Corning troubles...

[Swede]

Continuing a bit with the BP Processing thread, I decided to try corning on a larger scale. I used my homemade ram from the tutorials section. It is definitely on the small side, size-wise, but it does work well.

 

My mill powder already had about 3% red gum added. I moistened the powder with 50/50 alcohol/water, 10% by weight to the mill powder.

 

Loaded into the ram, got some nice disks:

 

http://www.5bears.com/firew/corn100.jpg

 

http://www.5bears.com/firew/corn101.jpg

 

These puppies are HARD! I tried to "grate" them against a 10-mesh screen, and it was quite difficult. So I did what I knew was the correct procedure - broke them up aggressively with a plastic mallet. It worked, but I was not thrilled with the result, as I got a lot more dust than I wanted.

 

My question is, what do you guys think is the best procedure to process these disks? Is there something I can do to minimize the quantity of corning dust, or is it simply inevitable? Is it best to let the disks dry 100% before breaking them up?

 

Basically, I'm looking for general advice on turning the pucks into various granulations of nice, dense powder! As always, thanks!

[Bonny]

For processing the pucks, aside from making a corning machine, you will need to smash them up. To reduce the amount of dust screen the crushed powder frequently to remove the sizes you want before smashing them to dust.

You will always get some dust however, but is can be used elswhere, so it's not really wasted. I break my pucks up when fully dry , but I think some people do them right after pressing.

[FREAKYDUTCHMEN]

Maybe it soaks some air so the density will be less after breaking them appart right after pressing.

Maybe you can press the dust again into pucks, i don't think the density will get higher. Making pulverone of the dust is also an option, it burns even faster than the 4FA BP. There will always be a variety of different particel sizes when corning it. I never use a binder in my BP, I only use 10% water.

[Swede]

I never use a binder in my BP, I only use 10% water.

Interesting - with no red gum or dextrin, do you find the grains any less sturdy? If you screened and then bagged the eqivalent of FG powder, do the grains retain their size well during handling, or do they tend to break apart into smaller bits?

 

The drying seems to take forever if left in the puck state. I've been weighing a sample puck now for 3 days, and it continues to lose weight due to evaporation.

[TheSidewinder]

Just as an observation, Swede, those pucks you made look especially nice. Very smooth and shiny. Your press may be small but it obviously has enough pressure to do the job.

[Swede]

Thanks Sidewinder. I think it is more the compression rig than the press itself, which is just a cheapie. I made the rig as kind of a lathe turning exercise. It's a bit too small for BP, a bit too large for being a star pump, but I have been working pretty small scale with BP so far.

 

I think the shininess comes from the pump itself. I took extra care to finish the piston and the bore nice and bright, to try and keep the powders from sticking. Seems to work well...

 

http://www.5bears.com/firew/ram07tn.jpg

 

It's odd how hobbies sometimes help each other. I've been a hobby machinist for maybe 20 years, and only now am really getting into pyro. The machines really go a long way towards making stuff like rocket tooling and pumps. I'm looking forward to making some star plates from plate aluminum and dowel pins, and other things like that.

[FREAKYDUTCHMEN]

Swede, I can handle my BP 4FA or 2FA pretty roughly. It is almost impossible to break the pucks by hand.

[Bonny]

I never use a binder in my BP, I only use 10% water.

Interesting - with no red gum or dextrin, do you find the grains any less sturdy? If you screened and then bagged the eqivalent of FG powder, do the grains retain their size well during handling, or do they tend to break apart into smaller bits?

 

The drying seems to take forever if left in the puck state. I've been weighing a sample puck now for 3 days, and it continues to lose weight due to evaporation.

If you are pressing the pucks with a bottle jack no binder is needed. I read that one (person at least) beleives that the sulfur provides the binder under extreme pressure. I press 3" pucks with a 12ton jack and usually allow them to dry for 4 or 5 days in my drying box before crushing into rock solid granules. For more info on pressing and corning search the forum, lots of info.

 

As for your die, maybe it's too large for stars, but could definitely serve as a great comet pump.

[justanotherpyro]

I break them up wet which cuts down a lot on the amount of corning dust and I still get high performance lift granules. What I have found works really well is to break the pucks up untill everything goes through a 6 mesh screen which ultimately gives me the right sized lift grains of around 6-10 mesh.

[Arthur]

The art is to recover all the corned puck and grade it by mesh size through screens.

 

If you read the older books inc COPAE they have uses for all the mesh grades right down to dust. If the grades you make do not become the grades you need then simply damp them again and re press them and re corn them. Corning mill dust is prized as the finest,fastest powder available. (in the BP world!)