Why you have to remove the sapwood

[joachimM]

A lot of it comes down to wood physiology.
Heartwood is dead, and has had time to dry out slowly. Sapwood is saturated with water, and will therefore shrink much more and more rapidly than heart wood. This difference in shrinkage speed causes cracks. Sealing reduces this differential.
This is also why bole planks become concave on the outer side: the outside of the trunk contains more moisture than the inside, hence it shrinks more.
 

[bjrogg]

Just curious has anyone tried curing Osage in water? I've seen it on YouTube. It's supposed to replace sap with water I think. Maybe it would dry more even then when removed from water? I really don't know just curious if anyone has tried it.
Bjrogg

[BowEd]

BJ.I've heard of that too.Heard it would take the sap out faster under deeper water under more pressure.I've never googled it but I'm sure there's some info about it.Also heard the old timers used that process when their wagon axle or spindle would break down on the trail west settling America and would quick dry a replacement part.Also heard with dry ice dried it faster too.
I'll still just cut enough and let it air dry naturally.

[bjrogg]

Thanks Ed I was just wondering if it might keep checking in check. I saw it in a bow make my video.
Bjrogg

[Marc St Louis]

No Osage or Locust grow here but I have cut a few whitewood species in late Spring/early Summer that checked with the bark on and bark off and sealed.  I suspect that timing plays a role in back checks.  If the sapwood has too much water in it when the tree is cut, such as in late Spring when the tree is starting to bud, then it is more likely to check.

[BowEd]

I've never done it but steaming the whole bow helps dry or drive the sap out too I've heard.Though not sure about the checking deal afterwards.

[PEARL DRUMS]

I will counter what you countered with, Kevin. I split up four big logs into bow size staves and ruined every one with checks, all of them. That's the only batch I've ruined and it wont happen again.

I wonder why there is a difference?

Heck I have no idea man. Climate maybe?   

[Eric Krewson]

In Alabama you can cut osage in the dead of winter and sap will run out of the log after you cut it.

I wonder if water curing was a primitive way to keep the bugs at bay until the stave could be worked. It looks to me that you still have to dry it after it comes out of the water.

[Badger]

   I don't harvest any osage myself and am dependent on several suppliers I use. It sounds like when to cut is very important. Most of the wood I receive with bark still on is usually less than 3 months cut and still pretty wet but past the high risk point of checking. I have had good luck starting at this point just taking them all the way down to roughed out bows. As long as I use a sealer on the back I seem to be ok. If I don't I stand a good chance of getting some minor checking in the limbs. I normally seal with tightbond glue or sometimes latex paint or even toilet bowl wax.

[BowEd]

In Alabama you can cut osage in the dead of winter and sap will run out of the log after you cut it.

I wonder if water curing was a primitive way to keep the bugs at bay until the stave could be worked. It looks to me that you still have to dry it after it comes out of the water.

Yes but water leaves the wood faster than sap moisture it seems after steaming or pressured water drying.
I doubt if the ground freezes very deep in Alabama.Up here it freezes up to 5' deep at times.Osage cut here in the dead of winter will not have sap running out.At least I've never seen it.
I've read the bugs will leave the wood alone after it gets below 20% moisture.Think Tim Baker stated that.

[Badger]

In Alabama you can cut osage in the dead of winter and sap will run out of the log after you cut it.

I wonder if water curing was a primitive way to keep the bugs at bay until the stave could be worked. It looks to me that you still have to dry it after it comes out of the water.

Yes but water leaves the wood faster than sap moisture it seems after steaming or pressured water drying.
I doubt if the ground freezes very deep in Alabama.Up here it freezes up to 5' deep at times.Osage cut here in the dead of winter will not have sap running out.At least I've never seen it.
I've read the bugs will leave the wood alone after it gets below 20% moisture.Think Tim Baker stated that.

  Ed, I think you are safe from bacteria and fungus below 20% but bugs will attack anytime if the bark is left on and as said above if you remove the bark and not the sapwood you are prone to more checking.

[joachimM]

Wood cured in water has interesting properties:

first, it removes the edible parts for bugs and fungi, as sugars and other yummy compounds are slowly extracted (like from a tea bag). So water-cured logs are much more resistant to decay. Since the wood structure is more porous after curing, the wood dries faster once sawn.

Second, it saturates the entire log with water, also the heart wood, which was drier than the sapwood. Slabs, boards and planks sawn from water-cured logs are dimensionally much more stable, have less warping and checking during drying, because there isn't any difference in moisture content across the wood.

Unfortunately, water-curing logs takes at least a year, preferentially even 2-3 years.

[BowEd]

Pressure water soaking goes faster than osmosis type soaking.Something setting under 20' of water is subjected to much more pressure than at 2'.

[bjrogg]

Wood cured in water has interesting properties:

first, it removes the edible parts for bugs and fungi, as sugars and other yummy compounds are slowly extracted (like from a tea bag). So water-cured logs are much more resistant to decay. Since the wood structure is more porous after curing, the wood dries faster once sawn.

Second, it saturates the entire log with water, also the heart wood, which was drier than the sapwood. Slabs, boards and planks sawn from water-cured logs are dimensionally much more stable, have less warping and checking during drying, because there isn't any difference in moisture content across the wood.

Unfortunately, water-curing logs takes at least a year, preferentially even 2-3 years.

I was thinking like these statements. It does seem to me like if you got rid of the sap you'd get rid of the sugars and maybe the bugs.
That's also why I thought replacing sap with water and evenly hydrating the entire stave may even though drying faster dry more even and help prevent checking. The video I saw they just put stave in a creek or pond was only a foot or to deep. I'm sure like Ed said deeper would be faster.
Bjrogg

[BowEd]

I just calculated it and @ 20' depth pressure is 23.5#'s per sq. inch.10' depth 19.1#'s per sq. inch.
Pressure or freeze type drying I think is definitely faster.
Water leaves wood a lot faster afterwards for drying than sap but like you said I'm not sure what that does to those resins and sugars in wood.