Thread: SG of Huon Pine

does this help?
http://www2.fpl.fs.fed.us/techsheets...dacrydium.html

one chart i have sets the density of Lagostrobus franklini at 537.

Density

Approximately 550 kg/m³ at 12% moisture content.
Unseasoned density approximately 950 kg/m³ .

other info is at..
http://www.tastimber.tas.gov.au/species/huon_02.asp
http://www.tastimber.tas.gov.au/spec.../huon_pine.pdf
http://oak.arch.utas.edu.au/tbia/tec...peciesID=49464
http://en.wikipedia.org/wiki/Huon_Pine
http://links.jstor.org/sici?sici=0305-0270(199511)22:6%3C1035:SSRAAS%3E2.0.CO;2-M

Thanks Reeves. I had visited all these sites except for the last one. None give the SG. I can get it by subscribing to The Wood Explorer - but a lot of money for just one SG. I have the SG of most other woods I use.

mm interesting, whats the difference between density and specific gravity ?

maybe PM jugo illic, he will know that info, hes the guy who looked after the CSIRO wood databse for years.

Also ring Tassie forestry and get onto the labs, that should know..

cheeeers
john

BobR,
Does this help?

According to what's below
550 kg/m<SUP>3</SUP> at 12% moisture content. - your SG would be 0.55
Unseasoned density approximately 950 kg/m<SUP>3</SUP> . - you SG would be 0.95

Ian

******************************************************


The Specific Gravity - SG - is a dimensionless unit defined as the ratio of density of the material to the density of water at a specified temperature. Specific Gravity can be expressed as

SG = = ρ / ρ<SUB>H2O</SUB> (3)

where

SG = specific gravity

ρ = density of fluid or substance (kg/m<SUP>3</SUP>)

ρ<SUB>H2O</SUB> = density of water (kg/m<SUP>3</SUP>)

It is common to use the density of water at 4 <SUP>o</SUP>C (39<SUP>o</SUP>F) as reference - at this point the density of water is at the highest.

• Thermal Properties of Water Density, Freezing temperature, Boiling temperature, Latent heat of melting, Latent heat of evaporation, Critical temperature ...

Since Specific Weight is dimensionless it has the same value in the metric SI system as in the imperial English system (BG). At the reference point the Specific Gravity has same numerically value as density.
Example - Specific Gravity


If the density of iron is 7850 kg/m<SUP>3</SUP>, 7.85 grams per cubic centimeter (cm<SUP>3</SUP>), 7.85 kilograms per liter, or 7.85 metric tons per cubic meter - the specific gravity of iron is:

SG = 7850 kg/m<SUP>3</SUP>/ 1000 kg/m<SUP>3</SUP>

= 7.85

(the density of water is 1000 kg/m<SUP>3</SUP>)

Thanks Ian. Whilst this gives me enough info to work with, and I understand the formula involved ( did not have it before now though), it raises more questions. Out of curiosity though. For the purpose of measuring MC can one assume that the timber industry selects a targer MC then calculates the SG based on this for each piece of timber. The 12% shown in your example would work well in coastal Aus. and fits in with a figure I extracted from another source, but the USA and therefore most moisture meters target 6%. In reality does this mean that moisture meters used in Aus.should be using different SG than that provided by the meter manufacturers. Just a thought

BobR,
I have no idea whether there's a standard moisture content for measuring such things, but to satisfy my curiosity, why is the SG important to you?

You mention huon pine, so I presume you might be building a boat. But if you were, the moisture content would probably increase from whatever value it was originally measured at anyway.

Give us a clue, because unless you messing about in water, I can't imagine why the SG is an issue.

Ian

Not boat building - boxes and cabinets. I use a Wagner moisture meter and when doing a MC reading you enter the SG for that particular timber. It is either that, or you need correction tables.

Oh

Bob
the CD that came with your moisture meter contains the Woodexplorer density data but there is no value for Huon Pine !

as to your other thought, as I understand the physics, the moisture meter measures the density of the timber from which you subtract the "wood" part to get the "water" part. The SD value allows the meter to work out how much wood to subtract. For wood densities abouve about 0.8 the meter struggles with the correction


ian

BTW, thanks for the tip re Amazon shipping, mine took 3 days door to door

According to the Australian timber buyers' guide, Huon pine has an SG abot 0.52

Thanks Alex.

Ian whilst I am willing to be corrected I think your last response is only partially correct. I think terminology is the problem. The meter has difficulty with giving an accurate reading when the SG goes above .80, not the density. With the Wagner meter I don't have to do any substractions, the MC is a direct readout providing the correct SG for the timber being measured has been entered. Hense my need for the SG of Huon pine.

Whilst the CD that comes with the meter contains the SG for a large number of US domestic timbers, and some US imports there are quite a few missing. Huon pine being one. This listing comes from The Wood Explorer database. To get at all the timbers on this database one has to purchase a subscription. Huon pine is there as I did a search of the database, but the relevant info is not made available without being a subscriber.

mmm form this dialogue it seems that the denisty and SG are closley related and that if you know the density you can calulate the SG, is that right ?

Originally Posted by reeves

mmm form this dialogue it seems that the denisty and SG are closley related and that if you know the density you can calulate the SG, is that right ?

Yes, they are different ways of referring to the same thing. E.g., the density of huon pine is 520 kg/cubic metre, SG is 0.52.