“ Hollow log “

[trimguy]

So if you were to take, say a red oak log approximately 24 to 28 inches in diameter, 36 to 42 inches long and hollowed out the center, leaving approximately 3 inches. Do you think this would dry without cracking or splitting ?

[Magicman]

Here is a Cherry log that meets that description, complete with a nail.  Presently resides in the burn pile and is available until 'light up' time. 

[Old Greenhorn]

Take a bunch of cookies off that log and make mirrors like I do.

 Mine are all RO, would love to try Cherry.

[trimguy]

Okay, maybe I wasn't totally clear, but i think I know what I meant. I have a green solid log that I would like to make hollow and have it stay intact at 36" to 42" long. I will need it 24" to 28" in diameter. If I leave approximately 2" to 3" to you think it would split when drying once it was hollowed out ?

[Magicman]

Oh you were totally clear, and I see no reason for it to split because there is no moist core to cause it to split. 

Your question simply carried me to that perfect example that I encountered last week with the Cherry log.  With the ring shake, it could have been hollowed out fairly easily.  It was dead, dry, not split, and I seriously doubt that it would have ever split.

I intended to saw jacket boards from it when I hit the nail.

[beenthere]

trimguy
Possibility, but likely would depend on how quickly you can hollow out the log from start (green, on the stump) to finished hollowing it out. 

Drying stresses will begin to set in right away, so time would be of the essence, in my opinion. 

That 3" shell (rind) will still have imbalanced shrinking due to radial shrinkage. 

What do you have in mind to do?

[doc henderson]

yes, first thought was of a natural hollow from rot, animals or insects.  I think it will be more likely a success than a solid log.  you may want a small fan to help the inner core dry as fast or faster than the outer core.  how to monitor that I have no idea.  @YellowHammer what ratio of inner flow rate relative to the outer flow rate should be used to match the water loss inner to outer.  So do not worry @trimguy Robert will let us know the answer within a few seconds. 

[Jeff]

Let me find what I did...

[Jeff]

https://forestryforum.com/board/index.php?msg=23576

[trimguy]

Very interesting Jeff. I will opt for power tools for my " gutting " I think. My wife wants a small island in the kitchen in the cabin and I have a cookie that is 34" - 38" by 3 1/2 - 4" thick for the top. I'm thinking setting it on a " log " would look neat, instead of me building a round cabinet.I need to hollow it out for storage and to make it lighter.

[Larry]

How are you going to hollow it?

I would split the log on the mill lengthwise. Next I would use the chainsaw to waste the bulk of center of the log. Follow up with a right angle grinder using a carving head to make the inside somewhat presentable. Once this is done you won't have to worry about splitting since the two halves can freely shrink. Dry the two halves to EMC. Next step is to glue the two halves back together. Use loose tenons or dowels to insure it doesn't come apart. To get a good glue surface you will have to flatten each side on the jointer, router bridge, or hand plane if you have the skills. Once glued back together the joint will be invisible.

Interesting project.

[Ianab]

Yes a hollow log will probably stay intact as it dries out. Reason that a log / cookie splits is that the wood shrinks more % wise in circumference than it does in diameter. You cant lose 10% in circumference but only 5% in diameter, yet that is how some wood shrinks as it dries. Where is the missing 5%, in a great big crack. 

But if the log is hollow, then you have some contractiun room / less differential shrinkage. How big the hollow needs to be is going to depend on "things", but your chances are many times greater than a fully sound log. 

[trimguy]

I thought about what Larry said, it would make hollowing a lot easier if it was halved. I'm worried that one side will close up or spread more than the other side when drying , is this a valid concern or am I worried about the wrong thing ?

[Larry]

I don't have a good answer for your question. If it did go back together wonky I think you could fair it up enough to match by carving.

[trimguy]

Thanks Larry, I will post pictures when I do this.

[Ianab]

I'm worried that one side will close up or spread more than the other side when drying , is this a valid concern or am I worried about the wrong thing ?

What you should find is the the 2 pieces will tend to flatten out a little, like a flat sawed board tends to cup.  (  )

It shouldn't be excessive, but it will probably need a bit of trimming to get the pieces matched up again, as the faces won't be exactly parallel any more. As long as the log is straight and no defects, the movement should be pretty much the same on each piece, so you should be able to get them to match up pretty close. A router bridge / "Slabmizer' type machine would be the tool to get the faces jointed to glue them up again, or a hand plane and a good eye. 

[rusticretreater]

Yes, you would have to rework the two halves to make the fit together again with flush surfaces and then redrill the center if you needed a perfectly round hole through the center.  But when done, everything would be spot on.

[trimguy]

Thank you guys.

[jimF]

As mentioned with no center of the log there is room for the ring to shrink into, so there is little concern for differential shrinkage due to tangential to radial shrinkage.
It can be thought of a plank that is three inches thick, which will generate significant drying stresses. Use a drying schedule for 3 inch thick material.