Boat rebuilders New Stringers help?

Discussion in 'Boat Repair Help' started by mdspoula, Jul 24, 2009.

  1. mdspoula

    mdspoula New Member

    Messages:
    297
    State:
    Kansas
    I need to replace the stringers in a 16' Dixie Devil tri hull that I just picked up cheap. I have experience with fiberglass and resin so that part is no problem. What I am wondering about is attaching to the hull. I have seen web videos that say you need a cushion underneath the stringer to prevent cracking. Also I want to know if I can use composite plastic decking for the stringer instead of wood. No rotting properties so I figured it would work the best for a new floor. Then I also thought about thicker plexiglass for the floor instead of wood which you have to seal. I am not 400 pounds and don't think I will have anyone ever on my boat over much 200 pounds.
     
  2. Mark J

    Mark J New Member

    Messages:
    9,407
    State:
    Four Oaks, NC
    Replacing stringers is a nasty job.
    Most unfortunately aren't glassed in really. They just chopper glass them.
    Can you say aint worth a crap?
    It's why I detest alot of boat manufacturers.

    Firs off, forget the polyester resin and go with epoxy. Yes you will need a spacer between the stringer and the hull but we're talking an 1/8 of an inch which will be filled in with thickened epoxy. Second, forget the plastic wood. You need a mechanical bond with your glass. You need wood.

    For the floor, use plywood, epoxy, and glass. It will outlast the boat and you.

    You aren't going to fix this boat right for a coupla hundred bucks.
    I would budget no less then 700 for the stringer and floor replacement alone.
    That is doing it yourself.
     

  3. metalman

    metalman Well-Known Member

    Messages:
    3,456
    State:
    IN
    Name:
    Winston
    Absolutely what he said. Plexiglass floor bad, bad, bad, bad, bad, bad idea...W
     
  4. Mark J

    Mark J New Member

    Messages:
    9,407
    State:
    Four Oaks, NC
    The Metalman is 100% correct. Bad idea.
    What I should have said is that in some boats the sole (floor) is an integral part of the boat. The ribcage to the stringers.
    I would treat it as such anyway and tie it into the hull with glass tape and epoxy.

    Imagine coming off a wave and the boat folding up like a paste board box around you.
    Not just that but another consideration is the outboard. They put out tremendous forces on a transom.
    I've seen the aluminum floor cracked in boats all the way up at the center console. Caused by the lateral forces of the motor. The boat hull wanting to twist.

    Your sole may be part of the structure. May not be totally but you can bet like it is it serves a little more purpose then something to stand on.
    Something has to tie it all together.
     
  5. mdspoula

    mdspoula New Member

    Messages:
    297
    State:
    Kansas
    OK,
    Thanks for the advice. I guess I never have driven a boat fast enough to worry about the twisting forces from the waves and steering. It just seems silly to me to use wood on something that is going to rot eventually because even epoxy cracks as it ages. When I was thinking of plexiglass I was thinking of 3/4" thick or better which would be thick but I see the point of it not bonding to the fiberglass like wood and enough epoxy would.
    Also it looks to me like the boat builders used polyester resin and fiberglass to make the original floor that was on the boat. I like epoxy as it is a strong bond but if the original floor lasted 30 years wouldn't this floor put on with the same stuff last as long?
     
  6. catin38

    catin38 New Member

    Messages:
    272
    State:
    alabama
    hi,
    i know alot of people use epoxy because it is just stronger period and it has better adhesion properties. i still think regular ole poly resin is fine. the boat lasted many years without having a good fiberglass job with poly how long do you think doing it right will last?
    There has been several debates over different use of wood in decks,stringers,etc. I would never use pressure treated plywood in boat simply because it isnt completely dry. if you can let it dry for af ew months then i think it would be ok. most people isnt going to wait months for a piece of wood to dry. i would use ab exterior ply. Plywood has greater strength because of its several layers and each laid in a different way.
    The stringers needs to have around 1/8 inch gap to prevent stress points in the boat. I can tell you a simple way to get this gap. go to any name brand hardware store and get a few industrial size pl adhesive. It comes in a tube like chaulk and is very easy to get the gap you need without the mess. Once cured it is almost indestructable. Then just get you some 1708 biaxe and go to work. hope this helps
     
  7. Mark J

    Mark J New Member

    Messages:
    9,407
    State:
    Four Oaks, NC
    Epoxy flexs. The only epoxy I've seen crack was epoxy put on wood that checks without glassing it and epoxy with long term exposure to sunlight without a coating on it like paint.
    The thing about epoxy is , when you put it and wood together it becomes one.
    You aren't going to be able to peel it off in sheets like you can polyester resins.
    The reason is boat building epoxies today are chemically engineered to bond with wood. It's not just a product that someone figured out they could use on a boat. It is made to use on wood in boats.

    Any doubts go to Bateau.com, Jemwatercraft.com, and if you want to see the seagoing behemoths made from plywood, epoxy, and glass and how they build them go to Jarrettbayboats.com .
     
    Last edited: Jul 27, 2009
  8. mdspoula

    mdspoula New Member

    Messages:
    297
    State:
    Kansas
    I will definitely incorporate epoxy in with the build. I have built model airplanes for years with the stuff and it does work great. I still say that epoxy does crack as I have seen it yellow over time and crack off. However you are correct if used with glass it will stick and not crack off. I guess it is another one of those corners that manufacturers cut when building boats. My next question is where do I get a couple gallons of good epoxy to use?
    Thanks,
     
  9. Mark J

    Mark J New Member

    Messages:
    9,407
    State:
    Four Oaks, NC
    We're talking about 2 totally different epoxies.
    The epoxy glues you buy in the plunger tubes has a nasty smell is a 1 to 1 ratio mix.

    Boat building epoxy has no chemical smell. It's generally a 2 to 1 or a 5-1 to ratio mix.
    Boat building epoxy doesn't crack and flake off. Unfortunately the only way I've ever been able to remove it from where I didn't want it was with a sander, grinder, or chisel.
     
  10. metalman

    metalman Well-Known Member

    Messages:
    3,456
    State:
    IN
    Name:
    Winston
    When I did the stringers and floor in the boat that now belongs to DH it took almost 10 gallons of resin and 2 gallons of hardener. I probably went just a little bit over the top:wink:...W
     
  11. mdspoula

    mdspoula New Member

    Messages:
    297
    State:
    Kansas
    That had to add some weight to the boat... 10 Gallons OMY... Yes where is a good place to buy the boat building type of epoxy? I don't think that I should buy it from a marina. They probably put a 200% markup on it.
    Thanks,
     
  12. metalman

    metalman Well-Known Member

    Messages:
    3,456
    State:
    IN
    Name:
    Winston
    Well, when I gutted out all the old crap from inside I had plenty of weight allowance to build the floor from hell!!

    Google Midwest Marine Supply. They are wholesale but I buy from them through my employer. Also, check to see if you have any composite supply companies or composite repair shops local to where you live...W
     
  13. mdspoula

    mdspoula New Member

    Messages:
    297
    State:
    Kansas
    For everyone that helped me in my boat reflooring process I wanted to say thank you. I have taken your advice and used a combination of ideas and it floated with no leaks. I really wanted to use my bilge pump that I bought and wasn't able to. I used Epoxy for putting the stringers back in place with fiberglass and epoxy. I then had some CPC plywood that came with the boat so I let it dry out for about 2 weeks in a shed in the 100 degree weather. I then cut the wood to fit which was the hardest part since I had to do a pattern first. Then I took it out to test if it had any leaks through the epoxy with a removeable floor. I found a couple areas that the epoxy didn't cover as good as it could.
    I used PC 11 marine epoxy putty and smeared it across the entire bottom glue joint where it leake a little. After that dried I put a layer of silicone over the entire thing. After that I put a thick coat of resin over the bottom of the plywood floor. I then screwed it into place over the stringers with some epoxy coated deck screws. After that I put about 4 layers of resin with fiberglass around the outside. Sanded it smooth then put another layer of resin down. Finally added carpet and took it out for a final test and like I said no bilge pump. Hopefully it will last since I used epoxy for the structural parts. The polyester resin is so thick I don't see any water soaking through.
    Thanks,
     
  14. Mark J

    Mark J New Member

    Messages:
    9,407
    State:
    Four Oaks, NC
    polyester epoxy?
     
  15. mdspoula

    mdspoula New Member

    Messages:
    297
    State:
    Kansas
    Thought the stuff was called polyester resin. Maybe fiberglass resin. You mix i with drops from a little tube. About 16 drops per ounce. I just used that on the wood floor to make it waterproof. It bonded really well with the fiberglass boat and is very strong. I used Epoxy and fiberglass cloth to glue the stringers in place. It worked well also. Thanks,
     
  16. Mark J

    Mark J New Member

    Messages:
    9,407
    State:
    Four Oaks, NC
    Just curious as to how you figure poly will bond with wood much less waterproof it?
    It does neither.:confused2: Especially since you had epoxy that does bond and waterproof wood.
     
  17. mdspoula

    mdspoula New Member

    Messages:
    297
    State:
    Kansas
    Yes I just used Poly on the wood flooring that I used. I used EPOXY over the stringers and bottom of the boat to provide structural integrity. The fiberglass resin did bond quite well as I don't see how anyone can pull it off of the wood. It binded to the wood fibers. Also I poured it on top of the floor a good 1/4" over the whole floor so I don't see how any water will soak Into the fiberglass resin before drying. You can't peel off the resin once dried, it is as hard as a rock. I don't see how water will even stand on the flooring for much longer than a rain shower. I will let you know if it ever rots and then I will say I should have spent another $200 on epoxy to cover the wood floor. As for a boat to take to the lake a 10 times a year I am calling it good.
     
  18. NEPATRIOTS

    NEPATRIOTS New Member

    Messages:
    11
    State:
    FL
    That is the same way I repaired my stringer.
     
  19. Mark J

    Mark J New Member

    Messages:
    9,407
    State:
    Four Oaks, NC
    If poly bonded to wood there wouldn't be all of these rotten floors in boats.
    It's the reason they rot. It's the reason you can grab a corner of that poly and rip it off the wood floor. Because it doesn't bond. At the very best it's a POOR bond.
    If poly bonded with wood you wouldn't have boat companies advertising "our boats don't have wood".
    Aint a thing in the world wrong with wood in a boat unless you are boat company that wants to spray some poly on it and call it done. Then it's a problem.
    I'd rather have the strength of the wood in the boat then the amount of fiberglass it takes to do away with the wood.

    Epoxy on the other hand is formulated specifically to bond with wood.
    You can't peel epoxy from wood. It becomes a part of the wood.