4 replies to this topic

[tomu]

Just away of pressing meal powder with out a hydraulic press. I did it this way before I build my own press. Pressing with a hydraulic press is better, faster and nicer but not everyone has one. So this is a way to go.


About pressing blackpowder with simple tools:

take or make a paper or cardboard tube like for a salute or small rocket engine about 4 - 5 cm ( approx. 2 inches) length and with about 10 - 15 mm ( something about 1/2 inch) diameter.

Cut to dowels of hardwood, strong plastics or a non-sparking metal (e. g. Alu, brass etc.) about half the lenght of the paper tube.

Place a dowel in one the ends of the tube about a half the way in. Secure it with a strip of scotch tape. Fill blackpowder in the other end and place second dowel on top.

The amount of blackpowder filled in should be the amount which would fill the space in the tube about the hight of the tubes diameter, e. g. diameter of tube is for example 15 mm than the hight of the filled in blackpowder colume should be no more than this 15 mm.

Prior to filling in the blackpowder must be wetted with a solution of about 1 part water and 1 part alcohol (e. g. rubbing alcohol etc.). Make the water/alcohol solution first in a separete container and mix about 5 - 10 % of the weight of the blackpowder withg the blackpowder. E. g. you got 100 gramm of blackpowder take a maximum of 10 gramms of alcohol/water solution. The blackpowder should be wet but not sloppy wet.


If you have a bench vise place the whole thing in the bench vise and screw it as tight as you can.

If you don't have a bench vise compress the blackpowder with about 10 moderate blows with a wooden mallet like if you would do to make a fountain or rocket.

After this remove the pellet of blackpowder and let it dry for at least a day. After this you can proceed to corn it.

This whole description makes this simple process sound more compilcate than it really is. With some exercise it's no problem to make about 100 gramms of blackpowder pellets with a bench vise in about 15 - 20 minutes.

Happy new year everybody!

[alany]

I've tried something similar, but had problems.

The puck tends to spread and jam in the tube in my experence. So unless you have a slotted tube with some kind of clamping (like the traditional hose clamps) it becomes near impossible to remove, especially in non-polymer tubes. Although a wack or two with the mallet on the side of such a plugged-up tube does half the corning for you, but renders the tube useless. :-)

It is also very easy to break a bench vice using it as a press! It is all too easy to strip them out, even cold weather has been known to break a vice left tightly closed. While I am always for expedient methods, I think a hydraulic press really is the right tool for the job when it comes to pressing BP cakes.

That said I used to press them with a syringe, a little added dextrin, and only the strength in my fingers. The result was only 1.3-1.4 g/cc, but it worked fairly well as lift. Honestly though, pulverone is *way* easier to make than corned BP and works OK, if you are lazy just make it and use more.

[tomu]

Never had any trouble getting the pressed pellets out. Distorting the tube could happen with the hammering methode, as occurs sometimes when ramming a rocket or fontain too hard.

But what really troubles me is your mentioning of breaking the bench vise. My God, I'm working now for a bit more than thirty years and never ever broke a bench vise. I must do something seriously wrong. It sounds that breaking a bench vise is a common occurence to you. What do I wrong? May be you can give me some advice on that matter. Where do you by your bench vises at toys 'r' us?

Or haven't you broken any bench vise either? May be you just heard from a friend who has a cousin, whos uncle has a friend, who knows somebody who has heard about of breaking a bench vise. Not that I believe breaking a bench vise is impossible, there might be somewhere a unfortunate chap who broke his, poor soul.

Yes, your are absolutely right about the hydraulic press, but not everyone is so fortunate to have one.

[alany]

Yes, I've stripped out a bench vice.

I've also sheared off the retaining pin.

My shop teacher in high school told me about several vices breaking in a cold snap, but I admit I have not experenced that personally.

[The_Djinn]

Most if not all bench vices are made from cast metal which does not take kindly to extreme cold temperatures. Cold temperatures have a tendency to make the metal brittle or more likely to fracture. A lot of it could also be put down to minor defects in the casting process as these items are mass produced.
I have never personally seen a vice break under these conditions but I have seen someone break an anvil which I thought was an impossibility.

Mark

Edited by The_Djinn, 31 December 2003 - 01:03 PM.