User:Foreverdank/Portable Passive Solar Kiln

Portable Passive Solar Kiln
for drying dimensional lumber

This kiln will be able to hold 1800 board feet of lumber and dry it in about 30 days

Sunlight will passively heat the kiln by warming the interior which is painted with black driveway sealer

Fans force the air through the pile of lumber to facilitate drying

The kiln is designed on an 18 foot trailer to maximize portability

Folded kiln will measure approximately 4' high, 18' long, and 7' wide

The roof angle is dependent on your latitude, for the summer months the angle should be equal to your latitude and for winter months it should be 10° steeper than your latitude

The kiln will be built with conventional framing techniques and insulated with paper backed fiberglass batt insulation

Each of the three high walls will fold down on top of each other

The high wall will fold down at 3' while the triangular walls will fold down at 3'5" so they will lay flat on top of the high wall when folded

The roof will be in two 18' sections to make it possible to stack it on top of the folded frame of the kiln

A sliding tray system will be employed to load lumber into the kiln from the end over the back of the trailer

Rate of drying should be monitored every day using a moisture content meter to ensure safe drying until a routine is established

Rate of drying is a function of the ratio between collector area (roof) and the amount of wood being dried

Rate can be increased by reducing the load of wood dried at once or decreased by covering some of the roof

Fans should not be operated at night to allow the wood to regain some of the lost moisture which relieves some of the stress induced by drying

Materials: 26 sheets of 3/8" exterior grade plywood - $260       45 2x4x10' boards - $100        106 square feet of paper back fiberglass batt insulation - $125        180 square feet of Woodmate's clear corrugated polycarbonate greenhouse roofing - $225        5 gal. exterior latex paint - $115        5 gal. latex-ite driveway sealer - $20        Miscelaneous hardware (nails, hinges, deadbolts, etc.) - $75        Total: $920, (+/- 10% for varying prices)