How to Make a Felt Hat
To make a hat from a felt hood, place a plastic bag over a wooden hat block. Then, turn your felt hood upside down and use a paintbrush to coat the inside of the hood with felt stiffener. You can get these supplies online or at your local millinery shop. After you've applied the stiffener, place your hood stiffener-side down over your hat block and secure the sides with pins. Let it dry for 30 minutes, and then iron your hat and add the brim.
Cover a hat block with plastic wrap to make removal easier. Purchase a wood hat block from a millinery shop or online. Set it down on a stable surface, then cover it with plastic wrap. Secure the plastic wrap to the base of the hat block with a rubber band or tape to keep it from sliding around. The plastic wrap will make it easier to remove the finished hat. It would be a good idea to work in a well-ventilated area. The hat stiffener can smell and make you feel lightheaded. Don't use a Styrofoam hat base. It is not the same thing. You need something more rigid. The shape of the hat block will determine the final shape of your hat, so choose the shape and size wisely! Turn a felt hood inside out and coat it with felt stiffener. Purchase a felt hood from a millinery store; it looks a little like a cloche hat. Use a paintbrush to apply felt stiffener to permeate the felt. Use enough felt stiffener to permeate the material, but not so much that it soaks through to the other side. You can also use a wool felt or fur felt sheet. You can find it online or in the needle felting section of a craft store. Do not use the acrylic felt sheet from the kids' crafting section of a craft store. It is not the same thing. Turn the felt hood right-side-out and stretch it over the hat block. Pull the felt hood over the hat block, stiffener-side-down, then flip the hat block over so that you can see the underside. Wrap the edges of the felt over the bottom edges of the hat block and secure them with pins. It doesn't matter if they are parallel or perpendicular to the edge. Start with a pin in each of the cardinal directions: North, East, South, and West. Fill the gaps in with more pins until the entire edge is pinned. If you are using a felt sheet, place it stiffener-side-down against the hat block. Pull and stretch it over the hat block, then secure it with pins along the bottom edge. Leave the hat to dry for 30 minutes. During this time, you can wipe your brush clean, then wrap it in plastic. Do not use water, or this will cause the stiffener to turn solid. Cover your hat with a tea towel, then steam it with an iron. Drape a tea towel over your hat, then fill your iron with water. Turn the iron on, enable the steam function, and set the heat to "Wool." Stretch the tea towel over the hat as you press the hat with the iron. Work your way around the hat, starting at the crown and finishing at the top of the brim. If your iron doesn't have a wool setting, choose a low or medium-low setting. Always keep the tea towel between the iron and the felt. Don't let it wrinkle under the iron; pull it taut. How long you press the hat will vary. You should press it long enough for it to hold its shape. This should only be 5 to 10 seconds. Wrap string around the crown where you want the brim to start. You can also use a rubber band for hat making instead, which you can purchase at a millinery supply shop. This will help create that crease between the sides of the hat and the brim. In most cases, the brim will lay right where the hat starts to flare out. It does not matter what the string looks like; you'll take it off later. Not all hats have a brim. For example, a pillbox hat is just the crown. In this case, you can skip this step. You can also stick a bunch of pins next to each other to create a line, but be aware that this will leave an indent. Continue to sculpt your brim with the iron. Keep moving the tea towel around the hat and pressing the hat with an iron. Be sure to iron out any puckering or wrinkling that occurs, especially in the crease and the edge of the brim. If you want to make a cloche hat, take the hat off of the block, then iron the brim on an ironing board. Always keep a tea towel between the felt and the iron. Let the hat cool, remove the string, and trim the edges of the brim. Remove the pins holding the brim to the underside of the hat block, then remove the string you used to make the brim. Finally, pull the hat off of the hat block. Use scissors to cut the folded-under edge. At this point, you can also trim the brim narrower or give it an asymmetrical shape. Sew millinery wire to the edge of the brim, if desired. Wrap a piece of millinery wire around the brim, then cut the excess off with wire cutters. Use a blanket stitch to sew millinery wire to the edge of the brim. The color of the thread does not matter because you will be covering the wire up. This will help give the brim more structure. If you don't want this, skip this step and move onto the next. Wrap and sew ribbon around the edge of the brim, if desired. Cut a length of ribbon long enough to wrap around the brim. Sew the ribbon to the brim with the right side against the top of the brim and the edges matching up. Wrap the ribbon over the edge of the brim to the underside, and sew it down again. You can sew this by hand or on a sewing machine. Use a straight stitch and a thread color that matches the ribbon. Use a ribbon that matches the design of your hat. Satin or grosgrain work well here. If you added wire to the brim, then you need to complete this step in order to hide the wire. If you did not add wire to your brim, you can still do this step for a nicer finish. Add a grosgrain ribbon to the inside side of the hat, if desired. If you look inside professionally-made hats, you'll notice a grosgrain ribbon band just inside the sides of the crown. Simply cut a length of ribbon long enough to fit inside the hat, then sew the ends together. Tuck the ring into the hat, then hand-sew the top edge down. The ribbon needs to go right where the sides of the hat start to flare out to create the brim. This will help the hat maintain its shape and prevent the felt from stretching out. It is not the same as the outside hat band. The stitching will be visible at the end. You will have to wrap a hat band around the outside of the hat later. Decorate the hat as desired. Here is where you can get as creative as you want. For a more professional finish, sew the decorations on by hand with a needle and thread. If you don't wish to sew, you can try gluing them on with hot glue or fabric glue. For a simple look, wrap a ribbon around the base of the crown, then sew the ends together. Cover the seam with a bow or flower. For a more rustic look, use ornaments made from felt, such as matching felt flowers or felt bows. For a vintage look, add a skinny feather into the hat band. Cover a Styrofoam hat form with a plastic bag. You can find Styrofoam hat forms online or in millinery shops. You can also make your own by carving a Styrofoam block into shape, or by covering a bolter pillow with sheet foam. As long as the hat form is the same size as your head and the shape you want your hat to be, you are good. When buying a hat form, make sure that it is labeled for felting. If it is too rigid, you won't be able to insert the felting needle into it. Do not use a wooden hat block; it is not the same thing. Don't use plastic wrap; it's not durable enough. Stick with a plastic bag instead. It will make removing the hat easier in the end. Cover the hat form with crisscrossing layers of wool roving. Cover the top of the hat form with a thin layer of wool roving; arrange all of the strips horizontally. For the next layer, arrange all of the strips vertically. Wool roving is simply raw wool that hasn't been spun into yarn yet. You can find it online and in the needle felting section of a craft store. You can use all the same color, or you can use different colors for a unique effect. Press the layers together with a needle felting tool. To do this, simply press the felting tool against the felt until you feel the needles embed into the hat form. Lift the felting tool out, and press it down again. Keep going until you have all of the wool roving felted into place. A felting tool looks a little like a brush, with a flat base and a bunch of pins sticking out of 1 end. You can find it online or in the needle felting section of a craft store. Be very careful when handling the needle felting tool; the pins are very sharp. Add more layers of wool to the sides and the top. Add crisscrossing horizontal and vertical layers of wool to the sides of the hat form first, including the brim if you have it. Felt them into place with your felting tool, then repeat the process. You want a total of 4 layers of wool roving. Start at the top of the hat (crown) and work your way down the sides and to the brim. A vertical layer counts as 1 layer, and a horizontal layer counts as another. You can do more than 4 layers if you want a thicker hat. Work in even numbered sets, so 6 or 8 layers (maximum). Pull the felted hat off of the hat form, then peel the plastic bag away. The wool is embedded into the hat form, so you need to gently pry it away first. Slip your fingers between the bag and the hat form, and gently begin to pry the 2 away from each other. Work your way around the brim, then up the sides and to the top. Once you have the hat off of the hat form, peel the plastic bag away from the felt. Be gentle when removing the plastic bag so that you don't distort the hat. Pour hot water over your hat, then add some dish soap to it. Take your hat to a sink, and pour hot water all over it, making sure to soak it thoroughly. Add a few pumps of dish soap to the hat as well. Don't concentrate the dish soap all in one area. This will make it easier to distribute it more evenly across your hat. Massage the felt between your fingers. Don't flatten the hat when you work it; you want to work your way around the hat's circumference rather than squashing it like a sandwich. As you continue to work the hat, the felt will shrink and compress. Felt is very absorbent. If it starts to become too dry, add more water and dish soap. Keep working until your hat is felted to your liking. Some people like to leave the felt thick, spongy, and "wooly," while others like to felt it thin and smooth. Press the excess water from the hat with a towel. Set a few towels on your work surface, then place the hat on top. Cover it with a few more towels, then press down on the hat firmly. Keep pressing until most of the water is absorbed into the towels. If the hat is too soapy and produces too much foam, rinse it with hot water first. If the towels get soaked, move the hat over to a dryer spot on the towel. Don't wring, twist, or wrap the hat in the towels, or you will ruin the shape. Set the hat back onto the hat form or a mannequin head so that it can dry. If the hat is misshapen, mold it back into shape first. Once you have the hat on the mannequin head, leave it alone to dry. This can take several hours. Decorate the hat as desired. Because these hats tend to look more rustic, it's best to keep the decorations simple. If you want to keep sewing to a minimum, you can glue the decorations on with hot glue or fabric glue. It would be best if you hand-stitched them on, however. Here are some decorating ideas: Wrap a grosgrain ribbon around the hat, stitch it in place by hand, then cover the seam with a felted bow or flower. Decorate the hat with needle-felted flowers or berries. Cut flowers out of felt, layer them together to make fuller, more colorful flowers, then sew them onto the side of the hat. 
Cover a hat block with plastic wrap to make removal easier. Turn a felt hood inside out and coat it with felt stiffener. Turn the felt hood right-side-out and stretch it over the hat block. Leave the hat to dry for 30 minutes. Cover your hat with a tea towel, then steam it with an iron. Wrap string around the crown where you want the brim to start. Continue to sculpt your brim with the iron. Let the hat cool, remove the string, and trim the edges of the brim. Sew millinery wire to the edge of the brim, if desired. Wrap and sew ribbon around the edge of the brim, if desired. Add a grosgrain ribbon to the inside side of the hat, if desired. Decorate the hat as desired. Cover a Styrofoam hat form with a plastic bag. Cover the hat form with crisscrossing layers of wool roving. Press the layers together with a needle felting tool. Add more layers of wool to the sides and the top. Pull the felted hat off of the hat form, then peel the plastic bag away. Pour hot water over your hat, then add some dish soap to it. Massage the felt between your fingers. Press the excess water from the hat with a towel. Set the hat back onto the hat form or a mannequin head so that it can dry. Decorate the hat as desired. 