Volume vs weight - need some help here!

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desert deuce
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Re: Volume vs weight - need some help here!

Post by desert deuce »

Confession after confession after confession, and is ain't even Friday.

What is this site coming to? :?:
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Yankee Bill
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Re: Volume vs weight - need some help here!

Post by Yankee Bill »

Kevin Tinny and martinibelgian,
Weight v. granulation size.

I studied Civil Engineering at UC Berkeley, 1964 to 1968. I've been an engineer 50 years. I got out my "Element of Material Science" book by Van Vlack, to bone up.
Topic is packing factor. It does not depend on size. Packing Factor (PF) for most densely packed spheres is the same for 1 inch and 0.01 inch diameters, as shown in bottom photo. Both have 74 percent volume filled. Top photo shows how it can be increased.
Weights of black powder 1F 2F 3F and 4F would act the same.

The difference comes down to the hows of the crushing process. My conclusions are that the smaller grains are like shards and the larger grains are more rounded, from being chipped off. Rounded would tend to have higher PF than shard chips. However the difference is small.
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Yankee Bill

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Trigger1212
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Re: Volume vs weight - need some help here!

Post by Trigger1212 »

Holy Smokes, now we are getting SERIOUS! Thats what I like about this site, never know what will pop out of the wood work!

Cheers!

Wade
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desert deuce
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Re: Volume vs weight - need some help here!

Post by desert deuce »

Hmmm...........I took out my volumetric powder measure tube that was set for 83.5 grains of Swiss 1.5 of one lot of powder. Threw five charges of that lot, weighed them and the average was 83.4 grains. But I already knew that.

I cleared the powder measure and refilled it with a different new to me lot of Swiss 1.5.

I filled the hopper with the new lot of Swiss 1.5, threw 5 charges, weighed each one and the average was 79.0 grains.

Dang IT, there goes that still small voice again, screaming in my ear :!: I'm out of here :shock: :shock: :shock:
Sometimes you get the chicken, and sometimes you get the feathers!
Trigger1212
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Re: Volume vs weight - need some help here!

Post by Trigger1212 »

DD, I believe YB's manual was looking at materials with the same given density. For example if you had a lot of 3F and 1.5F that had the exact same density (yah I know that will not happen) then the 1.5 would more than likely throw a heavier weight for a given volume for the reasons given.

In your example the grade is the same, 1.5, but there is an obvious density difference, not an apples to apples comparison.

But they you can further complicate it by saying you have a 3F with a heavier specific density than a lot of 1.5F and it may throw heavier than the same volume of 1.5.

Bottom line, it appears that it always pays to weigh and set your volume accordingly measure accordingly!

Cheers!

Wade
hepburnman
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Re: Volume vs weight - need some help here!

Post by hepburnman »

Not sure I understand the packing factor as used in civil engineering to hep explain the weight difference that might occur when filling the same size volume with say, spheres of different sizes, where the spheres, in each respective case are the same size, but differ in size in the two different cases.

Consider an example where we want to fix a box with inside dimensions of 2" x 2" x 2".

In the first case I suggest we place one sphere of 2" in diameter into the box. This size sphere would exactly fill the box but would however leave considerable space not filled. The boxes volume is 8 cubic inches. The volume of the sphere is 4.19 cubic inches. So, almost half or ~3.8 cubic inches of the volume is unfilled space.

In the second case consider that we fill up the box with much smaller same-size spheres, of the same density, with say, 1/16" in diameter, or even much smaller. I am assuming here too that the stacking of the spheres is optimum where there is minimal air space that is not filled.

My two examples above are extreme cases and meant to help try and prove a point. For the cases where different grain sizes of black powder are used such as 1.5 Fg compared to 3 Fg, where the grain sizes of 1.5 Fg are somewhat larger than 3 Fg, in theory, and with optimum stacking of the grains, 3 Fg should stack tighter and results in a heavier volume.

In practice however, with black powder, we are not dealing with perfect spheres. Also, the individual grains are also not all of the same size. There could also be density variations between the grains of 1.5 Fg and 3 Fg that could help to go contrary to the examples above where perfect spheres of the same density were used.
Yankee Bill
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Re: Volume vs weight - need some help here!

Post by Yankee Bill »

hepburnman,
You are missing the significance of the edge effect. The note in the bottom photo, far right side discusses that.
To compare apples to apples, the 2" sphere does have a volume of 4.18879..., but for 1/16" spheres, you must use the same "cubic" arrangement. That means 2" on a side will have 32x32x32, or 32,768 spheres. Each sphere will have a volume of 4/3 Pi times 1/32 cubed, or 1.2783 times 10 to the minus 4. Multpy these and you get the same 4.18879...
Put 2" balls into the Rose Bowl, and they weigh the same as 1/16" balls filling the Rose Bowl.
I stand by my first post. If granuals of BP were all the same shape, 1F, 2F, 3F and 4F will all have the same bulk density.

PS I love the Remington Sporting Rifle #3, the Hepburn. I own three originals and one repro. One of the originals has a Harry Pope bbl.
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Re: Volume vs weight - need some help here!

Post by NMLRA Past Pres. »

Grateful to all here:

Read somewhere a long time ago:
"Theory is good in the absence of facts."
Thanks, Yankee Bill, for providing the facts that resolve the theory.

With the weight variation shared above, I guess that we should test (weigh and check zero) each batch.

Years back, with GOI and then GOEX, we sifted to remove the "fines" (as much as 10%) when throwing volume charges in large bore bullet muzzle loaders. We found, via Oehler chronographs, that the muzzle velocity (10 feet) extreme spread was cut in half. Swiss is very clean and I no longer sift.

All the best,
Kevin Tinny
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Re: Volume vs weight - need some help here!

Post by rdnck »

I think we're gonna need more popcorn on this one. Shoot straight, rdnck.
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hepburnman
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Re: Volume vs weight - need some help here!

Post by hepburnman »

OK, Yankee Bill, I admit defeat! Can't argue with established theoretical fact! However, in our practical world what has been noted when using different BP grain sizes in the same volume where stacking may be far less than perfect?

I do love the Hepburn. Mine is a Jim Hamilton repro. As close to the original as possible I think. And it can be configured to exactly how you want it.
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Re: Volume vs weight - need some help here!

Post by Kurt »

Wouldn't it be easier to fill the case with 1F and settle it and screed it off flush with the case mouth, dump it on the scale and weigh it then refill the same case with 2F and 3F. 4F if you feel the need.
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Yankee Bill
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Re: Volume vs weight - need some help here!

Post by Yankee Bill »

I have wondered about if anyone has tried mixing black powder. Say 2F and 3F. I have never seen this posted.
There has been a deluge of discussion on compression, but not mixing. Compression is a method of reducing voids and crushes granuals in an unknown way. Might mixing different grades accomplish the same end result, without the need for compression?
I'm a believer in doing whatever works, but has anyone tried mixing various grades? Your thoughts?
Yankee Bill

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