Latewood / Earlywood

[meanewood]

I'm looking for advise on which sapwood ring to leave on the back of the Australian Blackwood warbow I've got underway?

I know its probably an unfamiliar wood to most of you but the sapwood is very much like other woods in that the thicker part is white and more fibrous and the thinner is darker and harder.

Which should I leave exposed as the back?

[DarkSoul]

Australian blackwood, or Acacia melanoxylon is diffuse porous. SG of about 0.54 - 0.64.

I don't have experience with the wood (as you said, probably not many people have). But since it's a diffuse porous wood, there is no mechanical difference between the earlywood and latewood. This only accounts for (semi) ring porous wood species.
I think you are mixing up your terminology. Are you talking about sapwood versus heartwood? Or really earlywood versus latewood? I have no idea if you should leave the sapwood on a Acacia melanoxylon stave. GraemeK states that "Acacia melanoxylon ( Tasmanian Black Wood ) (...) typical two tone timber but only has an S.G of about .6. I have tried it as a bow timber because it is common but it is only marginal as it takes a lot of set and splits badly."

[meanewood]

Thanks for that, yes I am referring to which is preferable to have exposed on the back, the Latewood or Earlywood and in this case, I'm leaving about 4mm of sapwood on the back.
I have made a Blackwood bow before and had crystaling problems but it shot well.
Now with a lot more experience as a bowyer, I will try a wider/ flatter profile and heat treat the back, very much as I do with Elm.

Australian blackwood, or Acacia melanoxylon is diffuse porous. SG of about 0.54 - 0.64.

I don't have experience with the wood (as you said, probably not many people have). But since it's a diffuse porous wood, there is no mechanical difference between the earlywood and latewood. This only accounts for (semi) ring porous wood species.
I think you are mixing up your terminology. Are you talking about sapwood versus heartwood? Or really earlywood versus latewood? I have no idea if you should leave the sapwood on a Acacia melanoxylon stave. GraemeK states that "Acacia melanoxylon ( Tasmanian Black Wood ) (...) typical two tone timber but only has an S.G of about .6. I have tried it as a bow timber because it is common but it is only marginal as it takes a lot of set and splits badly."

[PatM]

 What is the thickness of each layer? Most people who attempt to work a stave to a growth ring consider the latewood the end goal. Mostly because it is typically stronger in woods where it is even possible to reliably work a stave to a ring.
 

[meanewood]

What is the thickness of each layer? Most people who attempt to work a stave to a growth ring consider the latewood the end goal. Mostly because it is typically stronger in woods where it is even possible to reliably work a stave to a ring.
 

Hi Pat
The rings are about 1.5mm, comprising a white thicker part (1mm) and a darker thin part (0.5mm).
As I've worked down through the layers, the whiter, thicker part seems softer and more fibrous than the dark section.
I'm assuming that the whiter part is earlywood and the darker to be latewood?
This is the first type of wood I've used that has an apparent difference in the properties of a sapwood ring.
As a result, if one or the other is better for the back, it would be good to know!

[PatM]

You will have to decide which is which based on what sequence the outer ring has at the beginning or end of the growing season.

[Del the cat]

@ Meanewood.
I assume you mean heat treating the belly, just sayin' to avoid possible confusion.
Del

[meanewood]

Hi Del
Oops, you know what I mean!