Casting papier-mache as speaker enclosures

[Moondog55]

Yes I have searched
But unable to find answers to this question, ANYWHERE!!

I am asking this question as a result of my last patching job.
Background
I had a biggish hole that needed filling and being a tight*** wanted to use what I had on my shelf.
We shred a lot of paper here for privacy reasons so I had lots of shredded paper, I always have lots of PVA adhesive and I found an old bag of Plaster of Paris.
I mixed the shreddd paper with PVA until it wa sticky and properly wet and added enough dry plaster to make a thick paste.
OK I filled the hole and waited for it to dry ( 48 hours + ) and I'm now trying to sand it flush.
I have to say the mix is tough, very tough and doesn't sand as smooth as plain plaster, this is due I am sure to the plasticising effect of the PVA.
Now for the question Any thoughts on the suitability of this mix for speaker enclosures??
How would I mould it if I go ahead, it needs to be repeatable.
no point in making a "one-off" mould
More questions follow if any-one is interested enough to comment

Thanks
Ted

[jamikl]

There is some information somewhere on the net about paper mache horns. I think they were built up over a wire mold on a lazy susan type turntable. I cannot remember the source. I am at work now but I think I have a copy of the article at home. Will let you know later this evening.
jamikl

[c2cthomas]

Pdan used paper mache and other materials on her thread. If you contact her she might have some insights for you.

Cyclops Loudspeaker Photo's

[Moondog55]

Thanx,
I just contacted Cilla and re-opened that particular thread,
Perhaps for a change I'll take Andy G's advice and build something that isn't a square box

[jamikl]

Moondog I do have a copy of the other paper mache horn as a word file. It does not look like I can attach it to an email sent through here. If you are interested could you email your remail address to me through here.
jamikl

[Moondog55]

Hi Jamikl
YGM

[Moondog55]

You know one of the things speaker builders have is lots of rounds ( drivers like round holes ya-know ) so finding ways to fit drivers will be easy.
I see the problem being with having a smooth finish on the outside and consistent wall thickness

[Moondog55]

Interesting subject, some of the techniques for laying up could be applied to casting, especially the point about release agents

[cuibono]

I used to make paper mache and plaster sculptures, and the thought had crossed my mind to use it for speaker cabinets. I haven't yet, there are a few thoughts that deter me.

First, the structure will take several tries to make it both strong, light and acoustically dead enough. Neither medium (mache or plaster) are particularly robust, and break or deform easily. Similarly, giving them a nice finish would be hard. They tend to end up lumpy, and it would take a good eye/hand and a lot of work to make them not look like a high-school art project. Here in the States, I used to use something called Scupley, and my wife used Chavant brand modeling clay. Envirotex, an epoxy resin (I think), is what I might try to harden and finish the surface (its the sort of stuff used to finish surf boards).

The other problem is the flat mounting needed for a driver. I haven't been impressed with diy attempts at mounting flat drivers onto curved surfaces. You invariably end up with sharp corners close to the drivers or larger distances between drivers..

That brings us to the final problem - what are the advantages? More rounded corners? Looking different? Using a sculptable medium will add tons of work, especially prototyping, for not much gain, as far as I can see.

But don't let me discourage you. I actually think its a great idea, and going beyond a wood box has a lot of potential. Its just going to take a lot more work. I'm currently building only open baffle speakers, so I'm just fine with a sheet of wood.

[Pano]

I did a pair of paper horns about a year ago. Used very heavy Arches watercolor paper. It was hard to work with, being so heavy and stiff - but the results were pretty darn good. Weat paste was the only binder.

Very stiff, very neutral, no real sound of their own. Cheap, too.
But labor intensive - OMG!