Maintenance question

[OO1]

ApplePly white Birch plywood  4x8 sheets .....up to  1-1/2 inch   

 

 

 

[Marvel]

Andy posted about the marine ply five yrs ago...

 

 

HDBRbuilder

Posted June 2, 2018

It all depends on WHEN the speakers were made.  Early on, Heresys, Cornwall, LaScala, and Klipschorn speakers  were made out of marine-grade fir plywood, if they were "decorators".  But the finely-veneered speakers used poplar lumber core plywood, the same stuff used in most large panel furniture of the time.

 

Then they went to 7-ply (5 core plys with two veneer plys) custom-made "void-free" birch plywood for the decorator series into the birch raw series of speaker styles.

 

In the latter part of the 1970's Klipsch got a real "deal" on some Baltic birch plywood bundles...in various sizes and thicknesses.  They immediately looked for ways to utilize this stuff, and the first thing to get Baltic biirch used in it was the Klipschorn bass bin, where the 1/2" fir marine-grade plywood was replaced with the 9-ply Baltic birch in approximately 1/2" thicknesses.  Most of the formerly used 1/2" fir marine grade plywood panels used in the construction of the K-horn bass bin were replaced by this Baltic birch, which stiffened up the bass bin cabinet immensely, in addition to making the job of keeping things "square" in its assembly process a much easier endeavor.

 

Baltic birch plywood's biggest problem from a production point of view is its density and the multiple layers of urea-formaldehyde glue used in it.  This causes it to require redesign of some assembly details in order to utilize it.  For example(s), staples and finish nail guns are pretty much not gonna be able to penetrate and have to be replaced with other types of fasteners, AND the wear and tear on cutting edges, such as router bits, and saw blades is drastically increased, when using Baltic birch....sometimes to the point of creating more dangerous working conditions, as when the brazed-in edge of an industrial router bit explodes out of the bit in pieces ...or if one of the brazed-in saw teeth comes flying out while using a table saw.  So if the construction process goes from using staples and/or finishing nails from pneumatic guns, to having to pre-drill holes in order to use wood screws, then you have increased the production costs in both materiel AND labor hours involved.

[Marvel]

IIRC, one of our members paid extra to  get his Underground Jubilees built with marine plywood, as he used tem in an outdoor area at a restaurant in the summer. Not that he let them get soaked or anything but the humidity changes were not as problematic.