Hydraulic Jack Pressure

[atr]

A hydraulic jack press seems to be the common tool for pressing green cake in the manufacture of black powder . I can find no reference to the ammount of pressure required . A 6 ton jack will bend the plates so something less than 6 tons of pressure is required . Does anyone actually use a pressure guage or is it just done by feel where enough seems like enough .

[nesler]

It all depends upon how big the cake is going to be. The optimal density of bp is 1.7g/cm^3, so basically the press has to be strong enough to press the bp to that density.

[atr]

I'm thinking about 3 inches in diameter by 1 inch thick or about the size of a hockey puck .

[nesler]

Okay, 1 inch equals 2.54 cm.

So your puck would be about 2.54 cm deep by 7.62 cm across.
The surface area of one flat side would be 7.62xPI = 23.94 cm^2.

So the volume is 2.54 x 23.94 = 60.81 cm^3.

Thus, with the desired density being 1.7 g/cm^3....
1.7 x 60.81 = 103.37 grams.

So your puck should contain 103.37 grams

So what you could do is take the tube or whatever that you'd be casting the puck in, and mark off the desired depth of the puck (in this case, 1 inch). Dump in 103.37 grams of the meal powder, and press it until the top of the powder has been compacted down to the level of the marked-off line. At that point, the density will be roughly 1.7 grams per cubic centimeter.

I don't know how much force per square inch is required to compress black powder down to that density. But I can tell you this much. The top of that puck is going to have a surface area of 9.42 square inches. So lets say that the press you're looking at is capable of X tons of pressure on one square inch of material, the force that it'll exert on the puck is (X/9.42) tons per square inch. So, whatever amount of force per square inch is required to press that puck to that density, that pressure requirement must be less than X/9.42 tons per square inch. Otherwise, the press won't be able to do the job.

[atr]

Wow , Nesler ! That gets copied and buried in my treasure chest . I decided to visit the machineshop at work today to check out the industrial , electrically operated hydraulic presses . One of the machinists pointed out an older press that never gets used and it has a pressure guage . It's a 20 ton press and the guage is calibrated for a 2.5 inch ram . Easily removable and readily adaptable to a hydraulic 6 ton jack . Using your calculations i should be able to figure out how to read the guage should it ever be declared as surplus . There seems to be a good possibility that it will be declared as surplus by the weekend along with the fittings . North of the 49th black powder is $30.00 per pound . Rocket engines are very expensive but not for too much longer . 50 pounds of pyro grade potassium nitrate and 10 pounds of pyro sulfur are on the way . I've already made a kiln for willow charcoal .

[nesler]

Glad it helped. I'm not quite sure how they measure press strength (a 20-ton press can exert 20 tons of pressure over how much area?), so you might have to adapt my process a bit.

And yeah, I live in a pretty pyro unfriendly state, and black powder is pretty much non-existent. And yes, the cost of rocket engines is atrocious (last I heard, something like ten bucks for a four-pack of Cs).

And feel free to distribute that short little text I wrote, but tack my name on at the top. Credit goes to "Nesler". Perhaps I'll do a little research and write a more detailed paper on it. If I do, I'll send it to you.

[DeadCell]

Just FYI, I've found instructions on making a decent powder die on Dan Williams' page. I have yet to try this because I do not have direct access to a press at the moment. Hope I helped. :)

http://www.wecreate4u.net/dwilliams/powderdie/powderdie.html