Bending tubing with salt

Sand, Salt, Pitch, Ice Randy

I get better results if i weld/solder the ends of the tube closed to keep the pressure. Kind of tough with water and pitch

Eric R Snow wrote in article ...

Melting temperature of salt - approx 1600°F Melting point of steel - approx. 2700°F

Be careful if you heat the tube.

Salt also melts in water - sand doesn't.

Another useful material is brown sugar. It packs well, can be removed with hot water. I learned of this from guys who develop fuzes for artillery rounds. They'd pack and tamp the elex in brown sugar, send it up to the proving grounds to be assembled to a 155mm round and given a ride. (No HE in these rounds, of course.) After firing, they'd retrieve it (don't know how), send back the fuze for post-firing analysis. Soaking in hot water for a while completely removed the brown sugar without disturbing anything.

The environment in an artillery round is somewhat hectic. Shock, of course, and the G forces from spin are mind-boggling. It'd rip the wirebonds off the silicon dice in hermetically-packaged "MIL" parts, while industrial epoxy-encapsulated parts survived just fine.

Don, its a small world. My father-in-laws specialty was AP tank ammunition. Fuzing was a big part of it. Also depleted uranium projectiles as hard as tool steel. And of course the laser guidance system on board each round. He got a real kick out of all the field testing in Gulf war one.

Karl

I believe both of those methods are/were used in making brass musical instruments. Randy

"*" wrote in news:01c6e31f$c597f780$9194c3d8@race:

I think almost anything will melt in water...given time...;0)

That reminds me...a gent I talked to today said that LVDTs may be an option for determining muzzle direction.

He MAY know what he is talking about...

Gunner

"If I'm going to reach out to the the Democrats then I need a third hand.There's no way I'm letting go of my wallet or my gun while they're around."

"Democrat. In the dictionary it's right after demobilize and right before demode` (out of fashion).

-Buddy Jordan 2001

LVDT's are precise displacement sensors capable of very high resolution -- but they are not wideband sensors. 20 KHz would be a fast LVDT. Beyond that, LVDT's are pricey!

We're more interested in measuring expansion of the barrel at the muzzle -- strain.

I was refering to the direction the muzzle was in, during the fireing sequence. Putting a ring of 6 around the muzzle could get you a data picture of end of muzzle displacement from the moment the sear slipped to the instant the bullet left the end of the barrel.

Gunner

"If I'm going to reach out to the the Democrats then I need a third hand.There's no way I'm letting go of my wallet or my gun while they're around."

"Democrat. In the dictionary it's right after demobilize and right before demode` (out of fashion).

-Buddy Jordan 2001

I doubt that LVDTs are anyway near fast enough to catch a gun barrel; in vibration.

Joe Gwinn

I do too. 20 KHz seems to be about as fast as they get. Further, in order to use displacement sensors the rifle would have to be clamped down tight -- which is not the situation when one is actually shooting. Rigid clamping could change the dynamics.

There is evidence that there are quiet periods when the muzzle isn't moving much, and other periods when things at the muzzle are relatively chaotic. We're thinking that a circumferential straingage at the muzzle will tell us when those quiet periods are with a given barrel, bullet and load, so the load can be adjusted to have bullet exit coincide with a quiet period. We didn't invent this, another guy has done it with good results, and good corellation between group size and time of bullet exit. But he didn't do it with Fitch's rifles!

I wonder how much of this data is available already from Aberdeen?

Gunner

"A prudent man foresees the difficulties ahead and prepares for them; the simpleton goes blindly on and suffers the consequences."

- Proverbs 22:3

LVDT's are linear variable differential transformers. The output is AC voltage of the same frequency as is put in. After you demod the voltage, the frequency response would be lower than the AC frequency. So they are a relatively slow sensor. Typically the AC frequency might be 800 Hz, so the response would be about 2 milliseconds.

Dan

Each model of barrel would be a bit different. Would Aberdeen test anything but military rifles?

What might work OK are accelerometers made with PVDF film and masses made of mild steel (metal content), and glued to the barrel near the muzzle.

I imagine they have tons of data. But not in electronic form, and not necessarily releasable to the public.

Joe Gwinn

LOL...everything from 3040 Krag to 16" guns

Gunner

"A prudent man foresees the difficulties ahead and prepares for them; the simpleton goes blindly on and suffers the consequences."

- Proverbs 22:3