Use a hammer to create dents and scratches in your wood beam.
Use a soft cleaning cloth to get rid of any dust, wood debris, dirt or cobwebs on the wood beam.
Paint the wood beam with a black or dark brown latex paint. This paint color will show through cracks once the project is complete. You can use any two-color combination you desire, but if you want a more natural look, black and brown shades work well. Allow the paint to dry well.
Spread the carpenter's wood glue onto the entire wood beam surface with a clean paintbrush. The second paint color must go on top of the still-wet glue before it dries, so work quickly. A thick coat of the glue results in large cracks in the final product; a thinner coat of glue creates hairline cracks.
Paint the wood beam with the second paint color while the wood glue is wet.
Allow the second coat of paint to dry thoroughly according to the directions on the paint. You will see the beam take on an aged appearance as it dries.
Seal the wood beam with a final coat of glue and another clean paint brush. This protects the aged finish.