Wood has many variables that affect the outcomes of using it, like knots, checks, cracks, wood chipping out, wormholes, cross-grain, and more ... then there are the woodworker variables, like things we don't make accurate cuts on, or use the wrong piece and make mistakes with, in my workshop, they are called "a Colin glitch" and I make my fair share of them. 

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When I first started woodworking, of course, I made mistakes, but I didn't worry too much about them because I knew I could rely on "wood filler", either shop-made or commercial versions that would bail me out. What I learned over the years, at least for me, all of the wood fillers I have ever used have left me disappointed ... 

Most of the wood fillers I have used do not take stains of dyes very well, if at all. I tried making my own and that was even less successful. I could never really match the colors or the grain effects. What's worse, with most of these fillers, when you go back and look at them later on, sometimes as short as a few months, other times a couple of so years ... the wood filler has dried up and either fallen out or is loose. If it hasn't fallen out or loose, the filled part stands out like a sore thumb on your project. This is often because the filler did not take the stain properly, and now that the rest of the project has aged a bit and gotten slightly darker, the filled areas are still the original color and now they are much lighter in color so it looks like someone went around and putty'd up the project ... terrible looking. 

Wood Filler Repair

That has been my experience with fillers. They may look fine at first, but I have not found one that stands the test of time, even just a few years, so for this, I try really hard to never use fillers ... but sometimes there just is no other choice so I am super stingy on when and where I use them. The only ones that I have found somewhat effective are the "after" products. That is, products used to fill small nail holes or tiny chips, or even scratches in furniture. These often come in the form of a colored grease pencil or something like a felt pen. Be careful with the felt pen version, the tips are anything but fine so they can get away from you too. But always test before you commit.

Probably the most common fix is chair or stool rungs. 
If the rung is broken, it often falls into one of 2 kinds, the first is a long cracked rung where both ends are still attached to the chair legs. These are somewhat easy to fix (usually). All that is required is to apply a liberal amount of yellow glue inside the crack as best you can, using dental floss to help slide the glue in deeper and thicker can help. Then clamp the 2 pieces together, remove as much of the squeeze-out glue as you can, then re-clamp (watch that the clamp will not stick the chair rung). If the rung is round, plastic electrical tape works fine too. Let the glue dry and harden for 24 to 48 hours and that should amount to a good fix. 

If the rung is snapped in 2 pieces in the middle, this is not easily repairable and is probably best to replace the rung, often a dowel from the hardware store can be used, even if it doesn't have a taper (if your rung had a tape). 
To fix the leg, you may need to use commercial dowels and re-drill, or if you are lucky, you can find a dowel that will fit in the holes already in the legs.

If you have loose rungs or are attaching new rungs, in order to get a snug fit and ensure the glue will hold the best it can, make a fine HORIZONTAL saw cut at each end of the dowel, then making a matching, the thin wedge that will go into that slot, so that when you drive that new rung into the hole, the wedge will meet the back of the hole and will drive that wedge into the rung, expanding it and making a tight fit, and a better place for the glue to attach to.

Wood chair leg repair

Corner Fixes
If you are making boxes or other projects with 45-degree corners, that just don't fit as well as you would like. These can often be fixed by simply inserting a different colored wood into a fine cut you can make on your table saw. Make sure you have a good quality cross-cut blade, and again, make some test cuts, and you will be surprised how easy and effective this fix is ... and your boxes will great too !! 

Fixing 45 degree wood joints

Inlays, Butterflies, and Bowties ... 
These are similar to the box corners, another way of hiding nasty knots or cracks in the end of boards, where you don't want the crack to keep getting bigger. These fixes can be done by hand, but I like using an Inlay kit. These kits will not work on any of the Palm Routers that I know of, you need a bigger full-size router. 

NOTE: You will need some sort of adapter for the inlay kit to attach to your router, best to check with the manufacturer to see what they offer, some adapters are somewhat universal while others are specific, see your manual, or check with your dealer, or look it up online.  

Fixing wood cracks with bow ties

Router Inlay Kit from Woodworkweb Affiliate Taylor Tools see it - HERE
 or, click the image below

 inlay kit

The reason I like the inlay kit over hand cutting these is once you make the template for the size and shape you want, it's easy to cut both the pocket and the insert out with the router. If you are doing these by hand that is a lot of fussing you need to do to make a nice tight fit, which means you probably want fewer angles and sides. With the router inlay kit, you can make a template shape in any size or shape you want, bowtie, square, flower shape, animal shape, car shape ... you name it and cut out the pocket and the matching insert in a few minutes ... and multiples.

Lots of cool things you can do with this.  

Copyright to Colin Knecht