Repairing end-grain checking

[Jim C Martin]

Hello All:
I'm working on a couple of Morris chairs with steam bent arms and back slats. In order to bend kiln dried QS white oak, I've been soaking them in Downy fabric softener and its been working fine with one exception. I'm getting a lot of checking at the ends. Stupidly, I cut to length before soaking/steaming/bending so I can't cut anything away. These will be ammonia fumed so any repair probably needs to done right at the end.
Suggestions on how I can fill these cracks and prevent more splitting? Epoxy? Epoxy with sawdust? Other options?
Thanks,
Jim
362660

[Kevin Jenness]

Those checks are not going to disappear, no matter what you fill them with. You might get by with epoxy/sawdust under a dark stain. New material is the best fix, but look for air-dried rather than kd. End checking usually occurs with too rapid moisture loss at the beginning of the drying process, so I wonder if what you are seeing was already there, exacerbated by rapid moisture uptake. It looks more like honeycombing, but that typically is visible right away. End sealing before soaking might have helped.

[Mark Bolton]

Agreed. Those checks more than likely run through the entire piece.

[Jim C Martin]

Thanks Kevin and Mark. I'm not thrilled about wasting some of the most highly figured QS oak I've ever seen, but that's better than having the chair start splitting in a few years. I appreciate the heads up.
I just now steamed a piece from the same lot but I steamed for 2 hours/inch of thickness instead of 1 hr/inch. It bent really nicely. We'll see how much spring back I get when I take it out of the clamps. Traveling all next week so won't know for a while.
Cheers,
Jim

[Mark Bolton]

Perhaps resawing and a bent lamination.

[Mike Cutler]

Jim

Rot Doctor with black tint.You need an epoxy that will migrate on it's own via capillary action. Or you need to heat the ends and dip them a slow set epoxy and let the epoxy get "sucked in" as the wood cools.
Another solution would be to google Mohawk Finishes. They specialize in epoxy products for wood working repair, and finishing.
You'll never match the color and grain, unless you hand paint it post finish.

[Brian Holcombe]

As the others mentioned, thats not fixable. Occasionally I get a white oak board that has internal cracks that I do not find until I do something like resaw the board.

[Scott T Smith]

Hi Jim.

If if you look closely those appear to be checking along the medullary rays in the oak. This commonly occurs on the ends of boards that did not have end sealer applied when green. Usually the checks only extend a few inches into the board.

When you rewet dry lumber, the wood cells expand. As they dry they shrink and I think that may have been the source of your problem. I would seriously doubt that the checking extends all of the way through your boards, but you may see it going from the outside of the boards inward along the medullary ray lines. The checking will be more extensive at the ends of the boards because the cellular orientation allows easier moisture penetration.

They may not be salvageable, but before you throw them away try standing them vertical and applying Tightbond to the ends, using a shringe to force glue into the checks. Then clamp so that you are squeezing the checks together and let dry.

The lesson here is not to rewet dry oak!

[pat warner]

Dip the ends of the rough stock in liquid paraffin. When you first get them.
& inspect the hell of them before cutting.

[Scott T Smith]

All, most likely Jims problems are not related to incorrect drying of the original lumber, but rather due to soaking the boards in the water based fabric softener.

When you rewet dry wood it swells. Most likely his boards checked as they dried back down and the cells shrunk.

[Jim C Martin]

Thanks Scott. I agree that the soaking and drying is the cause of my issues. When I originally did test pieces it was still cold here in Utah so the pieces took a long time to dry. No checking in those pieces. We're now having highs in the high 90s and of course its bone dry. I reckon that's giving me much more rapid drying and hence the checking. I did try a piece with just steam and had no luck at all, couldn't even bend it on the form.
I have a couple of test pieces in the forms right now with three modifications: 1) I sealed the ends with paraffin before soaking 2) I only soaked for a day and 3) I'm letting them dry indoors. These bent onto the form okay and I'll know soon how well they hold their shape.
Cheers,
Jim

[Steve Jenkins]

Anytime you want to stem bend get air dried lumber rather than kiln dried

[Jim C Martin]

Anytime you want to stem bend get air dried lumber rather than kiln dried

Yes, air dried or green would be great but none is available around Salt Lake City as far as I can tell.

[johnny means]

If I were doing a repair on something like this, I would hog out the end if the board and fill it with a plug.

[Jim C Martin]

If I were doing a repair on something like this, I would hog out the end if the board and fill it with a plug.
That's a great idea! I can cut into it with my slot mortiser for a plug and that would allow me to see how far in the crack goes. Thanks very much!

[johnny means]

Yeah, I've used that technique to hide repairs and reinforcements with pretty good results.

[Mark Gibney]

Jim, I'm very interested in the outcomes you get with the different steaming / bending combinations you are trying. I also find air dried lumber difficult to get where I live.

It would be very useful to me if you summarized the different approaches and outcomes at the end of all this. Thanks.

[Jim C Martin]

Update: I cut into two of the ends with the worst checking. None of the cracks was more than 7/8" deep.
I'm about to redo the whole process but with a modifications:
1. I have sealed the ends with paraffin prior to soaking in water/downy. This time I'm using the Downy with no dye or scent.
2. I left the parts about 3 1/2" oversized (longest I can fit into my container) so I can cut off checking at the ends.
3. I will seal the ends again right after I bend them and let them dry in my house rather than outside. I'm in Utah and right now we're getting highs around 100 with single digit humidity so drying outside would be pretty fast. We use an evaporator cooler in our house making it relatively cool and moist so the pieces should dry much more slowly. I'll keep them in the house for a week prior to moving them back out to the garage.
Much of this may be overkill because 1" oversize on each end would have saved me last time around. Live and learn.
Cheers,
Jim



Agreed. Those checks more than likely run through the entire piece.