An apparatus for repairing a metal sheet, comprising: a base unit including: a frame; and a plurality of attachment features attached to a bottom surface of the frame; a cutting unit configured to cut out a damaged portion of the metal sheet, the cutting unit including: an axle bar; and a motor for providing a rotating cutting force for the cutting unit; and a welding unit including: a fixed platform; a gear ring on the fixed platform; a weld rotation motor for rotating a rotation platform over the gear ring; a drive gear configured to contact the gear ring, the drive gear being further configured to be rotated by the weld rotation motor to rotate the rotation platform over the gear ring; and a welding assembly configured to automatically weld a replacement metal piece to the metal sheet, the welding assembly comprising a torch configured to perform a weld, characterized by the base unit including: a plurality of guide pins attached to the frame; the cutting unit including: a plurality of cutting unit guide holes on the axle bar, the plurality of cutting unit guide holes respectively corresponding to the plurality of guide pins for removably attaching the cutting unit to the base unit; and a cutting arm under the motor and the axle bar, the cutting arm including at least one cutting blade; the fixed platform included in the welding unit comprising a plurality of welding unit guide holes, the plurality of welding unit guide holes respectively corresponding to the plurality of guide pins for removably attaching the welding unit to the base unit. a base unit including: a frame; and a plurality of attachment features attached to a bottom surface of the frame; a frame; and a plurality of attachment features attached to a bottom surface of the frame; a cutting unit configured to cut out a damaged portion of the metal sheet, the cutting unit including: an axle bar; and a motor for providing a rotating cutting force for the cutting unit; and an axle bar; and a motor for providing a rotating cutting force for the cutting unit; a welding unit including: a fixed platform; a gear ring on the fixed platform; a weld rotation motor for rotating a rotation platform over the gear ring; a drive gear configured to contact the gear ring, the drive gear being further configured to be rotated by the weld rotation motor to rotate the rotation platform over the gear ring; and a welding assembly configured to automatically weld a replacement metal piece to the metal sheet, the welding assembly comprising a torch configured to perform a weld, characterized by the base unit including: a plurality of guide pins attached to the frame; the cutting unit including: a plurality of cutting unit guide holes on the axle bar, the plurality of cutting unit guide holes respectively corresponding to the plurality of guide pins for removably attaching the cutting unit to the base unit; and a cutting arm under the motor and the axle bar, the cutting arm including at least one cutting blade; the fixed platform included in the welding unit comprising a plurality of welding unit guide holes, the plurality of welding unit guide holes respectively corresponding to the plurality of guide pins for removably attaching the welding unit to the base unit. a fixed platform; a gear ring on the fixed platform; a weld rotation motor for rotating a rotation platform over the gear ring; a drive gear configured to contact the gear ring, the drive gear being further configured to be rotated by the weld rotation motor to rotate the rotation platform over the gear ring; and a welding assembly configured to automatically weld a replacement metal piece to the metal sheet, the welding assembly comprising a torch configured to perform a weld, characterized by the base unit including: a plurality of guide pins attached to the frame; the cutting unit including: a plurality of cutting unit guide holes on the axle bar, the plurality of cutting unit guide holes respectively corresponding to the plurality of guide pins for removably attaching the cutting unit to the base unit; and a cutting arm under the motor and the axle bar, the cutting arm including at least one cutting blade; the fixed platform included in the welding unit comprising a plurality of welding unit guide holes, the plurality of welding unit guide holes respectively corresponding to the plurality of guide pins for removably attaching the welding unit to the base unit.