This is a trowel. This is a great tool if you have anything to spread across a large area of space. (Generally, this means terrain or vignette projects) This could mean glue, gel, putty and maybe even paint. Trowels come in a variety of shapes and sizes usually in plastic or metal and can be found at art, craft, garden or hardware stores. (Art stores will have the best options for the scale you're working with since hardware store models are probably for leveling concrete and garden models for digging) Reader Loquacious points out that cake/icing supply stores might have them too.
I picked up the one pictured above for the following reasons:
- Metal is higher quality than plastic. (though in theory, you could cut a plastic one into other shapes)
- Long, flexible working area to spread goop across a larger areas quicker and allow more natural smoothing.
- Thin working area, that comes to a nice rounded point. This allows for getting in smaller areas and for finer control of the spread.
- The handle tilts up away from the working area, keeping your hand / knuckles away from whatever goop you're spreading around.
- Comfortable and smooth handle.
These are just a few things to look for.
You can use the trowel to scoop whatever you're working with, a little at a time, and spread it on the surface.
As you can see, the tip of the trowel is great for working into smaller areas or working your goop with a little more control.
In the lower photo, you can see how the gel was spread out smoothly with the longer edge of the trowel and thinned until it blends into the surrounding terrain. The long edge is pretty key in smoothing everything out. You want to make long, smooth motions with it - any pauses or stuttering will leave noticeable lines. (Sometimes these lines may be intended, such as a wind-swept beach)
You won't need to apply too much pressure. Most goop you'll be working with will probably spread easily. Too much pressure will thin the goop quite a bit and possibly bend your trowel. It'll take some practice using the long edge to create smooth blending of your goop, but you can pretty much go to town with it until the surface is how you like it.
Not much else to say, as they're not really something you'll use all that often since most terrain work is limited to the base of your miniatures. This is the first time I've needed one in my many years. They're not expensive though and definitely handy if you want terrain ground to be a little more than just flat surfaces covered in flock.