Is there a difference between fiberglass resin purchased from Home Depot and the West System Epoxy resin? I have a small soft section where the core material got wet. I am going to pull out the rotten core, dry out and apply Git Rot to the section of core that is still good, fill the larger gaps with good wood, then fill the final voids with fiberglass resin from HD. Do I need to order the West System or can I go with the HD stuff?