Things You'll Need
Hot glue gun
Old broom made with synthetic bristles or natural boar bristles
Thin wire (florists' wire)
Scissors
Pine 2-by-4 scrap of wood (at least two inches long)
Saw
Medium or fine grade sandpaper
Stain
Varnish
Drill
One-fourth-inch drill bit
Pencil
Ruler

Brush makers made natural bristle brushes by hand until the early 20th century. They heated pitch, drilled holes in the brush stocks (wooden parts of brushes), dipped small groups of bristles in pitch, tied these bundles, called "knots," with twine and dipped the knots in pitch again before inserting them into the stock holes.
Brushes are usually made by machine using synthetic bristles today. Some brushes are still handmade with genuine natural boar bristles. Anyone can make a handcrafted bristle brush made with either natural or synthetic materials.
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Step 1
Cut the 2-by-4-inch scrap brush stock into a 2-by-2-inch square. Sand all rough edges with sandpaper.
Step 2
Mark points on the brush stock for the bristle holes. These should be spaced one-fourth inch (about the diameter of a bristle bundle) apart across the surface. No hole should be less than one-eighth inch away from the edge of the brush stock. Drill holes where all the pencil markings are located. You should drill about half way through the brush.
Step 3
Stain and varnish the wood. Do not stain or varnish the insides of the bristle holes.
Step 4
If you're using an old broom, cut the synthetic bristles from the broom with the scissors. Gather some bristles into a "knot." Experiment to see how large the knot can be and still fit inside a bristle hole. Adjust the size of the knot to leave a tiny bit of wiggle room for the wire and glue. Repeat this step for all knots.
Step 5
Plug in the hot glue gun. While the glue gun is heating, wrap wire tightly around the base of each knot several times to hold it together.
Step 6
Put a tiny amount of hot glue in the bottom of hole in the brush stock. Shove the wire end of a knot into the hole while the glue is still hot. It should fit very snugly in the hole and stay in place. If it does not, add more glue. Repeat the process with each knot.
Step 7
When the hot glue is cool, trim all of the knots to one inch in length with the scissors.
Tip
Cut fancy brush stocks out of wood scraps with a jigsaw. Use thinner wood to create a brush with a handle.
Carve or burn designs into the wood for an ornate effect.
Save time by purchasing pre-cut brush stocks.
Warning
Hot glue is very hot. Touching hot glue causes burns.
Don't use too much hot glue. Excessive glue will ooze out of the bristle holes and get on the brush stock.