Should I Fasten first layer of fiberglass in the layup process

Discussion in 'Boatbuilding' started by stranchy, Sep 15, 2009.

  1. stranchy
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    stranchy Junior Member

    New to this forum and I would like some advice/opinions. I have a 1966, 18' skiff that I am restoring (I think re-building is a better word). I am reglassing the interior sides and deck. I was given a book "Covering wooden boats with fiberglass" from the late 70's in the book the author/builder describes his layup procedure, first: lay the first layer of glass and while it is still green fasten it to the wood using Stainless staples, roofing nails etc within 2-3" in all directions... Then add other layers, he is more specific but my question is:
    Is Fastning the first layer of glass an excepted practice today. It makes sense to me since the old fiberglass on the boat was coming up a little but once I tugged on it, it came off clean. Any advice would be appreciated since I am just at the re glass stage.
     
  2. missinginaction
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    missinginaction Senior Member

    I'm sure that others will post and help you out. I'm in the finishing stages of a similar project on a 1973 Silverton. The only difference is that I replaced all the original equipment wood with new. If the wood is sound (on a 43 year old wooden boat I'd tend to doubt it but only you know) I'd apply a first coat of resin to seal the wood. AFter this coat cures beyond the tacky stage you'll probably notice that there are parts of the wood that look "dry". This is where the resin soaked in. Apply a second coat of resin (not to heavy, just wet it out with a 1/8" foam roller). After the second coat cures beyond tacky you will probably have a fairly smooth surface with no evidence of "dry" spots. At this point you can apply the fiberglass. I use 6 oz cloth on horizontal decks and 4 oz cloth on vertical cabin sides. I don't believe that it's a good idea to staple or poke holes of any kind in your decks. The holes just invite water infiltration and eventually rot.

    Take a look at the Epoxy Book at www.systemthree.com or any of the publications from West Systems for details on modern glassing techniques.

    Good Luck,

    MIA
     
  3. rwatson
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    rwatson Senior Member

    You are going to get a lot of "Dont use Polyester - use Epoxy" comments.

    All I have to say is "For Gods sake, dont use Polyester, use Epoxy"

    Missing in Action has it all covered beautifully.

    I might just add, where bubbles appear after the initial coat, make sure you ream them out, and keep re-applying the first coat till they dissapear. They will cause real aggro if you just cover them over.
     
  4. stranchy
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    stranchy Junior Member

    Thanks Guy's. Most of the wood was ok except for the 10' 2x8 Stringer that I vacuumed out due to it's rotten state. I have pulled all the floor and re ran some bildge pump hoses that were destined for failure.
    Next ? is: I will place the floor back down and I want to laminate it also, do I lay the floor and laminate it an go slightly up the walls or Lay the floor laminate the walls down onto the floor?

    rwatson what do you mean by ream out the air bubbles?

    Thanks again, I will post some pictures when it looks like a boat again.
     
  5. missinginaction
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    missinginaction Senior Member

    rwatson's right with his comment about epoxy vs. polyester. Please heed that advise.

    The bubbles that he refers to are caused by gasses (essentially air) in the wood attempting to escape through the layer of wet epoxy before it begins to harden. This can be a particular problem if you apply epoxy in the morning and then the temperature rises. The air in the wood expands and you get a ton of bubbles. These have to be sanded out if you want a nice smooth surface. If I'm doing sealing of bare wood I try to do it in the evening (inside or at least under some kind of cover, you don't want to get dew on your epoxy). Once you get the bare wood sealed you will not have this issue on followup coats.

    You can also get air entrainment in the epoxy layup from using 1/8" foam rollers (as I like to use). The foam rolls fine bubbles into the epoxy as you are applying it. One way that I've found to reduce air entrainment is to use as few strokes as possible thereby not "overrolling" the resin. I can often apply epoxy to bare wood with only one roller stroke, in one direction.

    A handy tool to have around to deal with bubbles is a heat gun. I've had a variable temperature heat gun for a long time. When bubbles crop up in the epoxy I've found that playing the heat across the wood causes most of the bubbles to "pop" and does a good job of leveling the coating.

    I'm not clear on your floor question so you might try to restate it. Are you are talking about placing a horizontal plywood floor down over your stringers?

    Regards,

    MIA
     
  6. stranchy
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    stranchy Junior Member

    Thank you guy's for the well thought out answers. To clarify my deck question. Once I lay the horizontal deck (Laminated High Strength Foam) over my stringers. What is the best way to seal the walls to the deck with fiberglass? I am concerned with the joint where the walls meet the deck, it had been a source of leaks in the past. Do I fair that joint before laying the glass?
    Do I lay the glass on the deck stopping at where the Deck meets the wall or do I go up the wall a certain distance? Or do I come down the walls and run onto the deck a certain distance (once the deck has glass on it). Then feather the edge of the glass either on the deck or the wall. suggestions needed.

    Also who carries the 1/8" foam rollers.

    Again, I really appreciate all of the help given, keep it comming I surely can use it. By the way I am only using the Epoxy Resin.
     
  7. fasteddy106
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    fasteddy106 Junior Member

    You want to get the resin rollers also. They look like a bunch of little pizza cutters and come in various widths. They help a bunch with air bubbles. Btw, use epoxy - lol!
     
  8. missinginaction
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    missinginaction Senior Member

    OK, now I get it. I'd approach the floor this way.

    You must be using a closed cell foam that doesn't absorb water. If the foam is exposed you'll want to cover it with a layer of fiberglass cloth to give it some impact and abrasion resistance. I've never used foam like that on a floor or cabin sole so I'll let someone else weigh in on the weight of cloth you might consider. Over plywood I use 6 oz cloth where I'm walking and 4 oz cloth where there is little traffic.

    Anyway, after the floor is coated and within 48 hours or so (because you want to get a good chemical bond here, where the second coat chemically links with the first) I'd use something like 8 inch wide 8 oz per square yard weight fiberglass tape to tab the floor into the inside of the topsides. It would certainly be a good idea to mix up some silica thickener and lay in a nice fillet so that you have a radius at the joint between the floor and the inside of the hull.

    Depending on the temperature that you're working in I'd suggest that you consider using a medium speed hardener so that you have time to make a nice fillet before the resin begins to cure. I've found that when you're new to working with epoxy the longer curing time enables you to relax a bit and think about what you're doing.

    As far as the rollers are concerned I get them from Mertons Fiberglass Supply in Springfield Massachusetts. The website is www.mertons.com look at the fiberglassing tools and assessories link for the foam rollers. They also carry the laminating rollers that fasteddy106 was refering to.

    If you decide to get them there give them a call and ask for Joe Merton. He's been very helpful to me especially when I was getting started doing my boat a few years ago. Tell him what you're doing and I'm sure that he'll have some good advise for you. Tell him that the guy doing the Silverton over by Saratoga Springs sent you.

    MIA
     
  9. naturewaterboy
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    naturewaterboy Steel Drum Tuner

    It is ALWAYS necessary to sand (80 grit or coarser) between coats of resin (yep, only use epoxy!) unless the previous coat is still tacky. If tacky, you will get a crosslink bond. If not tacky, you will get no chemical bond, only a mechanical bond. I've seen unsanded layers completely delaminate when a little stress is put on them. Sanding increases the surface area dramatically, and results in a much stronger bond. The best bond is chemical (add the next layer while the last one is still tacky) but this isn't always practical.
     
  10. rwatson
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    rwatson Senior Member

    Looks like you are well on your way, but if you get significant air bubbles rising from a hole or void in the underlying timber, (not so much the little annoying ones), I have mistakenly just broken the bubble surface, and filled it with epoxy.

    This resulted in another bubble.

    The only way to get rid of it is to get a large drill bit, and drill say 1/8 into the timber, so when you lay epoxy on it, the void in the timber causing the bubble is properly filled.

    If you dont attend to these persistant bubbles, on a hot day, the air expands and pushes the epoxy off the wood, leaving voids for rot.
     
  11. PAR
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    PAR Yacht Designer/Builder

    I think everyone has missed it or I'm reading something into it, but it appears Stranchy isn't using epoxy.

    I say this because it would be quite rare for a 1966 build to have epoxy, it's a very common practice to staple polyester to wood in an effort to improve peel strength, he mentioned the previous laminate "came off clean" when yanked on (clearly not epoxy) and the book he's using for reference was at the end of the "lets coat it with polyester" heyday.

    I'm assuming this is the A. Vaitses book "Covering Wooden Boats with Fiberglass", so at this point it would be wise to have the resin system verified.
     
  12. missinginaction
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    missinginaction Senior Member

    Hi PAR, I was wondering where you more senior guys were (rwatson excepted). Staunchy mentioned using only epoxy in his 3rd post here but you make a good point since that book deals with poly and you obviously have read it.

    I'm interested to see how the floor looks. Hopefully staunchy will post some photos.

    MIA
     
  13. stranchy
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    stranchy Junior Member

    Wow open the flood gates and out comes some great advice. Thank you all.
    Ok the original resin was polyester, and the book I mentioned is in fact dealing with polyester. But after all of the comments and all of the material people I spoke with saying only one thing "Only Use Epoxy" so that's what I'm doing (I'm an idiot just not a stupid idiot). I was also told that the epoxy will adhere (if surface is properly sanded to gain some teeth) to the older Polyester resin.

    As for sanding between coats, the west system book says if you re applying before 72 hours you would not need to sand. Should I just sand any way to save potential problems later, I mean I am knee deep any way what's another hour or so.

    MIA, as for the fiberglass tape, before I tape it will I have already glassed the deck and the walls cutting them flush at the wall / deck joint? As I read your thoughts on taping, will I lay the tape going with the joint and say 4" on the wall and 4" on the deck. Do I then coat the tape with resin let it set and then come back and lay in a nice fillet of thickened resin?

    One other thought, with my stringers exposed, I am going to seal everything with resin (per other reply's) and let it cure. What about taping the tops of the stringers, the sideds have already been done.

    Now when I go to fasten the deck and I drill through my glassed foam, do I need to squirst anything like bedding in the hole or just fasten it and make sure I cover the holes well with tape or resin or fairing compound?

    Again, I can't thak you all enough for the great advice.
     
    Last edited: Sep 17, 2009
  14. PAR
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    PAR Yacht Designer/Builder

    If you are applying straight, untickened epoxy as a coating, then the 72 hour rule applies, though I will scuff anything that doesn't dent when I push a fingernail into it.

    You should make fillets or build up a wedge from some other material, before applying tape to a dramatic transition, like a 90 degree joint. 'Glass fabrics need to have a radius to lay down neatly and fillets are a common method of providing this. Fillet first, then tape, ideally wet on wet.

    Yes, seal up your stringers with resin and fabric.

    If you're going to screw down something on a foam cored surface, you have to "bond" the fasteners. This is covered in the West System User's Guide. Basically, you drill and over size hole, fill with thickened epoxy, then insert your fastener while the goo is wet. If you want the ability to remove the fastener easily at a later date, then coat the fastener with paste wax or a release agent, before you stick it in the goo.
     

  15. stranchy
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    stranchy Junior Member

    Again thank you for all of your help. I will post pictures when it looks like a boat again.
    To confirm my initial question "Should I fasten the first layers of glass in a multi layer layup"
    From what I have received, the answer is no if you are using Epoxy resin. The fastening procedure was primarly used when wetting with Polyester resin to insure a good bond to the wood.

    I have also learned that you should coat EVERYTHING (wood) with resin to properly seal it from water and weather. Also you should seal and glass all stringers (assuming you have acces to them)

    I am going to bond my fastners in and also lay the last layer of glass over the entire deck once the fastners are cured.

    Question, what is a good thinner to use to make a thinned saturating resin (Git Rott type) I read that Xylene is fine. any body have an opinion?

    Thanks for the advice, please let me know if I missed something.
     
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