Mahogany is a beautiful hardwood that is used to create many fine furnishings. This type of wood is tightly grained and does not have knots the way that pine and oak does. As mahogany ages it changes from its natural pink colouring to a darker red with brown tone. One of the simpler methods to finish mahogany is by using a dark oil-based stain. Darker stain will give mahogany a more even finish due to the nature of mahogany having light and dark gains running together.
Sand the surface of your furniture using your 100-grit hand sandpaper. Follow the first sanding with 180-grit sandpaper, and complete a final sanding with your 220-grit sandpaper. The first sanding will remove any rough raised areas in the wood, the second sanding will remove any scratches from the first sanding, and the final sanding will create a smooth surface for the application of your stain. Only sand with the direction of the grain of wood. If you sand across the grain of the wood you will create scratches in the surface that can be difficult to remove.
Wipe down your furniture with a tack cloth to remove all dust before you stain it. If you stain over dust your furniture will have a gritty feel and will need to be sanded again. Use a shop vacuum with a crevice tool to remove dust from corners.
Brush your stain on in two to three foot sections at a time and wipe it off with a clean rag. Do not stop in the middle of any section and allow it to dry before continuing to stain. This will cause an obvious stop and start point. Finish staining your furniture and allow it to dry overnight before applying a second coat. It is not always necessary to apply the second coat of stain unless the first coat is not dark enough to suit you.
Use a clean brush to apply an oil-based polyurethane to the surface of your furniture. It is best to apply a light coat and allow it to dry overnight. If you apply polyurethane too heavily it will run. Lightly sand with your 220-grit sandpaper after the polyurethane has dried. First coats of polyurethane can slightly raise the grain of your wood and must be sanded before applying the second coat. Before you apply your final coat of polyurethane wipe your furniture down with a tack cloth to remove the sanding dust. The final coat of polyurethane will leave your furniture with a fine smooth finish.