mulberry bow stave reducing the back or "chasing a ring"

[PirateSurferDude]

A while back I posted some questions about mulberry wood and some of the tactics used to make bows from such.  I got some great responses and I split one log and reduced the bottom and sides down to 3''x3''x6'.  I left the bark on the top side or what will be the back of the bow.  This was done in early January.  This weekend I decided to remove the bark and reduce the sapwood down to 2 growth rings and leave it on the back of the bow as a backing as a couple of you suggested; however, upon getting a third of the way down the stave, I noticed this aftenoon, after letting sit overnight in my shed outdoors, two longitudinal cracks about an inch in one place and 2 inches in another in the sapwood.  I was upset and frustrated to say the least but not entirely surprised. 

My question is when one is going to attempt to use a couple or so rings of sapwood and is chasing a ring down the stave how do you prevent these cracks from occurring?  Did I remove the bark too soon?  Should I have immediately sealed the wood as I chased the ring? Or are there some other proven strategies that I am ignorant to in this process?

Any and all help is appreciated.

[El Destructo]

Sap Wood will shrink and lose Moisture rapidly....I would have sealed it immediately after following the Ring....thus slowing down evaporation....but not necessarily stopping the Longitudinal cracks....sometime they will still happen with Sapwood...I normally take it all off to a good thick Dark Ring....and on Mulberry that ain't too hard to find!!

[Pat B]

Your wood was probably still too wet to reduce to a few sapwood rings without sealing. Shellac works well for this application because it is easy to remove or add final finish over it.
   You might want to go ahead and remove the sapwood,asap, before the checks go into the heartwood. If you don't mind the checks being there you can fill them with super glue then seal the back. They shouldn't hurt the bow except cosmetically.
   On bows I kept sapwood on the staves were completely dry.

[Hillbilly]

I usually always seal the back with spray shellac or glue when I chase a ring, I've had too many check over the years (sapwood and heartwood). Sometimes wood that seems dry isn't when you get down inside it.

[George Tsoukalas]

The best scenario for osage, black locust and mulberry is remove the sapwood if there is enough heartwood. Jawge

[PirateSurferDude]

Thanks guys!  I've made some very nice hickory bows in years past but this is my first attempt with mulberry.  I realized that the main mistake I made this weekend was diving in too early moisture content wise on this bow.  I will begin removing the rest of the sapwood tonight when I get off work.  I  greatly appreciate any and all advice and helpful hints.

[PirateSurferDude]

Pat B,

Just for future references, how many sapwood growth rings did you leave on the back of your mulberry bows?  I was attempting to leave 2 growth rings.

Thanks

[Pat B]

Usually one or two. Be sure the sapwood is sound, though. 

[shamus]

The best scenario for osage, black locust and mulberry is remove the sapwood if there is enough heartwood.

+10 to that.

[Hillbilly]

I've left a couple rings of sapwood on mulberry bows before, looks good and no more trouble checking than heartwood-only. Heartwood will check too, especially locust, if it's not bone-dry. I just spray on some shellac or brush on some glue and it's good to go.

[PirateSurferDude]

Thanks Everyone!  I try to learn something new everyday.  Thanks for your knowledge and willingness to share it with others!

[Pat B]

One thing about mulberry is the annual rings are usually thicker than other woods. Take that into consideration if you leave sapwood on the back.