Is this the same stuff as sonotube?

Frank Carter

Screenwriter
Joined
Mar 12, 2002
Messages
1,187
I went to Sears and Home Depot to look for tools to start building my first couple of sonosubs(can't find that circle jig anywhere yet). During my search I was looking for 12" sonotube at HD(for a single 12" in my car). I checked where they had the concrete and found something called Kwikrete Tube Form(or something like that). I know there's different name brands of the stuff, but I imagined it being a little thicker, it didn't even look 1/4" thick(probably 3/16" but I had nothing to measure it with). It also didn't seem as stiff as I would have imagined. Is this the right stuff?

Thanx in advance,

Frank
 

Ron D Core

Stunt Coordinator
Joined
Mar 31, 2002
Messages
158
Yeah its the same stuff, but you can't get anything larger at HomeDepot. And it doesn't need to be stiff to work right. Since the pressure evenly distributed on the walls of the tube cannot create any bending moment no reinforcement is needing. Think about it, they fill them with literally tons of wet concrete. There is no way your sub will come close to those pressures. The only thing you'll have to worry about are the endcaps. And if you want to go even easier, fold the tube up into a T-line and just build a baffle at one end. Might be a pain for a car though.
 

Brandon B

Second Unit
Joined
Mar 23, 2001
Messages
263
The reason tubes are good for this is a circle is the shape that encloses the greatest amount of area for the least linear perimeter.

Therefore, if it distorts from a circle, the area has decreased which would increase the pressure, which can only be done by a force external to the circle. Or the circle can stretch to a larger circle. Since the laminated cardboard of sonotube doesn't stretch, no deforming.

Same reason surface tension makes water form a ball in 0-g.

BB
 

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