newbie epoxy question

[Kevinh]

Hello, I am new to the world of boat building. In fact, I am so new that I have not built a boat yet. I am currently purchasing the items I will need to start, and have hit a wall. I have been researching boat building for a while now and everyone apparently seals their boats with epoxy resin. I cannot find epoxy anywhere in my area and am not excited about ordering online because I like to be able to slip out and pick up whatever I run out of. I have come across some "waterproof fiberglass resin" made by bondo. Will this work the same as epoxy? will my boat be sealed? Thank you

[BobSmalser]

and everyone apparently seals their boats with epoxy resin.

No, they don't. Paint still works just fine...even on plywood.

West Marine and others sell epoxy by mail.

Bondo covered by polyester is guaranteed to rot your wood in short order and is a poor choice.

[capt jake]

"waterproof fiberglass resin" made by bondo.

That would be Polyester resin. Totally different beast than Epoxy. It is much cheaper but (you will get differing opinions here) I feel that epoxy is far superior. IMHO

[Kevinh]

I was hoping to use a polyuerothane varnish instead of paint. Have'nt checked it out closely, but I dont think that alone will seal my boat. Any suggestions for a good sealer I can probably find locally, or am I pretty much at the mercy of online ordering.

[BobSmalser]

Can't tell you much without knowing what it is you plan to build, but small plywood boats were built for decades using linseed oil to fill the plywood, then alkyd paint after drying.

You can still do the same, using fabric and epoxy on just the high wear areas and the seams. And you can varnish over the linseed, too.

There's an effective epoxy sealer called CPES from Smith Enterprises you can use ILO the linseed, but it will cost you as much as the plywood did and I don't believe you'll gain anything except unnecessary expense on medium grade plywood.

[Kevinh]

I live in southern pennsylvania, and am hoping to buy all my supplies from Lowes or home depot. As I stated before, I like the convenience of running out to a local store to restock whatever I need. I am planning to start with a plywood boat. I have decided to give bc yellow pine plywood a try, but think I probably need a real good sealer to be safe. In your opinion, i take it, polyester resin is a bad sealer and i should use linseed oil?

[Frank Hagan]

Kevinh, there are a couple things to consider. One is the type of plywood, and often that will force you to use other things as well. In my case, I built a Weekender using fir plywood ... similar to your pine ply ... and found I had to use fiberglass cloth and epoxy to prevent it from "checking" (getting numerous cracks in the top layer of the veneer).

An alternate source of plywood is to use the luan underlayment available from Lowes or Home Depot. Its cheaper than the fir plywood here, and may be cheaper there too. Luan doesn't need fiberglass cloth to prevent checking, so you save some money there too. The problem is that it is usually only available in 1/4" thick sheets. You can laminate it with epoxy resin for 1/2" stock, but again you're getting into some expense there.

The second consideration is the plan you want to build. Some boats, like the Weekeender, were developed especially for the first time boat builder and utilize a lot of materials available from home centers. Others are really not designed for home improvement center materials, and you won't be able to get advice from builders because they will be adament that you use only the best materials. Once you decide on a plan that you want to build, then find out if there's a supportive community of builders out there. There are for the Stephenson's Projects boats like the Weekender, and for the various Bolger Boats as well ... all designed to be built by amatures and out of the common materials found at Home Depot.

[tdrown]

I built a Stevenson Weekender and used polyester resin to fiberglass, and I would definitely suggest epoxy. I haven't had any major problems with the resin [*yet], but epoxy can be used as a glue and as a filler and works with wood a little better. It's actually not that much more, Raka epoxy has pretty good prices, I've ordered from them and I'm satisfied.

[PAR]

In the long run it's best to use the highest quality materials you can afford and employ the best methods and techniques you can muster. You can use polyester over wood, but your repairs will be much sooner then with epoxy or even just paint/varnish (same thing, one is just kind of clear)

Home Depot and Lowes carry home building supplies and their selection of plywood is limited to land based requirements. Though many have built with the sheet goods found there, I wouldn't recommend it on anything other then a small craft intended for a limited life.

I just replaced the Douglas fir plywood planking on a 45 year old cruiser. It was good quality stuff in 1960 and served it's master well. It was painted and repaired as necessary with quality methods and products. I would find it hard to believe a Lowes/Depot plywood boat could survive anywhere close to that amount of time, given reasonable use. My replacement planking was BS 1088 grade meranti below the waterline and BS 6566 above. The supplier I got it from doesn't bother carrying Doug. fir anymore and considering the prices and quality lately, understandable.

On the other side of the coin, a 18' hardtop powerboat, I freshened up (paint, varnish and some minimal repairs) 4 years ago was built from lesser quality plywood 10 years earlier, though many of the other materials and methods were very good. It was Lowes/Depot quality stuff and skinned with polyester and cloth to the chine, but I'm not sure if done at the time of construction (likely not judging by the application). I told the owner about the sheathing and gave him an idea of the task, but he found no reason to remove it. He stopped by yesterday with the boat in tow. The chine joint was covered with a rub strip and 'glassed over as was the keel and bottom. I found several foot long areas of rot under the chine rub, going completely through the ply in spots. The keel's rabbit will probably have similar areas. He now wants the 'glass skin removed and repairs made. He remarked about the 45 year old planking in a pile by my fence, "why did that last so much longer" my only reply was traditional and known methods using good materials beats questionable methods and lesser quality materials every time. Both boats used similar construction techniques, just there size differed, but the planking was the same dimension. 14 years verses 45 years (in this case), it's your choice.

[kydocfrog]

Horay for Mr.Smalser. The group's most agonizingly elegant craftsman speaking old, simple words.

Another webgroup to check out on general small boat construction is duckworksmagazine.com and the various designer's sites linked from there which range from bigbox store dirt simple to incredibly elegant work like Welsford's designs.

DocA

Charlie Girl II

[BobSmalser]

There's no reason at all why a Weekender shouldn't be made to last as long as all the snootier designs out there for the rich folks....it's mostly a matter of materials and joinery, not design.

I'm afraid that Home Center plywood only has a chance of long-term survival if you keep the boat well-painted and on the trailer under cover when not in use. If left out long enough for the coatings to deteriorate, there will be a host of problems. CDX and other exterior grade plywoods are made from the same phenol-resorcinol glue as marine grade, but there is no guarantee that the interior lams won't contain quick-rotting sapwood, which is one major contributor to delamming and rot when the protective coatings are cracked.

This 1955 Bryant was made with H. Mahog plywood as good or better as anybody's premium plywood today, and the boat was well cared for by the same family...but as you can see, it needs a new deck. Originally finished bright, it was painted over without removing the UV-deteriorated varnish...which acted as a slip sheet to crack the paint....which in turn let in water.....which in turn flaked the paint....which in turn let in uv, which did the most damage, as the boat was in an open shed facing out. Given the lack of rot in the boat, if that deck were solid wood, it probably would have survived at least in part.

And this was superb plywood. Had it been today's CDX in deck and hull, this boat probably wouldn't have survived to 1975, let alone 2005.

[Charlie Jones]

another thing to be very wary of, particularly with the "big box" plywoods. I've lately seen some 1/2 ply that was made with 4 plys rather than 5. Not worth bringing home.

In fact, I was buying some supposedly "marine" fir ply at a reputable dealer and was offered 4 ply- I refused it and they found another stack of fir marine that had the 5 plies.

That was my LAST purchase of american made ply for boats. From now on it's Okume or Meranti, built to at least BS1088 standards.

And remember this- the plywood in the long run is a pretty small portion of your costs, particularly if you assign some value to your labor. You're going to spend considerable time and effort building the boat. Why not spend the small extra amount on quality materials, and build something you can be proud of and that will last?

On the last boat I built for a customer, which in the long run cost some 22 thousand including sails, etc, the cost difference between fir marine and Okume was $600. That's NOT worth not using the quality woods.

[JeffM]

Kevin,

I'm with PAR and Charlie, et al. I'm putting a year of my life into construction of a Core Sound 20, and with all the sweat I've invested, I'm putting my cash into Okume ply, Raka epoxy and proper hardware, sails and lines. The way I figure it, even if I only "paid" myself minimum wage, materials are still less than labor. Graham Byrnes (designer of my boat) suggests that, if you're short of cash (as who isn't), you skimp on things that you can upgrade later, such as hardware and cordage. There's no worthwhile upgrade for a boat built of poor materials.

Raka, by the way, is a small outfit happy to help over the phone. If you place an order with them on Monday, you may have it by Saturday.

What are you going to build, by the way?

Jeff

[Howard]

For some of us trying to sort through the chaf, it gets awfully confusing. So many contradictions. As examples; choices in plywood, epoxy and paint.

Plywood: In his Sharpie Book, Reuel Parker says it's ok to use exterior plywood, as it has the same glue as marine ply, the standards for Marine ply have been dropped to allow more voids, so there is not that much difference in quality. He even says it's ok to use AC exterior fir....one good side....one knotted up bad side, putting the bad side out and covering it with epoxy and cloth. No problem and he has built several boats that way. But he also says it's best to use the best plywood you can get. So he appears to contradict himself.

The System 3 epoxy book says the same thing about fir plywood. Just use AB exterior fir, as it's not that much different than Marine Fir. But then they say that fir will check, so unless you are going to glass the whole exterior (which they recommend you do if you used fir) it's best to use sliced mahogany plywood (presumbably the okume, meranti, etc.), for smaller boats. Maybe for big boats the cost is thought to be too high? At any rate, they also seem to contradict themselves. And to throw in another monkey wrench, much of the literature mentioned above is now dated. I'm of the opinion that standards have changed again, and as Charlie mentions, quality is going down. Is the exterior they wrote about the same as you get if you go to Home Depot top pick up a few sheets? Probably not. Personally, I have given up on buying wood from the box stores. Most of it is simply poor quality, and when I've asked if they carry doug fir for example, I was told no...."it's not the market we serve". I was told to go to a real lumberyard for that kind of stuff.

Epoxy: Universal in opinion is to use epoxy and never use polyester on any boat project. But as to using it on interior or exterior panels...they differ. On the Glen-L website, they say to only coat the exterior. Just paint the interior....that way, the wood can "breathe" and any moisture that gets in can get out. Parker essentially says the same thing. The interior is just painted or varnished. The System 3 Epoxy book and RAKA literature both say to coat both inside and outside surfaces (ALL surfaces...essentially encapsulating anything wooden) on new boats, but not on old restoration projects. Then they differ as to how many coats. S3 says 2 or 3. RAKA says a minimum of 5 coats for anything in regular contact with the water.

Paint....no need to elaborate here, other than to say there are about 100 choices and about 1,000 opinions on what product works best and where.

Even on this forum, you will get different opinions from experienced builders who agree and don't agree with many aspects of the above, or even with each other.

Bottom line is for someone trying to sort it all out, it's confusing as hell!

[Frank Hagan]

...

Even on this forum' date=' you will get different opinions from experienced builders who agree and don't agree with many aspects of the above, or even with each other.

Bottom line is for someone trying to sort it all out, it's confusing as hell![/quote']

Yep! And some people are very strong in their opinions.

So the builder has to choose ... is he building a boat he wants to last 20 years, or 5? Is this just a "first boat" to gain experience, as a kind of warm up exercise for his dream boat? Is he playing around with a design to see if it will work, then planning to build again with better materials? Does he get great satisfaction from scrounging for materials, using recycled lumber, or being able to adapt non-marine (and cheaper!) materials?

I'm a proponent of all types of boat building ... fast and cheap, slow and premuim, and everything in between. In the end, the builder decides, and some are more comfortable with living on the edge with experimental methods and designs, and others are more comfortable buying pre-cut kits.

[Barry Pyeatt]

Even on this forum, you will get different opinions from experienced builders who agree and don't agree with many aspects of the above, or even with each other.

Bottom line is for someone trying to sort it all out, it's confusing as hell!

Certainly can be and since not all products are sold in all areas supply is an issue that must be faced as well.

Most experienced builders will tell you essentially the same thing, use the best materials available that you can find if you want a project that will last a long time and be worth repairing to last longer. The biggest difference with Doug Fir marine plywood currently is still the lack of voids and edge glued plugs in the faces as well as known wood in the inner layers. Yes, its surface will check and on the exterior of the boat it needs to be glassed to prevent that from happening, on the interior it generally isn't as much of an issue but other considerations come into play for finishing the interior.

Encapsulation in epoxy serves to ideally prevent moisture from entering the plywood from either side. But it doesn't prevent moisture from entering where it is penetrated by fasteners or other holes drilled in it. Or along cut edges where the grain of the plywood will wick it in over time.

Down side is that it also doesn't allow moisture to escape from it when it does soak up some. And despite common thought epoxy isn't totally waterproof. But then neither are most other resins either.

There are a couple alternatives to using Epoxy. For finishing and laying up glass, Vinylester is used widely in the commercial boat building business for bonding glass to plywood, it is far more waterproof than any of the Polyesters and more so than most of the lower quality epoxies. It finishes out as well as you wish to finish it and is a little less expensive than most quality epoxy. However it has a fairly short shelf life. So it should be used within roughly 90 days. You will likely need to order either product from out of state sources for good product anyway so freight is still additional.

But if you wish to use epoxy for adhesieve then I would just use it thruout once you get used to working with it. It doesn't like to be starved in joints and too much clamping pressure will starve the joint. Good ole' Dap/Weldwood Plastic Resin powdered glue will work just fine and last virtually forever and is repairable with epoxy down the road when needed.

Most layup shops use peel ply or just heavy guage clear polyethelene sheeting with glass cloth layups over plywood for a number of reasons, but primarily because it requires far less work and material which saves cost and labor which is cost as well as additional weight which can be a factor. Lay up the glass with either Vinylester resin or Epoxy and lay the peel ply over it and smooth it out with a squeegie or roller and wait of it to cure. Then it peels right off and leaves what is essentially a ready for finish smooth surface. That alone will save an incredible amount of sanding and filling and prep work for a high quality finish.

When it comes to finishing, it really depends upon what level of finish you want and how you plan on using the boat. Most of these spend their lives setting on a trailer in the weather, some under a tarp of some kind. Where they sit and how widely the temperature and weather changes are will have a lot of impact on how well various paints or finishes will hold up. Hence the huge differences in opinion on finishing from people in different parts of the boating world.

Yacht paint is expensive and depending upon how much you wish to spend and how much work you want to maintain it can be the perfect choice or a total waste of money. At the opposite end is the really cheap box store closeout latex exterior house paint. It will work and if if properly applied will last a long time and give reasonably good perfomance. But no finish is good without a good foundation for the finish and good prep work. And that is where the labor comes in.

Somewhere inbetween all the extrems is a place where common sense plays a huge factor in choices to be made. Avoid all the absolute opinions expressed and listen to the reasons why the choices were made, then ask questions and weight the answers the same way. Remember, most of the builders that participate on the forums are just like yourself, first time boat builders and there are a lot of wannabe professionals with a dream who have built one boat and it floats. So they think that they can make a living doing it. Good people but lacking in real experience. So listen and appreciate that they are offering good advice from their perspective and desires, but those may be completely different from what you are looking for. The other major thing is how and where they use their boat vs. your needs and don't forget budgets. Some are literally too tight to be realistic and others don't matter. So that will weigh considerably on the answers you may get.

[PAR]

In traditional boat construction the finest quality lumber is used for the planking and deck. There is a simple logic to this concept and it's easily understood. These are the areas that will receive the harshest treatment from the elements, be it on a trailer or mooring.

Exterior grades of plywood sold in this country have a Douglas fir or western larch face with hem/fir (a hybrid and real junk) or other core lams of rather inferior stock and pretty poor construction (voids, pith pockets, sapwood, overlapping edges in the lams, etc.). When it's used as a sheathing on the side of a house, it's covered with Tyvek house wrap and another materials like stucco, brick, vinyl siding etc. and it works out to be a fine product, because it's several layers of material away from direct contact with weather, which at worst will run off onto the ground.

Boats have to live with some of the panels fully immersed in water, take a beating as it's pounded to windward, up on plane, flexes under load, dragged across beaches, etc. The typical additional protection offered for a boat is a thin 'glass skin and paint. This usually means a better grade of plywood is in order.

The cost of the planking and decking stock is a pretty small percentage of the total outlay for any boat (less then 15% generally) and cutting quality corners in this area doesn't make a lot of sense in the long run. Costs can be kept down with the use of non-marine oil paints or acrylic, poly tarp sails, rigging options, equipment options, accommodation compromises, less vulnerable structural components built of inexpensive materials, etc.

It's a difficult and well debated set of construction decisions that will not be answered here. I offer all my clients these options with the understanding of my opinions on the values they provide. Very rarely do they opt for the lowest grade of planking stock, reserving to clip the costs in other places less likely to be attacked by mother nature.

My recommendation is to look over your materials list with a keen eye for the areas that can tolerate more forgiveness in material selection. An example may be cabin furniture which can use well coated exterior grades to a high level of reprise or compartmentalized spaces used for storage or interior structural members that are reasonably protected from the curling wall of foam covered water, rolling down the foredeck.

I just releived BoatBuilders Central of 22 sheets of 1/4" 5 ply meranti (their list price is about $27 a sheet). This is less then I would have spent on good Douglas fur in some places, is better looking, better quality, doesn't check and reasonably light for it's strength.

[BobSmalser]

Bottom line is for someone trying to sort it all out' date=' it's confusing as hell![/quote']

Didn't used to be.

Working in my uncle's yard in the '50's and '60's there were few choices. Cedar, oak, red or white lead, bronze or galvy, and alkyd paint was about it. And I'm certain many of those work boats are still around today. He began building boats in 1920 and thought plywood was the devil's own work.....we didn't use it for anything important. I still don't use it when I can avoid it, because it's needlessly expensive.

If I lived in Missouri, I wouldn't be fussing with plywood at all....I'd be building traditionally.

Plywood came about after we cut all the 1st-growth forests and lacked good wood. Rotary-cut plywood became cheaper than boat-grade wood and an entire industry built up over the decades to support you building with it.

Now that situation is reversed. The forests have grown back and sawmill technology has progressed that almost every local arborist outfit has at least one in the firm. For the home builder, boat-grade wood used traditionally is much cheaper than plywood-fabric-epoxy in many, if not most parts of the country.

The plywood industry has been propagandizing for decades that you don't have the skills to build traditionally, yet they require you to accurately bevel and join those difficult plywood edges for chines and fillets. I say you'll find carvel and lapstrake slower than ply...but no more difficult at all and a whole lot more enjoyable. "Swish" as opposed to "crunch and splinter."

The party line also contains the universal truism that traditional boats leak. That's often true if you suddenly confine an old carvel or lapstrake hull to trailer life after the hull has adapted to living in water for a season at a time. That's not true at all in a new carvel or lapstrake boat built for the trailer.

You can also mix it up....plywood hull and traditional topsides or vise versa.

As I said....a well-built, well-ventilated boat built with home center materials can last a long time if you also buy one of those 150-dollar COSTCO carport tents for it to live in during the work week. Use the door canvas, too. Sun damages faster than water.

[PAR]

Bob has hit the nail on the head on this issue. Seamanship is not only knowing how to handle the boat, but also the care it requires to service an owner a long time. They need ventilation and cover from mother nature's glare. I grew up on the water and it was very common to see folks out, just after sun up, wiping the morning dew off the brightwork, about their boats. You don't see much of this any more. The average pleasure boat in this country receives 20 hours of use per year (USPS figures). This isn't enough to cover general maintenance and cleaning, let alone enjoyment. With reasonable routine and care, boats built of less then yacht standards can live a long time.

[Kevinh]

wow! there is alot more to take in than I thought. One thing I am unsure of (actually there are many), do I understand that you can cover the exterior of a small craft with fiberglass cloth, and still get a nice paint job? I suppose that would seal well, but wouldnt it leave a rough "clothish" look on the outside?