many questions about repairing/replacing stringers

[Liam]

Hey sorry i misinterpreted what you where saying with the deck,you will be fine using the perimiter to attatch,i am doing the same.
I have saddle tanks so am raising the tanks 3/4 inch to allow for the overlap.
I am only using one layer of 1708 on the stringers,50 inch will do both my stringers,tabbed in with 6 inch 1708 tape and CSM in the tight corners.
I suspect your stringers are taller than mine though so you may need to use one length of 38 inch per stringer.
For the deck i plan to use one layer of 1.5 oz CSM on the underside then one layer of 1708 with a layer of 3/4 oz CSM on the topside.Thats with 1/2 inch ply.
My stringers are longer than 8 feet, as the stringer is made from 2 pieces of 3/4 ply i just cut one piece 12 inches shorter and do the reverse on the next section of stringer,glue with resin and stainless screws,then one sheet of 1708 over the whole stringer.

[carboncow]

Liam,

Glad to think average minds think alike...

comments in body of the text.

Originally Posted by Liam

Hey sorry i misinterpreted what you where saying with the deck,you will be fine using the perimiter to attatch,i am doing the same.
I have saddle tanks so am raising the tanks 3/4 inch to allow for the overlap.
I am only using one layer of 1708 on the stringers,50 inch will do both my stringers,tabbed in with 6 inch 1708 tape and CSM in the tight corners.

How come only one layer on the stringer (I see many guys online doing multiple. Is it because you have strength in the old ones at the base and pouring in the fill will give additional stability?

I've seen the glass tape online...why are you using it? Is it easier then cutting something long and thin for tabbing needs?

I suspect your stringers are taller than mine though so you may need to use one length of 38 inch per stringer.

Yes now that I see the newer boats have only two tall stringers and from your post you have 4 shorter ones (I believe) which presents some challenge of the wood height and getting it in there. I like your idea of leaving a few inches of the stringer for a guide.

For the deck i plan to use one layer of 1.5 oz CSM on the underside then one layer of 1708 with a layer of 3/4 oz CSM on the topside.Thats with 1/2 inch ply.
My stringers are longer than 8 feet, as the stringer is made from 2 pieces of 3/4 ply i just cut one piece 12 inches shorter and do the reverse on the next section of stringer,glue with resin and stainless screws,then one sheet of 1708 over the whole stringer.


Are you stating your will glue and screw those two stringer pieces together or are you screwing your deck to your bulkhead/stringers too?

What is CSM..."chopped" or "cut" matting? Obviously you have done some glass work before with the different weight usages. If we are buying a large roll of 1708 are we fine to use that for all deck needs and just change directions? How many layers would you recommend for the decking? (I see many opinions out there!

Again, this is great stuff. Thanks for letting me parse your comments as I learn this. I got a buddy who is off the charts handy with this stuff but green with glass but I like to understand everyone process to feed him the intel so we do our boat right and safe the first time.

[Liam]

CSM stands for "chopped strand mat"
As far as one layer,1708 is actually 2 layers it is one layer of 45 degree woven fabric with a layer of CSM stiched to the back of it. Providing you don't use polyester resin 1708 is extremely strong and waterproof.
The deck will be screwed to the stringers and bulkheads,there will also be a layer of thickened resin on top of the stringers/bulkheads to allow for any undulations. The stringers will be screwed at the overlap permanently,when i glued the two layers of stringer together i put resin between the two and screwed and clamped them until the resin had set then removed the screws.

Glass tape saves cutting as you mentioned and is used for tabbing in.

Your stringers are taller because you have a later boat that has a self bailing deck ,the deck was raised to be above the water line and they increased the cap height to allow for the loss in freeboard.

[bradford]

Excellent posts!

[carboncow]

Originally Posted by Liam

CSM stands for "chopped strand mat"
As far as one layer,1708 is actually 2 layers it is one layer of 45 degree woven fabric with a layer of CSM stiched to the back of it. Providing you don't use polyester resin 1708 is extremely strong and waterproof.
The deck will be screwed to the stringers and bulkheads,there will also be a layer of thickened resin on top of the stringers/bulkheads to allow for any undulations. The stringers will be screwed at the overlap permanently,when i glued the two layers of stringer together i put resin between the two and screwed and clamped them until the resin had set then removed the screws.

Glass tape saves cutting as you mentioned and is used for tabbing in.

Your stringers are taller because you have a later boat that has a self bailing deck ,the deck was raised to be above the water line and they increased the cap height to allow for the loss in freeboard.

Going to keep bugging you!

1. Why not poly...which one sticks better to the old glass too?
2. I'm trying to get a grasp on how many yards of 50" 1708. How much did you buy/use...or did I miss that somewhere?

We found one vendor selling a roll of 48" yard very reasonably but that seems like a lot if only doing one layer on the stringers and two on the deck. We'll take some measurements this weekend on the boat to come up with our theory of quantity.

3. How much resin would you also recommend based on my photo and if we had todo two tall stringers front to back. My buddy thinks 3 would due but I'm always the pessimist and think 5 is the safe thing.

[Liam]

Originally Posted by carboncow

Going to keep bugging you!

1. Why not poly...which one sticks better to the old glass too?
epoxy would be the best choice and will stick to old work the best,then vinylester,the fumes are pretty rough with vinylester though,then polyester which won't stick to epoxy nor is very waterproof over the long term. I am not saying it would be wrong to use poly, a lot of boat builders do,i believe the original construction on your boat is poly,but if you plan on keeping the boat for a while I would use vinylester,just get a good respirator,if money is not an issue and you are keeping the boat for ever use epoxy,lol

2. I'm trying to get a grasp on how many yards of 50" 1708. How much did you buy/use...or did I miss that somewhere?
I buy mine in smaller orders online from uscomposites,i buy enough for each part of the project,as I recall I bought 5 yards for the stringers

We found one vendor selling a roll of 48" yard very reasonably but that seems like a lot if only doing one layer on the stringers and two on the deck. We'll take some measurements this weekend on the boat to come up with our theory of quantity.

3. How much resin would you also recommend based on my photo and if we had todo two tall stringers front to back. My buddy thinks 3 would due but I'm always the pessimist and think 5 is the safe thing.

Your going to need a lot of resin,i used 3 gallons for the transom,1708 sucks up a lot of resin. You can keep the amount of resin down by building with the "wet on wet" method which makes for a stronger bond and uses less resin. I would guess 3 gallons would be about right for the stringers,make sure you order plenty of cabosil also,one quart of cabosil to one quart of vinylester will get you pretty close to a peanut butter consistency

[carboncow]

I've seen the mention of "peanut butter" before...where did you primarily use it on your build?

Does cabosoil only mix with the vinylester or does it mix with resin too?

[carboncow]

OK, looks likes the cabot mixes with resin fine.

EDITED:

1. We are going to buy from UScomposites. Their resin comes in thin and thick...but there is some warning about the thick not being idea for getting into cloth. Should we buy thick for doing vertical stringers and thing for everything else or will thin work for vertical with some patience and technique? Or should going with a faster dry...or just a few more drops of hardner. What is the best technique for vertical.

2. Can "peanut butter" be used about anywhere to fill a void? I have those small gaps we dug out near the edge of the sole where I need an inch of filler.

3. Liam, did you use tabing for deck work connecting to the sides or overlapping larger pieces...or just work with well cut larger pieces?

[dan4836]

I am using 3/4 A/C plywood with two coats of poly resin to seal it. After I install the plywood stringers into the existing cavity, I will laminate with 1708 and cap the top off with CSM.

I will be doing most of this work tomorrow so I will post some photos.

[carboncow]

Originally Posted by dan4836

I am using 3/4 A/C plywood with two coats of poly resin to seal it. After I install the plywood stringers into the existing cavity, I will laminate with 1708 and cap the top off with CSM.

I will be doing most of this work tomorrow so I will post some photos.

Dan,

We are going to use 3/4 AC too. We found all our bulkheads are mush too...so lots of cutting and reinstalling todo yet.

When you guys lay the 1708 on the deck...will you but the glass sheets to one another or will you over lap them...or some other technique? We are going to be using a textured paint when done so small imperfects will not bug us but we are still trying to figure out all the ways to terminate.