Durham’s® Rock Hard® Water Putty has a quick working time.  Depending on how large of a batch you mix, and how much water you add – Durham’s can start setting up in as little as 10-20 min. Once the putty begins to set up, you cannot add more moisture to extend your working time. While Durham’s may feel dry to the touch, it may require additional time to cure fully. Depending on the project, you may need to wait several hours or overnight before sanding and painting. This time frame will ensure that the filler has reached its optimate strength and adhesion properties.

For larger projects, you may want to mix a larger batch of wood filler and try to extend your working time. Keep in mind, we recommend that you mix several small batches to avoid Durham’s putty hardening while you are in the middle of your project. Also – we suggest that you apply putty in ¼” layers if you are making a large repair to ensure that the area thoroughly dries.

 If you are going to mix a larger batch, there are a few tips that may help extend your working time.

• When mixing water putty, try using cold water. Warm or hot water can often speed up the cure time.
• Vinegar can be added to extend the working time. When using vinegar, it is best to use less than 25% of the liquid added as vinegar. If you add too much vinegar, the mixture may become acidic, and paint may not adhere well.
• Mix putty in a disposable container with a stir stick. Mixing Durham’s with a trowel or putty knife in a pan can sometimes cause water to evaporate quicker which speeds up the drying time.
• Add more water. Our recommended mixture is 3 parts powder to one part water, but if you are having issues with the putty drying too quickly, adding slightly more water may extend your working time enough.  Caution: you do not want to mix putty so it is pourable as that will reduce the density and strength of the putty.

When adding water-based paint, or water-based stain to your putty, it can affect the thickness of your mixture. Keep in mind that you may need to add more powder to account for the additional liquid. You cannot add paint or stain instead of water, as water is still needed to activate the powder into putty form.

Applying wood filler correctly is important for achieving that smooth professional finish in your woodworking projects.

Remember to smooth your repair area as much as possible while putty is still pliable. Once Durham’s Water putty cures, it is Rock Hard which can make it difficult to sand. Removing excess putty or smoothing your working area can save you a lot of work when sanding later. Proper application techniques and patience when it comes to the drying and curing times will pay off overall, even when tackling challenging repairs.