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Thread: The end of epoxy coating?

  1. #1
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    Over the past couple years I have read accounts of builders no longer epoxy coating their wooden boats. Instead they are certain to use only the finest marine grade ply and paint the exterior with multiple coats of oil based paint. The interior was either painted (criminal in my mind) or "souped" with a witches brew of linseed oil and other liquid preservatives.

    The rationale was that inevitably there will be cracks in the epoxy coating and moisture WILL penetrate to the wood. Once it does there is virtually no way for it to escape since it is encapsulated. In no time at all rot sets in.

    Well I just got the new book from John Brooks entitled "How to Build Glued-Lapstrake Wooden Boats". It looks like the long wait will be more than worthwhile - a top rate comprehensive resource on the subject. You can imagine how the following to be found on page 25 caught my eye:

    "We do not epoxy-coat any boat we build nor do we recommend that you do so. We will re-emphasize the importance of building the boat with the highest quality marine plywood, however."

    Hmmmmm, seems like I've read this before. They cite the example of a rowboat they built that was used along the Maine coast and began blistering after a few years and then rotted away. Despite careful use the epoxy barrier was violated through scratches and then trapped the moisture and doomed their boat.

    The epoxy manufacturers may protest foul but is there a turnabout going on here? It certainly would save a serious amount of sanding and scraping if epoxy coating were not in the build. Imagine just painting the outside and applying Boat Soup to the interior.

    Makes sense to me, how about you?

    [ 08-23-2004, 11:43 PM: Message edited by: Captain Pre-Capsize ]

  2. #2
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    Captain:

    Certainly far from having an abundance of personal boat building experience, but from what I have learned (and seen) is that many guys who epoxy coat the interior/exterior/bottoms of their drift boats here in the NW regret it (in spades) later.

    In these NW rivers, it is an accepted fact that you're going to bash a few rocks...and then a few more the next trip...and a few every trip after that.

    Epoxy coats get compromised as a sharper rock scrapes the hull...water penetrates...etc. The "rest of the story" is written in prematurely rotted hulls.

    After seeing (and hearing) of this from buddies who have "been there", I decided not to epoxy the exterior of my boat, nor am I applying fiberglass to the bottom. I have 1/2 ply, and it is going to be covered with another 1/4" as a "skid pad".

    Mike

    [ 08-23-2004, 11:58 PM: Message edited by: Mike B ]

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    When we visited Brion Rieff's boatshop in Brooklin, he said that he uses Interlux 1026 to seal all his carvel planked boats instead of epoxy. He says it goes on like paint, it's clear, and it's easier to work than epoxy. I've been told that Brion is one of the premier cold-molders in Maine, so his use of the 1026 is a good reference IMHO.

    Greg

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    To highlight a point Greg made:

    About 1206, Brion Rieff also emphasized that it was somewhat vapor-permeable, like paint. Looking at it, I actually thought "easy varnish" but I guess it doesn't have the depth of finish and subsequent paint coats go on better.

    Jeff

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    Well, this thread certainly caught my eye. I'll be interested to see how people weigh in.

    It makes sense though - even if you just epoxy coat and don't use fiberglass, you are still making a plywood core, only the outer plys are acting as the sandwhich. Over the years, just painting isn't sufficient. The boat will have to dried, stripped of paint, and epoxy coated again, which I guess is similar to what fg boat owners have to do with blistering, etc.

  6. #6
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    Granuaile was splined and epoxied within and without in the mid-70's. I built Leeward of 1/4" doug fir ply in the mid-70's and epoxied within and without. Both have had hard use, including the occasional splinter raiser. Both doing well.

    It is absolutely true that epoxy and even epoxy with glass is not very scratch resistant. Everyone with an ounce of brains that I know who uses boats in shallow rocky areas puts a sacrifice plank on the bottom. At least that was the practice when I was out west. Maybe they got lazy in the last thirty years and then blamed it on epoxy. Anyone who made claims that epoxy made an impact barrior was a person completly unwilling to understand the material. Those are likely the slap-up goonies who put out boats for hard usage with just epoxied ply or maybe a layer of glass but without proper sacrifice planks. Their bad work is not epoxy's fault.

    A scrape in paint will let in as much water as a scrape in epoxy. Plywood, especially once the outer ply is compromised, lets water wick all over the place. Oil paint is lovely and traditional and danged near vapor proof so it will help trap moisture in the hull.

    OK - Now to be a bit more temperate:

    It's perfectly legitimate not to use an epoxy sealer on plywood, especially for a work boat that's only expected to last a decade or so.

    It's also absolutely true that no amount of epoxy will make up for bad wood.

    That said, epoxy sealed plywood that's then been painted will stand up to the weather far far far far better than just primed and painted plywood.

    If the plywood boat you're building is to have a quarter to half century horizon, seal it with a good sealer like CPES before painting. And anywhere you expect to hit bottom or drag traps over the side or whatever should have sacrifice wood outside the main structure.

    Edited to add: I should also be real about the economics. Epoxy sealing is expensive. For the home builder the expense is not such a hit because one's work hours are not a cost anyway, but in a production shop sealing with epoxy means both an expensive material and the time to put it on, let it cure, prep all overagain and then at last paint. And that's before adding the sacrifice planks. For hard use work boats not intended for much more than a decade's use, it's not worth it and the price difference to get a boat that, absent accident or a change in the fishery, could go on a quarter century or more is not going to be competative. I just don't like it when people blame a product for problems that are external to the product and try to make a rational cost saving sound like an quality improvement measure.

    [ 08-24-2004, 07:56 AM: Message edited by: Ian McColgin ]

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    Well now. Let me say this about that....

    Has there been any rigorous tests to shed light on this question? If we can't point to them all else is anticdotal. I'm totally confused by the diversity of claims made, more questions than answers.

    If epoxy seals in moisture, why doesn't paint?

    Paint breaths, some say, moisture comes and goes.

    Perhaps, but some more than others. Does latex house paint that some swear by "breath" more than a high priced two part polyurethane? No doubt. Does the latter "breath" more than epoxy? Doubtful.

    How much would twelve coats of the best varnish breath? Is wood going to rot away under varnish if it gets dinged?

    I'm also bewildered by the claim that the paint manufactures don't know how to make a coating that will stick to wood. Thus the need for CPES or perhaps an epoxy base coat.

    Ah, hell! Just slap some stuff on. It'll be fine. Perhaps. Or maybe not. It depends.

    Edited to add: If I had seen Ian's response I would either have just agreed with him or not responded. I'd still like to see some objective studies, WEST may have done them, but in the mean time my preconceived misconception tilts toward encapsulation. Depending.

    [ 08-24-2004, 08:51 AM: Message edited by: NormMessinger ]

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    I am with the Captain on this one...

    see this thread,

    http://media5.hypernet.com/cgi-bin/U...=1&t=007059&p=

    and as a more recent thread suggests I am indeed embarking on a couple of Mr Gartside's proper dinghies (two, because the first one is for practice).

  9. #9
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    Totally sealed wooden bouyancy chambers will rot somewhere almost no matter what. As they heat there's tremendous expansion that can cause cracks to develope. As they cool, the condensing moisture will find its way in and off we go.

    I used to think you could foam fill and seal a flotation tank but now have learned better. Whether foamed or empty, floatation chambers made of wood need an access port so that they can be left venting when the boat's not in use.

    In future efforts, I lean towards shaping the piece by foaming in place but then the finish will be some sort of slat structure to contain the foam but not the moisture, rather like the wooden Thistles do it.

  10. #10
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    Just a footnote to my "hole in my dinghy thread"; as noted in it, the dinghy, when kept afloat over a winter, developed "osmosis" on the bottom, and the small rotten spot in way of the bouyancy tank was indeed just localised. Tnis had nothing to do with the sealed buoyancy tank; it had everything to do with local failure of the epoxy encapsulation allowing water in and then trapping it.

    I am now wholly opposed to epoxy encapsulation.

    As Ian Wright says in the above thread, FES (Failure of Epoxy Syndrome) is not something talked about! The True Believers will always say you applied wrongly.

  11. #11
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    Fiberglass boats, anyone?

  12. #12
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    I'll admit to being an epoxyholic but I've not done any for about 97 hours and think I'm speaking with a clear brain:

    I happen to not like epoxy sealers on hard use varnished surfaces where damage is common - like spars. I am watching a CPES'd and varnished boom to see what the fourth and fifth years look like but so far so good. My dislike was based on twenty odd years ago when I used WEST on Goblin's spars and had to get the goodge off after only two years.

    In general, I can see the use of CPES and some other sealers with epoxy base on planks and such but whether it's really better than other primers very much depends on factors external to this discussion.

    I've only anecdotal evidence from a couple of boats but it appears that the solvents in CPES have tremendous travel in solid wood and have deadly consequences to decay. These solvents don't appear to travel with water vapor back out through cured CPES. For this reason, and I'd like more science on this, I believe that CPES is actually safer to the live-aboard than conventional wood preservatives.

    I remain convinced that CPES is a wonderful way to treat plywood prior to painting. It gets deeply enough into the wood - remember the uptake with rotary cut wood is huge - that it really seems to limit surface layer wicking even when somewhat compromised - at least limits better than just primer and paint.

    I go back to two Gloster gulls of exactly the same (very good) construction of excellent plywood, one CPES'd before painting and one not. The un-CPES'd boat could not hold its paint even through the first winter on the beach. The CPES'd unit is now over a decade old and holding just fine.

    I hasten to add that my brand name experience is limited to WEST, Gluvit and CPES. I've been unable to make WEST work well as a primer. That was the product that was so miserable on Goblin's masts. WEST remains my glue of choise, it's just not a sealer/primer. Gluvit is a superb primer for nasty work that may take some movement. CPES remains sui generis but one must not fall for excessive claims made by various rot physicians.

    A bad job with epoxy will fall apart faster than a good job without it.

    There is no miricale glop where you can just dunk the boat in and be done with maintenance.

    It's very interesting to compare boats like Lion's Whelp that was under construction during the last few Maine Boat Builders' Shows - all epoxy layup - to Nat and Ross's big schooner, which is true carvel. Turns out Gannon and Benjamine can do the job more economically the bad old fashioned way and they have a good claim that their boat is more repairable and will last longer. We'll see.

  13. #13
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    Captain Pre-Capsize ---

    There are a lot of authors, plywoods, epoxies, and paints. There are also a lot of builders.

    Some combinations do better some worse.

    It is a poor workman who blames his materials and tools. The author may not have learned enough to make epoxy work on plywood.

  14. #14
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    This thread is starting to take on the tenour of a political thread in the Bilge!

    I did not do a bad job with that epoxy, but it failed locally after 5 years ("osmosis" blistering on the bottom) and 12 years (the rotten patch) The dinghy is now in the 13th year of its life, it has been used every year, and it is in otherwise good order.

    I reckon epoxy coating plywood is not a process that I will care to use again.

    Mind you, people say that teak won't rot and won't be eaten by teredo worm. The people who say that have not lived in the tropics...

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    Andrew, I certainly figure you to have done a proper job and I am certain that you have identified the causes correctly. We may be drawing different conclusions based perhaps on differing experience.

    I've no experience with osmosis in epoxy unless the epoxy was itself unprotected. I have seen instances of moisture getting into a glass/epoxy finish and the wood and that indeed is a mess. Usually that's due to the glass being compromised and water wicking up along the wood.

    I misunderstood the rot problem you had, wrongly ascribing it to the floatation. I agree that when an epoxy barrior is compromised even by a very fine and well hidden flaw and this is not found for a longish while (easy to do since the damage is spreading subsurface) rot can spread out alarmingly.

    It's just that in my experience un-epoxy-sealed plywood does not last as long as epoxied. Once you've your new boats side by side this experience you'll have a better comparison to more fully prove for yourself your or my belief.

    I don't have another thirty year old dory to compare against Leeward so it's true - I'm operating on faith.

  16. #16
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    This thread is starting to take on the tenour of a political thread in the Bilge!

    Not quite. No one has corrected my spelling of anecdotal.

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    Ian, I agree with you that epoxied plywood lasts better than the other kind. I had been seeing epoxy as a wonder-material; I no longer do!

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    Well, I won't weigh in with any opinion on the question of epoxy coated boats being more likely to rot faster. But I will offer that on my own plywood lapstrake canoe I painted the wood outside with latex house paint and varnished inside with good old man-o-war. Only the keel got epoxy coated (and the laps where they were glued together).

    The boat is way too young for an evaluation but I can't imagine epoxy coating her. What a messy chore for not much gain IMO. The paint does just fine. As a note, the epoxy covered keel (2 coats fairly thick) has many small scrathes through the epoxy and needs a new coat already.

    Dave

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    I used pressure treated plywood on a flybridge rebuild and epoxied the outside no cloth just to prevent water from delaminating it.
    I used D.E.R. 331 resin (Dow) with versamid hardener and it is a thick epoxy like honey.
    Treated plywood can be really poor loking stuff, you have to be very selective of what you get, but it wont ever rot.

  20. #20
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    Heck, since I have more time today to post.. I'll toss my 2 cents in ..

    From everything I've read, spoken to designers, distilled from anecdotal experience, and many other sources, my own personal conclusion is that if you want a boat to last 20 years and is light, easier to maintain and simple to build, epoxy/glass encapsed plywood is a great material to use.

    Notice I said.. 20 years... Plywood in general, unless you use the very highest quality like Brunzeel (sic), is a limited life material when used in immersion applications due to its tendency to rot like a banshee if its core stays damp. So in 20 years you will likely have some major repairs to complete if you want her to remain sound.

    To get rid of that problem you would need to use anti fungal agents INSIDE the plywood, which would require custom plywood...it could be done, but gosh the price just went up. (note: Pressure treated plywood? my first news on that one)

    The whole controversy about epoxy'ing a regular wood boat is like talking about treating illness.. everyone has something that they know has worked for them, and everyone else knows someone for whom that treatment has failed. I don't think you can talk about epoxy'ing a wood boat unless you talk about a SPECIFIC boat. There just are too many variables in wood type, planking method, fasteners, current condition, etc.

    The only method (other than FC encaps) that I think works for any wood boat is the Vaitses method (using polyester or vinyl resin and FG), but that is essentially using the old boat as a mold for a new FG hull, without removing the mold. The old hull becomes somewhat redundant and so its planks' condition are not partucularly relevant. The nice thing about this method is that you could restore the old boat to original condition if you suddenly got the funds to do so, removing the FG hull and refitting the old hull.

    [ 08-24-2004, 12:26 PM: Message edited by: TimothyB ]

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    Just to put the fudamentalist point of view,,,,,,,,
    Epoxy used as a coating is just another paint, and like any other coating needs maintenance. Trouble is when it needs to be replaced it's a bugger to get off. I'll stick (!) to bog standard yacht paint thankyouverymuch, and re-paint every year. My old tender was cold moulded and epoxy coated. It needed painting after two years and wooding plus re-painting after five.
    Epoxy is not magic. Epoxy is not the only glue. Epoxy is not the only coating.
    Yea verily, I say unto you, there are no short cuts and nothing is forever,,,,,,,

    IanW

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    Ahh, the worm has turned.Now it is back to square one. There are many hard core discussions on this board concerning building techniques, but unfortunately the answers depend on what year you are reading.
    There is no doubt that epoxy encapsulation and before that fiberglass (polyester) was devised so as to obtain a easier and better paint job on douglas fir marine plywood.Which douglas fir defintely can telegraph checking through the paint job.Maybe there needs to be more discussion on how to obtain a prettier paint job.
    Then there are those that wanted to use exterior plywood for 1/3 the cost of marine, but felt it needed help to last like marine. Unfortunately they spent more money on epoxy then if they had bought the marine plywood to begin with.Sounds like a epoxy salesman's dream come true.
    And then there is the issue of how many football patches are on the B side of the plywood for those that wanted a bright finish on a small boat, where everything is visible.
    Then comes okoume and merantti, very pretty and finishes nice, without football patches.Merantti has delamination problems, probably due to the oils in the wood. And okoume has the rot resistance (as others have stated) of wet toilet paper.Okoume is classified as a non durable wood, and how in the world did they ever devise a non durable wood to be used to manufacture maine plywood out of, beats me.But it is pretty and does finish well, just may not last to long.
    On the forum of designs, is a recent post concerning simmon's boats. It is stated that why there are so many of the simmon boats still around, that where built in the 50's through the early 70's is that he changed over from solid wood to marine plywood, which is douglas fir marine. The test of time. Of course this is referring to trailer boats and not salt water boats that are put in and left in. Trailer boats have a heavy cycle of wetting, drying and being overly dried by sitting on a trailer on a concrete slab, or being pulled down the road.
    It is a hard core fact that fiberglass, polyester and to a lesser exstent epoxy allows water to be absorbed into itself.Look at all the rotten transoms on fiberglass boats and replacement of floor stringers. How did they rot if they where encapsulated?
    Some of the above posts, state where sealed air chambers, even foam filled and epoxy encapsulated now has soaking wet foam. How did the water get in, other then being absorbed through the epoxy and it is a lot slower to dry out then going in. Defintely a recipe for rot. The best way to prevent rot is through air circulation. No trapping of moisture.
    And my comments do not apply to a cold molded or laminated hull, that is a different animal.Each technique needs to be addressed upon it's own merits, or lack of.

  23. #23
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    IMHO, epoxy coating with fiberglass or other reinforcing fibers (Dynel, Xynole, Kevlar, etc.) has merit. It makes the plywood stiffer, stronger, more resistant to abrasion, and the fibers allow a thick layer of epoxy without much cracking (think rebar in concrete). Without the reinforcing fibers, however, epoxy is just brittle expensive paint.

    Honestly, I don't care how much longer it lasts, it's just too damn much work sanding the epoxy before painting. I hate sanding.

  24. #24
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    Thus spaketh Ian....

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    Originally posted by RonW:
    ...And my comments do not apply to a cold molded or laminated hull, that is a different animal.Each technique needs to be addressed upon it's own merits, or lack of.
    How is a cold molded hull different from an epoxy encapsulated hull? Wouldn't the waterproof glue between the ply layers act the same as epoxy between veneer layers? I see all types of older, cold molded custom boats still alive and well. These have reinforcing cloth (glass, dynel, kevlar, carbon fiber, etc.) set in epoxy. I would assume that any boat built in such a fashion would not lead to early rot. IIRC, FRG boats with rotted transoms/stringers were the result of the use of polyster resins.

    I agree that epoxy encapsulating the outer hull without reinforcing fabric (other than edge grain of the plywood) is a waste of precious time and money!

    Jeff

  26. #26
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    Cold molded is very different from epoxying conventional planks as the layers and individual sticks are much smaller. All things considered, cold molded is dimensionally stabile.

    The worst thing - there was a whole book of this silly idea back in the 70's which John Gardner rather brilliantly panned in the Fisherman - is trying to glue thick sticks together. The specific hull was a St Pierre dory with the hull build up of two Ashcroft style layers of 1"x1" sticks. The stresses when it finally started to swell blew the bow off!

    A carvel hull is ment to move a bit and swell tight. Viastse solved the problem of a somewhat elastic interface between wood and glass and, as mentioned above, it's really a glass hull with a left in place male plug.

    Just a layer or two of glass over carvel is an abomination.

    Some carvel boats, like Grana, work out well if they are soft wood splined and epoxied but no glass but I do not think this would work well on a wide shallow hull.

    Epoxy as a sealer is a different critter than epoxy as a glue.

  27. #27
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    Just a layer or two of glass over carvel is an abomination.
    Well, yes, most of the time , but . .

    There are a fair number of abominations around here which are doing very nicely, thank you. In fact, it's pretty much standard procedure to among the old powerboat crowd (1937 Chris-Craft with 112 coats of perfect mirror-like varnish) to epoxy and glass the bottom planking, and old carvel-planked racing scows are fairly often glassed sucessfully. It seems to work under certain very limited circumstances:
    - A small boat with thin planking. The strength of the wood-epoxy bond is independent of plank thickness, but the forces generated by wood movement are pretty much proportional to the size of the piece.
    - The boat lives on a trailer and only gets wet when it's being used, minimizing the shrinking and swelling of the planking.

    [ 08-25-2004, 09:43 AM: Message edited by: Keith Wilson ]

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    I don't think there's one "right" answer regarding the use of epoxy. People with vast, respect-generating professional experience have very different views.

    Tom MacNaughton argues that using his scantling rule, "sheathed strip" epoxy/fabric/wood construction produces the most "neglect resistant" hulls he's aware of. That after a long career of designing, building, and repairing boats in traditional carvel (which he likes), steel, fiberglass, etc. His experience speaks volumes to me.

    When I asked him point-blank about rot under glass sheathing, MacNaughton said he'd seen significant problems over 35 years when folks used polyester instead of epoxy, and/or inappropriate building techniques (i.e. sheathing carvel, epoxy-coating only one side etc.). If a sound sheathed strip building process was used at the outset (his scantling rule was published in '79, I think), he's found it very hard to start rot, and any that did start was quickly repaired.

    Tom Colvin, on the other hand, has ripped off rotten glassed-ply topsides after only 8-10 years of service ... he's NOT a fan. In fact, he got really incensed with me in an e-mail exchange on the topic, suspecting (wrongly) that I wanted to substitute goop for workmanship ... I must have caught him on a bad day. But his credentials are equally unimpeachable as a builder, sailor, designer, etc. etc. Colvin's preferred hulls are steel of course, but on his website and in a personal e-mail he also advocates carvel-building ... using pressure-treated yellow pine.

    And Paul Gartside completely dismisses epoxy/strip building, though on his website MacNaughton (respectfully) counters that the building techniques used must not have been sound to produce the problems Gartside describes.

    So - to goop or not to goop? My very subjective $.02 reading of the tea-leaves is:

    1. Not with ply if you want real longevity. Probably the water-ingress is too tough to completely preclude over decades, leading to rot/delamination.

    2. Probably epoxy's good with strip, so long as you use sound techniques, don't expect miracles, and do your maintainance on time.

    3. I'm guessing that responsibly built epoxy/wood boats of either stripe, if completely neglected, would probably decay more slowly than a completely neglected traditional wooden boat. But the epoxy boats would likely be toxic landfill if they really went over the hill, while a similar traditional boat could be rebuilt.

    My personal saw-off? I'll soon build an open daysailing/rowing boat in traditional lapstrake or carvel, for the love of the process, materials, and the aesthetic end product. But a project big enough for berths would use MacNaughton's sheathed strip scantling ... or be a Colvin steel design.

    Tom Fetter.

  29. #29
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    Yeowww, hot topic this one. Post a querry wait two days and man, over twenty responses. Imagine my relief that all of you agree. Now I know just what to do...

    Here is how my boat is used and, from my take on the forum members, how I think most of you use your boats: it lives on the trailer most of the time and hits the water on the weekend. Does that mean that epoxy coating is less important than if the boat remained in the water during the whole boating season? Seems to me that for most of us that fall into this catagory this epoxy coating is overkill.

    Since many of us have built our boats our very nature is to take especially good care of them. I know that for me this means enjoying touching up the paint and varnish when necessary. It will be well maintained and given that, is the epoxy coating redundant? I believe it is.

  30. #30
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    Watch me sail away from this argument (oops, discussion). Four coats of epoxy, three coats of Kirby. It had to be done as the boat was built with epoxy. I will be painting next year, but I LIKE painting her!


  31. #31
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    A very cool and salty looking boat there. Congrats on getting it wet!

    What does the interior layout look like - what were the plans?

    [ 08-26-2004, 06:46 PM: Message edited by: Captain Pre-Capsize ]

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    What about laying in 38 oz of biaxial / chopped strand mat with one and half gallons of epoxy on the bottom of a TRAILERED fourteen footer?

    I guaran freakin tee you that is superior to a painted-only hull thats not always immersed. I welcome the rocks as they scrape by this bottom
    The two primary qualifiers for this discussion should be: Trailered or not, and planked or ply.

    It never made sense to me to simply epoxy the ply. Either give it at least 60 mils (the 38 oz was close to 90 mils) of glass/epoxy, or don't epoxy. A full breach to the bare ply face, and epoxy is worse than paint, due to holding in the wicked moisture, so the issue is to never allow full breaching of the glass - unless you haul out and fixit.

    If you don't glass it (thick), paint seems just as good or better.

  33. #33
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    Two cents worth of thought from a guy who makes his living testing, evaluating and selling marine and industrial epoxies and is a boat nut (about 20 small boats in the backyard right now - just obtained a 'free' molded firefly sailboat in need of TLC).....

    Epoxy is really just a hard plastic. Epoxy coat your boat and you've 'dipped it in plastic' giving it a plastic shell - that can be good or bad....

    My current thoughts (also based upon some recent talks with a boatbuilder in Maine I talked to at a show in NH last week). Is to seal and penetrate the wood surface which means solvents... Use a solvent thinned epoxy (like ESP 155 or CPES) or make your own. Or, solvent thin your varnish, oil based paint, etc.

    Any of these solvent thinned options will help seal the top woods grains in your ply and, more importantly, provide a better bonding surface for your topcoat of paint, etc. which provides the real protection from sun, rain, and sea......

    paul oman
    www.epoxyproducts.com/marine.html
    progessive epoxy polymers

  34. #34
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    I'd sure like to come over & poke around your backyard, Paul.

    I'm an amature, and the epoxy scared the heck out of me when I first got started, but she was originally built with epoxy, so sealing her was the only choice. I would be worried if she sat in the water, but she's on a trailer one or two days a week. It's nice to be old enough to tell them at work that I'll be back... soon; someday!

  35. #35
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    Well I dont know for sure exactly what it was I used, but I glassed over my 20 ft canoe and proceded to drag and scrape that over just about every rock filled stream in Southern Ohio and by the way those are not rounded over rocks but sharp ones that cut. Then there was the trips to Canada where it did bounce off some rounded over rocks. End result is canvas or paint would not have lasted 10 mins the way we used that canoe.

    What was the question?.. glass or just paint?
    I guess your use will guide you.

  36. #36
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    I guess I'll put in another 2 cents worth...

    I can't imagine using epoxy and not using fiberglass cloth for anything that will be exposed to the weather and sunshine. After all the effectiveness of epoxy encapsulation is based on the mil thickness and it must be thick enough to insure a proper barrier. Fiberglass cloth not only stops the checking in fir plywood but also offers a stable matrix for the epoxy so that the stresses are minimized and thus cracks are much much much less likely to form. Prime and paint and your in business for a long time. Naturally choice of paint controls how often the boat needs to be painted. Also, the surfaces laying horizontal and directly exposed to the sun will need to be painted more often. (some info gleaned from Tracy Obrien's building experience in building over 60 boats in the last 25 years).

    I couldn't conceive of building a plywood craft and not glassing the bottom with epoxy/fiberglass cloth and adding an additional "skid plate" of extra material along the front portion of the keel. If weight didn't matter I would apply xynole below the waterline plus skid plates.

    There are many anecdotal stories of folks glassing the bottoms of craft and perhaps adding a layer of glass cloth or Xynole and adding some graphite powder to the final epoxy coats... and they are bullet proof... and will withstand all kinds of abuse, abrasion, etc.

    Anecdotal: Reuel Parker has built many boats encapsulated and used in harsh HOT, HUMID enviornments and has had to modify his building methods over the years in little ways to withstand said enviornment. As you know, most of his designs are sheathed plywood types.

    A good example would be the lazerette hatches (edges of seat/hatch sitting around the parameter of the opening to the lazerette hatches) which are in contact all the time with the edges of the lazerette opening edges. These are always one of the first areas to get rot in a boat period...!

    The amatuer builder could just take tons of time and radius corners and wrap glass around everything. Mr Parker told me they did not have time to wrap glass on the edges of the contact boards of the seats so they had to come up with a method that could withstand the abuse of the water, humidity, and heat but took less time for reasonable labor cost construction.

    The answer was to find older, dried out pressure treated material in say a Home Depot that had been sitting around long enough to dry out very well, They just used these boards as the under lip of the lazerette seats, glassed the top of the seat wrapping around to the bottom edge of the 1X2 that was the under lip of the seat. They just epoxy coated (3 coats I believe) the bottom edges (contact surfaces) of these boards then primed and painted with linear polyurathane.

    This has fixed the problem for one of the most difficult areas of a boat to protect... so epoxy does have its limitations and sometimes needs a little help and smart thinking.

    Mr Parker uses Xynol polyester fabric exclusively since if allows for a much thicker barrier when buried in epoxy and is much easier to work with plus doesn't itch. He also believes in applying a very thick sheathing layer on the bottom of his boats to withstand abuse over time and really reinforces the areas around the keel.

    I would absolutely glass the exterior of a small boat and also add skid plates "beefed up areas" to the areas that would receive abuse over time. I would also apply glass to any panels that would be exposed to the sun then prime and paint simply for the longevity it provides. That would also apply to the interior surface of the hull. Sand, prime and paint and you have a tough little boat that will withstand many years of use. Keep her covered and she will last forever. After all, a piece of furniture kept in a relatively dry garage will last for years and the barriers on its surface are no where near as good as epoxy. Reasonable protection from the elements is key. I guess this all depends on the budget you want to spend on said boat and whether you care how long it lasts.

    I have personally seen epoxy failures like a boat I recently looked at on the hot, humid coast of Texas. She was left on the dry in a backyard and ignored for several years and not covered very well.

    The interior was epoxy coated but not glassed and the plywood bulkheads were good quality fir.

    This 36 foot cruiser suffered severe rot in the entire cockpit floor, underlying longitudinal bulkheads, and spreading down into the ice box and even to some of the inner cabin sole plus the bulkheads beneath the cabin entryway. Intermittent exposure to solid water, high heat, high humidity and not using marine grade plywood made for a "worse conditions" test of epoxy's abilities. It makes one stop and wonder just what could have withstood such a test. (note: I am sure that interior glassed panels would have done much better).

    I have come to realize that if one spends the time and money to build such a boat for that enviornment you absolutely must use proper materials, building methods, and provide adequate protection over time from the sun, rain, etc...

    RB

  37. #37
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    even solid fglass boats that use epoxy as a resin take on water through osmosis... water will get into anything.

    I don't really wish to cash in on this epoxy debate, but wish to address it. It seems appalling to me that, especially in this forum, the traditional ways of building a boat would be poo-pooed.

    A new school, epoxy coated boat is only repairable as long as we can keep pulling oil out of the ground; or start cracking other oils to replace petroleum. Traditionally built boats simply require more trees (you can use treenails!).

    Using epoxy (and being dependent on it to build) is analagous to using electricity to power tools... what do you do when "they" stop making it?

    None of this is meant to judge. It's just important to keep perspective... I call my strip/glass canoe a wood cored fglass boat, and my lapstrake canoe a wooden boat.

  38. #38
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    Yes to what Ian said...

    Not to judge but, the facts are that some products available today help some materials
    withstand the enviornment better than ever before!

    In my experience many folks that lean towards trditional construction have no use for epoxy and think working with it is horrid. They enjoy woodworking and the smells of the shop, etc... Some of them look down there noses on those who employ newer methods.

    On the other hand, many of the "modern googue users think traditional boats begin to self-destruct the day they are finished and the necessary attention to keep them from serious deterioration seems daunting.

    I on the other hand feel that both methods produce great boats, both kinds of which will last many years if cared for properly. As I said above, even a piece of furniture left in a covered garage will last many years without damage, its just reasonable protection from the elements... ie., PROPER MAINTENANCE. and do not be APPALLED... because no one is criticizing traditional conctruciton, just offering some methodology that would result in a much tougher craft for withstanding the elements, namely, glassing plywood (sheathing) for improved ability to withstand harsh environments. Criticism of traditional boatbuilding was never even on the plate, we were talking about epoxy as a sealer/coating on plywood before painting...

    By the way, epoxy allows for the building of tons of boats that could not be built if proper traditional building materials had to be acquired, after all traditional materials are becomming more and more difficult to get and the cost is rising all the time.

    RB

    [ 08-29-2004, 07:56 PM: Message edited by: RodB ]

  39. #39
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    I was only appalled by the rather pointed comment about G&B and the bad old fashioned ways they use.

    I just think it's out of place to put down traditional wooden construction here. I'm not defending it, don't even practice it.

    I was under the impression that this mag and website were here to help preserve the traditions of boatbuilding, too.

    I wasn't trying to offend. We all know epoxy is good for what it's good for; sticking stuff together, be it wood to wood or cloth to wood ( or me to everything). My only problem with epoxy is the bottles always seem to be that much too small.

    I simply meant to defend our hosts, and some true craftsmen. I consider cold-molded boat builders to be craftsmen, too. I just think this should be a haven for the old fashioned stuff, as well as a deiscussion of progressive methods.

    That said, I really like my paper kayak.

  40. #40
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    I think that problems and controversy come up when folks try to mix traditional and modern methods... this seems to be a pandora's box for problems if one does not think things out clearly and also these type of solutions seem to spring up when folks are trying to cut corners to save time or money.

    As a relative newby to boatbuilding (3 years) I am very open to all methods and wish very much that I had grown up around the classic boats learning the pertinent skills therin.

    No offense taken here, I just wanted to get us back on track.

    RB

    [ 08-30-2004, 03:31 AM: Message edited by: RodB ]

  41. #41
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    Well I started this so let me not end it but rather summarize to date.

    It seems that epoxy coating by itself has few backers.

    Epoxy coating with fiberglass sheathing has many backers and for good reason. Many years of hard use with no rot to show for it.

    Not too many folks that advocate just painting the exterior and varnishing the interior.

    Again, I say that most of us just love our creations and labor over them out of desire to preserve what our hands hath brought forth. It is my guess that mostly we go overboard (pun intended ) with epoxy coating prevention.

    If it is to be on and off the trailer on inland lakes like those in the midwest then an epoxy coated fiberglass bottom is not absolutely necessity. In my case my eleven foot skiff is simply painted and I look forward to a fresh coat on the hull every two years. There just aren't enough rocks around to scuff things up.

    On the other hand one of the respondents above mentioned dragging his craft over rocks year in and year out with nary a scratch to show for it.

    Call me simple but part of the reason I have a wood boat is to feel the wood. That is one of the pleasures of such a craft. When loading, unloading or simply sailing along it is a treat to reach alongside and feel the texture of the wood. And yes, those evening visits to the garage, "Just to check on things, honey" are a chance to get a sense of your creation from it's flanks. Me, I like the wood.

  42. #42
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    Captain, I used epoxy on the boat I'm using now. Below the wale I coater her with a gallon and put on a piece of polyester cloth. The cloth stuck on like glue. Polyester cloth moves around a little especially with flexible epoxy like Gluvit. I then coated her with another gallon of epoxy with color tint and painted two coats of black over it. Above the wale I painted it with blue tint epoxy and two coats of royal blue paint. The sides have scratched on the dock and I've just gotten out a que tip and dipped it in some paint to touch it up. The bottom? It does not not leak and can be touched up as well. I trailer the boat and it gets knocked around but has stood up better than my last one which was meerly painted.

  43. #43
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    Originally posted by sr. jigaboni:
    I was only appalled by the rather pointed comment about G&B and the bad old fashioned ways they use.
    A classic case of why people get bent out of shape on the forum. A misreading or misunderstanding of what was said by Ian.

  44. #44
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    Good heavens and thank you Tom. I was one of the early G&B customers and in the early WB article about the yard you can see Goblin mentioned. The phrase was of course a tease, especially given Ross's love of "Egyptian technology," but the point is that absolutely 'traditional' methods are often more cost-effective and more long lasting than the latest googe - fond as I am of the stuff. There was also that old WB articl comparing strip epoxy v. carvel for making a monomoy surf boat.

    I myself have a larger collection of hand tools and a smaller collection of power tools because I live off the grid. And when you look at total cost effectiveness, there are days when it's cheaper to grab a shovel and spend a couple days digging the ditch than paying a few hundred for a backhoe to do it in minutes.

    It's about choises which should be made with the realization that almost anything works someplace and nothing works all the time.

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