MDF versus Baltic Birch?

MDF???? It is a NO NO in my book.
YMMV.
It sucks....... No really. It sucks the life out.

I see that I missed this recent thread, although quite diversified on MDF / Plywood construction. Not to belabor this topic, due to construction costs and availability I was thinking about using Baltic Birch on the acoustic side of the enclosure and laminating with readily available MDF for rigidity. Pros / Cons? And while we're at it, any feelings on adhesive conposition? Thanks

Baltic birch is a better choice for rigidty than mdf.

How about both MDF and Baltic Birch My speakers North Creek Music Systems the Manifest has a cabinet built with Baltic Birch on the inside and MDF glued on the outside. The MDF is easy to veneer and you get the stiffness of the Birch inside. The two layers also give you a stiff cabinet always a good idea I also used Birch for ladder braces inside the cabinet for stiffness. George from North Creek uses a hard glue between the MDF and the Birch and a soft glue between two layers of MDF plus a layer of Birch for the front baffle 2 1/4 thick front with two layers of MDF , Baltic Birch + MDF 1 1/2 thick back and sides and 3/4 inch Baltic Birch for ladder braces. The hard glue is tight bond and his own soft glue hope this helps Marc

It might work. I haven't try it tho. I had a similar idea ones but instead of old plain MDF, I was thinking of using the product which name escapes me right now (I can find out its name if you want). It is a laminated MDF and Ply in 5 layers (top, bottom,mid MDF and Ply between). Cabinetmakers use it on special occasions when rigidity is of up most importance. It's the perfect material for your project, easy to work with and finish. Price might be an issue but I do not believe that it is more expensive then Baltic Birch (void free) Ply. If I had to guess, it might cost somewhere around $80 per 8'X4' sheet these days. (year ago it cost $60).

I hope it helps

Mariusz

As to glue "Q". I use exterior (water proof) grade woodworker's glue in most applications.

Mariusz

Most speaker cabinet makers use special dampening glue or material. Depending on the designer they may use braces or special glue to provide better rigidty for MDF or layered Birch.

MDF is poor choice for loudspeaker cabs. Sure easy to work with and afordable but veneers don't hold as well to MDF as ply its easy to veneer MDF but venners will lift off MDF. MDF will absorb water like a sponge. MDF strores energy which colors sound. MDF is easy to crush or dent unlike ply. Dont see to many ply cabinets with crushed corners. MDF also since absorbs water will form scary molds within days. Try it for yourself dampen MDF slightly, lay it so no light reaches damp spot in days dangerous molds form. If you intend on using loudspeaker in humid or slightly damp places like basements I would pass on MDF. You can do the same with ply and little to no mold forms and the stuff that does form on ply can easily be removed unlike MDF where mold will penetrate deep into material. When I use MDF I make sure MDF is fully sealed inside and out. I have open MDF cabs and found mold growing on inside of cabs. So my finding are PLY like Baltic sounds better, holds veneer better, lasts longer. Is far stronger and safer than cheap old MDF. And I too have tried layers of MDF PLY other materials and doubled Baltic has always come out sounding superior.

Wow, great info guys. The MDF sheet that I have is the kind that can stay submerged in water w/o swelling (it's for use in the humid islands here and the supplier has had a sample piece in a 5 gal. pail of water for 2 yrs for display purposes). But even so, it sounds like biting the bullet and buying more Baltic for re-enforcement is the best way to go overall. Thanks to all

What type of glue are you going to use?

I'm presently at sea working on a ship, but as I recall it's called "Tight Bond". It's light brown in color and water based, very similar to Elmer's cabinet making glue but slightly higher on the food chain - unless someone can talk me into something different.......

Titebond II or III is what I use.

I use a professional grade spray on adhesive. Only $250 for a recharge ouch. it also dampens cabinets. But I have used similar to tight bond which is good.