MDF vs Blockboard Cab

[jazzbass_5]

Huh... all the speakers I made 30 years ago with MDF.... I did the sawing myself.... no mask.... toxic you say? hmmmmmmm uh oh

Yeahhhh, that's what I was thinking.

 

[seamonkey]

Track saws I have are built to hook up to dust extractors.
Hardly any dust escapes from mdf. What does escape can be pulled from the air with a fan with a furnace filter attached.
Still wear a dust mask if you can find one, or look at one of the many tutorials on how to create on.
Vacuum your clothes off afterwards too and the whole shop.

Track saws are cheap these days and much safer for the average person to use and the saws designed for dust extractors.

 

[Redbrangus]

It isn't necessarily a certainty that the formaldehyde in the UF glues used in MDF is toxic, but the regular ol' dust particles--the ones smaller than one micron--if inhaled, definitely ARE known to be carcinogenic. What us DIY'ers have going for us is that we don't generally have the sort of prolonged or continued exposure one would have in a professional woodworking setting. Still it would pay to use a mask, IMO.

And again, dust extraction is a really good idea, but if you're using a dust collector with the usual cloth bag filter or just a shop vacuum, you'll be propelling more of the hazardous, sub-micron particles into the workshop's air than if you just ignored the sawdust and swept it up with a broom. And those particles will largely escape being trapped by coarse, HVAC filter media, IME...only a HEPA filter will get those.

 

[beans-on-toast]

Many big box hardware stores, perhaps the Home Depot in Da Nang, will cut MDF to your dimensions for a small charge. Just bring a measured drawing.

 

[Jim Carr]

Isn't MDF the same stuff Behringer uses to build their tilt back combos? They melt.

If it's the same stuff I have seen, MDF will melt if exposed to sufficient moisture and turn into the crumbliest weak mess you can imagine—with a weird red mold.

 

[La Faro]

Many big box hardware stores, perhaps the Home Depot in Da Nang, will cut MDF to your dimensions for a small charge. Just bring a measured drawing.

Nope, none of that, those types of stores here don't exist.

I have tools

 

[Jim Carr]

Further word of warning on MDF and moisture: Medium Density Fibreboard (MDF) or Plywood?

 

[smart51]

Plywood is stiffer than MDF so you can use a thinner sheet for the same overall stiffness. That will make it lighter.
Block board (thin plywood on either face with blocks of wood in the middle) is just as good as normal plywood.

MDF is not nearly as toxic as panicky people think. Early MDF gave of twice as much formaldehyde as a plank of wood the same size. MDF made in Europe (and probably elsewhere) has no formaldehyde in the binder any more, so emissions are the same a plain wood. A simple dust mask will be fine.

 

[Rabidhamster]

I'd use MDF. I've had occasion to build a number of speaker cabs for permanent installs out of MDF and it's a pretty OK material to work with. Acoustically speaking, it's actually better than even the best plywood, in that it's so much denser and thus has a much lower natural resonance. All wood dust particles are toxic to some extent; one should take precautions, i.e., rated (N-95) dust-filtering masks, to keep from inhaling the airborne particulates of any sheet goods that you cut. I'm certainly no authority, but I've never heard that MDF dust is more toxic than, say white oak, mahogany or luan.

MDF absolutely is more dangerous than just unadulterated wood. They bind it all together with poison essentially. Loads of formaldehyde among other things.

I do agree you should always wear a mask, but MDF offgasses formaldehyde in your living space also.

I mean heck my kitchen countertops do too, but it’s important to know.


You can get “green” MDF now but it’s so expensive good luck finding it.

 

[seamonkey]

For people in the US who are afraid of MDF:
Formaldehyde Emission Standards for Composite Wood Products | US EPA

Calm your nerves.

 

[Skillet]

When possible, I like to set up to cut or sand outdoors with a good fan blowing with the wind to move the dust away.

 

[Dirk Diggler]

Why not use some of that local wood?
Solid would be great, you can actually go thinner that way as well.
Density would be great.

I thought plywoods were meant to be cheap replacements for true timber?

In any case have fun building it.
Dirk

 

[smart51]

I thought plywoods were meant to be cheap replacements for true timber?

Plywood has strength in both directions. Timber only in one. That's what makes ply good for speaker cabinets. You want strength across and along the panel. Solid wood with bracing across the grain works just fine though.

 

[Redbrangus]

Plywood is structurally superior to natural wood, and is (essentially) dimensionally stable in all axes, making it preferable to jointed, solid wood panels for speaker cabinets. It also has a much lower resonance. MDF is also dimensionally stable - obviously, you shouldn't let it get wet. And it is a still-better material acoustically...it's big drawback - other than disintegrating in water - is the beastly weight of it, which isn't going to be that big of an issue for the OP's little 112 box, I don't think.

 

[braud357]

Further word of warning on MDF and moisture: Medium Density Fibreboard (MDF) or Plywood?

View attachment 3808950

That looks like particle board - not MDF

 

[Jim Carr]

That looks like particle board - not MDF

Possibly true.

I couldn't find an image that looked quite like the cabinet I saw disintegrating.
The webpage I grabbed that image from (in the link in my post) claimed it was MDF.

Perhaps once the fibers have gotten soaked, they don't look all that different—also I believe there are different grades of each based on standards I've seen mentioned.

 

[seamonkey]

At building supply sellers you can also buy water resistant MDF
It's usually green color

 

[La Faro]

That looks like particle board - not MDF

I was going to say the same, but call it chipboard (which I think is the old name in the UK for it)

 

[La Faro]

Why not use some of that local wood?
Solid would be great, you can actually go thinner that way as well.
Density would be great.

I thought plywoods were meant to be cheap replacements for true timber?

In any case have fun building it.
Dirk

As mentioned in the opening post
"I never see pine here, most woods are dense, and heavy."

It's also unfinished, and generally in thick planks.

 

[La Faro]

Timber supplies don't seem to be the same here at all as the UK, this job would be so much easier in the UK. When I made my sax and flute cabinet, I went to a panel board supplier and worked with what they had. I had to make the spike for the sax, the flutes needed a 18mm dowel and a 22mm dowel. Dowel! Who would have thought dowel was difficult to buy. Searched the internet and went to every timber supplier in the city I could find. I spent so much time on that project looking for dowel. I even looked at roundover bits to see if I could make my own. In the end I found and some in the art shop (should have checked there first, I don't know why I didn't) But only one size. I had to whittle and and the smaller dowel to 16mm. It's 20mm, so one I gave a veneer of the (Ash I was told) to match the cabinet and thicken a little.

Then hinges. This is 10mm blockboard (the lid as 2 thick) could I get 10mm hinges. We have a street called "Screw street", not, went to street around the corner with doors parts, nope! Went to about 6 hardware shopes, nope. and that includes screws. So I took a file to one edge of a 1/2" hinge, and to the end of the screws that would go in that end.

Sp much of this projects was spent searching for things and not making. Glass, no glass shops. What you do is go to and aluminium framed window maker, and ask them for glass (twice and my project was on the roof, and a board that had been standing for two weeks, blew over and knocked my cabinet over smashing the glass)

Then there's finishes, I just wanted a tin of something suitable. Nope! not here. You buy the lacquer, thinner, hardener, an die and mix it yourself. A girl on facebook locally sells her fathers honey from cashew farm in the mountain, so I asked her if she had beeswax. I now have half a kilo of bees wax. Could not get boiled linseed oil in the city, but a mineral oil. So I heated that, and added the beeswax to make my own finish.

So when I say in my opening post. please note my location, it's really is different from our so called norms in at home. I have to work with what is available.