Conflicting stringer fiberglass layup diagrams

Stalmon

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Stringers_zps840bac88.jpgwest striger diagram.jpg

I have copied in two diagrams of how to glass stringers, one I found in this forum and one from a West Systems manual. One tabs progressively larger and then caps the tabs the other fully encases the stringers down onto the hull. Is this a personal preference type issue where they both work fine? Are there pros and cons with the two methods?

thanks for you opinions
 

jbcurt00

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Re: Conflicting stringer fiberglass layup diagrams

Which looks stronger to you?

Have you wrapped fiberglass across the hull, up a stringer, over the top & down the other side?

It's not easy to wrap up & over a stringer. Particularly a square edge stringer like West's drawing.

They both fully encase the stringers in fiberglass.

WOG's graphic builds bulk & strength as you add glass, and carries it further out onto the hull w/ each subsequent layer.

I'd follow WOG's graphic......
 

chconger

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Re: Conflicting stringer fiberglass layup diagrams

I see your looking at WOG's polyester layup, and comparing it to West's epoxy layup.

Poly is much cheaper, its probably what your boat is made from, and perfectly OK for stringers....but if you use it you need to add the CSM layer against the wood, which takes a lot of resin. I don't believe that is needed for epoxy. So you use less epoxy then poly at the end of the day. Probably poly is still much cheaper but I haven't seen any study.

Disclaimer; I haven't used poly since I was 14....so Ill let others who really know this stuff chime in here.
 

zool

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Re: Conflicting stringer fiberglass layup diagrams

Ive thought about this for a while, after reading the West 550 sheet.

Based on the reading, it appears West is less concerned with adhesion, and concentrates on horizontal strength. Which makes some sense given that epoxy adheres better than poly. The guide repetedly addresses the importance of cap width, for horizontal integrety. Meaning that a 1/8 inch cloth cap requires a 6 inch stringer height, an 1/4 inch cap requires a 4 inch sringer, ect ect.

They also incorporate a full layover method, widest layer 1st. This kinda makes sense being that the layered strength would be in the upper lam layer of the build, if verticle strength was the intended result.

For a poly layup, the generally accepted method used here is right on, but for eopxy, it could go either way, imo

For me, given my situation increasing hp and torque, i decided to do the overlap tab in woods sig, minus the csm, then the West decreasing full overlay to current cap thickness, thus getting the best of both worlds...im using us comp epoxy and west fillers. .just one mans psychosis..
 

Stalmon

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Re: Conflicting stringer fiberglass layup diagrams

thanks for the input guys,

I have never glassed anything and when I was ripping the old stringers out I just assumed putting the new ones in would go something like the west diagram, although I was thinking more top down at once on both sides instead of from the hull on one side up and over. when I saw WOG's diagram it at first seemed counter intuitive to me and when I had the two to compare I decided to seek opinions.

It did not occur to me that the two methods might be specific to resin type even though I knew WOG's was a poly layup because of the CSM layer. I do like the progression further on to the hull with each layer in WOG's method.

at any rate I am going to follow WOG, I think I will have a better chance to succeed.

thanks again, Stalmon
 

Stalmon

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Re: Conflicting stringer fiberglass layup diagrams

View attachment 203763View attachment 203764

I have copied in two diagrams of how to glass stringers, one I found in this forum and one from a West Systems manual. One tabs progressively larger and then caps the tabs the other fully encases the stringers down onto the hull. Is this a personal preference type issue where they both work fine? Are there pros and cons with the two methods?

thanks for you opinions

stringers-revised.jpg

So after all that I run across the new revised diagram from WOG that is a combo method like zool intends to do. hmm, might try it on the 4 inch stringer first or might just go with his original method. Will still need to think about it.
 

Yacht Dr.

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Re: Conflicting stringer fiberglass layup diagrams

View attachment 203938

So after all that I run across the new revised diagram from WOG that is a combo method like zool intends to do. hmm, might try it on the 4 inch stringer first or might just go with his original method. Will still need to think about it.

This is how I Basically do it. I will wet out the stringer with resin. Then layup/wet out all the layers of glass (in reverse order) on a sheet of wax paper. Pick up the stack and flip it over the stringer. You can use a spreader or your hands to initially get it down and big bubbles out. Then remove the wax paper and bubble roll the smaller air voids.

YD.
 
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Re: Conflicting stringer fiberglass layup diagrams

A couple of random thoughts. First off, the people at West Systems really know their stuff, the owners have been into boating and boat building for many many years now.

Also, if you lay down glass as thick as 1708 starting with the narrowest ply first there's going to be a void at the end of each layer because the layer above it can't conform perfectly to the transition. That's going to lead to a slight stress concentration along that edge.

I think someone mentioned it already, the thing to do with the top of the stringer is to round the edges so the glass has a chance of laying down.

Finally, I doubt that anything like this built with a reasonable amount of care is going to come anywhere close to breaking. I've seen some awful crappy workmanship from the factory on a couple of boats (NOT my Checkmate by the way) and they'd seen many years of service without any structural problems.
 

zool

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Re: Conflicting stringer fiberglass layup diagrams

For epoxy, If you just use biax 170 without the mat backing, those caps will be alot easier to make, plus the mat backing will just be a resin sponge, with little benefit...rounding the tops is a good idea either way.
 

Stalmon

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Re: Conflicting stringer fiberglass layup diagrams

This is how I Basically do it. I will wet out the stringer with resin. Then layup/wet out all the layers of glass (in reverse order) on a sheet of wax paper. Pick up the stack and flip it over the stringer. You can use a spreader or your hands to initially get it down and big bubbles out. Then remove the wax paper and bubble roll the smaller air voids.

YD.

wow, all layers in one fell swoop! I like that idea but I would be afraid that three guys who have never done any fiberglass work might just wind up with a big clump of cloth and resin!
 

Stalmon

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Re: Conflicting stringer fiberglass layup diagrams

Finally, I doubt that anything like this built with a reasonable amount of care is going to come anywhere close to breaking. I've seen some awful crappy workmanship from the factory on a couple of boats (NOT my Checkmate by the way) and they'd seen many years of service without any structural problems.

thanks, this last thought is important in giving a restoration complete rookie some confidence. if we read up, follow the good advice we are getting, and do our best, our best is not likely to fail.
 

Stalmon

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Re: Conflicting stringer fiberglass layup diagrams

For epoxy, If you just use biax 170 without the mat backing, those caps will be alot easier to make, plus the mat backing will just be a resin sponge, with little benefit...rounding the tops is a good idea either way.

ah, you already have answered my next question. 1708 seems to be the material of choice for epoxy work but what about a lighter material. thanks for answering that before I asked it. I was actually thinking about biax 90 but I guess that would be more layers. I guess that is the next thing I need to tackle, how may layers on my stringers.

thanks, stalmon
 

surlyjoe

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Re: Conflicting stringer fiberglass layup diagrams

I have heard from several sources that vinylester makes a better bond to old glass than polyester. I like epoxy but it gets expensive on big jobs, so I use the vinlyester
 

mwe-maxxowner

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Re: Conflicting stringer fiberglass layup diagrams

I might be wrong, but I don't think 1708 is used with epoxy. 1708 is useful with poly because it already has csm stitched to the backside. The csm is not needed with the epoxy. Maybe 17 oz cloth is popular with epoxy?
 

Stalmon

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Re: Conflicting stringer fiberglass layup diagrams

I might be wrong, but I don't think 1708 is used with epoxy. 1708 is useful with poly because it already has csm stitched to the backside. The csm is not needed with the epoxy. Maybe 17 oz cloth is popular with epoxy?

You're right, I got that wrong in my reading and anybody using 1708 must be using a poly resin. so there is no reason for me to use 1708. thanks for the clarification.

Stalmon
 
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