natural Wood and Resin
Live Edge Tables and Waney Edge Tables
Kiln Drying
Kiln process includes the drying of wood in a chamber where the air circulation, humidity and temperature can be appropriately controlled so the moisture content of the wood will be reduced without having any drying defects.
The Process
Checks and Splits
All wood should be end-coated as soon as it has been cut. Solid stacking and reasonable control of wood lengths will help prevent the ends from drying too quickly. High humidity above 40% MC (moisture content) is critical while moderate air flows and lower temperatures are also significant. Above all, the drying rate must be controlled; it all depends on the species and thickness of the wood.
Warp and Cup
Warp is caused by poor stacking, such as sticker thickness, poor sticker alignment or non-flat foundations. Cup is a result of rewetting partially-dried wood or over-dried wood.
Caseharding
The methods for stress relief or conditioning require rapid moisture to the wood surface whilst the wood is warm. More often than not, the heat in the steam is used for stress relief, increasing the kiln temperature above the required level, leading to poor relief. It is considered to use water to cool down the steam or wood. The dry-bulb temperature is a known technique for setting the air temperature to 82°C (180°F) MC. Stress relief will be unpredictable if the wood is not uniform when stress relief begins. Solar kilns do not require stress relief, as at night, high humidities provide freedom from case hardening.
Good Colour
By far, the most critical factor determining the colour or discolouration of the wood is log freshness. Old logs have 20 times or more risk of forming stain-fungal stains, sticker stains, browning, pinking and greying. Freshly sawn timber requires low humidities, low temperatures and brisk velocities immediately after stacking, and until the wood is under 30% moisture, it will be content to control stain. Narrow loads and partially-filled dryers will help. Poor stacking and exposure to rain will increase the risk of stain.
High Strength
Low humidities and low dryer temperatures will maximise the strength. Unfortunately, lowering factors, including bacterial, fungal and species effects, are beyond our control.
Good Machinability
Wood that is too wet will fuzz, while wood that is too dry (under 6% MC) will chip, split and develop other machining flaws. Ensure that you monitor the most dehydrated pieces of wood in the dryer along with the wet ones. Don’t underestimate the effect of over-drying on machining. Avoid temperatures over 71°C (160°F) MC and avoid very low humidities in the drying schedule. Conditioning or setting the resign at 82°C (180°F) MC is acceptable.