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Working with White Oak Slabs

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Forum topic by Sanding2day posted 05-16-2014 03:25 PM 2129 views 0 times favorited 15 replies Add to Favorites Watch
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Sanding2day

1001 posts in 1307 days


05-16-2014 03:25 PM

Topic tags/keywords: slab question

Work has attained two cross section slabs of White Oak with bark remaining on one side. They are about 6” thick and 39” across. Will post a picture later as I am unable to so at this time.

One will be turned into a table, and the other is to be displayed at the Illinois Military Academy with markers within the tree’s rings for important military dates i.e. start/end of U.S. Civil War and continuing forward to present day.

Having never worked with slabs I wanted to inquire on a few things.

Project is simple enough, flatten both slabs, sand, and finish them. I am picturing using a router sled and then belt/ROS but wish to ensure this can/should be done while wood is green as tree was cut 10 days ago. And have no idea how many years it would take to actually dry the slabs being left at 6”. Any methods to ease the likilhood/promenence of checking.

Guess I’m not even sure what to ask at this point, but any advice on turning rough cut green cross cut slabs into flat, smooth and finished display pieces would be appreciated. Thanks

-- Dan


15 replies so far

View Steve Peterson's profile

Steve Peterson

324 posts in 2543 days


#1 posted 05-16-2014 05:44 PM

Are they cookies or table top slabs? Cookies are guaranteed to split. I would expect that there will be at least one large split to the center and lots of small surface checks. It should still be OK as a museum type display.

Conventional wisdom says that most wood takes 1 year to air dry for every 1” of thickness. I don’t know what would happen if you try to finish them now.

-- Steve

View Tim's profile

Tim

3110 posts in 1422 days


#2 posted 05-16-2014 06:14 PM

There were several posts on the Lost Arts Press Blog about the 1 inch per year of thickness not being applicable to thick slabs. His modeling showed that a 6” thick slab could take as long as 60 years to reach equilibrium moisture.
http://blog.lostartpress.com/author/steveschafer/
Here is another that mentions a 50 year old slab workbench top that is still drying:
http://blog.lostartpress.com/2013/12/13/slab-top-workbenches-and-evil-spirits-part-2/

But like Steve said if these are cookies and not slabs that changes everything since wood loses moisture primarily through the end grain.

View pintodeluxe's profile

pintodeluxe

4853 posts in 2274 days


#3 posted 05-16-2014 06:25 PM

I have hauled tabletops into an industrial woodworking shop for final milling. The shop I used had a 50” wide combination planer / drum sander. It made quick work of my tabletops.
Working with green lumber introduces all kinds of extra challenges though.
And since your slabs are cross sectional, you wouldn’t want to plane them by machine, but the drum sanding should work.

-- Willie, Washington "If You Choose Not To Decide, You Still Have Made a Choice" - Rush

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Sanding2day

1001 posts in 1307 days


#4 posted 05-16-2014 07:01 PM

My apologies I was not familiar with the terminology, these are cookies. That is what I tried to convey with verbage of cross section.

Steve You are correct about the one large split in the center and several small checks

Tim Interesteing stuff…

Willie So your thinking I should just just flatten them up through sanding alone?

Or is it just a real poor decision to mess with these until they are dry, 6 years on 6” cookies then?

-- Dan

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Sanding2day

1001 posts in 1307 days


#5 posted 05-16-2014 07:03 PM

Meant to ask, what is it that causes the large split in the center?

-- Dan

View Don W's profile

Don W

17958 posts in 2028 days


#6 posted 05-16-2014 07:28 PM

I would use a low angle smoother or jack. I just did something similar yesterday. Mine did need to be as smooth as yours, and it was pine, but the same theory applies.

Click for details

-- Master hand plane hoarder. - http://timetestedtools.net

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Sanding2day

1001 posts in 1307 days


#7 posted 05-16-2014 07:41 PM

Awesome work Don, certainly do not have your skills with a plane but you certainly seem to prove that working with a green log shouldn’t be too much of an issue.

-- Dan

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Don W

17958 posts in 2028 days


#8 posted 05-16-2014 07:52 PM

for my application I’m not concerned about cracking and splitting. In your application I’d seal it up nice with wax. It will slow down drying, and it won’t stop the splitting, but it will minimize it to some degree.

-- Master hand plane hoarder. - http://timetestedtools.net

View Buckethead's profile

Buckethead

3140 posts in 1329 days


#9 posted 05-16-2014 08:08 PM

The thing about hand planing, a well tuned hand plane knows. You don’t need to. You just become the motor. I exaggerate, but truly, hand planing is in my opinion, the right choice here, barring access to monster equipment.

-- Support woodworking hand models. Buy me a sawstop.

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Sanding2day

1001 posts in 1307 days


#10 posted 05-16-2014 09:28 PM

Appreciate the advice Don/Buckethead… May very well prove to provide a decent/forced education on sharpening up the iron and tuning the plane correctly.

-- Dan

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Don W

17958 posts in 2028 days


#11 posted 05-16-2014 09:33 PM

We can help with that!

-- Master hand plane hoarder. - http://timetestedtools.net

View woodchuckerNJ's profile

woodchuckerNJ

1153 posts in 1095 days


#12 posted 05-16-2014 09:41 PM

I would seal the ends with wax or paint, or glue. That will slow it down.

You can resaw it while its wet, but you can not surface it. You need to leave it to dry.

If you have sawdust, build a bed of saw dust, lay it on top then pack it all around with the saw dust.
put some ply around it to hold it in, then load the rest of the saw dust on top.

In a few weeks replace it. Saw dust slowly and gently dries wood. But better than air, which dries the outside too fast. The sawdust draws the moisture out but keeps it near the surface. I’ve seen this done. It’s better than kiln drying which can do some bad things if not properly done. Many woodturners will throw wood in the DC to get the same, but for a big slab, you’ll have to build an enclosure to keep it from falling off and blowing off. you don’t want to enclose the top, just keep the saw dust in around the slab.

-- Jeff NJ

View pintodeluxe's profile

pintodeluxe

4853 posts in 2274 days


#13 posted 05-16-2014 09:50 PM

I just meant that I wouldn’t be comfortable sending end-grain slabs through a planer. However a large drum sander could work. They are amazing tools, and the shop I visit doesn’t charge much to run a couple pieces through.

-- Willie, Washington "If You Choose Not To Decide, You Still Have Made a Choice" - Rush

View Matt Rogers's profile

Matt Rogers

69 posts in 1431 days


#14 posted 05-16-2014 11:22 PM

I have built a few coffee tables with similar sized maple slabs (42” diameter cookies). You will get a split or two that goes all the way to the center and it will open approximately 1-4” in total width as it dries. If you want to have a single split, you can make a cut with a saw (chain/band/hand/etc) that is nice and straight and smooth from the outside to the center to give the slab room to move along that line and you should only end up with that one gap in your dried piece. Add a thick (60% or more of total thickness) butterfly key to hold the joint together, but only after the gap has stabilized to a moderately consistent size.

Drying is not that bad – remember that wood dries from the end grain much faster than edge grain. Since these pieces are all end grain, you are looking at a much shorter drying time. My maple slabs were 4” to start and finished around 3” and are fully air dry after 2-3 years with no special treatment (stored outside under sheet metal at the sawyers first, then in a barn for the next year. Think about a thick timber or slab, the first few inches of the end grain are going to be dry after just a year or two. This round slab is just like a 39”x39” timber that is only 6” long.

I will say that you are dealing with end grain, so your sanding and finishing are going to be that much harder and take that much longer. Sanding the maple took forever. I finished with Tried and True Danish Oil and Shellac.

-- Matt Rogers, http://www.cleanairwoodworks.com and http://www.cleanairyurts.com

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Sanding2day

1001 posts in 1307 days


#15 posted 05-20-2014 12:03 AM

Thank you all for the wealth of knowledge. Apologize for the delay on posting pics, came down with strep last week and was pretty well out of the game for a minute. Got these moved into storage as it looks like a distant project from the given advice but we will see what the state would like to do with them and go from there…

-- Dan

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