Hydroforming question

[GRUMPA]

I'm just curious if someone could answer this.

Just how much P.S.I. or close is created when hydroforming brass?

I'm using the Whack-A-Mole method and not hitting the plunger with what would consider full force with a dead-blow hammer.

[oneokie]

What is the weight of the hammer?
How long of a distance is the strike arc?
What is the area of the end of the pin you are striking (the end in the case/fluid)?

[GRUMPA]

What is the weight of the hammer?....1 1/2Lbs

How long of a distance is the strike arc?....10-12"

What is the area of the end of the pin you are striking (the end in the case/fluid)?... .3025

[GRUMPA]

Anybody???

[BK7saum]

Are the cases fully forming with your method?

I don't get fully formed shoulders fireforming with starting loads. Wouldn't you need equivalent pressure whether hydro or gas?

Are you trying to get fully formed brass or only 90% or so?I would imagine that it would take less pressure to get partial fillout.

[GRUMPA]

Are the cases fully forming with your method?

I don't get fully formed shoulders fireforming with starting loads. Wouldn't you need equivalent pressure whether hydro or gas?

Are you trying to get fully formed brass or only 90% or so?I would imagine that it would take less pressure to get partial fillout.

Most of your questions will revolve around a yes and no answer. You need to keep in mind gases are compressable while fluids aren't. Here's a picture of why I'm doing this in the first place, but keep in mind a factory 30-30 shoulder location is around 1.400 and on the 25Rem it's 1.500.

http://castboolits.gunloads.com/attachment.php?attachmentid=95240&d=1391279126

From left to right: Factory made 25Rem, homemade 25Rem hydroformed, factory 30-30, factory 30-30, 25Rem hydroformed, Factory 25Rem.

[SODAPOPMG]

Some answers at this link
http://bulletin.accurateshooter.com/?s=HYDR+FORM+CASES&submit=Search

[Walter Laich]

learn something new every day.
Looks to be a relatively easy process...another idea to catalog

[jmorris]

You would need to know the speed of the hammer at instant of impact, how long the impact actually takes/losses in the impact itself.

Newton's laws say force is the time derivative of momentum. So the duration of the impact has a large effect.

A material that absorbs the impact (more) lowers the "max" number from an impact with a ridged object because of the longer impact duration. Kind of like there is less force on your brain impacting your skull if it stops in an airbag, over a longer time, than if it stops in a shorter distance impacting an object with greater resistance.

[jmorris]

Thought about this thread today. Tried out a new mold release today that didn't work. The insert would not budge with repeated blows. The housing is cast iron and weighs around 5 lbs, surface was a 1/2" thick steel table on concrete. Maybe a 2 ft throw with all the down force I could muster, nothing.

Only took 5 tons in a press though...

[GRUMPA]

learn something new every day.
Looks to be a relatively easy process...another idea to catalog

Here's a visual aid for folks. Note the shoulder location of the parent case versus the finished product. Hydroforming does take some physical effort but the results eliminate the need to fireform cases.

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