1708 mat for stringers

[RidgeRunner]

PE or VE will work but you do have to grind before and in between layers if you let it kick. Wet on wet allows proper bonding and cuts down on grinding. Not as good of a bond as epoxy so the 40 grit scuff marks during prep give the VE/PE something to bind to. PE/VE stinks to high heaven too unlike the epoxy. Neighbors might not like it.. Get a nice industrial fan, and stay upwind.. When it gets hot out, mixing the correct ratio of MEKP to resin gets tricky, a couple extra drops in you mix bucket and you will be fighting to get it rolled out before it kick$$. Epoxy is expensive, but it has distinct advantages.
I think 2 layers of 1708 on the stringers is ample. I am itching to get some glass work started myself. Keep us posted, im excited for you.

[Kracker Jack]

I tabbed my stringers in with 1708 10 inches into the hull and wrapped it over the stringer and tabbed it 10 inches up the hull on the other side. For checking purposes I then put a second layer over the stringer clears and down the stringer 4 or 5 inches and my stringers do not move at all! Not even a snap or a crack when I purposely tried to move them before my sole was installed. It saved me on some cloth. I went with polyester because I'm new to this and I'm on a serious budget. If I were you I would go with a VE, it is perfectly exceptable for your application and you will save some change in the long run. Just my opinion.

[tartuffe]

Originally Posted by cterrebonne

Sounds like your hull needed some work. Mine is in really good shape. Just the transom and the stringers are probably needing to be redone towards the transom area.

Did you separate the liners on your boat? I am thinking about just cutting the floor out and then reglassing it back in and sanding all the old wellcraft factory non skid off and putting down some duraback or some gatorhyde.

The hull itself is in very good shape. The bulk of my repairs are related to the transom and stringers. I did separate the liner from the hull.

I did add a few layers of glass in high stress areas in the bow area just for the sake of making me feel better.

[cterrebonne]

Tartuffe, after reading this post again you said a single layer of biax would work? I'm trying not to overkill and add too much weight

[tartuffe]

Originally Posted by cterrebonne

Tartuffe, after reading this post again you said a single layer of biax would work? I'm trying not to overkill and add too much weight

You can use a single layer of 1708 which includes a layer of CSM stiched in. Biax by itself will not waterproof your wood if you are using VE or PE. Keep in mind that is only on the wrap from your sides and top.

You will need several layers of 17 oz biax like Kracker described when you tab your stringers to the hull.

[cterrebonne]

Originally Posted by tartuffe

You can use a single layer of 1708 which includes a layer of CSM stiched in. Biax by itself will not waterproof your wood if you are using VE or PE. Keep in mind that is only on the wrap from your sides and top.

You will need several layers of 17 oz biax like Kracker described when you tab your stringers to the hull.

I'm going to use epoxy. When you say tab, what do you mean. As in 6 inch strips where the stringer and hull meet?

[tartuffe]

Thats right. I went overboard and cut strips 4", 8", 10" and 12" but that was way overboard. You'll cut your stringers to size, I used spacers (my center bulkheads and barclamps to get my stringers the right distance apart as well as perfectly perpendicular and situated the stringers so everything lined up with all my measurements and marks I made prior to demolition. Once everything lined up inside the boat I traced the inside and outside of the stringers with a sharpie on the hull. Then I raised the whole assembly enough to put a thumb-sized bead of PB between the lines I traced under one stringer. Lowered it all back down on the bead. This gives you good contact and no hard spots. Take more PB and run a small bead on the inside and outside of the stringer and use a sponn to make a nice radius. Lay your first tab and wet it out. If its 6" wide then 3" on the hull and 3" on the stringer. Lay another over top of that one say 10" wide with 5" on the hull and 5" on the stringer. You can do another if you want but probably not necessary but I'm no marine engineer. Like I said, I did 4. Let that cure. Then repeat for the other.

The idea is that you want the fiberglass to dissipate shock loads from the immovable area (stringer) out to the very flexible area of fiberglass without any focus of forces leading to stress cracks.

Keep in mind the best results are to not allow the PB to harden before you get the fabric laid and wetted. Use the slow cure and mix many small batches. I large will cure in about 15 minutes even if it is slow cure.

[cterrebonne]

Thanks, really good info. I was plannig on going with the foam or 5200. As he bedding. That would give me as long as I needed. Unless you think the woody mix is much better

[tartuffe]

The foam is probably just as good but I would tab with the full 4 layers if you go that route. The PB is a mix of cabosil and resin. It isn't the wood flour.

Some people get all frothy mouthed about using 5200 versus foam versus PB for bedding. I read an awful lot and personally liked the PB bedding the most. They all have positives.

4 layers of biax is about 1/8" thick so you may have 1/4" of glass supporting your stringer. I figured if I'm buying high dollar 3/4" marine ply, I wanted the full strength transfer throughout my hull.

[tartuffe]

Here are a couple pics, one is before bedding and the other shows a test fit of the cap but you can see the layers of tabbing from the ink I marked the glass to cut the widths. See how nice that radius is....pretty proud of that