I’ve done lots of repairs over the years, some simple, some complex and some that have been “repaired” by Uncle Bob who took shop back in 1958. Sure Bob meant well, but his talents in woodworking fall a little short. Repairing his “repairs” usually takes a little longer.
There are some repair mistakes that I see frequently that cause the damaged area to fail again. The most basic error is trying to re-glue something back together. New glue won’t stick to dry glue. You have to have a wood to wood bond for your new glue to adhere to. So the first thing you have to do is sand or scrape off all of the old glue. Once your joint / repair is clean, you can glue it up and clamp it together.
Another common error in repairs is excess fasteners. I recently repaired an arm on a chair that had been “fixed” several times. This small joint, about 3 square inches, had seven screws and three nails in it. That many fasteners weakened what little wood was there. The repair in this case meant removing all the fasteners, filling and gluing the arm back together, cleaning up the old glue, and re-attaching the arm with just two screws and some glue.
An in home repair that I see a lot is “the cover up”. While not really a repair, covering the top of a table, desk, etc, with a doily or tablecloth hides the damage, it’s not the best solution. Scratches can sometimes be fixed with a wax stick. Water rings can often be lifted out with alcohol (rubbing, not tequila) or rubbed out with a mild abrasive. With a little work you can have the top of your furniture back and not have to hide it.
As for repairs to particle board furniture, well, let’s just say the best repair for those is replacement. Once the board has been cracked, chipped, torn, swollen, etc. there is no good repair. This material doesn’t take glue well, doesn’t hold fasteners well, and will never support weight again.
These are the most basic DIY repair errors that I see. Keep them in mind next time you have a repair on your hands. Of course if you’re not sure what to do, call your local professional woodworker, and leave Uncle Bob out of it.