Well the set is an abandoned warehouse complex and I really don't have the skills to recreate even a portion of the location in a "diorama".

8" pvc is ridiculously expensive.

$280 for an 8" cap.

I want something slightly smaller than this:

Well the shot I want is essentially this.... Bad guy runs into frame with RPG. He aims, fires, and the camera does a jerky pan right to see a large explosion roughly 200 yards away. So basically the explosion needs to be large enough to look like an RPG explosion....and since the camera is 200 yards...

Well since someone was cool enough to post that info on the Big Blaster XHV cannons....I emailed for a price quote and heard nothing back. Does anyone know how much they cost? Holding the burst disk to the barrel is the only real problem i see. The rest is feasible. I might be able to get some 8" pv...

Two questions: What material (hollow cap?) do i put around the opening to the barrel to hold the burst disk in place? And would the presence of dirt and debris on top of the burst disk material compensate for some extra "resistance" or would that make no difference? Essentially, If I use foil and pu...

Should work provided it doesn't send shards out on release. That would be bad.

Oh.... Well a $55 drum is too much for something I can only use once. Thanks for the input though! This is awesome. I went to Lowes and priced all the parts (larger PVC is no longer being sold after inventory is gone). It will be well over $300 to build it out of PVC. I'm willing to do that if it wo...

Ok.....so I'm not understanding the idea there.

The 55 gallon drum comes with a cap and a 2" threaded opening on the bottom? And I just pump it up until it blows? Is it reusable?

Yup that's it.

How's it work though? That's the question.

What about a large reservoir going into a 2" sprinkler valve, which is attached to a large barrel. On the end of the barrel is a burst disk. So I can pressurize the reservoir and (remotely) release the valve forcing the air into the barrel and thus making the explosion through the bust material. Has...

If I have two or three 6" reservoirs hooked into a 6" coupling which in turn attaches to a 2 INCH valve, which goes to an 8 INCH barrel...... ....how would that effect the blast? Less diameter = less boom right? The air coming from three 6" reservoirs though a 2" valve would be slowed considerably r...

I can't tell how they launched that up in the air....

Lord have mercy that's it!.....less creamer though.

I tell you, I know that Spielberg used massive air units to get the mortar explosions on SPR's beach landing scene. I don't know how he did it.

I envision the thing being less than 4' wide. A reservoir, valve, elbow and cone. That's it. I just need a valve system that can push 100psi out of a 8" tube real fast....

Sure I know vermiculite. Doesn't that have asbestos in it?

It has to go underground with a remote trigger.