Thread: Specific Gravity - list of Aussie species?

Originally Posted by FenceFurniture

. . . . they aren't aware that we have more than 2-3 species here (let alone about 700 Eucalyptus spp....).

There are apparently 700 Euc species just in WA, and 200 in the rest of Australia. OK most of them are no more than stunted shrubs.

The densities of eucalyptus can be highly variable (the first one I looked at my CSIRO Forest Trees of Australian book on forest products says 755 - 1043 and another one says 740 - 1005 kg/m^3) and then even on the same tree the density can vary significantly. The only way around this is to measure the density yourself otherwise if you want a reliable comparative MC measurement.

Originally Posted by BobL

The densities of eucalyptus can be highly variable (the first one I looked at my CSIRO Forest Trees of Australian book on forest products says 755 - 1043 and another one says 740 - 1005 kg/m^3) and then even on the same tree the density can vary significantly. The only way around this is to measure the density yourself otherwise if you want a reliable comparative MC measurement.

Maybe I am misunderstanding this, but I thought Specific Gravity for timber was the density at 12% moisture content. O'course, I don't know what the moisture content is, which is why I bought the meter. If I just measure the straight up density of any given piece then that will be giving false readings won't it? (because the MC could be anything).

Originally Posted by FenceFurniture

Maybe I am misunderstanding this, but I thought Specific Gravity for timber was the density at 12% moisture content. O'course, I don't know what the moisture content is, which is why I bought the meter. If I just measure the straight up density of any given piece then that will be giving false readings won't it? (because the MC could be anything).

Specific gravity at 12% is only what what moisture meters use but that won't necessarily be the SG or densities available our presented in books or tables. The likelihood of the SG for your piece of timber at 12% being the same as that of the what's in a book is only approximate. That's why using the density method only ever give approximate results. Accurate MC measurements calibrate the meter output direct to an absolute moisture content for a specific timber which of course has to be measured by drying a range of pieces of timber and measuring their moisture loss with a with a balance. This takes lots of time and effort which is why its only been done for a few meters and for a few timbers.

Yes I understand that even a particular piece of timber can vary (just like the grain does) and that it's only approximate, which is why 10-15% is the desired range (and preferably a little lower up here in the drier climate - no rusty tools here man!). This meter comes with a calibration device which is a piece of plastic on 25mm legs complete with serial number to match this particular meter.

However, I'd still like to be able to create a list of SGs in Excel to put in the phone as a PDF to use with the meter when I'm either purchasing timber or evaluating my own stash for "ready to use". Too many shrunken disasters tearing themselves apart when I thought the timber "probably/likely" dry enough, even after more than 1 year per inch.

Have you seen this.
http://www.tocact.org.au/wp-content/...properties.pdf

Originally Posted by FenceFurniture

Maybe I am misunderstanding this, but I thought Specific Gravity for timber was the density at 12% moisture content. O'course, I don't know what the moisture content is, which is why I bought the meter. If I just measure the straight up density of any given piece then that will be giving false readings won't it? (because the MC could be anything).

Brett
Don't let your OCD get the better of you.

I have a much older version of what I think you have bought -- you have just purchased a pinless Wagner meter?
BTW, Chris Becksvoort uses a meter which uses pins and says you can always find places to hide the pin holes, and failing hiding them, a little water will make them disappear.


If timber in your stash has been drying for a while, what you're really looking for is the variation in moisture content between boards and along individual boards. If you are looking at a selection of Jarrah boards (0.75 SG in Wagner's species table) what you want to know is how the moisture varies along a board and between boards. As long as it's pretty uniform, it doesn't really matter what the "actual" value is.

If your timber is fresh sawn -- i.e. green -- you can still measure the moisture, but just let it dry a little longer.

Originally Posted by ian

Brett
Don't let your OCD get the better of you.

I have a much older version of what I think you have bought -- you have just purchased a pinless Wagner meter?

Originally Posted by FenceFurniture

This meter comes with a calibration device which is a piece of plastic on 25mm legs complete with serial number to match this particular meter.

Yes, a pinless Wagner, with dual depth reading which should be very useful (6mm, 18mm readings)

Originally Posted by ian

BTW, Chris Becksvoort uses a meter which uses pins and says you can always find places to hide the pin holes, and failing hiding them, a little water will make them disappear.

With this meter I can just move it over the board and the reading continually changes - very, very fast to assess a board. That is not possible with pins (unless you subsequently run it through the thicky, which is probably likely - not very welcome in a timber yard though...)

I looked into this quite a while ago. I concluded that there isn't a complete list.

Bobs pdf,
Wood properties and uses of Australian timbers | Business Queensland
Australian timbers volume 1, by Ashley J Sewell

That's about all I'm aware of, hope it helps a bit.

Hi Brett

looking at the Wagner species list, I see
Douglas Fir (known in Aus as Oregon) -- 0.48
Gum, Black (US generic term for Eucalypti spicies) -- 0.50
Gum, Red (ditto) -- 0.52
Jacaranda -- 0.34
Jarrah -- 0.75
Jelutong -- 0.38
Karri -- 0.79
Merbau -- 0.67
Mountain Ash (Eucalyptusspp.) -- 0.62 (marketed as Tassie Oak?)
Myrtle, Tasmanian -- 0.64
Pine, Hoop -- 0.44
Radiata Pine -- 0.45
Rubberwood -- 0.51
Sapele -- 0.60
Sassafras -- 0.46


then there's other [to the US] exotics, like

Red Mallee (Eucalyptus oleosa and E. socialis), Average dry weight (1,050 kg/m3), SG (basic 0.79, at 12% moisture content 1.05)
Queensland Maple (Flindersia spp. (F. brayleyana), Average dry weight (560 kg/m3), SG (basic 0.45, at 12% MC 0.56)

etc
Look here Browse by Common Name | The Wood Database for more "exotic" species

Thanks chaps. In the absence of a copiable list, my accomplice (i.e. co-owner) is going to create a simple spreadsheet from his timber book of Aust species.

Brett
How many different species do you have in your stash?

I'm thinking no more than about a dozen that are not also common in the US, Europe, South America, Asia or Africa and therefore listed on Wagner's species list.

so looking up a dozen "exotics" shouldn't be too difficult

Originally Posted by ian

How many different species do you have in your stash?

I'm not sure - quite a few, but not too many by now that should need measuring. It's more about being prepared for whatever might come along, particularly when out purchasing, on a trip etc. Not a particularly onerous task to get the data from the book into an iPad apparently. Having a simple PDF in the phone will be pretty useful I reckon.

BTW, don't forget I have that FRG board here for you.

Brett
thanks for looking after the FRG for me


To contribute to your requested list

Mountain Ash, Victorian Ash (Eucalyptus regnans) -- Average Dried Weight: 680 kg/m3) -- SG (Basic 0.49 -- 12% MC 0.68)

Beefwood (Grevillea striata) -- Average Dried Weight: 965 kg/m3 -- Specific Gravity (Basic 0.78 -- 12% MC 0.96)

Bendee (Acacia catenulata) -- Average Dried Weight: 1,200 kg/m3) -- Specific Gravity (12% MC 1.2)

Australian blackwood, Tasmanian blackwood, Acacia blackwood (Acacia melanoxylon) -- Average Dried Weight: 640 kg/m3 -- Specific Gravity (Basic 0.54 -- 12% MC 0.64)

Red Bloodwood (Corymbia gummifera) -- Average Dried Weight: 865 kg/m3 -- Specific Gravity (Basic 0.70 -- 12% MC 0.87)

Grey Box, White Box (Eucalyptus moluccana (syn. E. hemiphloia)) -- Average Dried Weight: 1,120 kg/m3 -- Specific Gravity (Basic 0.83 -- 12% MC 1.12)

Yellow Box (Eucalyptus melliodora) -- Average Dried Weight: 1,075 kg/m3 -- Specific Gravity (Basic 0.81 -- 12% MC 1.08)

Brigalow, orkor (Acacia harpophylla) -- Average Dried Weight: 950 kg/m3 -- Specific gravity (12% MC 0.95)
Comments: Brigalow is not commercially harvested, but hobbyists and other craft mills may utilize this wood on a limited basis. Brigalow trees are most closely related to the smaller gidgee (Acacia cambagei)—though the latter’s wood is slightly more dense.

Australian Buloke, Bulloak (Allocasuarina luehmannii) -- Average Dried Weight: 1,110 kg/m3 -- Specific Gravity (Basic 0.86 -- 12% MC 1.11)

Australian Red Cedar, Toona (Toona ciliata (syn. Cedrela toona)) -- Average Dried Weight: 485 kg/m3 -- Specific Gravity (Basic 0.40 -- 12% MC 0.49)

Chinaberry (Melia azedarach) -- Average Dried Weight: 610 kg/m3) -- Specific Gravity (Basic 0.47 -- 12% MC 0.61)

Cooba, willow wattle (Acacia salicina) -- Average Dried Weight: 690 kg/m3) -- Specific Gravity at 12% MC 0.69

River cooba, shoestring acacia (Acacia stenophylla) -- Average Dried Weight: 735 kg/m3) -- Specific Gravity at 12% MC 0.74
Comments: A small to medium sized tree, river cooba grows slightly larger than the closely related cooba (Acacia salicina). Both yield attractive timber of moderate density (for Acacia) that’s easy to work.

Coolibah, Coolibah burl (Eucalyptus coolabah, Eucalyptus microtheca) -- Average Dried Weight: 1,085 kg/m3 -- Specific Gravity (Basic 0.81 -- 12% MC 1.09)

Creekline miniritchie, red mulga (Acacia cyperophylla) -- Average Dried Weight: 1,100 kg/m3) -- Specific Gravity at 12% MC 1.10
Comments: Sometimes called red mulga for its distinctive red bark, this small tree yields a dense, dark-colored timber. Due to its small size, the wood is limited to speciality and craft uses such as turned objects.

Curracabah, early-flowering black wattle (Acacia leiocalyx) -- Average Dried Weight: 850 kg/m3 -- Specific Gravity at 12% MC 0.85
Comments: A small tree with fairly dense, dark-colored wood. Another very closely related species, Acacia concurrens, also goes by the name curracabah. Curracabah is not available commercially and its used is primarily limited to hobbyist and other small specialty craft items.

Australian Cypress, White Cypress Pine (Callitris columellaris (= C. glaucophylla)) -- Average Dried Weight: 650 kg/m3 -- Specific Gravity (Basic 0.56 -- 12% MC 0.65)

and then there's

Huon Pine (Lagarostrobos franklinii) -- Average Dried Weight: 560 kg/m3 -- Specific Gravity (Basic 0.47 -- 12% MC 0.56)