ELECTRIC ENGRAVING TOOL
In our shop we use our TIG welder to remove broken exhaust manifold mounting studs from the exhaust side of cylinder heads. For setup we use DC straight polarity with high frequency start, a sharp tungsten electrode protruding about 3/8 inch from the gas cup and a stainless steel filler wire. It is important to use a stainless filler wire for added strength. The end of the broke off stud, which is usually about 3/16 of an inch below the surface of the head, must be clean before trying to weld on it. We have found that an electric engraving tool works great for cleaning the end of the broken stud, which is usually rusty or covered with carbon. Start the arc and melt a puddle about half the diameter of the broken stud, then dab the stainless filler rod into the puddle. Continue to add filler metal until you have built up the broken stud just enough to be able to grab it with a pair of Vice Grips. The heat from welding will usually free the broken stud so that it can be easily removed. The engraving tool works great for cleaning the surface you wish to weld.
Jerry McLain
McLain’s Automotive Machine Shop
Cuba, MO
April, 2017
