Felt you might ask? For those of us who do not dabble in wool projects, Felted Wool or Wool Felt might be a foreign fabric. So to quote American Felt and Craft:

“Felted starts the process as a wool or wool blend woven fabric. To make something “felt” (a verb) or “felted” (an adjective) implies washing a pre-woven, or knitted, wool or wool blend fabric in hot water to agitate it and force the fibers to lock making it impossible to untangle or loosen the fiber.”

This means your wool pressing mat is very dense. The denseness of the wool absorbs heat and traps it in the pressing pad. This allows the seam being pressed to receive heat from both sides at the same time. Not only does this increase your pressing efficiency, it also to creates a much flatter seam. One review claimed it cut her regular pressing time in half. In addition the small give in the wool surface almost absorbs seams and stitches creating an extra flat press. Overall, using a wool pressing mat means a better, faster press.

The other positive of the closely packed wool fibers is they hold your fabric in place while it it being pressed. This helps to maintain the fabric shape and avoid any stretching. For those us who sometimes ‘iron’ instead of ‘press’ (you know who you are), this is a plus. As quilters we are continually working with bias cuts, such as half square triangles or flying geese, these edges tend to stretch and can warp. A wool pressing mat uses it’s texture to hold them tightly in place stopping things from shifting.

The wool pressing mat also works very well for embroidery. Whether it is hand or machine embroidery, often times after adding all of those stitches the fabric wants to pucker. Wool pressing mat to the rescue! Just like it flattens seams, it also flattens puckers out of embroidery.

As for thickness, 1/2 inch seems to be the best option. There are vendors several offering felted wool anywhere from 1/8 an inch to a full inch. The 1/2 inch thickness allows enough room to trap the heat and created the double sided pressing effect, however it is also thick enough that the heat cannot make it to the surface below the pad. This means your wool pressing pad can be used anywhere, without danger of doing damage to the surface below it. It could rest right beside your sewing machine!

The beauty of the wool pressing mat is that due to it’s nature it can be used on any surface without worry of heat doing damage, as long as it is dry heat. If you are pressing with dry heat, no problems. They can be used with or without steam, but keep in mind that the wool will absorb the steam with the heat. It is possible for the moisture from the steam to make it all the way through the surface below.

There is some debate as to whether steam will warp and distort the small pieces in blocks. Some people love steam, some people don’t. Just keep in mind if you are using steam the moisture could injure the surface below your pressing pad, and the pad may need to be moved after use to dry both it and the surface. 

Corners.

Rounded corners are another attribute to be aware of when purchasing a mat. In one place I read the rounded corners decrease the likelihood that you catch things on it, and as a result decrease wear and tear. In another place, it said that rounding the corners increased the cost and was not worth it. So to each their own!
Aroma.
Also noted by many people, when you press on the wool pad there is warmed wool aroma. As with all smells, everyone has their own reaction, but be aware that this is normal. Lots of Quilters work with wool on a regular basis, so this does not bother them. Others cannot get past the smell.

Size
Now, what size is the best option? The purpose of our wool pressing mat is to create nice, flat, crisp seams in our blocks. In my mind, this means that the pressing mat should be a about the size of the blocks that I regularly stitch. Standard quilt block sizes range from 6” square to 15” square.
Currently, popular size is carrying 9×9”, 13×13” and 17X17” sizes. There are a wide variety of sizes out there, the important point here is that you choose a size that works for you.