Epoxy types and usage

Discussion in 'Wooden Boat Building and Restoration' started by steveroo, Mar 11, 2009.

  1. steveroo
    Joined: Dec 2008
    Posts: 38
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    Location: Portland,Oregon

    steveroo Junior Member

    My question ( always more questions!!!) is going out to the old salts among the group based on your trials and tribulations concerning 2 types of epoxies.
    In videos, step by steps, and in reading thru hours and hours of posts..What type or brand of epoxy works well/best on stitch n glue, or wood to wood construction.. I'm primarily addressing the goo that goes on to make fillets in corners, and along battens and strakes...I see the word epoxy but I rarely hear about a brand that has qualities like paintable, flexible, outstanding adhesion. Is 3m5200 the stuff for this?
    The other epoxy really has me scratching my head.. from what I gather it's used as a prime coat for varnishing...is there such a thing as a clear epoxy that I can apply as a 1st coat and then cover with multiple coats of something like Epifanes high gloss?, And looking at what I've written brings up another epoxy.. a bedding agent something I would bed windows with, or deck hardware like mooring cleats, or a windlass base.. I know that there's a lot of grandiose claims from the different manufacturers , but I'm seeking time tested materials that so many of you swear by. Thanks again, for all the great advice and information.
     
  2. apex1

    apex1 Guest

    Many questions, leading to different solutions. What is your definition of Epoxy?
    Very obvious, you mix several different things here. For example "clear EP", almost all resins are clear. And you can use all, to make your wooden surface water resistant, prior to varnishing.
    Bedding windows in EP is a mad idea. I´m shure you point to a different sort of goo, maybe silicon?

    So, what was your first problem to solve?
    Your second?
    And third?

    A recommendation for any sort of EP is´nt serious without having a proper info about the real application you are going for.

    Regards
    Richard
     
  3. steveroo
    Joined: Dec 2008
    Posts: 38
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    Location: Portland,Oregon

    steveroo Junior Member

    epoxy and such

    Richard, Thanx for your reply...correct the 3M product is not an epoxy but...that was in reference to a bedding agent,,my bad. As for the Epoxy application...it would be for exterior surfaces, All Mahogany, primararily rubrails, handrails, and spray rails, approx. 2"X2 1/2" I have photos on the "Monkman" thread in "wooden boats and rest" As far as I know, and obviously by my questions, that's damn little...the epoxies in my experience are 2 part mixes, and as yet I have never encountered a clear epoxy and sometimes this forum provides very good replies that eliminate hours and hours of chasing hundreds of products and actually ending up with more questions than the original question. I also wouldn't use epoxy to bed windows as I don't believe it has that type of flexibility nor am I aware of it's ability to repel water. I am more specifically seeking a brand name that others have used with success on similar applications...I imagine my 1st post was rather vague.
     
  4. apex1

    apex1 Guest

    ahhh that brightens the subject a bit.
    ALL Epoxies are two component (resin and hardener).All are transparent, although not all are clear as water! All are water repellent! All make the surface a bit harder. If you want to protect wooden applications they have some advantage in waterprotection. But they have a disadvantage too, thy need for themselves a UV protecting coat of varnish! Means you can apply a good quality varnish directly on the wood. If cost is a minor problem I recommend to apply two layers of EP on the dry wood for best rot (water intrusion) protection, followed by 3-4 layers of UV protecting PU varnish. Careful... UV RESISTANT is not UV PROTECTING !!!!
    Resistant just means the varnish gets not destroyed by UV rays, but the EP below will!

    Being in the US you should look for "RAKA" or "WEST system" IMHO. Both are well proven in the hands of novice´s.

    You can mix the EP with sawdust, cotton fibre, colloidal silica microballons etc. to make your own putty for fillets, fairing and the like.

    All not too complicated, but a bit more than just smeering the crap somehow on the wood.

    Ask again here for advice before you go to apply.

    Visit the "WEST" website to find some good guidance how to work with that goo.

    Windows should be sealed with a stuff of much more elasticity, like "Sikaflex", if sealed with Epoxy they become part of the structure, you´ll never be able to replace a broken window without serious damage of the structure.

    I hope that was enough to start with. If not, come back, you´re welcome.

    Regards
    Richard
     
  5. PAR
    Joined: Nov 2003
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    Location: Eustis, FL

    PAR Yacht Designer/Builder

    3M 5200 is a adhesive/sealant, not a structural glue. It dries to a semi hard rubber like consistency, but shouldn't be relied on to hold things together. It's a sealant with real good adhesive qualities.

    Epoxy can be formulated to do many things, but mostly you'll use marine grades of laminating epoxy. This stuff will wet out fabrics, make fillets, glue things together, etc. It can also be used as a sealer and a clear coat base.

    Now you can get epoxies that are designed to be more clear, which is fine if you have really light surfaces to finish clear.

    There also is a penetrating epoxy, who's marketing hype suggests it "soaks into the wood" for a better seal and bond. This is total rubbish and just a marketing ploy. The way it penetrates is with the addition of solvents in the epoxy.The solvents dramatically weaken the cured epoxy. The result of the solvent "flash off" also leaves the epoxy less then perfectly cured and cross linked on a molecular level. The reality of this type of epoxy is, it's not the amount of penetration into a substrate that insures waterproofness, but how effective the barrier is as a waterproof coating.

    In other words, a regular 100% solids, laminating epoxy, brushed onto a surface, will make that area more waterproof, then a penetrating epoxy can ever hope, regardless of the amount of penetration the penetrating epoxy has gotten.

    Bedding materials come in many different containers. Polyurethanes, polysulfides, polyesters, oil based, acrylic based, mother in law based, the list is endless. Other then stuffing the ground up remains of in-laws into planking seams, different applications require different products.

    For underwater wood to wood interfaces polysulfides work well. Polyurethanes can work in these applications, but must be under pressure (clamped inside a joint) during the full cure (typically 30 days). Oil based products work, like Dolfinite, but they have no elastic qualities.

    In the end, you have glues, sealants, bedding compounds, coatings, bonding agents and specialty goos. Which you use often depends on what you'll be apply goo to. For example, sealing acrylic windows to an aluminum frame can be difficult for a sealant to handle, but as much as I hate to admit it, silicone works well in this application.

    If you're looking to bed something, you don't want epoxy. You want a "bedding" compound suited for the materials and substrate you'll be sticking them to. It sounds like you need a plain old caulk for your hand rails. Try some "Boatlife".
     

  6. steveroo
    Joined: Dec 2008
    Posts: 38
    Likes: 0, Points: 0, Legacy Rep: 10
    Location: Portland,Oregon

    steveroo Junior Member

    input and more

    my, my my...my mind is reeling! You guys are just incredible. I'm sure after reading your replies for the 3rd time, that I'll begin to see the light somewhere around the 5th or 6th read. So much info and so few pigeon holes left in the ol brainbox. After my visit to the Monk today ( new winch for the dinghy davit) I'm going to the chandlery to begin my search. I'm going to attempt to narrow the field based on PAR and apex's suggestions, btw Richard, I had forgotten about Sikaflex ( used many, many times in my old job) and yes it would be fabulous for my windows. PAR I hope you're young enough to continue to be one of my responders as I spend the next year or so completing my projects. I'll keep ya posted on the results of my search, I'm gonna meet with my helper ( painter) this morning as well and I will utilize my newfound knowledge in a rambling sort of coherency, to see if he's had some experience as well( he looks a little like Poseidon..who knows??)
    Thanx again ya'll !!
     
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