fiberglass finishing ?

Discussion in 'Boatbuilding' started by jth21usa, Aug 21, 2013.

  1. jth21usa
    Joined: Jul 2013
    Posts: 4
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    Location: Rochester ny

    jth21usa New Member

    Hello, I'm knee deep in my first plywood boat project and I had question on fiberglass finishing. I've put 3 or 4 coats of resin over 7 oz fiberglass, it seem like I can still feel the fibers in the resin, I know that these fibers are covered in resin. The questions are:

    1. is it time to start sanding?
    2. or do I put more resin on until I can't feel the fibers in the resin

    any help would be great thanks

  2. missinginaction
    Joined: Aug 2007
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    Location: New York

    missinginaction Senior Member

    In my experience you should have filled the weave of the cloth by now with 4 coats already on. Can you see the weave of the fabric? If you can then you haven't filled the weave yet and need to apply another coat. I generally apply a seal coat to plywood before laying down fabric. After the seal I lay the fabric down dry and squeegee resin on getting the fabric pressed down firmly onto the surface. Once that coat has kicked off it's time to fill the weave. You can do this with a squeegee as well but I usually lay on the fill coats with a short napped, chemical resistant foam roller. The roller allows me to be a bit more generous with the resin and I generally have the weave filled with two coats.

    Good luck,

  3. tunnels

    tunnels Previous Member

    ok in this case you could have simply rolled and well wet out the 7 oz. glass and when it was hard one more coat of resin and then when that was hard a quick sand and troweled or screeded a coat of resin and Q Cell's over to completely fill all the weave of the cloth !!, then sanded back to A SMOOTH FINISH and carried on with high build undercoat , trick is to add a little Q cells to the high build makes it fill even better and sand even easier !!
    Remember th resin by its self will crack over time !! it needs glass to hold it together and the skin of resin and glass will protect the plywood !! the weave is better to be filled well so it can be sanded , just resin is slow and hard work but adding qcells helps with filling any weave or hollows and makes it easier to sand . Don't know what product you using but this you should read from cover to cover Manual 2012 Part1.pdf
    In there are answers to question you have never thought to aske yet !! makes interesting reading !!

    Quickest way to fill the weave is simply roll peel ply over the top when you wet out , lay the glass and wet it and then the peel ply ! when the peel ply comes off its ready for high build undercoat so save a lot of dicking about and saves on the use of resin saves on screeding filler coats !!
  4. michael pierzga
    Joined: Dec 2008
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    Location: spain

    michael pierzga Senior Member

    Once glass cloth is saturated to the proper resin to fiber ratio...say 50 dont need more use fairing compound or thickend resin to fill the weave..then sand flush

    Oh and as Tunnels says..Peel ply is magic stuff. Pick up a few meters and learn for yourself.

  5. tunnels

    tunnels Previous Member

    I have used peel ply for a long time and in yacht bulding cover the entire inside of the hulls surface and as we work through the construction of the boa in different areas peel it off lightsand and bond and when the hull is ready for it flow coat from end to end then the places that are left its peeled sanded by hand a coated . peel ply make good jobs better it is a way of seeing more clearly air entrapped in the glass layer it draws through surplus resin and if its not wet and shiny then the glass doesn't have enough resin so your laminating becomes much better . it has and does save hours and hours of hard work !, peel ply's uses are endless and yes it is magic stuff !!I totally agree :p:D:p
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