BP for Thunder Mugs

[nordicwolf]

Various thunder mug manufacturers mention Fg-FFFFg for use in their devices.  Can meal directly from a ball mill also be used?

Or would I need to puck/corn or otherwise granulate homemade BP for use in a thunder mug?

I am curious because the instructions I have read and videos I've seen all recommend ramming the BP before putting in the bread, hotdog bun, etc, to seal the bore.  I suppose the FFg granules are so hard they won't crush, but I have no experience with commercial FFg.

For those who use homemade BP in a cannon, what is it?  Meal?  puck/corn (water only)?  dextrin added to BP, wetted, then granulated?  and of course sieved to the appropriate size?

I guess it boils down to...lift granules or rocket BP?

Thank you.

[Richtee]

I would think the fastest stuff you can get. Being a short bore you’ll want it mostly combusted ASAP. Mill dust would be appropriate I would think.

 

Never used one of those. Kinda like to have one. Bread, eh? Interesting. Good use for crappy white bread

[All10Fingers]

I have one and the instructions it came with recommend hot dog buns and definitely not for golf balls. (The fact the bore is exactly golf ball size is just a coincidence lol). I would think the fines left after corning would be best since it can withstand bring packed without becoming a solid mass. 

But then again. A thunder mug/signal cannon is meant for a big showy boom and not for launching projectiles. So a lil unburned powder left to flash at the muzzle isn't necessary a bad thing..

Also, don't drop it on your foot.... Or anything important to you really. Just don't drop it at all. 

[nordicwolf]

I guess I'll have to get one and try meal dust and go up from there.  Perhaps not overpacking it.

I kind of think fine granules might be appropriate because when my 4oz core burner CATO'd, it made a nice boom presumably because fire had fissurers, cracks, etc. to propagate through.

Now I will have to search the forum to see how to make the fastest granules from pucking and corning.  Do I just compress my fastest hottest ball-milled bp (eastern red cedar, 75-15-10) with say 3% water, NO dextrin, puck it and corn it?  I have a puck tool from Woody's I have not used yet.

Or do I need to add some dextrin before pucking?  I may not be able to break it into small enough granules (FFg or so) if there is dextrin - I need to look into this.

Thanks.

[All10Fingers]

No dextrin if your pressing pucks. And you can probably use even less water. Just enough so that no dust floats off the powder when you stirr it. I use like 4 or 5 drops in a 200 grams batch.

Use a press or bench vise, squeeze em tight. If you see water coming out then you added too much. Let them dry for a while before you grind em into powder. When you think their dry... They probably not.

I grind my pucks in a ceramic burr coffee mill and pour it thru a stack of nesting screens. Then each screen gets its own jar. I don't even know what the actual size of any of them are... Just 5 jars with a number on the lid. 1 being the coarsest and 5 being the fines.  Jars 3 and 4 are my most used. Jar 1 and 2 make good lift. Jar 5 is for priming, dusting, spolets, and rockets. But I have no clue how many "f"s, or meshs, or microns any of them actually are.

[Richtee]

I use 50/50IPA-water. And JUST enough to stop dust from rising from the bowl. My pucks are like ceramic round tiles. No binder of any sort. And yeah, if yer corning, that fine stuff would be IDEAL. 8.5F

Edited April 16 by Richtee

[All10Fingers]

 

 

[nordicwolf]

you guys are spoiling me.  Thanks for the info.  I have not looked yet for a corning thread, but I will ask another question here.

For the 5 pucks in the one video, how much BP was needed for that?  (I know I know, whatever fits in the puck tool.)

I have a hydraulic press - what sort of pressure do you put on your pucks?

When and how do you do the actual corning?  I've read that sometimes you don't want the puck to be completely dry - otherwise it is too difficult to corn. I have rubber and dead-blow mallets.  I want to avoid sparks of course.

My biggest learning from your posts so far is:  NO dextrin (or any binder), and as little moisture as possible, only to knock down the dust.

Thanks!

[All10Fingers]

I usually make my pucks between 15-20 grams each. I use a 40mm die and squeeze em in a 12 ton hydraulic press. No pressure gauge, just go till it stops. Let it sit a few minutes. Squeeze it again. Then leave them in my old pickup to dry. I feel like useing a hammer to crush them creates thin flakes that crumble too easily. That's why I like my coffee mill. Once their 100% dry, they are pretty hard to break up. But I've always thought that a good thing.

If you find my very first post over in newbie questions. Someone shared a handy formula for determining your puck density 

[nordicwolf]

Can you recommend which ceramic burr coffee mill you use?  I see a few on amazon, one for $17 another for $25, but it seems you would have to break the puck into chunks that fit into the mill before the mill can do its thing.  My puck die 3" diameter.  It came with two delrin disks presumably to put between pucks so as to allow pressing 2 or 3 at a time.

I've never cranked my press to the max. I've only ever used it for 1# rockets and a star plate.  Should be fun to max it out.  Thanks again!

[All10Fingers]

I use this and I do have to break them with pliers to make them fit 

[nordicwolf]

awesome, thanks!  I'll look for something like that.  Calcs done (thanks for the pointer to your puck density post.)  need to mill some BP, maybe this weekend.

Fun!  Thanks!

[Richtee]

8 hours ago, All10Fingers said:

Noice! (clickclickclick) You mention dwell time. It’s important. I “hand” press. Threaded rod/piston setup. You notice the give in the puck by hand after the dwell time.

 

[All10Fingers]

Hey cool. I thought my press was leaking