Gluing Hairline Crack in Walnut

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Forum topic by ChesapeakeBob posted 01-10-2013 02:38 PM 8559 views 0 times favorited 11 replies Add to Favorites Watch
View ChesapeakeBob's profile


369 posts in 4396 days

01-10-2013 02:38 PM

I made a clipboard as a gift to my son for Christmas. The thickness of the clipboard is 3/8”. There a VERY small crack at one end of the board in the walnut, extending about 2” to 3”. The crack is so small it is barely noticeable. My son described it to me over the phone and I was hoping I could glue it, but I cannot even get a small opening to inject any glue. I thought of a small wood wedge, but the wedge would probably leave more or a mark than the existing crack. I also thought about running it in the tablesaw just far enough (for kerf about 3” long) to remove the crack, and then making a replacement sliver of walnut to glue into place. Does anyone else have any suggestions? Thanks.

-- Chesapeake Bob, Southern Maryland

11 replies so far

View bondogaposis's profile


5889 posts in 3265 days

#1 posted 01-10-2013 02:44 PM

Leave it alone. If it at some point gets longer or wider then glue and clamp it.

-- Bondo Gaposis

View ajosephg's profile


1890 posts in 4474 days

#2 posted 01-10-2013 02:58 PM

I’ve never tried it, but I’ve heard you can lay a bead of glue on top of the crack, then pull a vacuum on the opposite using your shop vac. That will draw some of the glue into the crack, after which you remove the excess glue and clamp the board.

-- Joe

View Wdwerker's profile


333 posts in 3147 days

#3 posted 01-10-2013 03:06 PM

+1 on try the vac to pull the glue in. I haven’t tried it either but it should work. If the gap Isn’t open enough for the vac to pull the glue thru then just fill the crack with filler.

-- Fine Custom Woodwork since 1978

View TrBlu's profile


386 posts in 3539 days

#4 posted 01-10-2013 03:42 PM

Put a piece of painters tape on the under side of the crack, then run a bead of thin CA glue along the crack. Allow the CA to flow into the crack. Run a second bead to insure full coverage. The clamp to pull crack together.

Let it sit over night, the remove tape. Sand and refinish glued area if needed.

-- The more I work with wood the more I recognize only God can make something as beautiful as a tree. I hope my humble attempts at this craft do justice by His masterpiece. -- Tim

View Planeman40's profile


1523 posts in 3674 days

#5 posted 01-10-2013 04:00 PM

This is very simple.

Go buy you a bottle of very thin (water-like) cyanoacrylic (CA) glue. Note that this type of glue comes in various viscosities from very thick to very thin. Apply the glue to the crack. it will wick into the crack going all the way inside. Apply some, then wait. Apply some more until the crack is full. If you can pull the crack closed with a clamp, do so, but quickly as thin CA glue can set quickly. Wipe away the excess. Leave the glue to set for at least an hour to make sure it has hardened before releasing the clamp.

A little sanding and you are done!


-- Always remember: It is a mathematical certainty that half the people in this country are below average in intelligence!

View Lee Barker's profile

Lee Barker

2172 posts in 3764 days

#6 posted 01-10-2013 04:07 PM

I wouldn’t try to close it. You’re just transferring stress to elsewhere in the piece. I would treat it as a surface defect.

I’d get some of the dark colored PVA and rub some into the crack and then sand the area with 180, ROS. The fines will get in the crack and the heat will speed the glue drying. After all is cured, resand and refinish the piece.

The crack will be absolutely invisible.



-- " his brain, which is as dry as the remainder biscuit after a voyage, he hath strange places cramm'd with observation, the which he vents in mangled forms." --Shakespeare, "As You Like It"

View _Steve's profile


85 posts in 3940 days

#7 posted 01-10-2013 05:29 PM

I have tried the concept of useing a shop vac to suck the glue into the crack. It works great, it leaves glue on both surfaces and when clamped, some will squirt back out.

-- McMaker Woodworks, Where you can give directive for a pending antique.

View dbray45's profile


3391 posts in 3690 days

#8 posted 01-10-2013 05:54 PM

One of the issues with walnut – it has stress in it. Put a maple key across the crack instead of trying to hide it. This will stop it from splitting, relieve the stress and look good.

-- David in Palm Bay, FL

View Terry Ferguson's profile

Terry Ferguson

203 posts in 3581 days

#9 posted 01-11-2013 02:36 AM

I use the CA glue method suggested by Trblu and Planeman40 and I also use Lee’s method. My approach would be to use the CA glue first. If you’re not happy with that, then use the PVA and sandpaper. Sometimes I will do both in that order.

-- Terry Ferguson, Bend Oregon

View Popsnsons's profile


440 posts in 3895 days

#10 posted 01-12-2013 02:48 AM

I would mask off both sides of the crack. Make some walnut sawdust (table saw) mix the sawdust with wood glue and sand it over the cracked surface. Remove the masking tape.

-- Pops ~ In So Cal...

View Tim Dahn's profile

Tim Dahn

1614 posts in 4478 days

#11 posted 01-18-2013 11:41 AM

I would also suck the glue in with a shop vac. You could try it out on a scrap piece first.

-- Good judgement comes from experience and experience comes from poor judgement.

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