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I am building a wooden audio horn. It has 4 sides but each of the sides is curved. Each side is about 45x32. I am looking to make each of the 4 sides about 2 inches thick. I will be veneering the top and bottom of each side so I don't care what the inside is made from. I'm thinking of cutting the pieces out of 1/4" 4x8 sheets of ???? and then gluing them to a curved template. I don't care if the laminated sheets are wood, plywood, plastic, whatever. I just need cheap and local. What could I use?
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Your on the right track but I would use Bending Ply, it is made for this application. Just have to specify which direction it bends in when you buy it.
An no, you don't find it at the Big Box stores.
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Kudzu Craft Lightweight kayaks
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(07-05-2021, 05:48 PM)Kudzu Wrote: Your on the right track but I would use Bending Ply, it is made for this application. Just have to specify which direction it bends in when you buy it.
An no, you don't find it at the Big Box stores.
Yes, bending plywood is what you want. You should be able to order it at any full service lumber yard. You are best off using glue that cures to a rigid bond, such as epoxy or plastic resin glue. Titebond Original will work OK, too, but stay away from TB II or III as they are too elastic. Oh yeah, Gorilla Glue would work well, too.
John
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I'd look at 1/4" OSB. It seems bendy enough any time I've used it
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Bending ply 2" thick? Not easy or cheap.
This is a perfect application for a traditional "Brick mold".
Use poplar cut into short sticks in a staggered glue up to create the basic curve then cut/grind/sand it smooth and to the final dimensions. Veneer over this.
3/4" poplar stock is inexpensive, poplar has been the substrate wood choice for hundreds of years and the brick mold uses smalller parts laminated together to resist movement, warping or cracking over time.
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Do you care about the sound quality? If so, choose bending ply or make your own by kerfing the wood before you bend it. A series of narrowly spaced kerfs will allow the substrate to bend. A dense core to your horn will help in keeping the sound inside the horn vs. having the whole horn vibrate. I'm assuming the horn is simply to direct the sound in a certain direction. Most audiophile sites use baltic birch as the core.
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Allan Hill
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I'm not sure about the quality of bendy-ply you can get in your area. But in mine, the inner and outer surfaces are ROUGH!
Talk about telegraphing through the veneer!
Does a wooden audio horn need to inert without providing its own sympathetic frequencies?
If so, I'd recommend MDF - inert and dense. Evil for dust, no question but you'll probably contribute minimal unwanted additional frequencies.
