Polyester Resin Shrinkage

Discussion in 'Boat Yard Basics' started by pgmelton, Jun 3, 2011.

  1. pgmelton

    pgmelton I Love microskiff.com!


    As I work on the hull of my skiff, I am starting to think and pre-plan how I am going to make my casting deck (the deck that is the top layer and sits on top on the gunnels). Today I was sharing this topic with my sales person at FGCI. He stated that he was making a small deck and only glassed one side, after curing it curved up towards the fiberglass side rendering the piece useless.

    I am wondering how any of you dealt with this issue? :-? :-?
  2. firecat1981

    firecat1981 BBA Counselor

    I only deal in epoxy, but have had that happen to me with my hatch covers. I think it's because you are applying a liquid that then cures and heats up so that makes the plywood want to twist on you. If it is bonded down, or weighed down this won't happen. If you are making a deck that will be bonded to the hull (non-removable) and glassed only on the top, then make your substructure then bond the ply to it, keep it weighed down till it's cured. Then glass the top and you will have no issues.

  3. oysterbreath

    oysterbreath Well-Known Member

    It's an issue with ANY sheet material and adhesive even if the adhesive doesn't shrink. It's the uneven tension created but an unbalanced lamination. If you glue two pieces of paper together the same thing will happen. Glue three...it will balance out much better. Balance for you will be glass on each side or to pretension the ply somehow...