[SML] Wiggle wood for a cannon?

[Jon Lagerquist]

Given the scale, big enough for a person to pass through, I do not think 
it would be to hard to make a skin of bendable ply, luan, or upson board 
work. You need to select a material that can bend the radius needed, an 
1/8" thickness is where I would start.

A well laid out frame with the locations of the skin seams considered is 
a key element. As Greg mentions the core is a major element, the person 
has to pass though it and if the audience can see into it the look sells 
the piece. And an inner skin will add stiffness before you put stress on 
it with the outer skin. This may be more challenging than the outer skin 
so you might need narrower strips. You most likely need cauls to pull 
the skin into the frame and hold it while glue sets.

Plan on having a bit of room in each sheet for adjustments and test fit 
to make sure your joints line up. While you can make a gore curve just 
by placing the edges in the correct place a framing piece in the middle 
can be a big help. I have gotten the best surface by doing two layers 
with the seams staggered, which is where more framing comes into play. 
Because there is more stress on the fasteners than in a flat application 
situation having a doubled frame so each side has 3/4" to attach to is 
likely to be helpful. a bunch of ratchet straps can be helpful in 
pulling the pieces into place. These can also be beveled to the 
appropriate angle, and one side can be a much narrower piece sistered to 
the primary framing piece.

Other options if seams are a concern is some moulding running the length 
of the barrel to mask seams or embrace the seams and put rivets along 
them to highlight them (I know that is not how one would really 
construct a cannon barrel but it is scenery).

Jon

On 2/24/2025 10:56 AM, Greg Bierly via Stagecraft wrote:
> I have had a few experiences with wiggle-wood.  I think trying to get a 
> conical shape will be just  frustrating.  You would be better off making 
> the cylindrical interior and creating the conical shape with a scenic 
> exterior layer. (i.e. foam, paper mache, etc).  You probably are better 
> off tapering 5/4 boards lengthwise and mitering all of the edges but 
> that sounds like a lot of math and glue up.
> 
> Greg
> 
>> On Feb 24, 2025, at 1:15 PM, Joe via Stagecraft 
>> <stagecraft at theatrical.net> wrote:
>>
>> So, it looks like I will need to construct it from scratch.  I have 
>> never made anything using wiggle-wood (i.e. bendable ply) that had a 
>> conical shape.  Though, perhaps I could cut wedge-shaped pieces and 
>> form it that way. However, I know that getting the edges of the ply to 
>> lay flat can 
> 
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-- 
Jon Lagerquist
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