Use setting-type joint compound (Durabond/Easy Sand) for deep or structural fills

Mix a powder-form setting-type joint compound (such as USG Durabond or Easy Sand) with water to a thick peanut-butter consistency. Press the compound firmly into the hole or crack with a putty knife, overfilling slightly. The compound hardens through a chemical reaction (similar to plaster) rather than by air drying, producing a rock-hard patch that does not shrink.

Why It Works

Setting compounds use a gypsum-based chemical cure that is independent of air exposure. This means the center of a deep fill hardens at the same rate as the surface, so fills of 1/2 inch or deeper cure solid without the cracking and shrinkage that plague air-dry spackle and pre-mixed joint compound. The cured patch is significantly harder than standard spackle, making it ideal for areas subject to impact or where you need to re-anchor a screw.

Tips

• Available in setting times of 5, 20, 45, and 90 minutes (e.g., Easy Sand 45 gives 45 minutes of working time) -- choose based on how quickly you work
• Mix only what you can use within the rated time; once it starts to set, adding water does not extend the working time
• For fills deeper than 1/2 inch, pack in two layers and let the first layer set before applying the second
• Setting compound is harder to sand than lightweight spackle -- apply it as smooth as possible to minimize sanding, or top with a thin skim coat of pre-mixed compound for easier finishing
• Clean tools immediately after use; hardened compound is nearly impossible to remove from putty knives and mixing containers
• A 3 lb box of Easy Sand 45 costs $8-12 and repairs dozens of holes
• Durabond is harder than Easy Sand after curing -- Durabond for structural patches, Easy Sand for general repairs where easier sanding is preferred
• Common mistake: mixing too much at once and having it harden in the mixing container before you finish