MDF and "particle board"

[jmar]

Ran across some MDF sheet at my local Meanards yesterday and here all this time I had been thinking that MDF is the same thing as what I've called particle board.

Obviously i had it wrong.

Particle board is the material used for flooring underlayment, roof sheathing etc and comes in 2 flavors --

medium density (common) and high density (cabinet grade that weighs a TON).

I can see now that MDF is a different animal.

Smoother, sort of a brown color, somewhat lighter -- looks a little like a type of "masonite".

So --

MDF is superior to particle board? Why?

Is particle board even used in speaker enclosures?

[Buckapound]

Yes, it's a lot like Masonite, just sawdust held together with glue.

It is denser and less resonant than particle board (more correctly called Oriented Strand Board, I think). You don't see too many people using OSB, as it's not very smooth on the surface and therefore hard to finish, veneer, etc, and tends to split out in the fine cuts like joints and speaker-mounting chamfers. Most people who want to use a more wood-like material go to a birch plywood, the better grades of which have numerous thin laminations.

--Buckapound.

[markus76]

Originally Posted by jmar

Is particle board even used in speaker enclosures?

Yes sure:



But if you want to paint particle board, be prepared to spend some serious extra time and money to get a smooth finish (especially when you're using butt joints). MDF is less problematic. For veneering particle board is just fine.

Best, Markus

[markus76]

Originally Posted by Buckapound

particle board (more correctly called Oriented Strand Board, I think).

No, this is OSB (has a very uneven surface):



Particle board:



MDF:



Best, Markus

[jmar]

Ok thanks.

I have used high density particle board before, which machines much better than regular, but it weighs as much as concrete.

I can see why MDF is the popular choice, I bought a 2 x 4 sheet yesterday -- very nice.

I'm anxious to get started on my project.

[cliffforrest]

Particle Board (called Chipboard in the UK) is indeed used foor flooring etc as it is strong enough and cheap! Easy to cut.

MDF takes the edge off tools quickly and produces nasty dust.

I fancy that real MDF only became available in the last 20 years or so (but I am getting old!) as I have several sorts of speaker cabinets (B&W DM220 etc) all made out of vaneered chipboard.

As stated, they break easily at machined edges and do not "thud" like a good MDF box.

[planet10]

As far as sonics go, high density particle board is probably better than than MDF. To get around finishing issues Peter from WD has been advocating an MDF/paricle board sandwich.

IMO, neither is as good as a good multiply like Baltic Birch (so much so that we'll happily pay $50 a sheet for BB, even when all the MDF we'd need is free)

dave

[planet10]

Originally Posted by cliff

do not "thud" like a good MDF box.

That "thud" is actually an indication of one of the big problems with MDF... the resulting sound with a knuckle rap on a good box should be much higher in frequency and have a higher Q. I colourfully describe the problem with MDF as its tendency to ouze out a low level time-delayed and blenderized version of what is inside the box reducing the potential downward dynamic range of the speaker system.

dave

[budwiser]

Make sure to use good dust mask when cutting mdf.

[spiette]

Originally Posted by planet10

IMO, neither is as good as a good multiply like Baltic Birch (so much so that we'll happily pay $50 a sheet for BB, even when all the MDF we'd need is free)

If you don't mind the side track. What thickness of BB plywood is preferred, how many plys?