Arrrggghhh... then OK

I was feeling pretty good about myself.  My son's desk had been in the corner of our warm, dry laundry room for a few weeks while I worked on other projects.  The laundry room is small enough that I couldn't finish all of the pieces at once, so I did the base and the desktop first, with the gallery to come next.  Finishing is frustrating for me, in part because you get to find all the defects you missed and in part because I have a real knack for runs and drips, but it went well and by Friday I was ready to move on to the gallery.  I was putting it in place when, what to my wondering eyes should appear but a CRACK and no reindeer:

With magnification, it appears to be partly on and partly off the glue line, right on the top in the most visible possible spot!  (Insert cloud of blue smoke here)  After the shock wore off, I sat consoling myself with bourbon and trying to figure out why it had happened.  I glued this up last spring, planed it at that time and it spent three seasons in my garage shop stable as could be.  Moving it into a dry, heated environment was the likely cause obviously, but much more than that I cannot say.  I had more or less done everything by the book and the most obvious possibilities seem unlikely to me.  The other end is fine.  Dunno.

Next subject, what to do about it?  Replacement was impossible without starting the gallery over.  Since I have never encountered anything like this before, I consulted my finishing books for advice on alternatives.  The two best candidates seemed to be:

1. Insert medium viscosity CA glue into the crack and then sand sawdust into it;
2. Make a filler of 5 minute epoxy and sawdust, let it dry and sand it flush.

I had a hard time deciding.  I have had good luck on small defects with an option I read somewhere of putting shellac in the defect and sanding over it, sometimes repeatedly.  This crack is too big for that but the CA glue option seemed similar.  I didn't have any medium viscosity CA glue and I did have 5 minute epoxy; further, it seemed like it might be a stronger repair and therefore more likely to prevent a recurrence.  So much for my reasoning.

I mixed up some epoxy and folded in what seemed like the right amount of sawdust.  Then I applied it to the crack, which I had masked off, and forced it in with a little spatula:

Five minutes later, this is what I had:

After about an hour (it would have been better to wait longer) I scraped and sanded it.  After a coat of stain the next day, here is the result:

If you know it's there, you can see it.  However, I doubt that, had I not told him, my son would ever have known and I doubt he will give it a moment's thought.  Sure irritates the heck out of me though.

Hopefully this will never happen again but, if it does, I think I will try the CA glue and sawdust option.  The thing that makes the epoxy show is its uniform color and smooth surface compared to the wood around it.  I think the sawdust might be more like the wood surface.

Interestingly, it seems like expert finishers don't regard defects like this as particularly uncommon or serious.  I have resisted learning about finishing, preferring instead to use the simplest, most foolproof finishes I can find.  With this project, I tried and to a significant though not complete degree succeeded in crafting a piece of furniture that would meet high-end professional standards.  This defect taught me that a part of the process of improvement is to learn more about finishing.