anyone using HDF as opposed to MDF

[UGP]

I've only seen it mentioned a few times for speaker building, has anyone used it and compaired it to MDF & Baltic Birtch to see how it stacks up?
How about price I've not really looked for it so not sure if it's a lot more or hard to find etc...

[MSaturn]

I tried to get some 3/4" HDF and my local lumberyards looked at me like I had two heads. I was pretty insulted.

[Sydney]

Deja Vu...
As for a "specialty item" and get a classic "Idiocracy" dumbfounded look.

[Texan]

I couldn’t find it either, at least not in any meaningful thickness.

[DjDisturbed]

It is almost the same to work with as MDF but alot heavier. As far as I could tell when using it , it had about the same strength as MDF. And Birch will always be stiffer than both of those and lighter at the same time.
Another great thing about Birch is it will always have less saw dust. I always try to use cabinet grade plywoods when possible.

[lunchmoney]

It is almost the same to work with as MDF but alot heavier. As far as I could tell when using it , it had about the same strength as MDF. And Birch will always be stiffer than both of those and lighter at the same time.
Another great thing about Birch is it will always have less saw dust. I always try to use cabinet grade plywoods when possible.

Birch is just way more expensive though.

[Starkiller4299]

I'm not convinced that baltic birch has less sawdust--but it definitely doesn't come out so fine and find its way into every little crevice of my shop like mdf, either :p.

[MSaturn]

For my dipole subs, I plan to laminate three layers of .5" HDF together to make a solid board. That's the thickest I can find (easily) - though I know thicker versions exist.

As far as its performance, it IS naturally better - because performance is generally related directly to density. There are few natural woods as dense as HDF. Making speakers from Ironwood would be .. rather loony.

[DoubleTap]

What you need to do is call your local Hardwood shops and ask if they have Medite or Medex ... those are the HDF's that don't swell and expand when exposed to any moisture, and are much higher quality stuff than typical MDF.

[killersoundz]

I'm in the Baltic Birch camp too, mostly because I build pro audio stuff but I think if I got into home audio stuff I'd still use it :) It's just so much better to work with than MDF. I did use MDF at one time and THE DUSTTTTTTTTTTTTTTTT. I always wear a respirator when cutting anything but the MDF was just outrageous.

My local supplier has "industrial grade particle board". It is one notch below MDF but it is a lot more dense than standard particle board. I've had some and when you cut into it you can see how much more dense it is than the regular particle board. I think it would make a good compromise for budget boxes at only $16 a sheet. I just wanted to throw that out there.

These are pictures that remind me of the nightmare of MDF....

http://sphotos.ak.fbcdn.net/hphotos-ak-snc1/hs196.snc1/6640_261403080330_871895330_8542163_3874974_n.jpg

That's when doing round overs on like 20 boxes at a time....I busted out some coveralls.

http://sphotos.ak.fbcdn.net/hphotos-ak-snc1/hs176.snc1/6640_261403110330_871895330_8542167_8075600_n.jpg

and you have to have dedicated dust shoes

[DjDisturbed]

Yea that's been my biggest problem with MDF or HDF . They have such tiny dust particles because it is saw dust to begin with then glue added and compressed. When ever you cut it , it makes a huge mess.
My local lumber yard has 1 1/2" MDF and 1" HDF , the HDF wieghs about twice the MDF. I built tons of enclosures with both , because I worked with car audio all of my life.

If your willing to put up with the mess , then check your local lumber yard. Plus they usually offer delivery if you don't have a truck to haul it. Lowes or Home Depot probably won't have it , because they usually have nothing worth buying anyway.

[diy speaker guy]

As far as its performance, it IS naturally better - because performance is generally related directly to density.

Density without strength isn't very useful unless of course you just want it to be heavy - which is sometimes appropriate.

Plywood is naturally much stronger than mdf (for the same thickness) but the material you choose should be chosen based on what you are trying to accomplish. Usually in a boxed speaker you want to keep the box's material resonance out of the audible bandwidth, and when that's not possible, to reduce the effect as much as possible. So it depends on the speaker's usable bandwidth. For a dipole it doesn't matter so much what you use as far as resonances are concerned but I'd go for plywood for the extra strength.

[benhinkle711]

I'm in the Baltic Birch camp too, mostly because I build pro audio stuff but I think if I got into home audio stuff I'd still use it :) It's just so much better to work with than MDF.

I would love to try the Baltic Birch but have never been able to crack the code on finding it.

[Pete Schumacher ®]

Laminted HDF makes an incredibly dense, and extremely strong material for constructing enclosures. I'd put it up against baltic birch any day for strength, rigidity, and far higher in density and the ability to damp out transmitted acoustic energy.

Below is 1/8" HDF layers with epoxy in between, though I'd wager that Titebond might work as well. The result is fantastic.

http://i517.photobucket.com/albums/u335/Ed_Rosenquist/Byzantine%20build/Byzantinebuild017.jpg

[diy speaker guy]

Laminted HDF makes an incredibly dense, and extremely strong material for constructing enclosures. I'd put it up against baltic birch any day for strength, rigidity, and far higher in density...

I agree so far (since it's hdf and not mdf), especially with the curved panels as shown but...


...and the ability to damp out transmitted acoustic energy.



...that depends entirely on the frequencies being played. Well braced baltic birch would have a much higher resonant frequency and would be much less excitable by lower frequencies which have the most transmitted acoustic energy.

I already know this is going to be an unpopular viewpoint that is going to be argued but I'm not going to get into this any further. A quick google search should show there's plenty of information on this topic.

[Pete Schumacher ®]

I agree so far (since it's hdf and not mdf), especially with the curved panels as shown but...



...that depends entirely on the frequencies being played. Well braced baltic birch would have a much higher resonant frequency and would be much less excitable by lower frequencies which have the most transmitted acoustic energy.

I already know this is going to be an unpopular viewpoint that is going to be argued but I'm not going to get into this any further. A quick google search should show there's plenty of information on this topic.

Stiffness is what raises resonant frequency, and this stuff, when laminated, is easily as stiff, if not more so, than an equivalent thickness of Baltic Birch. The fact that the grains are more randomly distributed in the HDF will allow it to more rapidly dissipate acoustic energy inside the material as heat. No reason you can't "well brace" this either.

I wish you could hold the plug cut from the enclosures for the RSS315. The epoxy/HDF combination makes for an end result that has the hardness/density of a bowling ball.

[killersoundz]

I would love to try the Baltic Birch but have never been able to crack the code on finding it.

I'll let you in on a little secret....do you have a local Menards? They carry it. :) I couldn't get it anywhere either until I walked myself into that new hardware store and about pee'd myself when I saw 12mm and 18mm Baltic Birch stocked! They'll even put it on sale sometimes at my local store because no one but me buys it.

I can list reasons why I'm in the Baltic Birch camp :D:

- Strength, Absolutely no sheet material is anywhere as strong as Baltic Birch

- Lightweight, Ok people are always saying it's light weight, but it's not! Baltic Birch is real hardwood and I find it to be barely any lighter than MDF. Now that cheap "Birch" plywood you buy at home depot is considerably lighter than MDF, like half the weight, because it's not hardwood at all, it's made out of friggin' weeds.

- Workability, You can cut whatever with Baltic Birch and it won't crumble like cardboard like MDF will.

- Moisture resistant, It uses exterior rated glue, I've soaked it in water before and holds up fine...MDF would disintegrate.

[mattk]

I...

- Lightweight, Ok people are always saying it's light weight, but it's not! Baltic Birch is real hardwood and I find it to be barely any lighter than MDF. Now that cheap "Birch" plywood you buy at home depot is considerably lighter than MDF, like half the weight, because it's not hardwood at all, it's made out of friggin' weeds.
....

Right, looking through the web, MDF has a typical density of 600-800 kg/m³ (from wikipedia and a few other sources), and baltic birch ranges between 600 and 700 kg/m³ (East Coast Plywood and a few others).

So, BB can be lighter than mdf, but not necessarily. Weight savings come from using, say, 1/2" BB as opposed to 3/4" MDF, taking advantage of its greater strength.

[diy speaker guy]

Stiffness is what raises resonant frequency, and this stuff, when laminated, is easily as stiff, if not more so, than an equivalent thickness of Baltic Birch.

Sure but stiffness is not the only factor, for equal stiffness the heavier one will have the lower resonant frequency.

And I should probably also mention that your project is a much higher level of quality (stronger) than most and with this level of strength the perceived audible qualities based on the differences between these materials is greatly reduced so it really doesn't matter nearly as much as it would in other cases.

As for the rest of what you said - I believe you and I agree.

[killersoundz]

Right, looking through the web, MDF has a typical density of 600-800 kg/m³ (from wikipedia and a few other sources), and baltic birch ranges between 600 and 700 kg/m³ (East Coast Plywood and a few others).

So, BB can be lighter than mdf, but not necessarily. Weight savings come from using, say, 1/2" BB as opposed to 3/4" MDF, taking advantage of its greater strength.

Bam! There you have it.

[gowa]

HDF is used quite widely in HQ office furniture.

[Texan]

I just wanted to add that some hardware stores carry an imported birch plywood. It is not 100% void free and I think it is softer than others, but it is extremely well priced and very dimensionally consistent. It does not finish well but it works great if you need something stiffer or lighter than MDF, and you are going to use veneer or carpet.
Here it is called china birch

[Sydney]

....do you have a local Menards? They carry it. :) ...
That's good to know for future ref. ( unfortunately no Menards locally ).
It doesn't surprise me - I've found stuff at those, not carried at the other 2 local outlets.

[killersoundz]

I just wanted to add that some hardware stores carry an imported birch plywood. It is not 100% void free and I think it is softer than others, but it is extremely well priced and very dimensionally consistent. It does not finish well but it works great if you need something stiffer or lighter than MDF, and you are going to use veneer or carpet.
Here it is called china birch

Yeah thats the stuff that I was talking about earlier that is made out of weeds. It's made on a boat on the way from China to the port in Florida after they gather up whatever the hell they can to process into plywood, and NONE of it is birch or even hardwood. This chinese "birch" plywood is absolutely horrific. When I first got started in building cabs I used it, it was a nightmare. Voids are everywhere...many larger than my hand, it's usually like swiss cheese. The veeners on both sides are paper thin so you can't laminate or glue anything to it because it will ultimately come off or chip off. Quality does vary, but it's just generally rubbish. I almost forgot, one time I was cutting into a piece and sparks started flying, there was a piece of sheet metal inside of a void!!! This was with my brand new expensive dado blades too..I took that piece back to home depot with the sheet metal clearly in it demanding a refund or something and they told me to F off.

I would favor using particle board over any of this chinese plywood. I'm 100% serious. Atleast particle board doesn't have 1,000,000 voids or a veneer that peels off.

[Pete Schumacher ®]

Yeah thats the stuff that I was talking about earlier that is made out of weeds. It's made on a boat on the way from China to the port in Florida after they gather up whatever the hell they can to process into plywood, and NONE of it is birch or even hardwood. This chinese "birch" plywood is absolutely horrific. When I first got started in building cabs I used it, it was a nightmare. Voids are everywhere...many larger than my hand, it's usually like swiss cheese. The veeners on both sides are paper thin so you can't laminate or glue anything to it because it will ultimately come off or chip off. Quality does vary, but it's just generally rubbish. I almost forgot, one time I was cutting into a piece and sparks started flying, there was a piece of sheet metal inside of a void!!! This was with my brand new expensive dado blades too..I took that piece back to home depot with the sheet metal clearly in it demanding a refund or something and they told me to F off.

I would favor using particle board over any of this chinese plywood. I'm 100% serious. Atleast particle board doesn't have 1,000,000 voids or a veneer that peels off.

For that matter, OSB would be superior.

[killersoundz]

For that matter, OSB would be superior.

Yeah I'd use OSB over chinese birch plywood as well. Anything would be better.....

Ok before I completely try to denounce it.... The chinese plywood I've seen at Menards appears to be a bit better quality than the home depot stuff. It still has the peel-able veneer though. Lowes also has some slightly better stuff from time to time. It's really a crap shoot. Sometimes it will be passable and sometimes it will be just rubbish. The higher end of the chinese plywood (if you can find some that looks to be ok) may be ok for some budget pro audio boxes that need to be cheap and lightweight, since it's made out of weeds it weighs next to nothing.

[diy speaker guy]

I've never used Chinese ply but I was happy with the Auroco (sp?) ply I got last year at HD. Not as good as baltic birch but quite a bit cheaper.

[RINNAV]

Right, looking through the web, MDF has a typical density of 600-800 kg/m³ (from wikipedia and a few other sources), and baltic birch ranges between 600 and 700 kg/m³ (East Coast Plywood and a few others).

So, BB can be lighter than mdf, but not necessarily. Weight savings come from using, say, 1/2" BB as opposed to 3/4" MDF, taking advantage of its greater strength.

Wouldn't the density of the overall material being used, affect resonance the most (D=M/V) therefore, causing a material with more density to resonate at lower levels—meaning damping? I am not sure about the “stiffness”, look at mercury for that matter—try to get a audio frequency to resonate a heavy metal.

Talk about density, 1400 kg/m^3, I thought about using some Paperstone or Ritchlite at one point:

www.thenaturalabode.com/green_home/paperstone_countertop_technical_specifications.htm

--made out of recycled paper and a phenolic resin, kind of like HDF/MDF on steriods! Although, very expensive...

[Pete Schumacher ®]

Wouldn't the density of the overall material being used, affect resonance the most (D=M/V) therefore, causing a material with more density to resonate at lower levels—meaning damping? I am not sure about the “stiffness”, look at mercury for that matter—try to get a audio frequency to resonate a heavy metal.

Talk about density, 1400 kg/m^3, I thought about using some Paperstone or Ritchlite at one point:

www.thenaturalabode.com/green_home/paperstone_countertop_technical_specifications.htm

--made out of recycled paper and a phenolic resin, kind of like HDF/MDF on steriods! Although, very expensive...

Resonance goes down, but the mass is also harder to push. And the inert nature of the microstructure of the HDF allow for more damping of vibrational waves in the material. It's not all about how you keep it from flexing (low frequencies), it's also how well damped that material is from transmitting acoustic energy along the panels (mid and high frequencies). A more random orientation of particles will dissipate the energy faster than longer, stiff strands.

[diy speaker guy]

Again, it all depends what frequencies are being played. Low frequencies create exponentially more energy so low frequencies are much harder to damp out. If you are using 2 foot thick concrete it's not much of an issue but even double thick mdf isn't heavy enough to be particularly good at low frequency damping by virtue of density.

If the box material resonant frequency is high then it is far less excitable by these high energy low frequencies, so there is far less need to damp them at all, all you need is a bit of lining or stuffing to suck it up.

I realize I'm not going to change anyone's mind though, I probably should have quit talking when I said I was going to...

[Texan]

Yeah thats the stuff that I was talking about earlier that is made out of weeds. It's made on a boat on the way from China to the port in Florida after they gather up whatever the hell they can to process into plywood, and NONE of it is birch or even hardwood. This chinese "birch" plywood is absolutely horrific. When I first got started in building cabs I used it, it was a nightmare. Voids are everywhere...many larger than my hand, it's usually like swiss cheese. The veeners on both sides are paper thin so you can't laminate or glue anything to it because it will ultimately come off or chip off. Quality does vary, but it's just generally rubbish. I almost forgot, one time I was cutting into a piece and sparks started flying, there was a piece of sheet metal inside of a void!!! This was with my brand new expensive dado blades too..I took that piece back to home depot with the sheet metal clearly in it demanding a refund or something and they told me to F off.

I would favor using particle board over any of this chinese plywood. I'm 100% serious. Atleast particle board doesn't have 1,000,000 voids or a veneer that peels off.

Man I have used it twice with good luck! I didn’t get it at the depot. It came from the local mom & pop Ace. It sure sounds like we got a different product. Mine was very consistent, but the veneer was thin and it did suck. The largest void I found was about the size of a penny. Oh well you never know till you try I guess.

[RINNAV]

Again, it all depends what frequencies are being played. Low frequencies create exponentially more energy so low frequencies are much harder to damp out. If you are using 2 foot thick concrete it's not much of an issue but even double thick mdf isn't heavy enough to be particularly good at low frequency damping by virtue of density.

If the box material resonant frequency is high then it is far less excitable by these high energy low frequencies, so there is far less need to damp them at all, all you need is a bit of lining or stuffing to suck it up.

I realize I'm not going to change anyone's mind though, I probably should have quit talking when I said I was going to...

Your right, it is all about the transfer of energy that induces the resonance. Given the same dimensions of the material, a denser material would have to have more energy to induce a resonance. My understanding is that MDF was better than grained wood due to 1) The atomic cell structure; meaning a more consistent density, which disperses resonance uniformly (due to energy loss/friction) and 2) the density per same volume compared to others. This is unlike grained wood, which has non-uniform density, especially parallel to the grain.

Jason

[diy speaker guy]

Think of it this way - if you make an enclosure for drivers that will only be playing midrange and high frequencies, then it is perfectly appropriate, and even preferable to use a high density, high weight material with a very low resonant frequency. In this way you can keep the resonant frequency of the box below the passband of the drivers and the resonant frequency of the box will never be excited at all.

The box will still vibrate but not at it's resonant frequency where it will make the most noise, so the vibrations are easy to control and the properties of mdf that you just described are beneficial in controlling the small amount of vibration in the panels. For the most part the panel resonances have been almost completely eliminated.

For a box with drivers that will be playing low bass it's not possible to get the material's resonant frequency low enough to be below the passband (unless you use 2 foot thick concrete) so it's more effective to use a very strong, lightweight material with lots of bracing to make it even stiffer and raise the resonant frequency of the box as high as you possibly can.

In this case, the box's resonant frequency will be excited (there's no way around that if the box is playing full range and you are using less than 2 foot thick concrete panels) but the box's resonant frequency is high where there is not nearly as much energy transfer.

Yes, mass does damp resonance but it's not particularly effective unless you have MASSIVE amounts of mass, it's a battle you can't win. The alternative, as I've described is to raise the resonant frequency as high as possible to minimize the amount of energy transfer, which is more effective than trying to damp a low frequency resonance with mass.

I didn't make this stuff up, there's lots of information out there if you care to search for it.

[rogoll]

I've never been able to find Baltic Birch. Does anyone know if Lowes will allow you to order it through them, and if so, do they add a surcharge for doing that?

Another question, probably a good one for Dave Pellegreen (spelling?)... Could I take OSB and pour a layer of fiberglass resin (with hardner) on it and get a good smooth surface to work with:confused:?

Thanks guys,
Leonard

[diy speaker guy]

I've never been able to find Baltic Birch. Does anyone know if Lowes will allow you to order it through them, and if so, do they add a surcharge for doing that?

Another question, probably a good one for Dave Pellegreen (spelling?)... Could I take OSB and pour a layer of fiberglass resin (with hardner) on it and get a good smooth surface to work with:confused:?

Thanks guys,
Leonard

I doubt a big box store would be interested in small special orders to accomodate you but my small local hardware store was more than happy to special order 3 sheets for me a couple of years ago and the price was very reasonable (~$50/sheet).

If the reason for using OSB is for low cost, I'd think it would be better to use cheap particle board instead of trying to make OSB look good. OSB is good stuff for the price but it's very difficult to make attractive.

[RINNAV]

Think of it this way - if you make an enclosure for drivers that will only be playing midrange and high frequencies, then it is perfectly appropriate, and even preferable to use a high density, high weight material with a very low resonant frequency. In this way you can keep the resonant frequency of the box below the passband of the drivers and the resonant frequency of the box will never be excited at all.

The box will still vibrate but not at it's resonant frequency where it will make the most noise, so the vibrations are easy to control and the properties of mdf that you just described are beneficial in controlling the small amount of vibration in the panels. For the most part the panel resonances have been almost completely eliminated.

For a box with drivers that will be playing low bass it's not possible to get the material's resonant frequency low enough to be below the passband (unless you use 2 foot thick concrete) so it's more effective to use a very strong, lightweight material with lots of bracing to make it even stiffer and raise the resonant frequency of the box as high as you possibly can.

In this case, the box's resonant frequency will be excited (there's no way around that if the box is playing full range and you are using less than 2 foot thick concrete panels) but the box's resonant frequency is high where there is not nearly as much energy transfer.

Yes, mass does damp resonance but it's not particularly effective unless you have MASSIVE amounts of mass, it's a battle you can't win. The alternative, as I've described is to raise the resonant frequency as high as possible to minimize the amount of energy transfer, which is more effective than trying to damp a low frequency resonance with mass.

I didn't make this stuff up, there's lots of information out there if you care to search for it.

OK, I see your point and agree. I was never trying to insinuate that one could totally diminish resonance with more density through added mass. I was just saying given two materials, one with less and one with more density, the most dense would likely be preferable.

So basically what you’re saying, is that it's all about controlling the resonance, the resonance that is impossible to eliminate (the lower, energy-packed freqs). Shouldn't it then be ideal to "tune" the resonance out of the 1K to 4K range--where it matters most in the audible spectrum or would a lower resonance (say 45Hz) be just as detrimental to the overall sound?

Jason

[diy speaker guy]

So basically what you’re saying, is that it's all about controlling the resonance, the resonance that is impossible to eliminate (the lower, energy-packed freqs). Shouldn't it then be ideal to "tune" the resonance out of the 1K to 4K range--where it matters most in the audible spectrum or would a lower resonance (say 45Hz) be just as detrimental to the overall sound?

Your panel resonant frequency will never be that high up in the midrange. You can only push them up so high. The panels will however, vibrate at all frequencies that the drivers produce, but a bit of lining on the panels will damp that out for the most part since they aren't that strong to begin with.

The resonant frequency is the most problematic, as it will vibrate much more (depending on the q of the resonance).

[Sydney]

I've never been able to find Baltic Birch. Does anyone know if Lowes will allow you to order it through them, and if so, do they add a surcharge for doing that?
... Could I take OSB and pour a layer of fiberglass resin (with hardner) on it...

BB is hard to find here as well ( I've known guys who traveled as far as Cleveland to haul it back ).
Lowes didn't carry/handle it.

( I've put polyester resin over plywood - works fine )

[tomzarbo]

I second and third the HDF being good especially for bending applications.
I used HDF 1/8" thickness for the back of these speakers. I tried with MDF but it just broke on me. HDF has more flexibility to it.
6 layers making just over 3/4" and solid as a rock. Used Gorilla Glue to adhere.
http://i49.photobucket.com/albums/f257/TomZarbo/DCP_2071.jpg
TomZ

[Wolf]

If the reason for using OSB is for low cost, I'd think it would be better to use cheap particle board instead of trying to make OSB look good. OSB is good stuff for the price but it's very difficult to make attractive.

I don't know about that. Ed LaFontaine did a good job making them look good:

http://i18.photobucket.com/albums/b117/wolf_teeth_speaker/InDIYana%202010%20pics/23025.jpg

...And these were SMOOTH!!!
Later,
Wolf

[killersoundz]

I don't know about that. Ed LaFontaine did a good job making them look good:

http://i18.photobucket.com/albums/b117/wolf_teeth_speaker/InDIYana%202010%20pics/23025.jpg

...And these were SMOOTH!!!
Later,
Wolf

Yeah, all you have to do is keep sanding it and it will eventually be smooth. Funny though, for as cheap as OSB is, it is usable, Crate proved that. They are a company that makes cheap rubbish guitar amps and their cabinets are made out of OSB. I've said it before and I'll say it again, it's not always the material that makes a cabinet crappy, it's the construction. I've made some particle board boxes before and they have held up fine because I know how to build. :) It's just that most cabinets made out of PB or OSB are put together with silly puddy because it's budget.

[bobhowell]

When I moved in this house 25 yrs back I found a 2'x3' piece of HDF- 1.12" thick laying around. It was laminated from 5 sheets. I used it last year for the baffel on a sealed 10" sub with a 240 plate amp. I used a router to cut out a circle. The dust seemed worse than MDF. It seems almost as dense as granite, so you might say it is about the denseist(?) material you can work with a router. I have watched commercial signs made of 1/4" material last outside for years. It is tough.

Seems like overkill to me. Laminating more would be more trouble than it is worth. I have used purpleheart over the years and it is very dense and dramatic/beautiful; Not that expensive. There are others you can get by mail if you want to experiment.

Bob

[benhinkle711]

I'll let you in on a little secret....do you have a local Menards? They carry it. :) I couldn't get it anywhere either until I walked myself into that new hardware store and about pee'd myself when I saw 12mm and 18mm Baltic Birch stocked! They'll even put it on sale sometimes at my local store because no one but me buys it.

Thanks for the tip. I used to be stationed in WI and there were Menards there. I loved that store! Unfortunately there aren't any in WV. I'll check for a smaller lumber yard or maybe at 84 Lumber.

[lunchmoney]

The dust from HDF must be a horror show.

[diy speaker guy]

I don't know about that. Ed LaFontaine did a good job making them look good:

...And these were SMOOTH!!!
Later,
Wolf

Ed did a great job on those, I've seen those pics before and it's the only time I've ever seen attractive OSB.

But I'm betting it took a LONG time to do that and I'd guess he spent more on sandpaper than on the OSB. That's why I'd recommend particle board instead if low cost is the main motivation.

[r-carpenter]

What you need to do is call your local Hardwood shops and ask if they have Medite or Medex ... those are the HDF's that don't swell and expand when exposed to any moisture, and are much higher quality stuff than typical MDF.

just stay away from fire rated panel. It's horrible to glue up or to glue anything to it.

[r-carpenter]

- High Density Fiberboard (HDF) is a dry-process type fiberboard panel with a density which falls between that of MDF and hardboard. This also gives it properties of strength and warp-resistance which fall between those two products. HDF is made with the same dry-process techniques as MDF. Dry wood fibers are mixed with polymer resin and then are bonded together using heat and high pressure. (Most hardboard is made from a slurry of fibers which are pressed together in a wet state, at higher temperatures.) HDF and MDF are considered the most stable of engineered wood panels. Laminated with fine wood veneers, they are often used in high quality furniture making and are prized for their warp-resistance and durability. They make excellent art panels. PRIMEWOOD™ panels are made of HDF. Terminology can get confusing: thin HDF (THDF) of 1/4" thickness and below is usually referred to as "thin MDF" or "TMDF" since more people are familiar with the term "MDF" than "HDF". (View our Fiberboard Comparison Chart .)
- (See: fiberboard and MDF.) TOP - jump to page contents


I've looked for HDF in local specialty lumberyards a while ago. There are about 20 or 30 varieties of MDF. Different prices, different properties, green, environmentally friendly, nearly formaldehyde free, etc. But nobody has HDF.
The best guesses I got from my suppliers that the closest thing to HDF is Ranger Board, Medex and such. Now we are not talking about some dinky lumberyards with 3 types of panels in stock. These guys are in business for 30 to 50 years. I say if you look for a very dense panel, just pull MSDS and look for weight/volume.

Here's a link to German variety of HDF and my understanding that the term "HDF" is just more common in Europe then US.
http://www.musterkiste.com/en/holz/pro/3917_HDF_panel_B1.html

[Pete Schumacher ®]

- High Density Fiberboard (HDF) is a dry-process type fiberboard panel with a density which falls between that of MDF and hardboard. This also gives it properties of strength and warp-resistance which fall between those two products. HDF is made with the same dry-process techniques as MDF. Dry wood fibers are mixed with polymer resin and then are bonded together using heat and high pressure. (Most hardboard is made from a slurry of fibers which are pressed together in a wet state, at higher temperatures.) HDF and MDF are considered the most stable of engineered wood panels. Laminated with fine wood veneers, they are often used in high quality furniture making and are prized for their warp-resistance and durability. They make excellent art panels. PRIMEWOOD™ panels are made of HDF. Terminology can get confusing: thin HDF (THDF) of 1/4" thickness and below is usually referred to as "thin MDF" or "TMDF" since more people are familiar with the term "MDF" than "HDF". (View our Fiberboard Comparison Chart .)
- (See: fiberboard and MDF.) TOP - jump to page contents


I've looked for HDF in local specialty lumberyards a while ago. There are about 20 or 30 varieties of MDF. Different prices, different properties, green, environmentally friendly, nearly formaldehyde free, etc. But nobody has HDF.
The best guesses I got from my suppliers that the closest thing to HDF is Ranger Board, Medex and such. Now we are not talking about some dinky lumberyards with 3 types of panels in stock. These guys are in business for 30 to 50 years. I say if you look for a very dense panel, just pull MSDS and look for weight/volume.

Here's a link to German variety of HDF and my understanding that the term "HDF" is just more common in Europe then US.
http://www.musterkiste.com/en/holz/pro/3917_HDF_panel_B1.html

Isn't Masonite, HDF? It's definitely hardboard. And that's what was used to build up the lamination with the epoxy in between in the Byzantium cabinets. Masonite panels are quite commonplace.

[edlafontaine]

I'm near Lexington in central KY. I've done the search by phone for HDF in the next larger cities, Louisville and Cincinnati, and still have not found it. I'd love to have some to build with & learn something about the properties, etc. They want to sell units, not single sheets.

I consider it unobtanium.

With regard to OSB finishing, I have access to a 40" flat bed sander and other professional scale equipment. A few passes through the grit sequence and I'm back to building. The shop includes a central vac system and a 30" exhaust fan in the back door that runs full time when temps allow. My work is a hack job compared to the guys making a living from it. I know I'm very fortunate.

OT: I can get 18 mm russian birch for $38 a sheet (60" x 60") in Lexington...wanna trade?

[Pete Schumacher ®]

I'm near Lexington in central KY. I've done the search by phone for HDF in the next larger cities, Louisville and Cincinnati, and still have not found it. I'd love to have some to build with & learn something about the properties, etc. They want to sell units, not single sheets.

I consider it unobtanium.


Masonite.

Everyone has it. It's the material used for garage pegboard. My Lowes has masonite panels by the pallet load.

Ask for Masonite next time, not HDF. You do have to laminate it to build it up to the thickness you're after, but doing so would make for a stronger piece than just a thicker hunk of Masonite.

[DoubleTap]

OT: I can get 18 mm russian birch for $38 a sheet (60" x 60") in Lexington...wanna trade?

That's a good price, the Russian 5'x5' is about $50 here.

I actually use the Chinese stuff. From the hardwood store where I buy, it's indistinguishable from the Russian BB. And the way I use it, if there were ANY voids you'd know. Contrary to what somebody said before, China makes as good of BB ply as anybody. Believe me, I've been through about 20 sheets in the the last 2 months alone.

[bambino]

I tried to get some 3/4" HDF and my local lumberyards looked at me like I had two heads. I was pretty insulted.

My lumberyard looked at me like that when i asked if they could special order 1" standard MDF. LOL!

[spasticteapot]

I already know this is going to be an unpopular viewpoint that is going to be argued but I'm not going to get into this any further. A quick google search should show there's plenty of information on this topic.

Mass, strength, and the flexibility of the material all should be taken into consideration.

Laminated HDF is very heavy, very strong, and doesn't really bend much. Especially if you've got it around a radius.

It's also about $6 for a 4x8 1/8" sheet. Bendy-birch ply is about six or seven times that.

Incidentally, has anyone been able to veneer this stuff?

[bobbarkto]

Isn't Masonite, HDF? It's definitely hardboard. And that's what was used to build up the lamination with the epoxy in between in the Byzantium cabinets. Masonite panels are quite commonplace.

From a post in another forum, edited slightly.

Fiberboard panels
Processing and density are the keys and play the most significant role in the ultimate properties of any panel.

The processes...

They all start with the same basic mixture, ground and expanded wood fiber. This is the key to the manufacture of these products. Any impurities or inclusions would damage the product and/or the equipment used to make it. There are no chips or bark or rocks or sheet metal in the mix. These impurities would not make it through practically any step in the process.

Wet process panels are a mixture of expanded wood fibers and water. The slurry is pressed under high heat and pressure to bind the fibers using the lignin in the fibers as the "glue".
A clue to a wet process board is the screened appearance on one side. But it is not a reliable indicator as some wet process panels are available smooth on both sides.
Wet process panels have very low moisture resistance and are prone to splits resembling delamination.

Dry process panels are expanded wood fibers mixed with synthetic resins/glues and pressed under heat and pressure. The lignin in the wood and the resin provide adhesion. These are superior to the wet process panels in several key characteristics. The fibers bind in a more 3 dimensional matrix and when combined with the added adhesive qualities of the resin binders yields an inherently stronger panel. The resins also increase moisture resistance substantialy compared to wet process panels.

The names or density indicators...

Hardboard is the densest/heaviest of these types of panels. It is the only panel commonly made using the wet process, but can be made using dry process methods. 70-80+ lbscuft. Usualy only available in thin sheets, 1/4" or less.

Tempered hardboard is hardboard that is treated with various resind/oils to improve performance in certain applications. Typicaly it provides a panel that needs no further finishing and increases moisture resistance. Be aware that some of the resins used may prove problematic to adhesives or finishes. Test first if in doubt.

Masonite is the trade name for hardboard manufactured by the Masonite corporation. The originator of hardboard.

HDF is next with a density of 60-70+ lbscuft. Normaly sold in thin panels like hardboard but occasionaly available in 1/2"-5/8" for special applications. A dry process panel.

MDF and the lighter LDF panels range from ~60 lbscuft at the heavy end down to ~40 or so for the super light panels. MDF and relatives are dry processed.

Color is not a reliable indicator of quality or suitability for ordinary hardboard, HDF or MDF.
Some HDF is dark, some light. Same for MDF.
Although, hardboard and HDF are most commonly found as a light tan color. While tempered Masonite and other tempered panels are normally very dark brown.

MDF varies most in color from light tan to as dark as tempered hardboard.

Weight and process are the true indicators used to distinguish these products. Manufacturers are free to call a panel anything they want but the above are industry accepted standards.
There are subtle differences when manufacturers tweak the formula. Different resins have the most impact. For example, Medite brand panels use a formaldehyde free resin that increases moisture resistance too. Subtle variations in the pressing of the panels or the mixing of the slurry or the fineness of the fibers can yield panels with subtle differences in surface appearance and machineability.
The wood species used has no significant impact provided an unsuitable wood is not used. Eg: oily, dense, waxy tropical hardwoods or woods unusually low in lignin content or high in acid content. Most manufacturers use a mix of ordinary woods that are rather benign. The use of pure pine for example will only yield panels that are more consistent in weight, by about .001% over the course of a year. :rolleyes:

Hope this is helpful.

[Pete Schumacher ®]

Mass, strength, and the flexibility of the material all should be taken into consideration.

Laminated HDF is very heavy, very strong, and doesn't really bend much. Especially if you've got it around a radius.

It's also about $6 for a 4x8 1/8" sheet. Bendy-birch ply is about six or seven times that.

Incidentally, has anyone been able to veneer this stuff?

If you're talking about hardboard, Masonite hardboard panels veneer very nicely.

http://i12.photobucket.com/albums/a203/pete_schumacher/Speaker%20projects/RSS315HF%203-way/IMG_4444.jpg

[r-carpenter]

Pete, your speaker is very nice. :)
bobbarkto's explanation pretty much covers all aspects of what HDF is (thanks!). If one is looking for HDF, the search just needs to be done by weight/volume. From my own experience, the pain of handling heavier denser panels is hardly worth the price.
Masonite is Masonite. I don't think it's HDF just based on my handling the 4x8. It's common and inexpensive. 1/4 MDF or Ranger can be used for lamination as well. My guess is that the gluing method is giving the shape the rigidity redundant of the material itself.

[bobbarkto]

Pretty much.
Civil engineers do that with pre-stressed concrete.
Rods extend the length of the form, they're passed through steel plates at the ends, threaded, and tensioned with nuts. The concrete is poured and when cured the nuts are loosened and tension is relieved from the rods. Presto. Instant increase in rigidity.

Curving the panels and gluing, without kerfing or otherwise weakening the panels to accomodate the bend will accomplish the same thing. The glue acts like the tension rods in effect.

Using a slightly denser panel won't hurt, but adds little.


.
...
My guess is that the gluing method is giving the shape the rigidity redundant of the material itself.

[50 watt head]

Wow! Those OSB cabs are really striking! Something you don't see everyday. I especially enjoyed the comment "probably spent more on sandpaper than for the OSB itself" :)

If you have a Rockler nearby, they carry Russian BB. They even sell it online, but the costs involved might not be worthwhile.

IIRC Masonite doesn't make nearly as much mess as MDF. I'm all for that!

[diy speaker guy]

Wow! Those OSB cabs are really striking! Something you don't see everyday. I especially enjoyed the comment "probably spent more on sandpaper than for the OSB itself"



They really do look good, don't they? I was seriously shocked the first time I saw those pics. I've never seen anything like that before.

Those 4 boxes probably contain about $3 or $4 worth of OSB. That stuff is almost as cheap as dirt.

[edlafontaine]

These small projects are stretching exercises for me. I look for a way to incorporate a different wood or construction method into the effort. It keeps things interesting.
The OSB was chosen because it is a combination of cheap and sufficiently strong for the dimensions required in those boxes. Pieces that size are often found in the burn pile. :rolleyes:
The purpose was to make identical speakers and include the EnABL treatment on one set. Thus giving people a chance to hear "what" EnABL does.

[D, Rose]

Nice speakers, Pete!;)