Crack or seam repair (both handled very differently) are both handled with terrific care. Usage of the proper adhesives, clamps and alignments is imperative. It is important to note that repairing a crack in a violin or cello is a delicate and time-consuming process that requires a high level of skill and expertise. It is generally best to entrust this type of repair to a professional luthier who has the necessary knowledge and experience to do the job correctly. Trusting your instrument to a repair person without the proper knowledge and understanding of orchestral instruments (specifically) may prove to be a massive long-term mistake.