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Author Topic: eucalyptus at 14% need some advice  (Read 445 times)

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Offline Iroll4rts

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eucalyptus at 14% need some advice
« on: July 11, 2017, 04:02:38 am »
hey yall im sure this has been answered 1000 times on here. 
i just bought a pair of book matched eucalyptus slabs that are about 85" long 18-24" wide and 3" thick with a 14% moisture content. 

 i live in southern california wheres its been 100 degrees daily and just want a little advice on the rest of their drying future.  do i need to have them in my garage or just stickered level on concrete behind my house and out of direct sunlight?


work with all sorts of lumber daily but never worked with a live edge slab.  these guys are going to be turned into my breakfast area countertop intigrated with the other tops made of concrete

also a little advice on finishing and keeping a satin look to them not super glossy like epoxy resin. i do plan on filling any cracks or splits with epoxy prior to sanding to ensure strong bonding and the closure of gaps or holes

any advice here would be so helpful...thanks in advance
cory

Offline Ianab

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Re: eucalyptus at 14% need some advice
« Reply #1 on: July 11, 2017, 05:02:22 am »
Well the good news is that at 14%, you can't really mess them up. Any drying damage will have been done back in the earlier stages of drying, and all you might expect now is a little bit more shrinkage as it dries down to your final moisture content, and that depends mostly on your average humidity.

Now even at 100 F, if the humidity is 70%, the wood will only dry out to about 12%. If the humidity is 30%, then it's going to dry down to more like 6%. There are tables that let you calculate how many % shrinkage this will be.

Now locally we run 70-80% humidity pretty much all your round, and i have to use a dehumidifier pretty much all year round to keep the RH down. So 14% dry is "good to go", as long as you allow for some seasonal movement.

But best results will be stacking them in "similar" environment to where there are going to eventually live. Sheltered spot outside may be OK in your climate?

I've done the epoxy filling stuff, and it seems to work fine, but I'll leave the finishing advice up to others.
Weekend warrior, Peterson JP test pilot, Dolmar 7900 and Stihl MS310 saws and  the usual collection of power tools :)

Offline WDH

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Re: eucalyptus at 14% need some advice
« Reply #2 on: July 11, 2017, 08:01:52 am »
You could bring them inside and sticker them in your climate controlled house in an out-of the-way place for about 6 - 8 weeks making sure that there is good air flow space on the floor under the bottom slab like a 2x4 base with the 2x4's set on edge every 16".  Place 1" stickers on the 2x4's, then the first slab, then another set of stickers lined up with each 2x4 on the base, then the 2nd slab, then another row of 1" stickers, then place some type of cover over the top of the stack on the last set of stickers.  Plywood would be a good cover.  They will dry down to the equilibrium moisture content in your house.
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Offline Iroll4rts

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Re: eucalyptus at 14% need some advice
« Reply #3 on: July 11, 2017, 07:12:31 pm »
awesome advice guys! thank you!  the humidity here tends to stay in the 30% range so its fairly dry most of the year.. i gues ill bring them in and see how they do in a few weeks.. the house was a total remodel and im ok with waiting our a few extra weeks with plywood countertops till my slabs are properly cured

heres a few pics of them  they book match pretty well to make 1 big slab










Offline Ianab

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Re: eucalyptus at 14% need some advice
« Reply #4 on: July 11, 2017, 07:30:31 pm »
If they have dried to 14% with only that much cracking, then you are going to be OK. The cracks may open fractionally  more as they dry the last few %, which is why you want them stable before your start with the epoxy. Fill and finish them now, and they dry a bit more in place, and those cracks get 1/16" wider, and you have new cracks in the top. Get them properly dry, then fill the gaps, and things will stay stable.

Reason your climate makes a difference is weather here today, we have 41F and 90% humidity. House DH is working to keep the inside humidity down to 60-70%.  But in those conditions I would call 14% wood "dry", and if I took it outside, it's going to actually gain moisture today.  :D

Those should finish up looking pretty good. Not sure what species of Euc you have there, but it's all hard, dense and strong. Main downside is getting it dry without degrade, like that cracking that you can see in it. But that's not a problem in your intended use, and a few pots of resin will soon sort that out.
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Online GeneWengert-WoodDoc

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Re: eucalyptus at 14% need some advice
« Reply #5 on: July 11, 2017, 11:15:08 pm »
Appreciate that there are perhaps 25-30 species we can call eucalypts.  Some are high shrinkers with even a little moisture change.  It is likely that starting at 14% MC now with you home at 30% RH (not unusual for many locations in Southern California) or equivalent to 6% MC in wood that you will get close to 2% size change as the pieces dry to 6% MC.  In addition to this normal shrinkage, we can get varying shrinkage that causes warping that would be an issue for a counter top or table, especially if the two pieces are close to the center of the log, near a branch, or with high stress from the tree (all three as shown in the pixs).  Therefore, you need to dry them further and very carefully (slowly) to minimize warping and aggravating existing splitting.  You would be best off covering them with mesh fabric, like burlap, to retard drying.  Your garage if enclosed is also good as there will be little wind.  The stacking with weights at the low MC can help somewhat, but not much.  WDH has some good ideas. 
Gene - Author of articles in Sawmill & Woodlot and books: Drying Hardwood Lumber; VA Tech Solar Kiln; Sawing Edging & Trimming Hardwood Lumber. And more

Offline Iroll4rts

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Re: eucalyptus at 14% need some advice
« Reply #6 on: July 12, 2017, 12:53:49 am »
Appreciate that there are perhaps 25-30 species we can call eucalypts.  Some are high shrinkers with even a little moisture change.  It is likely that starting at 14% MC now with you home at 30% RH (not unusual for many locations in Southern California) or equivalent to 6% MC in wood that you will get close to 2% size change as the pieces dry to 6% MC.  In addition to this normal shrinkage, we can get varying shrinkage that causes warping that would be an issue for a counter top or table, especially if the two pieces are close to the center of the log, near a branch, or with high stress from the tree (all three as shown in the pixs).  Therefore, you need to dry them further and very carefully (slowly) to minimize warping and aggravating existing splitting.  You would be best off covering them with mesh fabric, like burlap, to retard drying.  Your garage if enclosed is also good as there will be little wind.  The stacking with weights at the low MC can help somewhat, but not much.  WDH has some good ideas.

gene, are you suggesting to not acclimate them in my house now? i brought them inside about an hour ago and put them on stickers per advice a few responses above.... so far they are very flat and even hopefully they maintain that profile in the ac... let me know what ya think

cory

thanks again everyone for the great advice!

Offline Ianab

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Re: eucalyptus at 14% need some advice
« Reply #7 on: July 12, 2017, 01:50:32 am »
It's not spontaneously going to turn into a pretzel.

Gene is correct that it's probably going to shrink something like another 2%, but it's already shrunk maybe 4-6% since it was green. Any warp or cup that it's got now, may get slightly worse. The cracks will likely get slightly bigger, but this is just a fact about wood drying out.

Now when it's green you can certainly mess up wood like this by drying it too fast, even air drying in your climate. The outside dries and shrinks too quickly for the water from the wet core to migrate out. So the shell dries, shrinks and cracks (surface checking) Then once that's dry the core eventually catches up and shrinks, but now it has the solid dry shell around it, and so it tends to crack internally (honeycomb). You end up with a horrible piece of firewood.

But once it's at 14%, right though, it's hard to mess up by any sensible air drying. You could grab a chunk of Bluegum like that out of my shed, where it's been sitting for a couple of years, at ~13%, and put it in your house. It will still dry a bit, shrink a bit, and some cracks might get bigger. But drying it slower at this stage wont really change that.

The important thing is you get it stable before you build anything "non-rustic" out of it.
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Offline JustinW_NZ

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Re: eucalyptus at 14% need some advice
« Reply #8 on: July 12, 2017, 04:08:33 am »
If you can check where it was tested with a moisture meter, make sure it was a good probe meter hammered into the core of the wood to be sure.
Its easy to case harden this wood and end up with a wet core and the honeycomb effect or worse.

Otherwise like Ian says, it looks like its dry and stable now.
Those cracks running along the side of that top slab looks like some core or pith wood.
That is very unstable in eucalyptus so if its only cracked like that i think someone dried it nice and slowly.

Cheers
Justin
Gear I run;
Woodmizer LT40 Super, Treefarmer C4D, CAT 528 swinging grapple, 10ton wheel loader.