Where is the MDF in/on the New LaScala?

[dougdrake]

Hmm. In my simple way of thinking, it looks like MDF just creates a better sounding (or more accurately, non-sounding) enclosure. So since sound is what it's about, I guess all the headaches of working with the stuff must be worth it!

Doug

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My System

[snackguy]

BOA12 I agree,

what's so wrong w/ companies making more profit? as both a consumer & shareholder, i'd rather they do it thru cost reduction than price increases.

[John Warren]

I have address each concern of HDBR-

1. It's veneers (when veneered to LOOK like wood) don't tend to stay on it for any great length of time.

(jw) urea resin + high contact pressure = long lasting

2. If it ever gets wet...it is history!!

(jw) agreed, MDF + water = oatmeal BUT so was the case with particle board, the *mainstay* enclosure material of the 60s, 70s and early 80s.

3. If one bashes a corner, it is almost irrepairable damage...and is much more susceptible to greater damage from a small bashing than plywood is. And you can't just wet it a little and swell minor dent damage back out with an iron like on plywood.

(jw) if it's hit hard enough to cave in the MDF corner, the loudspeaker magnet broke off too.

4. It doesn't hold most glues, nails, or screws as well as plywood...and the likelihood of a screw-head being "torqued off", broken screws from over-torqueing, strip-out of the "threads" in the media when replacing components, etc...is much more likely with MDF...due to that same great density we like for sonic efficiency so much! (also a problem in baltic birch...for the same reason)

(jw) I used to believe these things until I started to work with MDF. Yellow glue, heavily applied with lots of clamps is more that adequate strength for enclosure joinery, also screws driven into it (holes pre-drilled) have good bite. Rub blocks are essential too.

5. It is a ***** to sand down flush when leaving overhangs on lap joints...and the resulting sanded edges look like crap when attempting to apply a nice smooth finish...and seams tend to never get hidden well after a finish is applied...unless one gobs on a "flexible finish" like urethanes.

(jw) agreed, but plywood end-grain, veneer delams,

end-voids are no joy either.

6. It is heavy as hell (a by-product of the consistent density mentioned in this thread above).

(jw) Not all heavy transfomers are good transformers BUT all good transformers are heavy transformers.

Sometimes weight has a *quality* all its own.

7. It is ugly as hell...too!

(jw) that's why we veneer. Also, they can be painted to *glass-sheet* smoothness. I think natural wood finished are way over-rated.

8. Sawing, routing, and sanding it is an exercise in filling one's lungs(with no dustmask), eyes(even with eye protection), ears, and every nook and cranny in ones being with a fine annoying sawdust that clogs the pores of the skin very badly...no matter HOW GOOD one's dust collection system is!!

(jw) agreed, this is a real down side. the material is tough on 12" 80 tooth carbide saws operating on a Tannewitz table. BUT that's the price you pay for high density. if balsa wood worked....

9. It is full of chemicals that exhaust out of it over time...definitely not good for homes with chemical allergy problems within them!! (this is also why it tends to have its applied veneers lift off from it as these chemicals try to escape it and are trapped under the veneer, creating bubbles)

(jw)I've heard this and understand that this is possible since the *glue* that holds MDF together is urea based and it does give off gas (out-gassing).

I'm skeptical about the bubble thing though since to lift the veneer would require a significant pressure which PV=kNT may prove a fantasy.

10. It is very hard on sharpened tools, like router bits, saw blades, etc...dulling them up rapidly!! (but so is BALTIC birch...so damned much glue in it!!, BUT baltic birch is also heavy and dense as hell...making it a good sonic quality media, too...and it actually, on occassion, looks good!!)

(jw) agreed, but MDF is cheaper.

All in all, I appreciate the spirit that HDBR is added to the discussion. He brings up good points.

Bottom line plywood is still alot easier to work.

[Herc]

As my wife made the actual MDF panels at a plant here I know very well what goes into each panel.

-yes they are heavy about 88lbs for 4x8 3/4" sheet, but keep in mind that higher end(not custom) furniture makers use MDF it is much more stable in humid environments (dont use water based finishes)-to make regular particle board takes about 45lbs of pressure to bond the resins and wood fibres togetrher,MDF is around 150lbs. Most consumers dont realize there are 3 grades of regular particle board.You have to ask for it

- if you are having problems with your substrate delaminating use a sanding sealer first before you apply the adhesive

-contact glue works good for the novice but use solvent based glue not water, the water based contact glue tends to soak in more and thins out(it might also penetrate through the veneer!)

-apply a couple of coats to boths surfaces to be bonded (let dry completely between coats)

-if you have fastener problems use biscuts to join it all together

There you have the start of a strong stable enclosure!