Recommended Oxyacetylene Procedure: Bevel cracks or heavy sections where possible. Clean the area to be welded as thoroughly as possible. Use a neutral or slightly reducing flame. The extent of the excess fuel gas is measured by the length of the streamer? or feather? of unburned fuel gas visible at the extremity of the inner cone. The streamer? should measure about 1/8 to 1/4 of the length of the inner cone of the flame. Excessively long ? streamers? should be avoided since they may add carbon to the weld metal. If forehand welding (welding rod precedes the torch flame), distribute the heat and molten weld metal by using opposing oscillating motions of the flame and welding rod. If backhand welding (welding rod is interposed between the flame and molten metal), then there is significantly less manipulation of the flame or welding rod.