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Stabilizing Crack in maple slab

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Forum topic by d85 posted 09-26-2018 12:50 AM 406 views 0 times favorited 13 replies Add to Favorites Watch
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d85

8 posts in 26 days


09-26-2018 12:50 AM

I have a 6’ maple slab that has a crack that is about 2’ long. The distance isn’t that wide through the length of the crack. I am going to use bow tie/butterfly inlays, and epoxy to stabilize it so it doesn’t pull apart any more than it already has. The advice I’m looking for is how to stabilize the up and down movement of the split.

Right now there is about a 1/4” different between the two sides of the crack. I put a couple pieces of wood on either side of the slab and used C-clamps to press the two sides level.

What would be the best way to keep the up and down movement of the two sides? Someone had suggested using pocket hole screws in addition to the inlays and epoxy to keep even it out and keep it from moving more. Are there better solutions?

Thanks in advance for your input.

Here are some pictures of the crack.


13 replies so far

View lumbering_on's profile

lumbering_on

362 posts in 636 days


#1 posted 09-26-2018 01:17 AM

You could do epoxy, or bowtie/butterfly/dutchman repair on it.

https://www.youtube.com/watch?v=Iryk-76bmH4

James Write is a member of LJ, so he definitely knows what he’s talking about.

View jbay's profile

jbay

2677 posts in 1045 days


#2 posted 09-26-2018 02:16 AM

I would go in a couple or 3 inches from the end and rout out a 1/4” recess for a steel plate that would be screwed into both sides of the crack.

View RichBolduc's profile

RichBolduc

415 posts in 262 days


#3 posted 09-26-2018 11:20 AM

Bowties of a complimenting wood.

Rich

View bondogaposis's profile

bondogaposis

4990 posts in 2497 days


#4 posted 09-26-2018 12:27 PM

I wouldn’t try force the sides back into alignment. I would plane the high side until it is level with the low side, then do the same on the under side. Then bow tie and epoxy the crack, that should stabilize it from further movement.

-- Bondo Gaposis

View LittleShaver's profile

LittleShaver

398 posts in 765 days


#5 posted 09-26-2018 12:45 PM

I had a similar problem with a white oak slab. My solution was to align the sides with some vigorous clamping. I then dug a mortise in the end grain as deep as I could that bridged the gap. In the bottom of the mortise I epoxied in a piece of 1/2” steel rod that bridged the gap. I then embedded a butterfly into the end grain to hide the steel. After waiting a few days to allow everything to cure, I released the clamps and was pleasantly surprised to see everything held as planned.
Added more epoxy to fill the split and some others, finished the project and it has been our dining room table for nearly 7 years now. Everything has stayed in place and there is no evidence that the split was ever out of alignment.

-- Sawdust Maker

View swirt's profile

swirt

3163 posts in 3118 days


#6 posted 09-26-2018 12:45 PM

+1 on Bondogaposis’ recommendation. Much safer to work with the wood than try to force it into shape only to find out later that you can’t. Make your dutchman go deep (at least half-way) and you should be fine

-- Galootish log blog, http://www.timberframe-tools.com

View mathguy1981's profile

mathguy1981

39 posts in 50 days


#7 posted 09-26-2018 04:53 PM

+1 on bondogaposis fix.

View pottz's profile

pottz

3146 posts in 1130 days


#8 posted 09-26-2018 10:31 PM

ditto on bondogaposis also.

-- sawdust the bigger the pile the bigger my smile-larry,so cal.

View d85's profile

d85

8 posts in 26 days


#9 posted 09-27-2018 01:20 AM

Thanks for the advice everyone! I really appreciate it.

I agree with bondogaposis in not trying to force things back. Would I need to shave the whole slab. It seems like any positive bend would be ok, but any bend away from the planed side would result in a slope unless the whole slab went through a planer again.

Also, In the future will the bow tie inlays prevent any further warping?

I apologize for the questions, but this is the first slab I’ve worked with.

View msinc's profile

msinc

524 posts in 649 days


#10 posted 09-27-2018 03:06 AM

Sounds like your mind is made up. It warped once…what are you going to do when it warps back, but now you have it “planed” to make it worse if it does move? The only way I have seen this done is to use caul boards to press it flat where it belongs then drill horizontally thru the center of the slab across the crack and epoxy in a steel rod. You will probably need more than one. The more the better it will hold. Depending on how much stress or tension you are up against you might need pretty substantial steel rods…1/2” or better diameter. You can hide the outer holes with plugs and if you are going to install bow ties you can hide the rods in the crack. Otherwise fill the entire crack with casting resin or epoxy. I don’t care for the look of bow ties, when I have to do this I fill the entire crack with dyed resin or epoxy. Don’t get me wrong, bow ties, when properly executed denote first rate work.

Edit: you are already questioning this method…”will the bow ties prevent…” No, they are very unlikely to prevent further warping. They will do a better job of preventing the crack from spreading, but they will do very little to stop one side from raising up or down, especially in a slab that thick. Bow ties will stand some stress, but think of how much you have there to move wood that thick.

View swirt's profile

swirt

3163 posts in 3118 days


#11 posted 09-27-2018 01:20 PM

Yah as msinc says, the bow ties (dutchman) are not intended to keep it flat, they are intended to keep the crack from growing. For a crack that long I would shoot for a minimum of 3 across the top If they were at least half the thickness of the slab deep and you put another beefy one in on the bottom side, they would likely go along way toward stabilizing that slab in more than just the direction of the crack.

You didn’t say how long this slab has been drying. If it has been more than a couple of years, you will likely not see enough additional twisting/warping once you have that crack stabilized and you plain it flat. If it has been less than a couple of years. Stabilize the crack then put is away to age some more.

-- Galootish log blog, http://www.timberframe-tools.com

View d85's profile

d85

8 posts in 26 days


#12 posted 09-28-2018 12:40 AM

Thanks for all the suggestions! I’ve seen epoxy mentioned several times. What suggestions do you have for brands and types for a project like this?

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d85

8 posts in 26 days


#13 posted 10-05-2018 02:34 AM

Update: I used several of the ideas for stabilizing the slab. I cut a channel in the end about an inch and a half as Littleshaver said he did. I went to the local home depot and got a threaded rod that was slightly bigger than the channel. I hammered it in the channel and sealed it in with liquid nails. THe reason Use the threaded rod was from the suggestion of msinc. A threaded rod going all the way through would have been ideal, but what was feasible was a channel that had a threaded rod in it.

I also added three bow tie inlays along the crack to help stabilize it.

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