Waterproofing any type of wood, including beech wood, can be a tricky business. There are different methods to waterproof wood for different uses. Before you begin, consider whether the wood will be indoors or outside and how often it will come in contact with water. The following are some tried and tested methods that will water proof your beech wood to appreciable levels of effectiveness.
For Indoor or Infrequent Contact with Water
Purchase any good brand name water proofing sealer or varnish and apply as per directions on the label or use the following directions. Decide if you want a clear or tinted sealer. Use a pump sprayer, a painting pad or nylon brush to apply the sealant.
Spray small sections at a time, or paint in long overlapping strokes to comprehensively cover the beech wood. Lightly sand the wood and reapply sealer to maximize coating and absorption of wood once the first coat is sufficiently dry. Leave to dry for at least 24 hours before using the beech wood. Re-coat the wood at least once every year.
For another method, dilute ‘pure’ Tung oil and white spirit in a 1:1 ratio. Soak the beech wood in the solution until the entire wood is visibly wet, and repeat for 2 more days. Coat the wood once every day with the solution for a week. After the first week, coat the wood once every week for a month. Once this month is past, coat the wood once every month for a year. For maintenance of the water proofing, just rub the solution onto the wood surface every now and then with a soft rag.
For Outdoor or Regular Contact with Water
For outdoor or regular contact with water, there is no easy method to waterproof beech or any other wood, though water proofing beech wood can sometimes prove to be more of a challenge than other types of wood.
A very old and venerable waterproofing method, submerge the beech wood in turpentine oil and decks oil, until the entire wood is visibly wet. Repeat the process again once the wood is dry again, repeat several times regularly initially. Also keep the concentration of turpentine oil higher than that of the decks oil as you start with the concentration of decks oil getting higher as you proceed with the soaking. Repeat this process once to twice every year after the initial coatings.
As an alternative, purchase a good epoxy that provides good adhesion with beech wood specifically. You may purchase a clear penetrating epoxy sealer or a clear epoxy sealer. Check for varnishes that the epoxy is compatible with which provide UV protection. Coat the beech wood carefully and completely with the epoxy as per label instructions. Wait until dry and then coat another layer carefully onto the beech wood. Paint the varnish onto the beech wood once the epoxy has dried. Wait till the varnish dries completely, and then paint another coat of varnish onto the beech wood. Re-coat the beech wood once every year.
While this list is by no means exhaustive, it does provide a useful and practical insight. Other well regarded methods, beyond the scope being discussed here, that you should also look into are the resin-acetone and linseed oil methods.