Poured Concrete Hybrid Chambers
Posted: Tue Apr 01, 2008 6:45 pm
Today I was casting concrete around the breach of my SCTBDC after the incident on Saturday, and suddenly had this thought:
What's to stop someone from casting reinforced concrete around a relatively weak ABS pipe to make it into an exceptionally strong hybrid chamber?
Here's the method: Get a suitably sized pipe, put on whatever fittings you want for fueling, ignition, etc... Put that inside a large stovepipe (6", 8", whatever is needed). Suspend the chamber pipe a few inches up, and cut holes in the side of the stovepipe to run through whatever pipes are attaching your ignition and fueling to the outside world, then epoxy the space around the holes. Built a rebar/steel mesh cage, then pour in the concrete, creating a pipe with walls about 2" thick that won't break unless you set off high explosives inside it.
Advantages:
Low cost, high availability - anyone can get concrete, anyone can get drainpipe and stovepipe, and anyone can get rebar.
High strength - you could also reinforce standard SCH 40 steel for much higher mix capability, and you could make a weak DWV pipe into a 10x hybrid chamber. ABS pipe or similar should take the direct shock off the concrete as well, and a layer of something else could be added if needed to increase shock absorption.
Insulation - most of the power in any combustion gas gun is heat. The less heat that is lost, the higher the power. ABS and concrete are far better insulators of heat than steel or aluminum
Ease of construction - no sparkplugs required, as the chamber material is an electrical insulator, and the wires are simply epoxied into holes in the stovepipe, as the concrete provides the strength
Disadvantages:
Weight. That's all I can think of, really. Concrete weighs about 2.4g/cm<sup>3</sup>, roughly similar to aluminum. Since most hybrids of the size this would be practical for aren't handheld, it shouldn't be too much of a problem, as long as the chamber is wheeled.
What I'm hoping for here is response from the black powder gun crowd on how well this will work, how thick the concrete will need to be, and how to create the reinforcements to offer the most, well... reinforcement.
As with all my theory topics, I ask that if you have nothing useful to contribute on the actual question, you refrain from responding at all. If all you want to do is comment on how heavy it will be, keep it to yourself. I've already ran those numbers, and they really aren't impossible to work with.
What's to stop someone from casting reinforced concrete around a relatively weak ABS pipe to make it into an exceptionally strong hybrid chamber?
Here's the method: Get a suitably sized pipe, put on whatever fittings you want for fueling, ignition, etc... Put that inside a large stovepipe (6", 8", whatever is needed). Suspend the chamber pipe a few inches up, and cut holes in the side of the stovepipe to run through whatever pipes are attaching your ignition and fueling to the outside world, then epoxy the space around the holes. Built a rebar/steel mesh cage, then pour in the concrete, creating a pipe with walls about 2" thick that won't break unless you set off high explosives inside it.
Advantages:
Low cost, high availability - anyone can get concrete, anyone can get drainpipe and stovepipe, and anyone can get rebar.
High strength - you could also reinforce standard SCH 40 steel for much higher mix capability, and you could make a weak DWV pipe into a 10x hybrid chamber. ABS pipe or similar should take the direct shock off the concrete as well, and a layer of something else could be added if needed to increase shock absorption.
Insulation - most of the power in any combustion gas gun is heat. The less heat that is lost, the higher the power. ABS and concrete are far better insulators of heat than steel or aluminum
Ease of construction - no sparkplugs required, as the chamber material is an electrical insulator, and the wires are simply epoxied into holes in the stovepipe, as the concrete provides the strength
Disadvantages:
Weight. That's all I can think of, really. Concrete weighs about 2.4g/cm<sup>3</sup>, roughly similar to aluminum. Since most hybrids of the size this would be practical for aren't handheld, it shouldn't be too much of a problem, as long as the chamber is wheeled.
What I'm hoping for here is response from the black powder gun crowd on how well this will work, how thick the concrete will need to be, and how to create the reinforcements to offer the most, well... reinforcement.
As with all my theory topics, I ask that if you have nothing useful to contribute on the actual question, you refrain from responding at all. If all you want to do is comment on how heavy it will be, keep it to yourself. I've already ran those numbers, and they really aren't impossible to work with.
