Get a piece of 1"x1" wood about 30" long and 4 x 4" flat-head nails. Drill 4 holes for the nails and hammer them right in. The two end nails should be 16 3/4" apart to fit within the frame end-bars. The other two nails should be evenly spaced between those two. Then hammer the ends of the nails flat on an anvil and file the ends square. Twist the nails with pliers so that the flat ends are at a right-angle to the bar. Then drill a hole vertically through the bar, about 1 1/2" away from the 3rd nail to take a 1/4" bolt with a nut underneath. Last step is to make a switch - get a piece of spring-wire from an old chair or bed and cut a piece about 5" long. Straighten it and twist one end under the head of the bolt. Make a little wooden knob for it and you have your switch. It should be fitted so that when you press it down with your thumb while you are holding the bar in both hands, the spring wire contacts the flat head of the end nail and activates the electric current. Then attach 2 lengths of lightweight insulated electrical wire, one to the head of an end nail and the other to the head of the bolt. Soldering is best, but tight twisting will work OK. Stand it on the workbench and ensure that the two centre nails are not longer than the two end ones which carry the current. The two middle ones are to hold the wire down when it buckles with the heat. Finally, get a cheapo car/motorcycle battery charger 6V or 12V and clip the leads onto the two wires of your new embedder. Just need to press the switch and let it go to get the right amount of current to embed perfectly. A nearly-dead car battery works OK instead of the charger.