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Help With Slab Table Crack

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Forum topic by Marshall posted 01-28-2015 03:30 PM 892 views 0 times favorited 16 replies Add to Favorites Watch
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Marshall

151 posts in 1517 days


01-28-2015 03:30 PM

A few of you may have seen my previous posts as I was working on my walnut slab table. I finished it and attached the base to the top last week and its been sitting in my kitchen since. Last night I noticed a crack across the grain that certainly wasnt there before. Obviously I’m not pleased about it…

Any thoughts on why this would happen? I would’ve expected a crack to be with the grain, not across. The slabs have been stored inside since they came out of the kiln, and we’re in MN in winter… there isnt much moisture fluctuation this time of year.

The top is attached using figure 8 fasteners. The crack is between the two cross members – not near any screws.

Any thoughts on how to fix it? Can it be fixed at this point w/o sanding down and refinishing? More importantly, any thoughts on how to prevent it from spreading?

Thanks

-- Marshall - http://mcomisar.tumblr.com


16 replies so far

View bondogaposis's profile

bondogaposis

4026 posts in 1813 days


#1 posted 01-28-2015 04:12 PM

How thick are the slabs and how long have they been drying? I bet they are weren’t as dry as you thought. Don’t do anything until the wood fully acclimates. Then if the crack is small fill w/ epoxy sand down and refinish. Checking across grain is common with the wonky crotch figure you have on your slab. It’s beautiful.

-- Bondo Gaposis

View Tennessee's profile

Tennessee

2410 posts in 1977 days


#2 posted 01-28-2015 04:19 PM

Agree with Bondo. Even with pin moisture meters, you only get sort of a surface measurement of moisture. And just because it went through a kiln, doesn’t mean it cannot take on water again, then lose it again.
Actually, looking at your crotch grain pattern, the crack is with the grain at that point. And being far from a cross member or fastener, it would be a place where the wood would find a way to move. (In this case, shrink due to the low humidity winters of MN)

Also agree that after letting it do its thing for another few months, fill it and refinish just that spot.

-- Paul, Tennessee, http://www.tsunamiguitars.com

View Troy Cleckler 's profile

Troy Cleckler

384 posts in 833 days


#3 posted 01-28-2015 04:23 PM

You say that you brought it in the house last week. From a shop I assume? If so, I bet the house is much tighter and dryer than the shop and it’s going to move around some till it acclimates to it’s final living spot. I’m with Bondo on this one, best left alone till it quits moving. My brother brought his bed room furniture from Illnois to Alabama and the joints loosened up quite a bit shortly after the move. Wood does some strange stuff sometimes.
The wood is georgious though, lots of charactor.

-- Troy. - Measure twice, cut once and fill the gaps....

View Marshall's profile

Marshall

151 posts in 1517 days


#4 posted 01-28-2015 04:36 PM

Thanks for the responses all.

@Troy: No, i attached it last week, but its been stored in the house since I bought it in Nov. The only time it was out in my shop (garage) was when i was sanding it, then back inside.

@bondo: The slabs are 1.5” finished (started at 2”). I dont know for sure how long theyve been drying. They were kiln dried and then stored inside once out of the kiln. I’m not sure when they came out of the kiln though. It was at least a few months if not a year before I bought them in Nov.

@Tennessee: Is it possible to sand and refinish just that spot? Its finished with Arm R Seal… Not sure it can be blended with the rest of the table?

In general, while I’m not happy about it, I’m not terribly concerned with it as long as it stays tight and doesnt spread. I’ll give it a few months—but by then it’ll be getting humid in MN…

-- Marshall - http://mcomisar.tumblr.com

View bondogaposis's profile

bondogaposis

4026 posts in 1813 days


#5 posted 01-28-2015 05:35 PM

I’ll give it a few months—but by then it’ll be getting humid in MN…

I would work on it at the tail end of your heating season, maybe the end of March? By then it should have opened all it is going to. Arm R Seal is pretty forgiving and hopefully you won’t have to refinish the whole top.

-- Bondo Gaposis

View mahdee's profile

mahdee

3551 posts in 1230 days


#6 posted 01-29-2015 01:21 AM

I am thinking if it was 2 inches and you took most of the material from the top, that was the cause for the crack. I would use a thinnest feeler gauge you can find to see how far the crack goes down. It may be that it just has raised some. Nice looking slab BTW.

-- earthartandfoods.com

View gfadvm's profile

gfadvm

14940 posts in 2152 days


#7 posted 01-29-2015 01:39 AM

I have had exactly the same experience with wild figured walnut that was VERY dry. The cracks weren’t deep but ruined the nice smooth finish. I had finished mine with shellac so just sanded the cracks smooth and redid the shellac via Semi-French polish. The shellac and sanding dust filled the cracks but others may occur.

-- " I'll try to be nicer, if you'll try to be smarter" gfadvm

View Marshall's profile

Marshall

151 posts in 1517 days


#8 posted 01-29-2015 01:53 AM

The crack goes all the way through the slab… I cant say for certain how much material came off the top vs bottom during sanding, but it was probably pretty close to even.

Thanks

-- Marshall - http://mcomisar.tumblr.com

View gfadvm's profile

gfadvm

14940 posts in 2152 days


#9 posted 01-29-2015 02:09 AM

If it is that deep, I would fill it with epoxy (use a shop vacc underneath to pull it into the cracks).

-- " I'll try to be nicer, if you'll try to be smarter" gfadvm

View Marshall's profile

Marshall

151 posts in 1517 days


#10 posted 01-29-2015 02:16 AM



If it is that deep, I would fill it with epoxy (use a shop vacc underneath to pull it into the cracks).

- gfadvm

The shop vac is a good idea… I hadn’t thought of that. Thanks!

-- Marshall - http://mcomisar.tumblr.com

View Kelly's profile

Kelly

1113 posts in 2406 days


#11 posted 01-29-2015 03:08 AM

Out of curiosity, did you focus on both sides and and ends equally?

Remember, counter tops, though made out of “stable” material, often get laminated on both sides to keep them from warping and such.

When I’ve done monster pieces of wood, I thinned the finish an absurd amount and allowed it to soak up so much, I’ve had six inch thick pieces show moisture on the underside. Then I did that side. It made for a pretty stable piece of wood.

View Marshall's profile

Marshall

151 posts in 1517 days


#12 posted 01-29-2015 02:28 PM



Out of curiosity, did you focus on both sides and and ends equally?

Remember, counter tops, though made out of “stable” material, often get laminated on both sides to keep them from warping and such.

When I ve done monster pieces of wood, I thinned the finish an absurd amount and allowed it to soak up so much, I ve had six inch thick pieces show moisture on the underside. Then I did that side. It made for a pretty stable piece of wood.

- Kelly

Both sides got 4 brushed coats of arm r seal followed by a fifth wipe on coat… The edges were the same.

-- Marshall - http://mcomisar.tumblr.com

View a1Jim's profile

a1Jim

115202 posts in 3039 days


#13 posted 01-30-2015 05:08 AM

The cause may be that it was built in such a way that wood movement was not taken into consideration.

-- http://artisticwoodstudio.com Custom furniture

View Marshall's profile

Marshall

151 posts in 1517 days


#14 posted 01-30-2015 02:42 PM



The cause may be that it was built in such a way that wood movement was not taken into consideration.

- a1Jim

Hi Jim. I accounted for cross grain movement with figure 8 fasteners.

-- Marshall - http://mcomisar.tumblr.com

View upinflames's profile

upinflames

209 posts in 1624 days


#15 posted 01-30-2015 04:14 PM

You can tell from the pics it’s from drying not construction failure. If the slab was air dried it should have been at the minimum of 2 years, kiln dried will still be a while before it’s “stable”. I agree with the epoxy or resin.

showing 1 through 15 of 16 replies

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