How-to: Build Your Own Spot Welder

June 23, 2009 by Steve Watkins 85 Comments

Spot welders are used in the fabrication of automobiles, PC cases, power supplies, microwave ovens, electrical junction boxes, Faraday cages, and various electronics. A spot welder is used because it produces a highly defined point of contact weld. The materials are welded without excessive heating, so working pieces are handled easily. The weld is also highly controlled and repeatable. In this how-to we cover the basics of a spot welder, and then show you how to build one from a microwave oven transformer.

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Induction Furnace

June 22, 2009 by Steve Watkins 19 Comments

induction furnace

[Tim Williams] made his own induction furnace. A copper tubing coil forms the primary winding, as the material to be heated becomes the short circuited secondary. The load material is subject to high power magnetic fields operating at radio frequency. The rapidly changing field induces current flow within the material, creating a great deal of heat. The brute power required a cooling system to match. In the video below, the induction furnace can be seen melting common table salt.

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Homemade Toroid Winder

June 20, 2009 by Steve Watkins 17 Comments

[eclipsed78], built an automatic toroid winder (Internet Archive). The drum splits in order to load the toroid. Then wire is wound on the drum, much like any other coil would be wound. The drum rotates as a slider pulls the wire off the drum, while revolving in and out of the toroid. A side tension keeps the slack out of the wire during operation. The winding coil is stepped as the drum rotates, in order to control the turns ratio. [eclipsed78] created a stepper driver from a schematic, so he could drive the motors. You can watch the winder in operation as a series of videos. The first of which is embedded below. If you have ever needed to wind a massive toroidal transformer, this is the project for you.

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Arduino Powered CD Changing Robot

June 18, 2009 by Steve Watkins 21 Comments

arduino cd robot

[ross], a reader is working on a CD changing and ripping robot. The arm picks up a CD and the platform then rotates, stopping in front of the tray to drop the CD. A JB welded tire pump provides the vacuum pick up, while a brake light acts as a resistor to trick a PC power supply into operation. A Motor Shield beefs up an Arduino in order to drive the servos.