You may have heard the terms “putty” and “filler” used interchangeably, but they are not the same thing. It’s important to understand the fundamental differences between the two before you start using them, to make sure you’re getting the best performance. Read on to learn what separates these two compounds and when it’s best to use them.
Wood filler typically contains wood particles, fibers, or cellulose mixed into the compound. It sometimes even contains limestone and other minerals you would typically find in drywall for added durability. It hardens as it dries. You can sand it and stain it, and it’s best for use on unfinished wood.
Wood putty is typically made of plastics such as polyurethane or epoxy mixed in an oil-based compound. Unlike wood filler, you can’t sand putty. It also doesn’t harden like filler, which means you can’t stain it. Fortunately, you can buy it in different wood tones to match your project. Use it on finished and stained wood.
This epoxy-based filler will give you the best of both filler and putty functionality. Mix it first, until it’s the consistency of cookie dough. Then mold it to the wood and wait for it to harden before sanding, drilling, carving, or painting.
Putty is best for exterior use. Though it doesn’t harden the same way as filler, it can expand and contract enough to withstand temperature changes. Finish the wood before applying it, however, since it won’t be paintable or stainable. It works great for furniture, too. But for larger outdoor projects and refurbishment, a two-part filler is your best bet. It will give you the flexibility you need to sand, paint, and complete other finish work.
Wood filler works best for interior work. It hardens better, you can sand, stain, or paint it, and you don’t need to worry about extreme temperature changes making it expand or contract. It’s also more durable than putty, since it contains fibers and minerals to reinforce it. Again, two-part filler will be better for larger projects, since it’ll give you the flexibility to complete detailed finish work like sanding and painting.
While putty and filler are often described interchangeably, you can see how different the two compounds are. It’s important to determine where you’ll be patching the wood and to what kind of temperatures it will be exposed before you choose which one to apply. If you want the best of both worlds, however, a two-part epoxy filler may be best. Good luck with your project!
Header image credit: Rlsheehan, Wikimedia
Ryan is a freelance writer from Arizona. When he's not blogging about his favorite hobbies, he's writing fiction, hiking or running in the great outdoors, and spending time with family.