# Sonotube diameter question

Discussion in 'Archived Threads 2001-2004' started by TimForman, Mar 5, 2003.

1. ### TimForman Supporting Actor

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I'm planning to buy some Sonotube for a sub. Since I've never purchased this stuff before I would like to know if the diameter measurement is an interior or exterior measurement.

2. ### TonyiBe Stunt Coordinator

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Well it depends on you, i just bought 18" diameter by 12 feet long. They don't sell it any shorter than 12 feet around here in Fla..

3. ### Patrick Sun Studio Mogul

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It's a bit variable. The best way is to measure the outer circumference (use a piece of string and then measure the string). Once you have the circumference, you divide by 2*pi (around 6.2832) to get the radius to the outside of the sonotube. Multiply by 2 to get the diameter.

If you need the inner radius, subtract the measured thickness of the tube from the original outer radius value.
Multiply that by 2 to get the inner diameter value.

4. ### TimForman Supporting Actor

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I think you misunderstand. I'm speaking of the manufacturers specifications and what they mean when they say, for example, 14 inch tube. Is that 14" the interior diameter or the exterior diameter.

5. ### Brian-K-Owens Stunt Coordinator

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The tube I bought was advertised as 24" and measured 24" inside the tube (I.D.)

Brian

6. ### Patrick Sun Studio Mogul

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But it's variable to a slight degree. It's best to measure the actual piece you have purchased. Mine had an inner diameter of 23.75".

7. ### TimForman Supporting Actor

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That's what I needed to know. Thank you.

8. ### Arthur_King Stunt Coordinator

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Remember that this stuff is originally designed to pour in concrete. The vendor is going to tell you the diameter of the CONCRETE when its done, which, logically would be the inside diameter (since when the concrete is hard, you basically remove the sonotube). As for "variable", since this is construction, not sculpture, they are going to be a bit "variable" though more than 1/4" off would seem to be excessive since all they are doing is wrapping reinforced paper around a mold...

Daffy Arthur King

9. ### TimForman Supporting Actor

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The variance may be different for each manufacturer. I would think that all Sonotube brand tubes are pretty close to the same whereas other manufacturers have a different tolerance. It also may be similar to lumber. We all know that a 2x4 isn't really 2x4. I guess I'll know for sure tommorrow. I picking up some "14 inch" tube to build a 6 foot sonic cannon that will lay horizontally in the back of my room. Should be interesting. I'll let you know how it goes.

10. ### TimForman Supporting Actor

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FWIW-The 14 inch Sonotube had an ID of 13 7/8 ". I cut my caps at 14" and tapered the edge until in fit snug.