Making bottom of boat scuff resistent

Discussion in 'Boatbuilding' started by 300wm, Dec 10, 2015.

  1. 300wm
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    300wm Junior Member

    I don't know....I treated some rotting knife handles with resin and no hardener and you can't get the stuff off with a sledge hammer, now.
     
  2. 300wm
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    300wm Junior Member

    I wet sanded a portion of what I covered, last (the 12x12 piece). It did not delaminate. It is hard to sand and at the same time, it clogs the paper. I used a dish soap solution that aided in sanding, but not by much. I believe the less activator gives me time to coat the whole bottom at one time. After 5 or 6 days, this stuff will be hard as a rock. I've got my solution. Thank you to everyone who contributed to this thread.

    MC
     
  3. PAR
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    PAR Yacht Designer/Builder

    MC, like I mentioned, if you used 50% hardener, it will not cure, regardless of what you might think or what anyone else might have told you. Epoxy requires the resin/hardener ratio to be within a few percent or it just doesn't finish the chemical reaction. Even if you're lucky enough for it to get past the gel stage, it'll not be very strong. If it's clogging the sandpaper, it's not cured.

    Again, I'm not sure where your information or assumption are coming from, but you're incorrect, it will not be cured.
    If you need longer working time, you have two choices, the first is the appropriate hardener, for the pot life time you need and second is lower the application temperature, so the goo doesn't cook off as quickly.

    Lastly, I'll repeat the need to know what you're doing and screwing this chemistry you don't understand, isn't the way to get good results. Log onto the industry leading epoxy formulator's site (West System) and System Three too, so you can get your head around these procedures. Or you can be stubborn about it and live with the arrogance of this approach.
     
  4. Mr Efficiency
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    Mr Efficiency Senior Member

    The bottom of the kayak may come to resemble a decorative driveway, if the thing bumps over a gravel patch, if it stays tacky. :D
     
  5. PAR
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    PAR Yacht Designer/Builder

    Depending on the brand and formulation he's used, he may end up with a semi hard plastic coating of some sort, but it's peel strength will be dramatically weakened (likely in the 80% range). Elongation modulus will be equally as affected.

    You and I have seen literally dozens of this sort of wrong ratio event over the years and the answer is always the same, grind it back to uncontaminated material and start over. It's sort of like painting over a dirty surface and expecting the new stuff to stick.
     
  6. rwatson
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    rwatson Senior Member

    This sound advice can be improved with the addition of better wetting out technique.

    If you try to cover the whole boat in one session, it may be problematic.

    BUT - you really only have to have a 6 inch "corridor", with one side of the corridor being the properly wet out fabric, and the other side being bare cloth. You don't have to risk the whole hull trying to do it in one go.

    The other advantage is, if you break a leg and the not quite wetted out section goes hard, you only have a 6 inch section to grind back and re-cover.

    There are plenty of videos on you tube to show how its done.
     
  7. PAR
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    PAR Yacht Designer/Builder

    I think MC has "bailed" on this thread, reading what he didn't want to read. I also question if he's using epoxy at all, as some of his comments just aren't possible.

    Maybe he'll come back and tell use what brand epoxy he used, that permits a full cure without a hardener or with only 50% of the recommended ratio. I doubt it, but I can wish.
     
  8. 300wm
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    300wm Junior Member

    I don't know what the brand is...the labels are not on the jugs. Apparently, they are not the original containers. At any rate, the 50% isn't getting hard enough to sand. The idea was to give me enough time to do the whole bottom and sides without any overlaps due to pot life. I'm figuring to just roll the stuff on, quickly, and then sand any rough areas out after it cures. I still believe this is my best way, but with the right mixture and hope I can get it covered quickly enough.
     
  9. gonzo
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    gonzo Senior Member

    Where did you get the mix ratio information from? No amount of hope is going to make the chemical reaction happen. Epoxy is a crosslinked polymer. That is a chain of repeating molecules, which are formed by a very specific number of atoms. If you fail to put enough atoms of an element, the molecules will not be able to form and will stay either as a liquid mix in the polymer or a softer material than desired. Painting more epoxy on top will not solve the problem.
     
  10. PAR
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    PAR Yacht Designer/Builder

    Not for nothing 300wm, I've a great deal of experience with the major formulations of epoxy and my previous comments are still valid. It can't cure, simply because there's not enough of the appropriate ratio, for the two chemicals to reassemble themselves into the new molecule. Quickly, epoxy is an activated chemical concoction, which means two chemicals are brought together and they literally attack each other, resulting in a redistribution of the individual elements, just with a new molecular alignment. There has to be a specific amount of each chemical, within a small percentage window, or the resulting realignment will screw the pooch in regard to desirable results (can't cure, dramatic loss of physical properties, etc.). This isn't debatable, but just the way it is.

    The only solution is removing the previous, wrong ratio goo, which is a pain in the but, as those of us that had done this before (read all of us at some point) well know, but it's the only solution. No waiting longer, no adding this or that will change the physical attributes, of the molecular combination, you have on the surface.

    Over coating the previous layer will not fix this, though it will provide a harder skin, bonded to a very weak and soft skin (like painting over dirt and expecting it to stay stuck). Epoxy formulations come in various mix ratios and though a small window of error is possible (with predictable results), without knowing the ratio, the goo in the jugs is worthless.

    Use a heat gun to soften up what's there and a putty knife to scrape off what you can. A cabinet scraper after this step, will help too. Next you'll have to eat up a bunch of sanding wheels, disks, etc., but the surface needs to be ground down, below the previous epoxy penetration, so the next coating (epoxy, paint, whatever) can get a good tooth (grip) on the exposed wood pores. Unfortunately, there's no other acceptable route to continue, if you want, what we think you do.

    Earlier in this thread, you said you were using 50% less than the manufacturer's recommended hardener ratio, but you've just said the labels are missing from the containers. How is it that you know the ratio and the manufacture (formulator), if the labels are missing? If you do know the formulator, which is it? What was the ratio that you used 50% of?
     
  11. 300wm
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    300wm Junior Member

    The dude that gave it to me said 1 part resin to 1 part hardener. I cut the hardener amount in half. You guys were right...it got hard, but not hard enough to sand, and I used it on a test piece of wood. I'm not putting on boat 'till I got it right. The stuff I want to use (I think it's called 'clear systems' and is fairly inexpensive) is also 50:50 ratio. Has good reviews.
     
  12. PAR
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    PAR Yacht Designer/Builder

    Being familiar with most of the formulators, I don't recognize the "clear systems" brand and being a 1:1 has me wondering if it's at all suitable for marine use. See if you can find the exact name, as it's likely one of us has used it at some point.
     
  13. pauloman
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    pauloman Epoxy Vendor

    mix sand into the epoxy and paint it on. replace as needed

    paul oman
    progressive epoxy polymers
     
  14. 300wm
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    300wm Junior Member

    You have to forgive me...I'm a retard with stuff like this, and I'm OCD. The name of the product is 'Crystal Clear'. It's cheap is why I was looking at it and it's for table tops...like in restaurants.

    Question...since I'm painting over it, would two coats of epoxy garage floor paint work as a scuff shield? It seems easy to work with, is inexpensive, and the one's I've looked at have a good pot life. Sorry to make such a fuss over a kayak. :)
     

  15. pauloman
    Joined: Jun 2010
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    pauloman Epoxy Vendor

    from my experience the table top stuff is crap - sold by marketing companies that find a cheap raw resin sounds like the floor epoxy is waterbased epoxy. pretty useless for boats except perhaps as a wood or weathered gel coat primer

    paul oman
    progressive epoxy polymers inc
    www.epoxyproducts.com
     
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