The core of this invention is to replace lamp cups with recycled metal cans (after pretreatment processes) as a good heat sink of the LED lamps. The heat sink adheres to the lamp bases, LED circuit boards and lamp covers through advanced technology, thereby producing a variety of LED lamps. As a result, the invention achieves a complete metal construction of LED lamps which not only improves the thermal performance of LED lamps but also develops a low-carbon, environmentally friendly and economical way of metal containers recycling. Consequently, these improved LED lamps are suited to be widely used for the purpose of illumination or decoration. A semi-knocked-down DIY kit for end users to assemble such improved thermal performance LED lamp and the method of making it are provided herein.