laying fiberglass on vertical surfaces/adding fillers

Discussion in 'Fiberglass and Composite Boat Building' started by old man, Aug 15, 2007.

  1. old man
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    old man Junior Member

    I have fiberglassed decks, engine boxes, etc... But i am no expert in glass work.

    If I am applying fiberglass to a vertical surface do I need to add a filler to thicken the epoxy so it wont run? What is the best method to apply epoxy to vertical surfaces without it running? I will be using a brush/sqeegy.

    Second question, for the final coat of epoxy (3rd coat uaually), should I add a low density filler to make sanding easier? This is not yacht quality work, its an old workboat. I dont need it to look like a mirror, just trying to get it looking halfway decent.
    Thanks for all your help.
     
  2. PAR
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    PAR Yacht Designer/Builder

    I use two different approaches. The one most commonly used by folks, is to wetout the surface with a uniformly thin coat of unthickened goo, then let it get tacky, which depending on humidity and temperature can be a few minutes to an hour. While tacky, it will hold your cloth and a fresh batch of unthickened epoxy applied over the now tacked down fabric. Wetout the fabric completely, with the squeegee, but just enough to wet the fabric. When this gets tacky or just after it's been tacky (green stage) then apply another coating of unthickened goo, to fill the fabric weave. Sometimes it takes more the one coating to fill the weave, but each can be done (work thin) during the "green stage" which is the best time, as it provides a chemical bond (which is the best kind).

    The other method is one I use while over head. I use a very, very light dusting of spray adhesive (I use 3M 77) on the surface. Let this "flash off" for a few minutes and then place your fabric in position. The spray adhesive doesn't hurt anything and holds the fabric up, so you're not using your bald spot as a third hand (like I do). Then wetout (think thin now) and apply weave filling coats when the goo kicks into the green stage of the curing process.

    You should be able to apply several coats of goo, if you wait for the just barely tacky or just past the tacky stage of the cure. This will fill the weave and provide a smooth surface. A smoother surface (like a mirror) can be had if you use a reasonably thick sheet of polyethylene or Mylar (Mylar is costly) over the last coating. Let the coating settle a little, then spread out the plastic sheet. Work out wrinkles with a smooth roller (rubber), plastic spreader or squeegee. It will turn invisible, when done right, and give you an idea of how the finish will look (before paint or varnish of course). This technique is for nice finishes. Peel ply or a more cost effective way is to do the same thing, but substitute "rip stop" nylon fabric. Apply this the same as the plastic sheeting. When it's cured, just grab the edge and yank it off. The peel ply or rip stop fabric will leave a slightly textured surface which is easily sanded smooth, with little fuss.
     
  3. nero
    Joined: Aug 2003
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    nero Senior Member

    PAR, an excellent post as always.

    I skip over the first step by dry laying all glass and clamping it by the top edge on vertical places. I sometimes use a few staples that are shot thru a piece of ice cream bucket lid. Either way, I wet out the fabric and wood strip planking (in my case). Keep chasing the epoxy backup into the weave with a squeege. Then as PAR explained go back over it when the resin starts to get tacky.

    All the staples get janked out by hand as I wet the glass out. I am using unidirectional and bidirectional glass so it tends to be self supporting as compared to a weave.
     
  4. KnottyBuoyz
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    KnottyBuoyz Provocateur & Raconteur

  5. old man
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    old man Junior Member

    Par,
    Your method is going to be very helpfull.
    Thanks
     
  6. old man
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    old man Junior Member

    Par,
    thanks for your coment and you answered my first question. My second question was about the final coat of epoxy. Should I add a filler to help make sanding easier?

    Also while I am asking what is a good paint to use? This is a workboat so it doesnt have to be yacht perfect but i want something nice. I bought a two part epoxy paint at sherman williams for my decks "sure clad". It didnt hold up after about 6 months the UV rays tore it up, it faded and got chalky.
    Thanks again for all your help.

    I have the entire cabin ripped off the boat, i am building a new cabin and installing new windows.

    PAR,
    Did you get the pics I emailed you of the Block island sailboat?
     
  7. KnottyBuoyz
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    KnottyBuoyz Provocateur & Raconteur

    I've read some guys building use this on their decks.

    http://www.ultratuff.net/marineprod.htm

    They make a fine grade anti-skid that is extremely durable. I think it's available from Cabela's online.
     
  8. nero
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    nero Senior Member

    When filling the weave, colloidal silica works well. After that, anything that will be sanded and is above the waterline, add microshperes and a bit of colloidal silica sands well. If you want to color it add a few squirts of chaulk. It is very cheap and comes in a few colors.
     
  9. PAR
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    PAR Yacht Designer/Builder

    I'm not a fan of the dry mount method of laying fabric. I've used stables, including the cool plastic ones, but it seems to bag, float and other wise screw up (like move when you yank a staple and the slightly bent leg catches the cloth and makes a big bubble or worse). I'm one of those guys that absolutely insists on saving the Christmas wrapping papper tubes (she thinks I'm eating them or making really big, disposable bongs). I wrap the fabric around real neatly and roll it out in the tacky goo, where it stays put, but can be moved when you need to. It's been my experience that 50% of the people I know, that do this kind of work, use the dry method, so it must work.

    No, I didn't get the pictures, can you re-send them?

    I think sanding ranks up there with hemorrhoids and ex-wives. I do everything I can to eliminate the process as much as possible. As you fill the weave, you'll get a reasonable idea of how the surface is going to look (wavy, humps and hollow areas, etc.) and I'll concentrate on low spots while leaving highs alone until I "catch up" with the lows. A squeegee is a great tool for this as is the plastic sheeting.

    If you can't get a reasonably smooth surface, then use a thickened mixture of micro-balloons with a little silica added to stiffen it up (otherwise it'll sag). Mix until it is real smooth and creamy and apply it thin, again the squeegee can be your best friend and the plastic sheeting. Mix the balloons in first (you'll need a lot) then add a silica, until it thickens up (you shouldn't need much, nor do you want much silica). Then break out the long board and think pretty thoughts.

    As for paint, it's hard to go wrong with topside enamels. If you're just doing a work boat then use high gloss exterior house paint. If you don't want the high gloss (which shows up every little surface defect and you'll wish you had used prettier thoughts with the long board) then two coats of gloss followed with semi or flat. You see, high gloss is the most water proof and toughest, with many flats actually absorbing moisture. The gloss under coats will protect the substrate. You can spend a fortune on paints, but they all seem to die in a similar amount of time, unless you spend several hundred bucks a gallon. Even the "good" stuff (linear polyurethanes) die and you'll feel like hell when you have to buy another bucket of hundred dollar bills. Besides house paint sands much easier. Use oil based stuff, acrylics (latex) suck and many absorb moisture, though many a work boat has Wal-Mart brand latex slathered all over it.
     
  10. old man
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    old man Junior Member

    thanks again for your help. I will re-send the pics tonight when I get home.
     
  11. old man
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    old man Junior Member

    PAR,
    I sent the pics again to your email. If you dont get them let me know. Its a pretty big file. I will send two picks at a time in multiple emails if you didnt get this past one.
     

  12. PAR
    Joined: Nov 2003
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    Location: Eustis, FL

    PAR Yacht Designer/Builder

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