Trupan (light MDF) for box construction?

[redfox697]

Has anybody use/encountered/have any insights regarding the use of Trupan for cabinet construction? A friend of mine told me about it. He builds furniture, and was raving about it over MDF. He's not terribly knowledgeable in the audio realm, so in the beginning I wrote it off due to its lower mass, but then he got my attention: He said that when you pick up a sheet of MDF, it bows, but when you pick up a Trupan sheet (same size), it stays stiff. Hm.

From the manufacturer:

TRUPAN

THE MERCEDES OF MDF

Trupan is a double refined medium density fiberboard produced from only fresh debarked Radiata Pine logs harvested from sustainable forests. By using only fresh Radiata Pine logs, no other species, or wood waste, Trupan is able to produce a very light colored medium density fiberboard. The use of Radiata Pine in the production of Trupan produces a fiberboard that is extremely easy to machine. The Radiata Pine content of Trupan tends to prolong cutter life. The double refining produces a board that is very consistent throughout its core, thus making it the perfect choice for edge profiling, moulding, and routing. Trupan is produced in Chile and imported into the United States. Because of the longer lead times it is important to have a supplier that carries an adequate inventory. At Schaller Hardwood Lumber Company, we carry perhaps the largest most diversified inventory of Trupan in the Midwest.

TRUPAN LIGHT---weighs approximately 80% of a standard mdf or about 80 lbs per sheet of 3/4" 4x8. Trupan Light is the best choice for producing moulding, raised panels, and edge profiling.

TRUPAN ULTRA LIGHT---weighs approximately 60% of a standard mdf or about 60 lbs per sheet of 3/4" 4x8. Trupan Ultra Light is the best choice for any use where weight is a factor. Trupan Ultra Light will machine very well.

from http://www.schallerhardwood.com/new_page_2.htm

The downside is that it's around twice the price of MDF.

Any thoughts on this one?

[---k---]

got me curious.
Acording to this PDf for the TruPan molding (which I'm guessing is the same) on page 11,

http://www.arauco.cl/arauco_wood_products/pdf/cat%C3%A1logo%20moldura.pdf

E = 313,000 psi
MOR = 4000 psi

As compared to MDF:

http://www.sierrapine.com/products/mdf/SierraPineMDF/SierraPine%20MDF%20and%20Thick%20MDF%20Spec.pdf

E= 350,000 psi
MOR = 3,200 psi

If this is correct, regular MDF is a little bit stronger.

EDIT: That is for the TruPan Ultralight panels. So, the E maybe a little higher for the regular. I can't see it being significantly better than MDF. So, the only benifit would likely be weight.

[cjd]

Or just skip the MDF and go 13 ply birch...

[ThomasW]

Or just skip the MDF and go 13 ply birch...

Correct, if this stuff is double the cost of MDF, that's BB ply pricing

[redfox697]

Yeah, I contemplated going Baltic Birch- I'm in the Pro Audio (specifically live sound) world and everything is BB, for weight and durability, but I've read on some forums that it's not as good for home stuff due to the fact that it's (whether measured or percieved, I don't know) less acoustically inert than MDF.

If I knew that they (mdf vs. BB) were comparable, I'd probably use BB- originally my great-uncle who is a badass veneer artist was going to help me out with the construction and finishing of my MDF enclosures, but he can't, and none of my friends (many of whom know a fair amount about carpentry) know much, if anything, about veneering. Therefore, I know that a BB cabinet, properly finished and stained, will look quite nice. Don't need to worry about veneering to make the wood-look happen- it's already there.

[cjd]

Less acoustically inert? maybe. Doubtful. It has more mass but it's less stiff. And a solidly constructed box of either will inherit more from proper stuffing/wall covering or whatnot (if needed) than from the difference between BB and MDF.

MDF is also far more toxic to work with and less kind to tools.

It's one of those things where I don't care if it's that tiny bit less good in some respects, 'cause in others it's better, and I don't mind working with it.

C

[ThomasW]

If you want the best of both worlds make a sandwich, inner layer of BB ply with an outer layer of MDF.

[jdybnis]

My $0.02: I stopped using MDF after my second project. I think BB is better for speaker building, but even if it wasn't I'd use it over MDF just for health reasons.

[JonP]

Or just skip the MDF and go 13 ply birch...

Less acoustically inert? maybe. Doubtful. It has more mass but it's less stiff. And a solidly constructed box of either will inherit more from proper stuffing/wall covering or whatnot (if needed) than from the difference between BB and MDF.

MDF is also far more toxic to work with and less kind to tools.

It's one of those things where I don't care if it's that tiny bit less good in some respects, 'cause in others it's better, and I don't mind working with it.
C

BB is lighter than MDF. I calculated the relative density once. Forget what it was, off the top of my head, but it was on the order of 10-20% lighter.

I agree with the thinking that its more how you build it and damp/brace it, so though it may be "ringier" than a simliar piece of MDF, with proper consruction, it can do well. And, if it has nice wood for the outer layer, it can look great without veneering... if a light wood will work for you. That and all the other things going for it... it's nice material...

I can get cheap offcuts of quality 5/8" BB at the local Rockler, so on my next project I'm planning on taking advantage of the stiffer nature. Going with the thinner stock, either adding 1/4" MDF or hardboard or gluing on scrap pieces of 5/8th's to stiffen the panels, with perhaps a semi-rigid glue, and see how it works vs a single 3/4" BB or MDF box.

I'm kind of fascinated by lighter, well damped and braced boxes, vs the 1.5" thick "wooden safe" style of construction. One day, I plan to do accelerometer experiments to see what should go into a good, light and well damped box.