Somebody help me make a f'n decision, Which resin and how to do it

Discussion in 'Fiberglass and Composite Boat Building' started by jrork, Nov 19, 2011.

  1. jrork
    Joined: Oct 2011
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    Location: Silverdale

    jrork Junior Member

    Hi guys, so here’s the deal.

    I have a 1983 21’ Eliminator Daytona lite layup that I’m working on and I need some advice on glassing.

    The boat originally had super small Douglas fir stringers. The dimensions were only ¾” thick by 1 ¼” tall.
    According to Eliminator, they used 2 layers of 7 oz cloth and 1 7 oz matt in between to wrap them.

    I’ve removed the stringers as they were riddled with holes and plan on installing some clear straight grain 5/4” x 4” Douglas fir. This material is kiln dried and an actual 1” x 4” material with no knots. I want to tab them in with some tape and then begin to wrap them with cloth.

    One key issue/desire is because the Balsa floors are pristine on this boat I want to make sure my glass work does not ruin the looks.

    Sooo, my plan is after the stringers are in, sand and then flocoat them and the floors to give a nice polished look.

    My problem is;

    1. I’ve had great experience with Epoxy (West Systems) on a previous project boat however, I’m concerned that I won’t be able to flocoat afterwards because flocoat is polyester based material and won’t adhere to the epoxy.

    2. I’ve seen the “clear” epoxy as well. With that, would I be able to bypass the flocoating and just rely on the epoxy for the shine and protection?

    3. I like epoxy because I could likely get away with less fabric and still have considerable strength (larger stringer size as well as better material in epoxy)

    4. I do like the idea of polyester for reduced cost, ability to lay material without worrying about having to sand in between as well as dealing with blush (I’m going to be doing this in raining Washington with high humidity).

    5. My shop is heated but not well insulated so I’m concerned about varying temperatures.

    6. If I was to go epoxy, I’m thinking some light fabric (remember, the manufacturer used only 21oz total on the stringers) and would limit the unsightliness of my install.

    7. If I was to go poly, I would likely use something much thicker with some matt.


    So, my gut is telling me to go epoxy (system3 is manufactured locally) and you guys can talk me thru any issues so it looks as nice as possible.

    Or am I just over thinking this thing. It’s a light layup boat that lived (and was raced) for all these years with no problems even though it was polyester, why change now?


    I’m also wide open to suggestions on fabric, layup schedules. My son will be home from college next month so he’ll be able to help me and we can have good control on mixing of material so we don’t mix too much or not enough at a time.

    Thanks for any and all advice you’re willing to offer……….john

    Here's some pictures to help. Please feel free to throw out any ideas. I'm all ears

    [​IMG]

    [​IMG]

    [​IMG]

    [​IMG]

    [​IMG]

    And this what what I was thinking of doing but maybe it's overkill to wrap that much past the stingers.

    [​IMG]

    The black is the hull profile, the green is the balsa, the blue is the new stringer material and the red is the what I was thinking about for how to wrap the stringers without having a nasty seam. Maybe the new material wont leave the big obvious seam and what I'm suggesting is overkill and not needed.

    Thoughts?
     
  2. CatBuilder

    CatBuilder Previous Member

    IMO, the epoxy will just be easier to work with. System Three epoxy is great stuff and I haven't had a blush yet with the General Purpose or the SilverTip in all kinds of very humid situations. I've gone through about 60 gallons so far.

    The top coat might be done by a System Three product as well. Take a close look at some of their top coats. Also, if I recall, there is such as thing as epoxy flow coat, if you go that route.

    There are UV-resistant, clear finishes you can apply over the top to keep thing durable for the long run.

    Ask System Three some of these questions too. They are very helpful and will suggest a good fit. They even made up a batch of custom infusion resin for me because I was thinking about using them for that type of thing. Very very helpful.

     
  3. OFFSHORE GINGER
    Joined: Nov 2011
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    Location: Mich

    OFFSHORE GINGER Junior Member

    Jork , like i suggested on another site...........i would go with two layers of 17 oz for strength staggered , vaccuun bagged.............. opposed to two layers of 7 oz with Matt......considering bagging will pretty much take two layers of fabric , and compress it to the point of one , and if you would like to make it look even nicer......... finish it off using 4 oz Chesse Cloth / Finish Fabric , just to make the layup that much more pretty....... which also will hide the seam if taken somewhat below the inital layup .(staggered) John , this stuff is awsome which is made by Adtech Plastics Systems , with UV qualities . http:www.adtechplastics.com/pc-1424-26-proclear-clear-epoxy-coating-system.aspx
     
  4. sabahcat
    Joined: Dec 2008
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    Location: australia

    sabahcat Senior Member

  5. Yellowjacket
    Joined: May 2009
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    Location: Landlocked...

    Yellowjacket Senior Member

    While most hydroplanes and lots of very high perfomance boats use Douglas fir or Sitka spruce, neither is very rot resistant. If you don't keep it from getting wet it's going to rot, as you can see with the previous stringers.

    I'd use Honduran mahogany, since it is more rot resistant, and it looks a lot better than spruce when you glass it and it weighs the same as the Douglas Fir. It is also stronger.

    Unless you want to add a lot more weight the bigger stringers and a lot more glass over the existing floors and down sides is overkill.

    These stringers really don't do much other than provide a place to attach things. The beam stiffness of the tunnels is huge and, coupled with the cored area results in plenty of strength.

    You could easily use 1 x 2 magahony and have more strength than you had before as well as have plently of strength to attach things to it. If you cover it with two layers of 8 oz of the right cloth and the right epoxy it will wet out clear and look great.

    The biggest difficulty you are going to have is getting the glass to get down into the corners where it the stringer meets the floors on the first layer of glass. Vacuum bagging is the best way to do this and it will come out nice lookng and strong with a minimal amount of glass. You don't need to go all the way over the edges of the tunnels with the glass. To keep the floors looking nice you might go all the way across them with the two layers of cloth, but on the other side you only need to go for about three inches from the stringer.

    More important is how you attach things to the stringer. If you use wood screws water WILL get in and, over time damage them. If you pick the places where you are going to put the screws or bolts, then predrill the holes and fill them with thickened epoxy you will be able to drill them out to a smaler diameter and then bolt thru the stringer and not have any water intrusion.
     
  6. jrork
    Joined: Oct 2011
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    Location: Silverdale

    jrork Junior Member

    Thanks so much everyone for the help and ideas.

    One thing I failed to mention is that the stringers need to be 4" tall in back to mount my engine to and then drop down to a minimum height as it moves foreward as the only purpose they serve up in the cockpit is to mount seats and pedals too.

    Artie, I like your idea but the vacumn bagging idea scares me into thinking that that is something I would need to take the boat to a shop able to do that and I tend to be a do it yourself kinda guy. Thanks for the tip on Adtech.

    Sabahcat, thanks for the link to ATL. Looks like there are plenty of products out there to do what I want to do without being stuck with Polyester.

    Yellowjacket, to help get the glass into the corners, what if I bedded the stringers in some epoxy first and fillet the edges with the epoxy giving a good bond and nice radius? Would that help on getting the glass to lay into the corner? Again, the vacuum bagging worries me that I cant do it myself.

    Maybe I need to read up more on vacuum bagging...... hmmm, more research here I come.

    Great tip on the holes out of epoxy but unfortunately, I wont know where the holes are till after I begin assembly and setting my motor alignment. I'm really starting with a blank slate on this one.


    Thanks again for all your thoughts, tips and help guys. I really appreciate it.........john
     
  7. OFFSHORE GINGER
    Joined: Nov 2011
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    Location: Mich

    OFFSHORE GINGER Junior Member

    John , West system has a brief guide to the principles and practical application of vacuum bagging on there Web site which will give you a general idea of how to .......if you havent already tapped into that resource . John , you can do this without taking the boat to a shop and yes................ bedding the stringers in with a thickened epoxy and using a fillet at the base of the stringer is the right way to go .
     
  8. jrork
    Joined: Oct 2011
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    Location: Silverdale

    jrork Junior Member

    Nutz, didnt work Artie but I'm googling how to do it and what the equipment would cost me. Kinda neat!
     
  9. OFFSHORE GINGER
    Joined: Nov 2011
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    Location: Mich

    OFFSHORE GINGER Junior Member

    John , just a quick mention seeing that you are considering taking your layup into the tunnel sides to hide the seam make sure no matter where .......you decide to end your layup weather it be..... three inches from the stringers or on the sides of the tunnel remember to stagger your lay up , and once again if you decide to keep the layup on top of the tunnel .....Chesse cloth / finish fabric does a great job on hideing the seam . Hey guy , just curious seeing that you live on the west coast have you ever done business with these people ? http:www.sherfab.com
     
  10. Yellowjacket
    Joined: May 2009
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    Yellowjacket Senior Member

    John,

    If you bond down the stringer (without glassing it) you can locate and drill all of the holes that you want. Then you could oversize the holes, and fill them with filled epoxy. Then go ahead and glass the stringers in. Finally you can then redrill the holes in the proper size and you are good to go. If you want to get really picky you could also add a local patch of glass between layers at each of the bolting points to add some more local strength. A lot more work than any builder would be willing to do, but since you are doing it for yoursef it is more than worth it. Not having to ever deal with this problem again is worth it in my mind.

    Yes, doing a fillet and then glassing it will do what you want and will work.

    Annother approach is to use a sheet of .030 plastic over the glass as described on this page.

    http://duckworksmagazine.com/03/r/articles/glass/bottom.htm

    The advantage to this approach is that the plastic will force the glass into a pretty small radius, which would eliminate the need for a big messy looking fillet on the side where the stringer is up against the floor. If you are using 8 oz cloth you should be fine doing it this way. I used this approach on some stringers and interior bottom glassing and it worked really well. You have to be careful in cutting and fitting all of the plastic before you start glassing. This takes some time, but it does work well. I found the plastic for about $24 for a 4x8 sheet. That come out to about 75 cents a square foot. Cheap when you think about how much sanding and filling it takes to make the glassing look good without it.
     
  11. jrork
    Joined: Oct 2011
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    Location: Silverdale

    jrork Junior Member

    Thanks Artie. If there's no need to wrap all the way across and down the tunnels I wont and that will save supplies and work. Thanks. Easy to stay more than 3" way from the stringer if I dont. The tunnels are 13" wide to one side and over 6" to the other side.
    Exactly how do you use the cheesecloth trick Artie?

    Great tips YJ! Thanks.


    Guys, I'm all ears and really appreciate all of your ideas. I'm just a putz that likes to do stuff on my own and learn from my mistakes.

    Here is that last project that I completed. Bought a hull that was one step from the landfill and rebuilt it capping the deck and filling all the holes and then eventually painting and installing a new interior. I used West Systems that project and the ease of the epoxy really surprised me. I had always been afraid of doing glass work prior to this one.

    [​IMG]

    [​IMG]
     
  12. jim lee
    Joined: Feb 2007
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    jim lee Senior Member

    jrork, If you end up wanting a shop to do the stringers. I have a couple really really good fiberglass guys here. And, as you know, we're close by.

    -jim lee
     
  13. OFFSHORE GINGER
    Joined: Nov 2011
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    OFFSHORE GINGER Junior Member

    John , l@@king g@@d & i like ................... no dis respect to to any one on this thread but .........over the years ........i have seen more failures due to the fact that there was no fillet added to fill in the radius or gap on the stringers which resulted in failure causing the glass to crack which in turn meant water seeping thru the crack causing the entire stringer system to rot which usually meant or means a deck off restoration in most cases , and this was a Co without mentioning any names that built smaller production boat's with a name and reputation for building quality priced Boats who after a few years went back to adding a fillet in there layup .
     
  14. jrork
    Joined: Oct 2011
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    Location: Silverdale

    jrork Junior Member

    Thanks Jim. I really want to do this part myself but I do have a small issue in the side that needs repair about the size of a silver dollar and I may have to have you guys do that. Can you also match gellcoat?


    Thanks Artie.

    Okay guys, Since where I live there are no good local spots to pick up material, I'm going to have to go to Seattle or north towards Jim Lees stomping grounds (minimum 1 1/2 hour), clearly I dont want to run out so could you give me a general recommendations for the following puzzles I'm struggling with?


    • I need enough resin to glass in two stringers that are 1 1/2" tall and 14' long. Would a gallon of resin with a 1/2 gallon of hardener be enough?


    • I'm thinking of using some 2" tape to tab the stringers in. Should I do the entire length with tape on both sides or can I just tab in a handfull of places figuring that I'm going to be wrapping them in glass anyhow?

    If it's easier to just talk me thru this mess, my cell is 360 620-0792. Thanks for all the help, I really appreciate it..........john
     

  15. Yellowjacket
    Joined: May 2009
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    Yellowjacket Senior Member

    John,

    Less is more and easier. I'd bed the stringers into place with a thickened epoxy. I use wood flour from Raka, it has a very nice mahogany look to it. Mask beside the stringers, where you want the fillet to end, bed them in the thickened epoxy and then use a tongue depressor as a fillet shaper that will hold the stringers in place just fine. As the epoxy starts to harden pull off the masking tape and you will have a nice straight line at your fillet edge. After that sets up you can sand the stringers and clean them up, then do your glassing.

    Working around strips or tabs of glass is just going to be more of a mess and it won't be any stronger. Figure out how you want to jig the stringers into place and hold them there first and then just glue them down. After that is set up then work with the cloth. Trying to work cloth if the stringers are moving around is going to be a PITA and it isn't going to come out well at all. Once the stringers are in place and won't move you can glass to your hearts content.

    I like to use cloth tape for this kind of work since the edges are bound and they don't fuzz up and make a mess of things. Not as big an issue if you are putting plastic on top to get a smooth surface, but a bigger pain if you don't. You might not be able to use tape since you are probably looking at a wider strip than 8 inches, but you might be able to if you laid up one side at at time and then wrapped it over the top with a couple of layers later.

    A half a gallon of resin and a quart of hardner should be plenty. Depends on how much glass cloth you are using, but a gallon is probably overkill.
     
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