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Old 9th August 2011, 02:09 PM   #1981
gedlee is offline gedlee  United States
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I am sure that they carry Renshape 5045, but the 3/4" thickness has always been a custom order for me, so I am not surprised that you can't find it. I am sure that a spec for Renshape 5043 is available on the web. It is a very common material, just not in lessor thicknesses.
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Old 11th August 2011, 01:58 AM   #1982
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Haven't found anything on RenShape 5043 googling around. Is RenShape 5045 close enough spec wise to substitute?
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Old 11th August 2011, 02:07 AM   #1983
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Quote:
Originally Posted by jason_watkins View Post
I'm considering rebuilding my Nathan kit using polyurethane baffles (as well as another project).

What density of board should I use?
If you want to make it stiffer, why not just add some carbon fiber on the outside and the inside? If I'm not mistaken, my Summas are a carbon-fiber / MDF / carbon-fiber sandwich.

The downside of this construction is that it's very labor intensive. The upside is that it's about as solid as a hunk of granite. Even at high volumes, my Summas don't vibrate a bit.

Might be an option for you, particularly if your baffle is already MDF. Just add carbon fiber and you're good to go.
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Old 11th August 2011, 02:35 AM   #1984
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Patrick:

I don't have a specific performance objective with the material vs mdf such as stiffness. It's looking likely I'll have some waveguides cast in polyurethane, and I'd much rather finish out the enclosures using poly boards bonded, rather than some mixture. Also composite materials seem to be growing in popularity with high end makes, so I'd like to just learn a bit about how to work with them.

I've never seen Summas, but I recall someone saying they were a solid surface composite similar to corian. Fiber and resin covered MDF does sound labor intensive, but stupidly strong.
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Old 11th August 2011, 03:19 AM   #1985
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Jason,
I believe the Summas and now many of the other Gedlee speakers have a fibreglass skin with urethane foam. Fibreglass for the finish and tough surface, urethane for the combination of strength and damping.
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Old 11th August 2011, 04:02 AM   #1986
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Jason

My appologies, its 5045 - just learned that (I had the number wrong) today when I picked up another batch!!!

John's Summas were a unique set of carbon fiber skins, with a "corian" type of back fill on the baffle and MDF on the sides and back. I do not use fiberglass at all anymore because it's basically an obsolete process given the advanced polymers available these days. Yes it's "stupidly strong", but absurdly heavy.

My enclosures are now all polyurethane. Its light, but strong and very well damped. By all accounts its the future.
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Old 11th August 2011, 06:17 AM   #1987
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Earl,
So in other words, you use polyurethane sheets instead of casting now?
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Old 11th August 2011, 06:24 PM   #1988
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Awesome, thanks.
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Old 11th August 2011, 07:51 PM   #1989
gedlee is offline gedlee  United States
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Paul

I answered this once - don't know where it went.

My enclosures are now constructed as basic frames in polyurethane boards and then the waveguide is cast from a polyurethane composite into this frame. The frame is then routed to finish. The whole construction (aside of one small board inside) is polyurethane with no nails or screws at all
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Old 16th August 2011, 03:04 PM   #1990
AllenB is offline AllenB  Australia
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Earl,

All this talk of plastic has me wondering (and has since you began mentioning it). I'm just a bit of a skeptic. Of course I wouldn't expect you to make a common mass market kind of decision with something as important as this.

I had the misfortune once of listening to a plastic speaker in a pub. A tripod mounted, 12", generic horn kind of speaker emblazoned with a plaque bragging of its ABS construction.

I had only once or twice before heard the sound of plastic more than any speaker I'd paid more than $5 for. (There was this early sixties powered tabletop phono with detachable 3 litre fully plastic enclosures with 5" full rangers, for example).

My current bike has a fibreglass fairing which is larger and heavier than others I have owned, and it is more sturdy, not needing much attention. I was once thinking of learning the art of plastic welding for the trouble dealing with the others.

But then we are talking about polypropylene (I think) here. I hope you can see why I'm skeptical. But I do like the idea of using P/U boards. Is it something that can be done in a DIY kind of way?


@paulspencer,

Paul, you were writing an article called "Bass Integration Guide". I bookmarked it a couple of months ago and I was just going through my old bookmarks. Are there any plans for a follow up?
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