Spackle is used frequently to patch holes and give drywall an even surface. After spackle paste is applied, it will harden and become part of the wall. It is no surprise that the paste will eventually harden in its container, as well. If this happens, you can add water to it to loosen it up so it can be used again.Click to see full answer. Keeping this in consideration, can you mix spackle with water?It is best to mix as much as you can use up under half an hour. This will prevent drying of the material. When mixing, add small amounts of water at a time until you achieve a smooth peanut butter-like consistency. Excessive water will cause the spackle to run.One may also ask, how thick should spackle be applied? Layer the spackling into the area 1/4 inch deep at a time and allow it to dry between layers. Vinyl spackling will typically dry within one to five hours, depending on temperature, humidity and material depth. Vinyl spackling may shrink or crack slightly when applied in layers deeper than 1/4 inch. Likewise, people ask, how do you fix dry spackling paste? Reconstitute Dried Spackle Step 1: Water. Add a liberal amount of tap water. Step 2: Mix. Break up the dried clumps and mix it with the water just a bit. Step 3: Nuke. Put the jar in the microwave for 20 seconds. Step 4: Nuke It Again. Put it back in the microwave for another 30 seconds. 2 People Made This Project! bluehowlite made it! 9 Discussions. How long does spackle last? Average Shelf Life Most wet compounds are rated for around nine months to a year so long as the compound is kept in the right conditions. Dry compounds have a similar shelf life of around a year so long as the proper storage methods are used.