Absolutely-just make sure you pick the right one, and you'll be good to go! High-quality putty knives are sturdy enough to handle most adhesives, unlike cheap ones that'll bend or break. Let me give you some examples: I used my 4-inch Stanley knife to spread tile adhesive when I retiled my bathroom backsplash. The blade was thick enough to push the adhesive into the gaps between tiles, and the sharp edge let me spread it evenly (no lumps, which is key for tile!). I tried a cheap plastic spreader first, and it broke under the sticky adhesive-total waste of time.
But there are a few things to keep in mind. First, avoid using flexible blades for thick adhesives (like construction adhesive or tile mortar). Flexible blades will bend, and you'll end up with uneven spread. Go for a stiff or semi-stiff blade-they have more pressure to push through thick adhesives. My Stanley knife has a stiff blade, and it handled the tile adhesive like a champ.
Second, clean the knife immediately after use. Adhesive dries hard-if you leave it on the blade, you'll have to scrape it off with a wire brush (which can damage the edge). For water-based adhesives (like wood glue), warm soapy water works. For oil-based or construction adhesives, use mineral spirits or adhesive remover. I wiped my knife with mineral spirits right after tiling, and it came clean in 2 minutes-still looks brand new.
Third, pick the right size. Small blades (1-2 inches) are good for tight spots (like spreading adhesive on small wood pieces), medium (3-4 inches) for most jobs (tile, wood panels), and large (5-6 inches) for big areas (laminate flooring). I used a 6-inch knife to spread adhesive for my laminate floor, and it covered the area fast-way easier than a small blade.
Pros use putty knives for adhesive all the time! A carpenter friend of mine uses his Warner knife to spread wood adhesive for cabinets-he says it gives him more control than a trowel. Just make sure your knife is high-quality (stainless steel, stiff blade), and you'll be fine.
putty knife from hanke tools
