Fiberglass Question for Bow Eye

[luckyinkentucky]

This is a multi-part question, so please bear with me.

I will be fixing the bow eye today after removing all of the 'flakey' area on the interior of the hull last night, and removing all of the old wood. I've got the surface down to bare glass with a clean surface.

Would I be better off using something like Marinetex to fill the existing holes, or will fiberglass/ resin serve the same purpose? I want something to fill the holes that will not chip or crack under the stress.

How thick of an area can I lay safely without having to worry about any ill effects such as too much heat, not setting up, etc ... Would I be better off in laying one layer, waiting 45 minutes, sanding, then laying another? Or, is it best to lay all layers at once and let it cool as a mass?


Does a fan blowing on the area help it to cure faster, and keep it cool?
Thanks for the patience!

 

[KnottyBuoyz]

Re: Fiberglass Question for Bow Eye

Hey Kentucky

Are you going to redrill the holes for the bow eye? A bit of resin mixed with some fiberglass would probably work better. Use the marinetex when you put the bow eye itself back in.

Make sure your old glass is clean but roughed up so that the new resin has something to hang onto. You're creating a mechanical bond, not a chemical one so the resin will need a roughened surface to grab onto.

Lay on your layers of mat & glass wet on wet. This will allow a chemical bond (strongest). If you work wet on wet there's no need to sand. The resin will likely heat (exothermic) up a bit as it kicks off but that's not a problem unless you're piling on an inch or so of stuff. A fan can help keep it cool but will extend the time it takes to harden.

Good luck with your project.

Rick

 

[luckyinkentucky]

Re: Fiberglass Question for Bow Eye

Actually, I may be adding around an inch of stuff. I want to lay down 2 layers of mat followed by 6 to 7 layers of cloth. Does this cause a problem?

I have roughed up the area with 60 grit sandpaper. Is this good enough?

 

[KnottyBuoyz]

Re: Fiberglass Question for Bow Eye

You should be good to go. Overlap your layers so the margins don't line up. Feather the layers out as best you can. The more surface area you have for a mechanical bond the better.

You much have some pretty heavy glass to get 6 or 7 layers to reach an inch! I just did a layup with 17 oz glass and it came out at .044". Ten layers would have still been less than a half inch thick.

Keep in mind more resin doesn't make the repair stronger. The strength comes from the glass. Use just enough to wet out the glass and squeegee away the excess. Ideally you want a 50% glass & 50% resin matrix.

 

[luckyinkentucky]

Re: Fiberglass Question for Bow Eye

Would it be better to do a criss - cross pattern alternating the pattern?

Also, I have access to 1 yard of Kevlar. Would that be good to add also? I'm wanting to repair this so I never have to do it again.

As for the thickeness .... I was just assuming I would use the whole package of cloth. It is folded at around 3/4" right now in the package.

 

[KnottyBuoyz]

Re: Fiberglass Question for Bow Eye

Would it be better to do a criss - cross pattern alternating the pattern?

Also, I have access to 1 yard of Kevlar. Would that be good to add also? I'm wanting to repair this so I never have to do it again.

As for the thickeness .... I was just assuming I would use the whole package of cloth. It is folded at around 3/4" right now in the package.

Alternating the patterns at right angles would help a little that's why biaxial fabrics are stronger. Kevlar won't do much. It floats in the resin so you'd have to apply some sort of clamping pressure to get it at the correct fiber to resin ratio. It would look neat though!

Hand laid up glass w/o a vacuum bag will result in a higher resin to glass ratio and be thicker. No way around that. Unless you're doing this repair on the Titanic you should be fine. Provide a backing plate or large washers to your eyebolt afterwards and you should be fine.

 

[luckyinkentucky]

Re: Fiberglass Question for Bow Eye

I'll be laying down a 4" X 6" iron plate that measures 1/4" in thickness for the backer, and a 1 1/2" washer to each bolt before adding 2 nuts to each bolt. I've already put 3 coats of Rustoleum paint on the iron so I won't have to worry about THAT for a long long time.

 

[ondarvr]

Re: Fiberglass Question for Bow Eye

Unless this is a yacht and a big one at that, this is over kill, it will make little difference what glass (mat, cloth, roving, biax, kevlar) you use if you're going to make it that thick (1/2") and then using a large plate. The area you are building up will never fail, but the surrounding area will if stressed enough (unlikely). If you plan on using the plate, then 1/4" of glass or so will be fine. As KB said, spread out the load by going wider than the plate or you will creat sress points at the edges of the laminate. There will be no stress on the bond as it's all clamped together and the stresses will be compressing it, not pulling it apart.

What I'm getting at, is this a very simple low stress layup, don't try to over engineer it and then worry that it will fail.