If you are using old timber to make a new table or any other type of wood project, you may run into a bit of mold or mildew. In many cases, it is possible to avoid or eliminate the mold or mildew. Here are the steps to work through:
1. Opt for treated timber.
If you have the choice of selecting from multiple types of timber, try to select timber that has been treated. The most popular types of treatment for timber products is copper and borates. Both of these elements are natural biocides. That means copper and borates kill living things like mold. However, if you don't have the option of choosing treated timber, you need to know how to remove mold.
2. Make a mold-killing solution.
If moldy timber is your only option, you need to try to kill the mold. In many cases, the mildew just forms a layer over the wood, and it's relatively easy to wash it away. If the timber is sealed or painted, try cleaning off the mold with detergent dissolved in water. However, if the timber isn't sealed, the mold may have penetrated the surface, and in this case, you need a cleaning solution that can penetrate into the wood and kill any spores that are in there. In this case, try some borax dissolved in water. Just throw a few handfuls or teacups full into a bucket of hot water.
3. Clean the timber.
Once you have your solution, scrub the wood. Use a soft scrubbing sponge if the wood is finished and use steel wool if the wood is unsealed. In both cases, after scrubbing the wood, plan to sand it a bit. If the wood is painted or sealed, you will need to reapply the sealant. Ideally, you should wait until your project is done and seal the whole thing at once rather than doing each piece of timber one at a time.
4. Dry the timber.
Drying is the final step in removing mold from timber. To dry your clean timber, find a warm spot to place it. Ideally, you want to create a pile of timber in the sun, but if you have to store it inside, make sure that you have a warm room with lots of ventilation and low humidity levels. If the room is warm but humid, the mold spores are likely to start growing again.
When stacking the timber, leave lots of gaps and spaces between the pieces. That allows the air to circulate between the timber to help it dry.
5. Check for rot.
When the timber is done drying, look it over for any residual signs of mold. If you see any lingering black spots, check them for wood rot. Simply depress a screwdriver into the blackness. If it goes deeply into the wood, it's rotten, and you may need to consider buying new timber. If you really want to work with old timber, find a dealer who sells reclaimed old timber. On the other hand, if the timber doesn't yield to the screw driver, it is not rotten, but you may want to clean it again to make sure all of the mold is gone.