What is in this thing?

[KuzkinaMat]

http://img28.imageshack.us/img28/8064/censoredgrenade.jpg

 

I'm being asked by a friend to help with special effects for a relatively low-budget independent film, and they need simulated grenades. Obviously I'm not buying from the "retailer" above, but I'm interested in that practice sound grenade. The noise is between 132-134 decibels, which is much less taxing on the actors than the 140+ decibels of most flash-based crackers, and the cameras can't capture the effect of impulse noise (sub-200 ms noise which bypasses the ear's defense mechanisms) anyway, so the audience wouldn't notice the difference.

 

So, what is in the fuze here? And are such devices legal in the United States or do they qualify as a destructive device?

[Oinikis]

the fuze is the trigger mechanizm. the ring holds the lever, whitch holds the hammer, with compressed spring. you take the ring out, and you hold the lever. when you throw and release the lever, spring and hammer gets realesead and hits shock sensitive material, whitch gets on fire, and ignites the fuse. the fuse burns for about 4-5 secs (depending on the grande) and it ignites the detonator (small charge of primary explosive) whitch detonates the main charge. for training grenades, the grenade is made without explosives, with weight instead, and with a hole in the bottom. the fuze is made with a powerfull firecracker instead of detonator. the grenade weights as much as real one, makes bang and can be reused by changing the fuze. The fuze and grenade are held seperatly, and fuze is put in the grenade before tossing it.http://preview.turbosquid.com/Preview/Content_2010_12_08__16_38_36/f1_5.jpge500c386-42f5-4aaf-9e82-8e061d2eefd8Larger.jpg

You can make a creamora shell, with pull-ring mechanizm, made by using matches. it would produce explosive-looking fireball, and the sound could be added later when edditing

http://www.skylighter.com/images/newsletter/101/big-cremora-01.jpg

Edited January 17, 2013 by Oinikis