Let’s face it: wood sustains damage over time, whether from wear-and-tear or household accidents. But before you toss beloved pieces of furniture or quit your home improvement project, consider a little wood repair first.
I talk a lot about how to repair damaged wood on this blog because old houses get a lot of it. There is one thing I have been adamant about and that is not using Bondo as a wood filler, because it’s not made for that. Instead, I advocate for actual wood fillers and epoxies that were designed for wood not the auto body shop.
As if I haven’t talked about this enough yet I feel like it’s never enough because I see it so often. So today I’ve got the definitive list for you of 6 reasons NOT to use Bondo as a wood filler.
1. Conceals Wood’s Natural Beauty
Wood is used so prominently in the construction of homes, furniture, and even instruments because it’s strong and beautiful. If you use Bondo as a wood filler, however, you will conceal the natural color and markings of that wood. This means you’ll be forced to prime and paint over the surface and, in so doing, eliminate any hopes of enjoying the wood in its natural state. I guess if you’re painting then this doesn’t matter to you, but there still 5 more reasons.
2. Does Not Stain Well
Another thing that isn’t a big deal if your painting, but just so you know Bondo does not stain well…at all. It is largely impervious to water and oil-based stains so your patch stands out like a sore thumb. Trying to overcome this will only yield two different colors on your surface that serve as obvious indications you’ve made repairs.
3. Does Not Release Moisture
In most cases, wood can safely absorb a substantial amount of water before reaching a point of decay. But when the wood is suffocated by Bondo, that threshold becomes much less.
Bondo is also well-known for holding moisture; the problem is that it does so without release. And just as moisture can become trapped between metal and Bondo when performing auto body repairs, it can likewise develop between wood and Bondo. The end result can be wood rot which is likely the reason you used Bondo to begin with. Repairing rot with a material that encourages rot is the antithesis of working smarter not harder.
4. Does Not Move with Wood
When wood comes into contact with moisture, including humidity, it is going to swell and then shrink again as it dries. Architects and designers account for these movements to ensure durable wood-frame buildings and furniture.
Bondo, on the other hand, does not move. Like at all! This is highly desirable when making auto repairs, for which this substance is well-suited. But when you try to fuse Bondo and wood together, you’re likely to encounter the following scenario:
- Air and weather changes prompt wood to move
- The Bondo used to fill this wood remains constant
- As the wood swells and shrinks, it applies pressure to the Bondo that forces cracking
- Your patch is forced off the wood in short order needing re-repair
5. Poses Hazards to Your Health
Bondo came into being as a replacement for lead, used in earlier times to repair damaged auto bodies. Lead worked well for this purpose but presented two major concerns: it required extensive skill to apply and is toxic to people. Heralded for its fast drying time and easy application, Bondo is today safer than lead, but that isn’t saying much.
If you’ve ever opened a can of Bondo you know exactly what I’m talking about when I say the fumes are intense. And they’re not only intense, they are toxic because Bondo is made with fun ingredients like glass microspheres, talc powder, and titanium dioxide. You may also suffer burns if it comes into contact with your skin.
- Chest pain
Don’t all those symptoms sound like fun? I’m having chest pains just thinking about the smell. Still wanna use Bondo?
6. You Have Plenty of Other Options
This is the biggest reason not to use Bondo as a wood filler! There are so many great products on the market today from simple wood fillers to wood restoration epoxies that there is no need to Bondo anymore.
Some of my favorites that I use every day at my restoration company are below.
Any of these products allow the wood to move as nature intended, meld well with its porous character, and reflect the same hues after staining (or painting). In short, reaching for a wood-specific filler or epoxy – not Bondo – is always a better choice.
Founder & Senior Editor
I love old houses, working with my hands, and teaching others the excitment of doing it yourself! Everything is teachable if you only give it the chance.