Another Stringer Topic

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Danny Bailey
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Post by Danny Bailey »

Google 'Merton's' or 'System Three' for epoxy resin, thickeners and additives that are about one third the cost of 'West System'.
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Mac32
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Post by Mac32 »

I am in process of fiberglass layup on my new stringers. Does anyone know how thick the build up should be? I am currently using thick heavy roving and with 2 layers it only seems to cure at about 1/8 to 3/16 thick but the original layup is easily 1/4" thick. Was this over kill on trojans part? This would explain why she was able to run for a few years with rotted stringers without too much hull deflection?
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Post by Mac32 »

Paul, do you recall how much fiberglass layup (thickness) to do over the stringers? What is sufficient? I dont want to skipmp but every layer = $$
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Paul
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Post by Paul »

I would usually use a couple layers of fairly heavy roving with epoxy resin. Since you've epoxied the stringers in place, they've already added a lot of strength to the hull even before being covered with roving.
Paul
"Cruise Control" 1978 F-26HT
"No Control" 2012 9' Grand RIB
Mac32
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Post by Mac32 »

Thanks for the confirmation. Its looking like (3) layers with (1) or (2) extra layers tabbed in where stringers meet cross members.

Thanks again.....we willl be finished soon, I hope :shock:
MAC32 "Fingers crossed for Flotation"
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trepka2001
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Post by trepka2001 »

how would cutting the stringers down to the hull save time and money????
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Paul
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Post by Paul »

Trepka 2001,

When replacing a stringer, it's easier to install a newly built stringer than to work within the parameters set by the fiberglass shell of an old stringer as seen in Mac32's pictures. Although Mac32 did an exeptional job with the old fiberglass shell, this required alot of work.

He had to cut off the glass on the top of the stringer, dig out the rotted and remaining good wood then scrape, sand & prep the three internal surfaces. (all of which is easier said than done) He then had to custom fit the new wood to the existing pocket and use lots of filler to achieve proper adhesion. Then comes the final roving and resin.

Removing the stringers completly would require cutting along the base of the stringer with a sawzall then disc sanding the remaining glass flat to the hull. Then bed in the new wood stringer and cover it with roving and resin. Less work and less time.
Paul
"Cruise Control" 1978 F-26HT
"No Control" 2012 9' Grand RIB
trepka2001
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Post by trepka2001 »

Thanks Paul, I recently purchased a '75 F32 and a little worried about the stringers because I hear it's been a problem with these boats.

Would I need to cut out the decks of the boat (fore, mid and aft) or are they attached at the bulkhead and easy to remove?

Any help with the investigation and replacement of the stringers would be a HUGE help. Before I possibly tackle the stringers I have to replace the foredeck because of sponginess. I'm thinking of doing this from below because I'm not real comfortable doing alot of glass/gel work.
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Post by Don Lumber »

I'm guessing you had to sand the inside of the fiberglass in order to bond with the new stringer. Did you do it by hand? Just curious as I always see folks stress that the existing surface be as clean as possible from contaminants for a good bond.

Also, did you put a bed of glass mat in before you lay the stringer in? Should clamps be used until the bond is made or was it tight enough that you didn't need to do that?

I'm assuming a layer or two of roving was applied over the top when all was said and done?
****************************************
1976 F-32 - twin 233hp Mercruisers
I've been told a boat is nothing more than a hole
in the water you throw money into. Meh
****************************************
Mac32
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Post by Mac32 »

Don,
I ended up getting creative with the cleaning tools for the inside the old stringer inside surfaces. I used abrasive brushes, 8" dia grinding sanding wheels, and lots of elbow grease This process was very time consuming, and i had the least fun during this process.

After the new wood was all cut and ready to bed in, I filled all the voids with west system mixed with filler (this was at least 4 gallons alone). Yes i did clamp the sides together, and have about 30 new wood clamps to prove it.

After the wood was bed in the old channels I put on 3 layers of heavy roving , and tried to tab the first layer back down to the hull where possible.

With all this done i realized I probably over did it, but I never wanted to even think about having to do it again. And if I ever do this again, I will cut the stringers down to the hull and save at least 1/2 of the time I spent cleaning and filling the gaps.

There was a sense of less risk when leaving in the side walls, but now I have the experience and confidence to do new ones back to the hull. So I am going to recomend this process for a portion of stringer rot but if you have to do a stem to stern job go down to the hull.

If you want to look at my job, here is the link.

http://good-times.webshots.com/album/558394609dmictG
MAC32 "Fingers crossed for Flotation"
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trepka2001
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Post by trepka2001 »

Mac, My boat is 400 miles away and haven't had the chance to look at my stringers, but do you have to cut the deck of the boat (living space)out or are they floor panels above the stringers that you unscrew?
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Post by Don Lumber »

My floor was replaced once I think as the floor in the berth/dinette area was in two pieces of plywood and had finger holes in them to pull them up for inspection. My ribs are wet and punky but I haven't examined my stringers yet. I'm assuming I'll have some repair to do if not a full replacement as mac has done here.

I'm not sure what you'll find in yours though. Do you have carpet over the top or wood floor?
****************************************
1976 F-32 - twin 233hp Mercruisers
I've been told a boat is nothing more than a hole
in the water you throw money into. Meh
****************************************
Mac32
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Post by Mac32 »

I did not have to cut anything pertaining to the floor, it all unscrewed. Allthough I did put a new floor in because I moved the step forward about 2 feet in the v-birth are to give more head room. (I also replaced the 1/2 marine ply with 3/4 marine ply just for good measure and keep the flex down when walking on it, just so it FEELS better)

But you should be able to unscrew all the panels in the salon floor and re-use them if in good condition.
MAC32 "Fingers crossed for Flotation"
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lakeguy72
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Another Stringer Topic

Post by lakeguy72 »

Don, the finger holes were factory on my 1977. They should have also put them on the forward panels under the v-berth cushions. That's where my holding tank is. I added holes to make it easier to check the tank level.
Don Lumber
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Post by Don Lumber »

Thanks for the info lakeguy.

Sorry about hi-jacking this thread.
****************************************
1976 F-32 - twin 233hp Mercruisers
I've been told a boat is nothing more than a hole
in the water you throw money into. Meh
****************************************
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