Replies

1. 
   ETG | Apr 29, 2003 08:37pm | #1

   Suprisingly, polyurethane glues (like Gorilla Glue) are not as strong as regular woodworking glues.  Epoxy does have the strength level if mixed correctly but it is expensive.  I just fiinshed some work using modern hide glue heated in a pot - I was astounded with its strength level - as I find out through some web sites, it really is far superior strength-wise even to woodworking glues.  Mixing it is far easier than epoxys and it is lower in price.  It is not waterproof but does work well for assembly becasue it "tacks" very quickly and you don't get the "creep" you normally get with other glues.

1. 
   ownersrep | Jun 02, 2003 06:59pm | #12

   Without hijacking the thread - how do you mix the hide glue?  I bought some from Garrett Wade and it just came in a plastic bag with no directions.  I know that you just mix with water in a double boiler and to not mix more then you intend to use.  But how much water per ounce of glue or what kind of consistancy am I looking for when it's mixed?

   Thanks

   Jim

1. 
   ETG | Jun 02, 2003 07:13pm | #13

   I did a lot of research before I did the deed - one web site I used - http://deller.com/newpage8.htm states mix 1 cup water with 1 cup hide glue - in other words, equal amounts.  The water to glue ratio does influence how long the glue stays viscious - I did add a little water  towards the end as the glue got to be an oatmeal consitency.   Practice before you do it on a good piece - it really isn't as hard as it sounds and I am very impressed with the infamous "death grip" once it hardens.  And remeber, all that very old antique furniture in places like Winterthur, Williamsburg, etc. were assembled with hide glue and many are still in fine shape!

1. 
   ownersrep | Jun 02, 2003 07:19pm | #14

   Thank You!

   Jim

2. 
   Kell | Apr 29, 2003 08:39pm | #2

   Ken,

   What kind of pressure?  If it's an acoustic suspension loudspeaker with a completely sealed cabinet, the drivers themselves move in and out creating pressure and then a slight vacuum thousands of time per second.  I can't imagine that the joinery would be able to sustain the abuse less than the drivers themselves which are made of far weaker materials.  If it's the vibration of which you speak, the mass of the cabinets usually offsets that.

   The joinery I've seen has largely been simple miter and/or butt joints.  With a good tight joint and enough glue, there shouldn't be any failure.

   Kell

1. 
   kenewald | Apr 29, 2003 09:03pm | #4

   Sorry, my musician friend gave me the impression that the "extreme pressure" was coming from the driver and not the roadies.  Perhaps the latter is true. 

   A butt joint with some decent glue should work well.

   How about fasteners?

1. 
   CheekyMonkey | Apr 29, 2003 10:02pm | #5

   Fasteners for the enclosure are not neccessary. If you're talking about fasteners to mount the drivers in the enclosure or for making removable grills, check out http://www.partsexpress.com or http://www.madisound.com

   They both have pretty much anything you might need.

2. 
   Kell | Apr 29, 2003 10:32pm | #6

   Again, if the joints are tight and properly glued, fasteners are superfluous.  The glue joint is stronger that the wood itself.  If you want to throw some brads in there to better hold things during a glue up, that wouldn't be a bad idea.

   If you ever see road gear for a band, it's designed to take a shell hit but not from the music.  It's the beating they take from moving every nite.  A friend of mine had some folded-horn drivers form AC/DC's Back in Black tour.  18" drivers and the cabinets weighed well over 150 pounds a piece.  They could produce some serious bass!

   If these are for home use, there's no need to over-build them.  If they're road gear, screwing and gluing the joints probably makes sense.  That web site mentioned in the other note is probably a good place to look for more hints.

   Good luck,

   Kell

3. 
   CheekyMonkey | Apr 29, 2003 08:45pm | #3

   What gives you this (incorrect) impression? Butt joints and yellow glue will suffice for all but "pro" applications. Anyone seriously interested in speakerbuilding should check out http://www.diyspeakers.net and join the mailing list.

   PS - by pro applications, I am referring to loudspeakers accompanying a touring band, thus subject to the abuse of the roadies.

   
   

   ---

   Edited 4/29/2003 1:48:21 PM ET by markstu

1. 
   ampermc | Jun 02, 2003 06:37pm | #11

   Actually, having been a gigging musician and sound engineer for about 20 years, I can tell you that even most "pro" level gear has butt joints, usually reinforced with battens, and is screwed and glued.

   My advice would be, if these are for live sound reinforcement, do not use MDF! Although it is sonically superior to ply, it weighs a ton. Use a good void-free ply (birch, ApplePly) in 23/32", and if you don't like butt joints, use a lock-miter (assuming you have a router table or shaper). Batten all the joints with 3/4" or 1" square solid stock, and glue and screw to both sides of the joint. That should be plenty strong enough to survive gigging/touring.

   Always remember to build enclosures so that the drivers can be easily replaced (removable baffle, removable rear panel), use non-paper cones if you can get them (for weather/beer resistance), and use a heavy-duty steel grille (for foot/hand resistance). Casters and comfortable handles are always nice!

4. 
   mwestenberg | Apr 30, 2003 04:03am | #7

   Like others above have said, glued and or screwed.  If you're really leery, use  something like PL 400 subfloor adhesive as its somewhat more flexible than something like titebond.

5. 
   Elcoholic | Apr 30, 2003 11:38pm | #8

   I few years ago I had my B&O M70's (circa 1976) re-built after "Top Gun" made the amp clip and destroy the tweeters.  Had them Bi-wired and replaced the woofers because of bad rubber while they were at it.  The shop leak tested the cabinets and sealed them with plain old silicone sealant.  Leaks hurt the efficiency of an acoustic suspension speaker so I'd seal them with silicone. 

   BTW: These speakers are no longer in my main system but they're still going strong in the pool room.  My wife thought I was nuts when I bought them way back then for about a grand.  Actually I dropped $2300 on the speakers, Yamaha CR600 reciever and a B&O turntable and cartridge.  We paid $3200 2 years for a Honda Civic out the door.  The Yamaha is still going strong too although all the light bulbs have burned out.  After 27 years I think I did pretty well in the long run.

   Also I've heard that MDF is "deader" than plywood and therefore makes a better enclosure.  I built the enclosures for the single 10" woofer and the pair of 4" MB Quartz 2 -Ways in my El Camino which has a 240w amp driving it.  No box-buzz at all.  Never skrimp on speakers, spend 'til it hurts and then spend a little bit more.  You'll never regret it in the long run.

   John O'Connell - JKO Handcrafted Woodworking

   Life is tough.  It's tougher if you're stupid - John Wayne

1. 
   WorkshopJon | May 02, 2003 03:49pm | #9

   Ken,

   Since you seem serious about building speakers I am going to suggest you check out MCM Electronics (if you haven't already) They have EVERYTHING for building stuff like that at fair prices.

   http://www.mcmelectronics.com

   I've been doing business with them for well over 15 years and no complaints.

   Jon

2. 
   eddiefromAustralia | May 02, 2003 04:07pm | #10

   HI John,

   As far as I'm aware, the really high end speaker boxes are built from a composite MDF/chipboard board.  As the two have different hardnesses, they resonate at different frequencies.  WHen they're joined completely (as in glued together), the two resonant frequencies cancel each other out so neither vibrates significantly, effectively 'deadening' the board acoustically.

   Cheers,

   eddie