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Concussion Mortars


Wiley

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I'm still looking for a safe, economical noismaking device for the 4th, and I've been thinking more heavily about "concussion mortars" rather than "thundermugs." Firefox sells this one: http://www.firefox-fx.com/specialfx.htm (at the top of the page). The price is right, they say it was made for professional use, and you can use up to 1oz of concussion powder in it. That means 70:30 flash right? How safe is this thing really? I do know that an ounce of 70:30 is going to cost a lot less per shot than 4oz of commercial BP, so that is definitely appealing. Would firing this with a Christmas-tree bulb igniter or fuse work the same as with a real ematch? However, my most important question is this: what are the legalities governing this sort of device compared to a BP powered thundermug?
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That means theatrical salute powder, which is sold in binary kits. I am not sure if theatrical salute powder is the same as our 70/30, but I'd make dang sure before trying it! This may take a little research - I spent a few minutes on google and didn't find anything. The last thing you want is to turn your flash pot into a bomb.

 

Also, the cost of 4 oz of BP should be about the same as 1 oz of flash. KNO3 is about $1/pound and perchlorate is about $4 per pound, in hobby quantities. Edit- just saw that you meant commercial BP. But you can always make your own (assuming you have enough space to do so safely).

Edited by flying fish
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Thanks flying fish, but no, I don't have the space to make BP. It's commercial only for me. And yeah, after thinking more about flash blowing up in a steel container, time after time, I decided against this scheme. I'll just go with good ol' (expensive) BP and just use more of it. Besides, a lower pitched report is always cooler! B)
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Most of the stage pyro flash powders I've seen are nitrate based, hence a LOT weaker than dark pyro flash.

 

Dark pyro flash will confine well in a card tube, BP will confine well if string bound like a cylinder shell but even more string (99% cover!).

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You can put a gram or so of flash in a bottle cap and put tape over the top, with a good piece of visco in it. That makes a decent little bang, quite cheap also.
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I can't help you for the legality because i don't know where you live, but I can tell you that these mortars are really reliable.

I use them a lot with nextfx concussion flashpower (70:30) and i even put sereval layer of ducktape over it to give a bigger bang in large stadium. These mortars have been shoot hundred of time and they never had fail drastically (can devellope small crack over year).

 

Before you buy anything, remember that the mortar I use have 1 inch steel wall and are approve for professionnal use.

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If I used it I would probably go with a slow Nitrate-bright Al based flash. Good 'ol 5:2:3 probably. I'd still go with the BP cannons, much cheaper (for me) and clearly safer.
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I found a post in another thread that seemed very informative on this topic. He says the next-fx flash is 70/30 made with *atomized* aluminum, and of course requires a very specialized concussion pot. This is much tamer than even 70/30 made with bright flake aluminum.

 

The formula for cannon simulators is most definitely NOT perchlorate/aluminum.. it is magnesium/strontium nitrate. KP/AL would blow the tube to bits. The whole idea of indoor pyro is to not throw shrapnel of any kind and hurt your audience or performers. Steel concussion mortar type binary kits are not any one formula and it depends on the manufacturer of the binary concussion used. MP associates is KP/MG, Pyropak (now Ultra) uses SrNitrate/MG/S and Next FX uses KP/Atomized AL. Each manufacturer specs what size and strength of steel concussion mortar to use with their binary product and they are very different. If you were to use Next FX powder in Pyropak steel.. you would end up with a multi-piece mortar. Yes it has been done, three different times that I know of, on show site indoors. Way lucky no one got killed!

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Thanks Mumbles and Flying Fish, but I think I'll steer clear of concussion mortars and stick to black powder cannons.
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AFIK in the UK concussion pots only come from one pyro supplier and only one of their range of devices is approved for conncussion pot use. If you use the maker's pair of pyro and pot then the job's good. If you start mix n matching with DIY then it's an uninsurable risk.

 

The UK available pots are about 3" OD with a 1" hole bored in it for the pyro to fit. The concussion pot is no weakling, I've no idea what sort of steel alloy it's made from.

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Good idea going with BP. Putting an ounce of flash in anything metal is making a bomb. You have to use concussion powder for use in a concussion mortar bought from an FX company which isn't cheap. I know one company used 50:50 strontium nitrate and magnesium. I still don't think I would trust it. And it would need to be binary and mixed right before use. It would also need to be in a completely sealed bottle and the strontium really pure and really dry, otherwise the water and magnesium wouldn't be good.
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I don't see why they need to put so damn much into the pots. As little as 5g-10g should make plenty of a boom, even you use a fast burning comp.

 

I think if they made the hole in the cannon to be tapered, expanding outward, it would put less stress on the cannon/mug itself.

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  • 1 year later...

Hello, i'm an dutch pyrotechnician and read this topic.

Is there one of you who uses concussion mortars, because there is à lot of BS thats written here.

 

We use à lot of concussion mortars and the biggest is à solid billet machined 6" OD 2" ID 15" long packed with 50 grams of kclo4/al/mg taped tight.

We use it only in open air to simulate bombs, cannons, crashes and so on.

We tested it for concerts but it's to powerfull and loud.

I don't know the amount of decibels anymore it produces but believe me it's nothing you've

Ever heard or felt before.!!!!

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What BS is written here?

 

Being careful and NOT using flash is BS? Advocating (esentially) the use of flash in a concussion mortar is not? Because that is basically what you are doing.

 

Who designed your mortar? How much has it been tested? What kind of load was it proofed with?

 

No one should EVER put any flash in a metal tube unless they are OK with a grenade going off at some point.

 

Edit: and are you saying 50 g fills it? You said packed?

Edited by FlaMtnBkr
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Where are you getting your concussion powder Musketier?
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As Ordenvlitz wrote back in February 2011:

 

"The formula for cannon simulators is most definitely NOT perchlorate/aluminum.. it is magnesium/strontium nitrate. KP/AL would blow the tube to bits. The whole idea of indoor pyro is to not throw shrapnel of any kind and hurt your audience or performers. Steel concussion mortar type binary kits are not any one formula and it depends on the manufacturer of the binary concussion used. MP associates is KP/MG, Pyropak (now Ultra) uses SrNitrate/MG/S and Next FX uses KP/Atomized AL. Each manufacturer specs what size and strength of steel concussion mortar to use with their binary product and they are very different. If you were to use Next FX powder in Pyropak steel.. you would end up with a multi-piece mortar. Yes it has been done, three different times that I know of, on show site indoors. Way lucky no one got killed!"

 

​I can only imagine the concussion pots use a similar mix, certainly not 70:30 dark Al.

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Yes it is. We use KP and atomized aluminum with cabosil.
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  • 1 year later...

THE flashpowder we use is 34/33/33 kp/al/mg binary made by a spanish company at our specs.

It is very powerfull and tested at a govermentcompany called TNO.

The concussionpots are also tested there.

Edited by Musketier
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lots going on here.... lets sort some stuff

Next FX "high power" binary is KP/spherical aluminum... less reactive then dark AL formulas, this is done to make on site mixing safer (this is strait from Russ)
. yes if you put it in a pyro pack mortar you can chunk it, proven again and again. The NFX cannon sims are nitrate based, bigger ones are 9 grams, 5 grams of dark 70/30 will dust the tube with no cap

musketier-The US standard is max 1oz binary loads in 3" od mortar with 1" walls. I am sure bigger will work as well your set up seams to be dubble the size and dubbel the powder. this is all well and good till a failure happens, not a big deal if it used here and there, bit different if your on tour shooting 3-4 times a week for months on end. Just because something worked for you doesn't mean the rest of us are full of crap. Rember our leagle system is quite different here and loading dark 70/30 in to a prox mortar would open up a lot of liability if something went wrong...that is why we pay $6-8 an ounce for a binary kit instead of mixing our own for much cheaper.

 

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