I've cut the fiberglass down, within an inch or so of the hull. Is it recommended to leave some, to ensure you get them back in the exact location? Or grind down, and start over?
I've cut the fiberglass down, within an inch or so of the hull. Is it recommended to leave some, to ensure you get them back in the exact location? Or grind down, and start over?
I use cardboard to pattern replacement stringers. You do not want to bed the stringers with a hard edge directly to the hull. What happens is a hard edge limits hull shell flex causing the hull to crack right along the hard edge created. You will see stringers taped in after kinda floating off the outer hull skin. The taping prevents the hard edge but still provides compression support. Personally I radius the bottom of all the stringers I replace. Then I bed them to the hull with a semi-rigid compound. Afterwards I cut all the fabric fitting each piece first, using a heat gun if necessary to form & relax the memory out of the material. Wetting out with epoxy prevents me from using chop mat of any kind on stringers. All work I do inside structurally speaking is done with epoxy. Vinylester is 300psi adhesion, Epoxy is 3000psi adhesion, big difference in toughness. Really well laid up stringers don't need the core. If you study the latest stringer systems they are foam filled fiberglass moldings not individual pieces anymore. Kinda cool evolution. I dig out all wood just like a transom replacement job but leave a bit of the old taping to use to hold the bedding compound and new stringer in place. Since I lightly filet the radius for the 1708 before wetting out I really don't do too much prep to the old taping just clean with acetone well first.
Thank you.
I believe the guy that did the stringer work on mine left some, maybe not an inch, and maybe not both sides, but I think he did leave some of the fiberglass for relocating the stringers to the original positions. Mine was done with coosa. He may have radiused the edges as well, he was pretty meticulous. Otherwise, 100% agree with above. I may not be the best one to address the epoxy vs vinyl resin issue, but I thought part of the issue with epoxy was in regard to adding on top of epoxy that has already cured, and that it requires more steps or something compared to vinyl ester. I don't recall for sure.
Kevin | 2000 Champion 191 | 2000 Yamaha OX66 200hp
To continue to clarify, epoxy has to be sanded if cured before continuing laminating over. Big pain as epoxy does not like to be sanded, it's a very tough material. Poly & Vinylester can be worked over if within their specific cure time parameters without sanding allowing a chemical as well as mechanical bond (the best bond) assuming no wax was added. You don't put vinylester over epoxy but you can put epoxy over Vinylester. Vinylester is in between Polyester & Epoxy, has a shorter shelf life but stronger than Poly too. Using Epoxy on underdeck repairs, stringers, bonding, places not seen, is great. Several very experienced glassmen told me in the past "new Ester's don't like to stick well to old Ester's and to use Epoxy if possible", this has always stuck in the back of my mind as who wants their work to de-laminate? I personally leave a small amount of the tape on both sides using the gap for direction on what thickness of Coosa 26 to cut the new stringers out of, something to filet to, and to hold the bedding compound. I never use wood.
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