From: kmr4@po.CWRU.Edu (Keith M. Ryan)
Subject: Re: Particle Board and Plywood
Reply-To: kmr4@po.CWRU.Edu (Keith M. Ryan)
Organization: Case Western Reserve University, Cleveland, OH (USA)
Date: Sun, 30 Aug 92 18:38:01 GMT


In a previous article, cjm9321@hertz.njit.edu (The InfoMan) says:

>
>	I know to use Particle board (Thanks net). I went to a hardware
>store the other day and they only carry 5/8" and 3/4". That's a little
>to thick for me. Does it come any smaller like 3/8"? I will look again
>Monday.

Yes, most places do carry thinner stuff.
However, you really do not want to use anything thinner than 5/8" or 3/4"
if at all possible. Particle board is inherently better at damping out
resonants. I believe that is because of its construction, the fibers are
all which way. However, the thinner stuff is not as rigid or strong. I have
seen someone who had used 1/4" particle wood, when he cranked the bass,
literally blew out a side of the box! Also, screws may pull out, etc. 
I use 1", minimum usually. Or, for that very special box, I use 3/4" with
a lamanent of 1/4" to 3/8" of a hard wood. That way, they stain really
pretty. In a world of black painted and carpeted enclosures, a nice 
walnut stain stands out better than any dayglow! My best box that I ever
built was a sloped trapazoidal with interal braces. It has twin 1" PB's
for the bottom, 1 1/2" PB sloped sides, front and back and top, with
1/4" walnut coverings. The PB provided all the strength, with the walnut
glued on, cut to precision. Then it was all stained. Massive, heavy, yes.
But as damped and solid of a box as you can get. It took 3 people to get
it in and out. You knew that no theif could quickly steal it. And, oh so
beautiful. Unfortunatly, it was destroyed ( as well as the car ) when a 
drunk driver hit me. :-(
 



>
>	When I put the speakers (12") in the particle board should I put
>a sealent around it? What kind? Or would the screws be alright?

Yes! When using any woofer, an airtight seal is important. ( except if you
have a port! don't want everyone running out and plugging their ports! )
for the internal of the box, you can use a variety of things, from glue
to caucking. But, for the woofer, you want something that will not permi-
nantly bond the woofer, should you want to remove it. You can use a soft
rubber gasket if you have one. [ many woofers come with their own, or your
store may carry them. ] You can also use rope chaulking. But, only use
sealants such as aquarium sealant and the like only if you are *sure* you
will never remove the woofer.

Usually, if you screw in screws using a smaller pilot hole [ never use
nails, and a small pilot hole helps to prevent cracking the wood ], you
will not have an airlead. But, they way come loose. So, i suggest using
some kind of woodglue, liquid nail etc. It also, before it dries, helps
to lubricate the nails, so it goes in easier, and preventing cracking.

>	One more question....
>
>	If I was to build a box, would it be alright to have the woofer
>side particle board and the other sides Plywood?

you *really* do not want to use plywood. I have never heard one that
sounded right. Also, I have heard [ but never seen ] that the glue that
keeps the layers together comes apart under heavy vibrations/temperature/
humidity. 

remember, a hour of short cuts rarely pays off. you have to listen to the
box for a while. and if you do the extra steps, you may decide to use the
box for years.

ps: i am running out of time, so i am unable to proof-read my post. i apolo-
gize for any typos, bad grammer, etc.
-- 
and the latest economic news is in...
  It seems that Bush's economic plan has lead to a dramatic increase in the 
growth of small businesses..
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