The process of fingerjointing is complex and requires numerous efforts in order to evaluate the various workable and optimum conditions of jointed wood members. Many factors are known to affect the strength of fingerjoints. Some are related to wood, such as species, density, natural defects, moisture content (MC), temperature, and gluability of the species. Others are related to wood machining, including type of adhesive and gluing processes, such as condition of the cutting tools, curing time and applied assembling pressure.
Hemlock can have higher moisture content than most other native trees, causing them to sink. Hemlock lumens have large pits (valves) that allow easy transport of water into the wood.
Bigger rings = bigger lumens. Younger hemlock or hemlock tops are more susceptible to sinking. The bigger the rings the more likely to take on water.