The "Inscrutable" Cast Softpoint EXPANSION TEST

[Nueces]

Thank you, Mr. Lapp.

Yup.

Saw it, right off.

[powderburnerr]

There is a lot of "plastic "cardboard around, most election signs are made of it .. and the rubber comes from mine distributors , they have a lot of tag ends from large rolls that you can pick up pretty easily...and pretty reasonable .. talk to some of your mine guys they may have some laying around.........Dean

[Bass Ackward]

I'm a little disturbed at the waste of 80 pounds of rice, though. The stuff was pouring off the tailgate like lava from Mauna Loa. Fortunately, there were no witnesses except all you fellers here.

Maybe next week I'll have it set to try again.

Bruce,

Maybe? Expensive lesson, but when the results are in, you will be more comfortable and that will pay back over time.

Ahhhhhh, what happened to the first bullet? Did it get washed away in the title wave you mentioned?

One thing you might consider is a single gallon jug of water in front of the trap to absorb some of the shock.

[BruceB]

Once again, thanks for the input.

OH, yeah, it needs a top! On that one fateful shot, I'd set up the top with about an inch of room to move vertically on its eight bolts, and it did indeed lift FAST, with rice spewing from the gap at high speed.

Y'know, I've seen hydrostatic shock vividly demonstrated many times before this, but I was still impressed with the commotion that a simple cast bullet at 1800 fps caused. The bullet did get lost in the disaster, but I'll cast and load a couple more .30s for the next try. 311299, with its long narrow profile, seemed like a good "worst-case" trial bullet, meaning that if 299 expanded well, then anything with a blunter shape should work even better. I think that 311291 and 311284 are good candidates, and I should be able to make a few softpoints in those designs before the next outing, probably next Thursday or Friday.

"The next outing"....The Box is now much-improved. I replaced the smashed-up part of the bottom with another piece of 1/2" plywood, and then added a new, additional bottom on the outside made of 3/4" plywood. Then the side walls were doubled in thickness by sheathing them in another layer of 1/2" ply. Since the major impact and pressure wave occurs on first contact, the new bottom and side sheathing are attached with drywall screws on about 3" centers over the entire surface of the new additions for the first two feet of the Box.....that is, the screws are in rows of five across the 12" width and the rows are 3" apart. I will be mightily surprised if THIS comes apart!

The rubber did come from the mechanical department at the mine. I'll be checking to see if I can arrange to buy some through company sources.

The various suggestions for waterproof partitions are excellent. When it comes time to refine the testing to the degree that I want to see WHEN the various expansion stages take place, the plastic-type partitions look like a very good bet. I have a strong feeling right now that the max expansion was pretty nearly instantaneous on first contact.

A video of the event wouldn't be very dramatic, I'm afraid. There was just the jumping of the top to the limit of its travel, along with some rice flying out around the edges. No external damage appeared at the shot. All the "action" was on the bottom of the box, out of sight.

The fat lady hasn't sung yet, by gum!

[montana_charlie]

The rubber did come from the mechanical department at the mine. I'll be checking to see if I can arrange to buy some through company sources.

I also have a need for some rubber sheeting like you describe. After you learn more about it, I would like to talk to you about getting some, myself.
CM

[floodgate]

Bruce, Charlie:

Check out the butyl(?) rubber sheeting used for pond liners; it looks like good, durable heavy stuff. Does the mine have any lined settling ponds?

Doug

[leftiye]

If you're getting suction at the first part of the box after the boolit passes, then the rubber inside the box with many holes drilled to let air in under the rubber to keep the suction from destroying your box might be a good idea, FWIW. Maybe the rubber bladder inside a metal cage would be good.

[waksupi]

Bruce, I'm having a great time, watching this topic. You may yet, defeat high school physics class!

[NVcurmudgeon]

Nothing to contribute technically, but I just figured out why this thread is called "inscrutable." Now onward to even more puzzling things, like understanding SWMBO.

[melw]

Nothing to contribute technically, but I just figured out why this thread is called "inscrutable." Now onward to even more puzzling things, like understanding SWMBO.

It means She Who Must Be Obeyed!
Mel W.

[NVcurmudgeon]

It means She Who Must Be Obeyed!
Mel W.

Mel, I understand the acronym, it's the mind behind it that puzzles me.

[melw]

Mel, I understand the acronym, it's the mind behind it that puzzles me.

Well ask the imposable why don't you!
Try as I might I am in the dark there as well!
Mel W.

[Typecaster]

Another sheet material could be the gray EPDM/vinyl sheeting used for shower pan liners. I think it's thicker than the pond liner stock. Comes on a roll, cuts with scissors, and can be solvent-welded to seal seams. Bought mine at Home Depot to make custom oversize developing trays for photos for a convention booth.

[powderburnerr]

I have been wondering if the rubber face on the box stretched into and buckeled the box before being penetrated by the bullet maybe you should be looking at reinforcing the end behind the rubber , ply under the rubber with a hole marked for shooting through...Dean

[Wayne Smith]

Bruce, absolutely awesome subject! I am following it with fascination. I don't have anything else to offer except some information I gleaned from some of LOML's reading. She's a geologist.
In short: Landfills are made with multiple layers of lining, one of which is a material very similar to what is being described here. I offer this only to say that it therefore should be available in reasonably large sections!

[scrapcan]

As far as water proof depth markers you could go to the post offic ena dget a handful of tyvex envelopes and slip cardboard into them and then slip into the frame. shoot a hole in it and you can then patch and replace cardboard or replace envelope and cardboard.

You could also talk to one of the local realty agencies about the little plastic signs they put out, should be the same as the election signs mentioned above.

Less liquid in the medium will help with hydrostatic shock. You can cook the rice a bit to make it expand and soak up some liquid. But on the other hand if you want to get a realistic test you need to consider what percentage of a living creature is water.

[powderburnerr]

Bruce this is short notice but I do have some of that plastic the mines use under their leach pads , AND I am going to reno this weekend ,, actually leaving tomorrow and returning Fri night ,If you need this I will be happy to drop it off to you . you can call me at 775 738 8655 today or tomorrow if you want it......Dean

[floodgate]

NV Curmudgeon:

It comes from a character in a series of English mysteries, a lawyer named Rumpole, who refers to his wife as "She Who Must Be Obeyed". But it really goes back to a turn-of-the-century series of English adventure novels by H. Rider Haggard: "She" and "Ayesha, the Return of She", about an Indiana Jones type, Allan Quatermain, who gets involved with a sort of witch-priestess a few thousand years old, whose subjects are forbidden to speak her name, and refer to her by that phrase, and..., and.....

Oh, never mind; check it out of the library and read it for yourself; it's a real hoot.

floodgate

[NVcurmudgeon]

NV Curmudgeon:

It comes from a character in a series of English mysteries, a lawyer named Rumpole, who refers to his wife as "She Who Must Be Obeyed". But it really goes back to a turn-of-the-century series of English adventure novels by H. Rider Haggard: "She" and "Ayesha, the Return of She", about an Indiana Jones type, Allan Quatermain, who gets involved with a sort of witch-priestess a few thousand years old, whose subjects are forbidden to speak her name, and refer to her by that phrase, and..., and.....

Oh, never mind; check it out of the library and read it for yourself; it's a real hoot.

floodgate

Now you've done it! Didn't you know that recommending a book to me is like leaving a jug of "Old Redeye" on the sidewalk of Skid Row? Seriously, thanks very much. Isn't Quartermain the hero of "King Solomon's Mines," or at least mentioned in it?

[MT Gianni]

Back before Sharon Stone decided she looked better with her clothes off, she and Richard Chamberlain made a movie about it, also there was a B&W about She. BOth are more funny than serious. Gianni