Problems with Rubberwood
Rubberwood has not traditionally been used for furniture and utensil manufacture. However, as highly-prized tropical hardwoods have become scarcer and more valuable, rubberwood furniture, toys and other implements have become more common.
According to the United Nations Food and Agriculture Organization, the beginning of the use of rubber in many industries revitalised the Malaysian sawmill and wood processing industry.
Rubberwood is susceptible to fungus and oxidation stains. Although the stains can occur any time before finishing, it can be an especially serious problem before rubberwood has been dried. According to the United Nations Food and Agriculture Organization, rubberwood is naturally high in sugars and can, therefore, attract fungal infestations. These problems can be minimised by quick and proper drying procedures. Rubberwood is frequently impregnated with a borax-based chemical solution to reduce problems with biological pests. This is done under high pressure. In some cases, initial moisture content of the wood after pressure treating can be as high as 200 per cent, according to Thai Science.
Rubberwood can be attacked by wood boring insects if not dried promptly. Like problems with fungal infestations and stains, the high natural sugar content of the rubber tree is a component in attracting boring insects. This is an especially serious problem in tropical climates. The best way to ensure fewer insect problems is to saw and properly treat the wood as soon as possible after the tree is felled. The pressure treatment that minimises fungal stains is also effective in limiting insect damage.
Because rubberwood is naturally high in moisture and often pressure treated in a way that adds more moisture, it has a tendency warp, twist, bow and sometimes split. Avoiding problems with warping in rubberwood starts with how the wood is cut. Backsawn rubberwood has less of a tendency to warp. According to Paneltech, using wide spacers between the boards when drying the lumber can also lead to more warping during the drying process. By using a kiln at between 140 and 185F and drying the wood for between 8 and 12 days until it reaches 6 to 16 per cent moisture, warping problems can be further reduced.