enough water is added when granulating.

 

Like I have mentioned, it actually hurts my fingers to break down a large piece into smaller pieces. And very little crushes down to a powder/dust and most are smaller granules. It can't hurt to separate a small amount after milling and try it. I have said this dozens of times over the years and not once has some replied that I'm full of it or that it works so I would bet no one has ever even tried it. As long as it's like modeling clay and you dry it fast it is plenty hard and plenty fast. I guess you have to make a video for anyone to believe you these days.

 

In fact, I have only used a binder once in all my years of making BP. It wasn't needed and didn't work as well ramming rockets. And using my FPAG designed BP tester I have made stronger BP than I have heard any of the other club members report.

[dangerousamateur]

Ok, I'll give wet ricing a try.

 

How much water should I add? Is drying fast so important?

 

Because I don't have drying box.

[FlaMtnBkr]

Amount of water depends on the charcoal really. I add 18% and creep up from there. Sometimes it gets to 25%, sometimes even 30%. If you have a bunch of the same charcoal, and keep close notes on how much water it takes, it will take that same amount from batch to batch using that charcoal.

 

The consistency is key really. You want it like nice pliable modeling clay. I don't put mine in a drying box either. I make a nice even but thin (1/4"-3/8") layers on plastic trays and put in the sun. Sometimes if I'm worried about some clouds I will blow a fan across them to. After an hour or so I will pinch it and brake it apart and stir it around some. You want it drying on the outside so it brakes apart and not mash together in a mess. This helps stir it so it dries faster and only takes a couple minutes to do on a kilo batch. Usually 2 or 3 hours and it's dry but if I have time I let it sit for a few more.

 

The faster you dry it, the faster the powder. If it takes all day to dry it will be noticeably slower. If it is still strong enough for your needs then it isn't that important. If you want it strong as possible than drying fast is more important.

[mkn]

Hi Da,

 

I think I am doing what you are talking about,

I mill one type of BP, with 3% Dextrin, Pine coal and 3 hours for my mill. Then I can use it for rice hulls by using water to activate the binder, or granulate it ( don't do much of that lately, mostly rice hulls, easier and quicker, less mess, plus I have lots of rice hulls at work

 

or for my rockets same BP with Dextrin, only I wet it with Naphtha and mineral oil. that way the dust is gone, it compacts really well and the dextrin was not activated by the Naphtha. My rockets are only nozzle less with this hot BP. I don't think you want any type of a hard granule to ram rockets, only want to keep the dust down.

 

so when ever I need BP, I have one type of mill dust ready to go and wet it with the appropriate agent to activate the Dextrin or not,

 

as for speed, I don't think the dex or gum will make much difference, I saw the biggest improvement going from commercial hardwood coal to home made pine / spruce coal, the first time I tested the new coal, it startled me, huge BOOM, massive lift , I lost sight of the test baseball, wow that is what I want, now that's all I make. One powder for all my needs, keep that mill cranking !!

 

Matt

Edited September 10, 2014 by mkn

[Ubehage]

I learned by this:

https://www.youtube.com/watch?v=dj-HGHzCFos

However, I use a lot less water than he does. I let it heat up slowly, and adding water as needed. Just enough to make it an acceptable liquid, and then I dry it without sifting the water out.

 

I also haven't used any binder - yet. I even left out the alcohol, and it fits all my purposes.

With my next batch, I will try adding some Dextrine, and see if there is any noticable difference.

Edited September 10, 2014 by Ubehage

[FlaMtnBkr]

I didn't watch very much of the 18+ minutes. But the test at the beginning and the end both seemed fairly slow. It also looks like some adaptation of the CIA method. Which doesn't get very high marks in the pyro community. BP really isn't that hard. Yeah there are lots of little things you can tweak to make the process your own.

 

But if you have a good ball mill and hot homemade charcoal it's hard NOT to make good powder. There are little things you can do here and there to get a little more power out of it, but if you use those 2 things you will crank out BP as good and likely better, than commercial BP available today such as Goex.

[schroedinger]

DA did you think about making a puck press yourself? It's made quite easy and fast and really helps?

All you need is two parts of a pvc pipe, on fitting snuggly into the other (the thick walled type) and two plungers made from wood or similar fitting into the inner pipe. Now just a couple hose clamps around the outer pipe and here you go.

[LambentPyro]

Ned told me that select charcoals contain resins that act as a binder.

 

I have found this true while granulating BP using Black Willow charcoal, Eastern Red Cedar, Pine (some more than others, sappy pieces tend to be more potent), and Whitewood. Charcoal cooking method also was a significant factor in the grain hardness results too. I would say that it was between Black Willow and ERC charcoals that produced the hardest grains out of all. These BPs did not use any additional binder (no Dex or RG) but granulated just using Denatured Alcohol. The BP was intentionally over-wetted to activate those resins too.

 

Like FlaMtnBkr said, it produces grains that do in fact hurt your fingers trying to crush them.

[wildcherryxoxo]

most if not all charcoals have some resin, its a product of the destructive distillation of sap, what I think you meant was that certain woods have more resins than others, that is true. Yellow Pine resin was a massive cash crop in the southern states, and other parts of the world. Sweden was a leader in wood resin derivatives, and the tar is still called "Stockholm tar". I suspect that the resin we activate in charcoal is largely Colophony Resin.