Best Heavy Duty Super Stretcher Bars The Super Bar is truly that - a very super bar. The Super Bar is made of pine that has been finger spliced. Finger splicing is a method of bonding pieces of lumber together to form a very long straight bar. Since the spliced joints are actually stronger than the natural wood, we can now get longer, straighter bars than ever before. First designed for the construction industry, this high tech method is giving better bars than ever before. Recommended for canvasses over 48" although several customers love the effect of a thick wood frame on much smaller canvasses as well.