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Fiberglass cloth and roving questions

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  • Fiberglass cloth and roving questions

    I'm in the process of replacing transom, stringers and deck in my 17 foot runabout. Here are the supplies that I have already.


    9 yards of 6oz cloth 50" wide.
    3 yards of 24oz woven roving, 50" wide.
    1 gallon of West Systems Epoxy 105
    1 quart of West Systems Hardener 205


    My plan is to use a thickened epoxy to bond the stringers to the hull followed by filleting an edge along the joint to the hull. Then to use a 8" strip of cloth over the joint between the hull and stringer. (4" of cloth extending up stringer and 4" onto the hull).

    Then I plan to place a strip of the 24oz roving, 12" wide over the first layer of cloth. Then to finish it off another layer of cloth wrapping over the entire stringer and extending 12 inches out on the hull from the joint.

    Does this sound like enough strength and waterproofing for the stringers? can I do this job using the cloth and roving that I already have?

    Advice would be much appreciated, I've never done this before.

    Thank you.
    sigpic

    1969 Slickcraft SS170v

    In the garage:
    1996 Evinrude 115hp Rebuild in progress
    1995 Evinrude 70hp
    1997 Evinrude 70hp
    1994 Evinrude 4hp


  • #2
    Re: Fiberglass cloth and roving questions

    Not an epoxy guy but strength wise sounds fine, but 1 gallon ain't gonna do it.
    A good brand of engine is one that runs

    Comment



    • #3
      Re: Fiberglass cloth and roving questions

      Originally posted by Cadwelder View Post
      Not an epoxy guy but strength wise sounds fine, but 1 gallon ain't gonna do it.
      Hey, thanks for the reply. Do you think the 1 gallon of resin will be enough for 3 stringers? They are 1.5"x 8" high. I planned on buying more resin for the transom and floor last.

      Do I need to do the transom first? Now that I think about it that would probably be easier but I don't know.
      sigpic

      1969 Slickcraft SS170v

      In the garage:
      1996 Evinrude 115hp Rebuild in progress
      1995 Evinrude 70hp
      1997 Evinrude 70hp
      1994 Evinrude 4hp

      Comment



      • #4
        Re: Fiberglass cloth and roving questions

        Add up the total weight of glass you plan to put on each stringer and it will about equal the weight of epoxy you will need. You will actually use more epoxy than that due to some waste and inexperience though.

        Comment



        • #5
          Re: Fiberglass cloth and roving questions

          Originally posted by ondarvr View Post
          Add up the total weight of glass you plan to put on each stringer and it will about equal the weight of epoxy you will need. You will actually use more epoxy than that due to some waste and inexperience though.
          Hey ondarvr, I was hoping you might reply. I've read many of your posts and you really know your stuff.

          What do you think about the cloth/roving/cloth idea I outlined in my first post? Is that what you might do if you were in the same situation with the same supplies? Would it be sufficient to just use the cloth or to just use the roving?

          As you can see I'm totally inexperienced but I'm trying to learn.

          Thanks
          sigpic

          1969 Slickcraft SS170v

          In the garage:
          1996 Evinrude 115hp Rebuild in progress
          1995 Evinrude 70hp
          1997 Evinrude 70hp
          1994 Evinrude 4hp

          Comment



          • #6
            Re: Fiberglass cloth and roving questions

            Welcome to iBoats!!!!

            Usually the Stringers tie into the Transom so you should always install the Transom First. You are going to need a MINIMUM of 5 gallons of resin. You do NOT have to use epoxy. It is OK but MUCH more expensive to use. Easier on the lungs and nose but not the wallet. If you stay with the epoxy you could use the 6oz cloth to cover your stringers and the deck. The roven woven would be good for the transom. I'd guess you'd use 2-3 gals on your stringers.
            1961 Lonestar Flamingo - SPLASHED...Kinda!!
            Fabricating Decks, Stringers, and Transoms
            Paint Your Boat with Tractor Paint

            Comment



            • #7
              Re: Fiberglass cloth and roving questions

              Originally posted by Woodonglass View Post
              Welcome to iBoats!!!!

              Usually the Stringers tie into the Transom so you should always install the Transom First. You are going to need a MINIMUM of 5 gallons of resin. You do NOT have to use epoxy. It is OK but MUCH more expensive to use. Easier on the lungs and nose but not the wallet. If you stay with the epoxy you could use the 6oz cloth to cover your stringers and the deck. The roven woven would be good for the transom. I'd guess you'd use 2-3 gals on your stringers.
              Hey woodonglass, thanks for the reply!

              The main reason i chose epoxy is I can't have strong chemical fumes where I am working on the boat. I have the budget available for this project so even though cost will be high I'm will to do it.

              I guess I will try to do the transom first with the 1 gallon I have. With the hardener mixed in it's a little more than a gallon all together.

              I guess my concern is strength on the stringers. I read somewhere that cloth doesn't have much strength to it. But using epoxy with several layers of 6oz cloth do you think that will be sufficient?

              Thanks everyone.
              sigpic

              1969 Slickcraft SS170v

              In the garage:
              1996 Evinrude 115hp Rebuild in progress
              1995 Evinrude 70hp
              1997 Evinrude 70hp
              1994 Evinrude 4hp

              Comment



              • #8
                Re: Fiberglass cloth and roving questions

                It's not that cloth isn't strong, it's that you need many layers of it to equal the same strength of heavier weight fabrics and that cloth is very pricy per pound. 17 oz Biax will cost less for the same strength, 18 oz roving will cost even less. For the most part the strength is determined by the total weigth of the glass used in the laminate (leaving out the mat), so two layers of 6 oz cloth won't be as strong as 1 layer of 17 oz biax. This is just a general statment because each type of glass (woven or stitched) will have different properties.

                Comment



                • #9
                  Re: Fiberglass cloth and roving questions

                  Hi trendsetter, I don't want to give you miss information on your use of 6oz but will try to help by telling you what I used on my transom. For my transom I used 3 layers of 1708 biax cloth. One layer of 1708 is about the same as three layers of 6oz. I am also using epoxy and it took me about 2 gallons but there was some waisted epoxy. My stringers will also get three layers of the same. I could have probably got away with two layers of 1708 but I wanted to be safe. I hope this helps a little. If you have any questions about 1708 biax then I will gladly help as much as I can. The main persn I would listen to in my opinion would be ondarvr. I certanly hope he will one day take a look at my project.

                  Comment



                  • #10
                    Re: Fiberglass cloth and roving questions

                    Hi guys, believe it or not none of my local fiberglass suppliers carried the 1708. Initially that is what I was trying to find. Even tried for the 1700 Biax (which I understand is the same as 1708 but without the mat).

                    In the end I only went with the cloth and woven roving because I got it dirt cheap in bulk. I mean, I could potentially buy more glass but I'd like to use the stuff I've got if I can.

                    Using the roving for my transom and the cloth for my stringers and deck is where I'm leaning at the moment. Maybe I will have to go 4 layers with the cloth on the stringers. I should have enough for for that. I have 112 sqft of the 6oz cloth.
                    sigpic

                    1969 Slickcraft SS170v

                    In the garage:
                    1996 Evinrude 115hp Rebuild in progress
                    1995 Evinrude 70hp
                    1997 Evinrude 70hp
                    1994 Evinrude 4hp

                    Comment



                    • #11
                      Re: Fiberglass cloth and roving questions

                      Using Epoxy You do NOT need the 1708 Biax. It has 8 oz of mat sewn onto the back and is NOT needed with epoxy. In fact it is a waste in that it adds no strength and just soaks up more epoxy thus cost more. the 1700 biax ondarvr suggested IS what I would also recommend for your transom. 88 IS correct in that you will probably use about 2 Gallons for your transom. You will also need some cabosil or some sort of thickening agent for filleting and for attaching the transom to the outer skin. I think 3 layers is over kill. Two should be sufficient for the transom. I agree with Ondarvr that the 6 oz cloth is not much good for your application. Possibly for the underside of your deck.
                      1961 Lonestar Flamingo - SPLASHED...Kinda!!
                      Fabricating Decks, Stringers, and Transoms
                      Paint Your Boat with Tractor Paint

                      Comment



                      • #12
                        Re: Fiberglass cloth and roving questions

                        Originally posted by Woodonglass View Post
                        Using Epoxy You do NOT need the 1708 Biax. It has 8 oz of mat sewn onto the back and is NOT needed with epoxy. In fact it is a waste in that it adds no strength and just soaks up more epoxy thus cost more. the 1700 biax ondarvr suggested IS what I would also recommend for your transom. 88 IS correct in that you will probably use about 2 Gallons for your transom. You will also need some cabosil or some sort of thickening agent for filleting and for attaching the transom to the outer skin. I think 3 layers is over kill. Two should be sufficient for the transom. I agree with Ondarvr that the 6 oz cloth is not much good for your application. Possibly for the underside of your deck.
                        Let's say that I use the 24oz woven roving (which I already have) for my transom. Would a single layer be enough? The outer skin is going to stay intact. I will only be replacing the inner skin.

                        Maybe I am confusing myself. Is it safe to say that for my transom I could use a combination of roving and cloth totalling 30oz? And for the stringers 3 layers of the 6oz cloth totalling 18oz?
                        sigpic

                        1969 Slickcraft SS170v

                        In the garage:
                        1996 Evinrude 115hp Rebuild in progress
                        1995 Evinrude 70hp
                        1997 Evinrude 70hp
                        1994 Evinrude 4hp

                        Comment



                        • #13
                          Re: Fiberglass cloth and roving questions

                          I suppose that would work, but You will REALLY soak up a LOT of Resin IMHO. Especially on the stringers. Hopefully Ondarvr will revisit or you could PM him. I typically use Poly on Glass boats and Epoxy on wood boats. Don't use roven woven much. He would be much better qualified to comment.
                          1961 Lonestar Flamingo - SPLASHED...Kinda!!
                          Fabricating Decks, Stringers, and Transoms
                          Paint Your Boat with Tractor Paint

                          Comment



                          • #14
                            Re: Fiberglass cloth and roving questions

                            Originally posted by Woodonglass View Post
                            I suppose that would work, but You will REALLY soak up a LOT of Resin IMHO. Especially on the stringers. Hopefully Ondarvr will revisit or you could PM him. I typically use Poly on Glass boats and Epoxy on wood boats. Don't use roven woven much. He would be much better qualified to comment.
                            Ok, thank you. I really do appreciate your input. Soaking up lots of resin means soaking up lots of $$$ so I will be keeping that in mind.

                            I would love to be able to use the fiberglass I have but I will go shopping again if it means saving money on resin and a better rebuild on the boat.
                            sigpic

                            1969 Slickcraft SS170v

                            In the garage:
                            1996 Evinrude 115hp Rebuild in progress
                            1995 Evinrude 70hp
                            1997 Evinrude 70hp
                            1994 Evinrude 4hp

                            Comment



                            • #15
                              Re: Fiberglass cloth and roving questions

                              Maybe I am confusing myself. Is it safe to say that for my transom I could use a combination of roving and cloth totalling 30oz? And for the stringers 3 layers of the 6oz cloth totalling 18oz?

                              This would probably be fine, just use the glass you have on hand and if you think it looks thin or weak add another layer.

                              Comment

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