Elmer's Wood Filler has been a go-to product for woodworkers and DIYers for a long time now. There are many wood fillers on the market, but Elmer's cellulose-based fillers are sandable, paintable, and even stainable, to a degree. They are safe and easy to use, unlike some vinyl or epoxy-based fillers. And Elmer's also now makes pre-stained wood fillers that let you closely match the tone of surrounding wood.
All in all, Elmer's wood filler is a good product. However, this statement pertains mainly to the product that comes in tub form. The same product packed in a squeeze tube is another matter entirely.
Wood filler in tubes? A clever inventor had a great idea. Plenty of other home remodeling products come in tubes: caulk, silicone, construction glue. Why not wood filler? But this is an idea that should have remained just that: an idea.
Wood Filler Does Not Belong in Tubes
For the longest time, I tried to make the tube-based filler work, and by this, I mean Elmer's ProBond Wood Filler. This is a product that is said to contain "ceramic microspheres" designed to minimize shrinkage and improve the sand-ability of the product. But I had little success with it, at least in tube form. Wood filler, at least this kind, doesn't lend itself to a tube delivery system. It's too thick and grainy, and it just doesn't push out of the tube. I have even cut the nozzles all the way down to the tube and still could barely squeeze out the filler. Warm weather helps a bit. Or you can put the tube in your back pocket for an hour to absorb your body heat before using it.
In some cases, I have resorted to slicing open the entire tube and scooping the filler out. That kind of negates the whole idea of putting the stuff in tubes.
It may be best to avoid tub wood fillers at all costs. However, the product is now also sold in a tub form, and you may have better luck with this.
Elmer's Filler in Tubs
By contrast, the Elmer's Interior Filler is a joy to use. Someone at the company must have noticed that putty knives are straight, not curved, and therefore do not lend themselves to the traditional round metal or plastic containers. "Let's make square tubs," someone must have decided, and thus the skies opened up for countless DIYers.
Elmer's Carpenter's Interior Wood Filler is creamy and easy to use. It scoops out easily and it applies nice and flat to the wood–not bumpy and grainy. Likewise, it sands down with little trouble.
NOTE: Elmer's also makes both products in an Interior/Exterior formula, designed to be weather resistant. This product includes a greater ratio of resins to improve its water resistance. It's texture, though, seems to be exactly the same as the straight Interior formula.
I have to acknowledge that the tub product tested has a slightly different chemical composition than the ProBond product, omitting the "ceramic microspheres" found in the ProBond product. What contribution this omission makes to the product's smooth texture isn't entirely clear. It is possible that the standard Interior Wood Filler delivered by squeeze tube might be better than the ProBond version.
Based on my experience, the recommendation is to opt for Elmer's standard Interior Wood Filler, or the Interior/Exterior Wood Filler, in the square-shaped tub. It is better to avoid the Elmer's ProBond Wood Filler in squeeze tubes.
NOTE: Elmer's has recently introduced a "Color Change" interior wood filler that is pink when applied, but dries to a white finish that can then be sanded and painted or stained. This can help you ensure that the filler is entirely dry before you attempt to sand or stain it.