Corning BP with limited supplies

[justvisiting]

Aaaaarrggghh, I'm done trying. I've done it before, it was easy. It just won't work at all on my end. No possible way to make a picture go to my gallery or anywhere else. It acts like it's processing my request, and then nothing. I must have tried 50 ways. I don't see the picture you see. Can you make it be on the page of a post without clicking? If you can, I'd feel like it was a win, even though there's no post with it. I hate it when I just plain.... can't.

[Arthur]

Even not all forums allow all users to post images, Mumbles pays for the forum so it's up to him to grant rights. Remember that included pictures are about 1000 times more data-expensive than text every time the thread is opened.

[justvisiting]

It can probably be done with ramming, but in my experience having a press to make BP pucks is advantageous. You can ram comets, there's no real reason you can't ram pucks, but I don't think you'll achieve the same density. Comets are taller (generally) and will have a bit more to them to help keep them together in their somewhat fragile wet state. The real reason I believe pressing is better for something like pucks is really two fold. First, you can achieve a higher density. Off hand, I believe I got a density of about 1.4 g/cm3 by ramming. Secondly, and probably related, is that BP tends to relax or settle a bit. When pressing you can bump up the pressure, let it dwell, and keep pumping the pressure back up until it stabilizes. I believe this is part of what is behind being able to achieve higher densities.

 

You can actually get to densities higher than 1.7 as well. I've gotten them up to close to 2.0 if not a touch higher. I did some very unscientific tests many years ago, and of the various grades I tested, 1.7 performed the best. There was a subsequent decrease at higher densities. It's something I'd like to repeat some time now that I have a little better idea of what I'm doing and know more about it.

 

 

I've found pretty much the same thing. On the point of bumping up the pressure, I started thinking about using a vise. I have a 2" diameter puck die designed to make pucks 1/2" thick. In a 4" vise, my P to F gauge got to 5000#, fairly comfortably. In a 6" vise, I got 7000# with similar exertion. Since commercial powder is pressed at over 3000psi, I would need over 9000# of force between the jaws, and I don't have it. I figured I would try it anyway, because I think between dwell and cranking up the force, less force might get the job done.

 

I took some paulownia-based 75-15-10 mill dust that was dampened with +2% water, and pressed squeezed it to a density of 1.7 with my neighbor's 6" shop vise, using a cheater bar. Unfortunately, after the die was fully closed (see pic for die detail), I gave the vise another crank and broke the drive screw, damn. Anyway, a 1 1/2" diameter puck would have been fine. And this puck did come out to 1.7. If I had used a bit more water I would have felt it better when I bottomed out the die. My mistake.

 

With a 1 ton arbor press, I was only able to get around 1.5g/cc. on a 1" diameter puck. The vise would have done 1.7. Good to know a vise can be used, if somebody is really intent.

 

EDIT: Arthur, yes I realize, but this forum does have the ability to show pictures in posts. I've done it. My frustration is probably due to my inability to do it today

Edited March 30, 2021 by justvisiting

[Arthur]

The thought of a brake caliper for pressing was only one thing I thought could be repurposed simply from junkyard scrap to useful item. Do USA big trucks have front discs? With big calipers?

 

Especially for people who are time-rich and cash-poor repurposing other items may be a way to get tools for cheap. If I wanted I could design a puck tool an inch high with little effort, I'd plan a puck thickness of 0.125 finished and 0.375 as loaded and make the top middle and bottom plates fit those figures into my (found) caliper. This way a caliper travel of 0.25 inches would make a puck weighing about 10g easily cheaply and quickly.

[SeaMonkey]

Quote from Mumbles:

Secondly, and probably related, is that BP tends to relax or settle a bit. When pressing you can bump up the pressure, let it dwell, and keep pumping the pressure back up until it stabilizes. I believe this is part of what is behind being able to achieve higher densities.

 

You can actually get to densities higher than 1.7 as well. I've gotten them up to close to 2.0 if not a touch higher. I did some very unscientific tests many years ago, and of the various grades I tested, 1.7 performed the best. There was a subsequent decrease at higher densities. It's something I'd like to repeat some time now that I have a little better idea of what I'm doing and know more about it.

 

 

That Is I believe is the real secret to successfully pressing Black Powder. At least, according to the Historical

Documentation on the processes of producing finished Black Powder.

 

It seems there are physical reasons that Pressing to high density cannot be done quickly or with a single momentary

application of pressure. It seems to take some amount of time for the particles to settle into their dense positions.

 

In your experience Mumbles, approximately how long did you press to attain the 1.7 to 1.8 density?

Edited March 30, 2021 by SeaMonkey

[BasedAndRocketpilled]

All of this is very useful. Thanks to all who have chimed in so far. I think my current plan of action is to make a batch of granulated so I can continue my experimentation as I work on creating a smallish die and press. I think a vise is going to be my first attempt since I already have access to one, although with some time, money, and a buddy's welding equipment the brake caliper idea sounds like it could be pretty slick. Will PVC pipe work for a die if I keep it small or is metal tooling advisable?

[Mumbles]

Fixed the picture Just visiting. Let me know if you need a refresher on how to do it. It's pretty straight forward on a computer at least. Mobile devices are probably a little different.

 

As far as pressing, it really doesn't take that long. Maybe a few minutes total for a single puck. Stacks of pucks may take longer. Letting the comp settle is much more important for stacks of pucks as well so everything is as close to uniform as possible. I just press it up and let it sit for a bit while I take care of other items or weigh out another one. You'll almost certainly notice at least a decrease in pressure if you have a gauge as the comp relaxes. I definitely find it easier to press to height based on the mass of powder. Even if you get to the desired density right away, I have found benefits to letting it dwell for a bit. The pressure will drop as the BP settles in, but I tend to have less issues with it cracking or expanding or springing back when I take it out. In terms of pressure I've often seen numbers around 3500-4000psi on the comp to get about right. For reference, when I pressed the one to 2.0, I used well over 10,000psi. Those densities were all based on what I pressed them to, I'm not sure what the final density was as I didn't really measure the puck, but there was a visible difference in height at the very least.

 

I don't press much BP for use. Most of these lessons were learned making comets, but the concepts are all the same and applicable.

[Arthur]

With a 1 ton arbor press, I was only able to get around 1.5g/cc. on a 1" diameter puck. The vise would have done 1.7. Good to know a vise can be used, if somebody is really intent.

 

 

 

 

With that info what would the puck density be with a half inch die and a half ton press?

[justvisiting]

 

 

With that info what would the puck density be with a half inch die and a half ton press?

With the 2000lb press used at capacity to make a 1" diameter puck, we get a pressing force of +2500 pounds.

 

With a 1000lb press used at capacity to make a 1/2" diameter puck (.196 sq. in.), we get about double the pressing force.

[ChrisPer]

This discussion is really helpful; thank you all!