need input on new thundermug

[06xlt]

ok so i currently have a "mortar" that stands 6" tall and has a 2" bore- i shoot with 2 oz. of pyrodex packed with about 10 newspaper sheets-- it is quite loud, but i want to know if i order a 12" piece of 1018 that is 2.5 inches round and bore it out 1-1/4" about 10 inches deep, will it be any louder than what i currently have?-- these are for salutes only, i would like to make the same amount of noise without so much powder.  any help greatly appreciated!

[dan610324]

on a 1 1/4" bore you should have a minimum outer diameter of 3 3/4"

[06xlt]

ok so say it is 4" od, will it be any louder?

[gulfcoastblackpowder]

Without modifying the charge, it probably won't be louder.  In fact, it could be quieter.  You may not need to increase power too much, but you'd need to have at least close to the same amount of compression in order to achieve the same amount of report.  Having a larger barrel should give you the ability to have a louder report, by allowing a bit more stout of a charge (The more compression doesn't necessarily mean more powder - it's better to increase your wadding a little than to add too much powder).  Also the size of the bore should allow a deeper tone.

[Double D]

First, Pyrodex is a poor blank powder. Get some black powder.

Newspaper wad is a poor wad, its a fire hazard, projectile hazard and messy.

It sounds like you have a straight bore no chamber, so start by making a cartridges and see if that helps. Work up from 2 ozs. to 4 ozs using Fg or cannon grade..  Safety guidelines say 2 ozs. per inch of bore is the max load for a projectile firing cannon.   You can go heavier for blanks.  Experiment.  You will need to worm as well as swab if you use a cartridge.  

[wolff]

If you haven't already read the excellent replies to my "barrel tuning" post - I hope you'll take a look at it; good dope there.

That said, in the post I mentioned tuning a Big Bang Cannon for even louder sound.  I'd planned on doing some tests before posting, but I'll share a recent idea I had for testing loudness; my Radio Shack SPL meter only goes to 120db, so I gotta fix that! 
     I have a decent selection of large-ish diameter tubes with thin or thick walls, long and short `uns.  I'm thinking of simply sliding a particular diameter tube over the intactcannon, at a set length, then fire it per the instructions - it's safe since I'm NOT substituting barrels -- just seeing if an 8" dia. tube x 2' long for example would enhance report.   If I don't get satisfaction, I'll consider setting up the same type of test, only without the factory barrel, and rig a lanyard firing mechanism for safe distance testing. (I live in Palm Springs - we have lots of open, desert space!).
     Don't see why  a person couldn't rig up a test bed  using a mortar's powder chamber - built to safe spec., with lanyard firing - but without a lot of barrel length.  Then safely affix different tube diameters/lengths and let the testing commence!
(I absolutely believe that safe, correct wads will be found to account for 25-40% of the "loud" that a tube can achieve)
     Thumbs up to whoever said "NO" to Pyrodex.... BP! BP!  And I also think the right granulation will account for a decent percent of "whump" from a tube too!  (I didn't see a stickie on making BP...have to see about that)


my .02

wolff

[06xlt]

well thanks for all of the input, but what would you guys suggest for wads instead of newspaper, i never thought of it as a hazard, seeing how my MOWED lawn is like 3 acres, and no one is around these when they go off, guess i'll have to find somewhere else on the 180 acres to set it off? all of the 2" shells i set off and other assorted fireworks are also cardboard/paper?? are you telling me i don't need wadding to get the same noise with BP?? any help appreciated!

[RocklockI]

well thanks for all of the input, but what would you guys suggest for wads instead of newspaper, i never thought of it as a hazard, seeing how my MOWED lawn is like 3 acres, and no one is around these when they go off, guess i'll have to find somewhere else on the 180 acres to set it off? all of the 2" shells i set off and other assorted fireworks are also cardboard/paper?? are you telling me i don't need wadding to get the same noise with BP?? any help appreciated!

I wouldn't say you dont need wadding . If you roll a cartridge in heavy foil that will help too .

Oyvids idea of a layer of flour equall to the amount of BP is a good one . Thats my .02 caents worth ,

as always 'I AM No Lawyer' and Good Luck ! Science can be fun , just make sure you know what popped and when .

2" inch shells ! Do tell .   

IM