I'm a tool junkie. I read the magazines and scour different catalogs. Even when I don't have a reason to, I just like to look. The same goes for various construction and woodworking materials. I have bookmarks in my browser for various materials I "might" want to use someday. I just find the construction world and the related products interesting.
Well building a boat requires materials and tools from multiple disciplines. For a guy like me it's nirvana. The purpose of this page is to highlight some of the things I'm using, my impression of them and where you can buy them yourself. Additionaly, I'll give you my opinion on a few other things as well.
Lets start with the lumber. Depending on where you live will determine which types of lumber are readily available to you. George spec's dimensional lumber for many of his builds so long as it's douglas fir. Douglas fir is not always available in the dimensions you might need. You'll see stuff called "hem-fir" and "white wood" These are made from lesser quality trees and while fine for an interior wall framing job, it's not as strong as you would like for your boat. If it's all you can get than you do what you have to do, but if you will be building with dimensional lumber, do your best to find Douglas Fir.
Besides the obvious tropical hardwoods that have been used for boat building historically, there are many domestically available woods that are great for boat building. Things like Larch (tamarack), white oak, Douglas fir, black locust are great examples. These types have very good strength and excellent rot resistance.
We are fortunate to be in a region where white oak and larch are readily available and pretty cheap. In my area I'm paying $1 a board foot for white oak and $.60-$1 a board foot for larch. So if you are looking for lumber, besides the big box stores, the first place I would look is craiglist. Many small mill operators advertise their services their. To be honest, if you can find decent douglas fir stock at your local big box store you wont be spending that much more than having custom stuff cut. I found that when you figure in the hassle of driving, loading, unloading and then drying your custom lumber the cost are pretty close between big box and custom.
When I began this process all the different glues being discussed had my head spinning. However after much reading, research and actual use here is what I learned.
Rescorcinol is the only structurally approved, fully water proof adhesive available to the average person. If you have a joint that is critical, where nothing but the best will do, then this is your glue. It's extremely strong, fully water proof and impervious to various chemicals and fuels. The downside is that you need to mix it yourself very accurately and then clamp with high pressure and closely spaced clamps. I have used 6 gallons of this stuff so far with 2 more gallons on order and all the glue ups have been successful so far.
I'm using Aerodux 185, which is a modern rescorcinol. I say modern because it's important to distinguish it from the rescorcinols of the old days. The old style needed 70 degree minimum application temperatures and had minimal gap filling abilities. Aerodux 185 can be used down to 50 degrees and has modest gap filling properties. Additionally, Aerodux 185 can be thickened slightly if needed.
You'll read horror stories about rescorcinol and how difficult it is to work with. That well may have been true of the old stuff but in my experience with the modern stuff, it's really no problem. Yes it is a pain to have to mix the stuff up. You need to measure both resin and hardner by weight accurately but it's not hard to do. As for high clamping pressure, yes you need to really crank your clamps down but nothing beyond what the average woodworker is capable of. I've been spacing my clamps around 16" and have had no problems. It's expensive at $120 a gallon but I'll sleep good at night knowing I used the best. You can buy Aerodux 185 on Amazon or direct at CP Adhesives If you buy enough from CP, they'll probably give you a little discount!
Epoxy is the next strongest and is nearly waterproof. It's pretty easy to mix up with metered pumps. It can be thickened and has excellent gap filling properties. It's the wood butchers friend! I'll be using and have used epoxy from system 3 and total boat in this build. I'll be using it to encapsulate most of the boat along with fiberglass fabric. There really is no substitute for it's encapsulating properties. Epoxy's weakness is heat and UV exposure. As temperatures rise, epoxy weakens and can eventually fail. If you think about a boat, exposed to the sun and heat, you have epoxies two biggest enemies. You can protect it with paint or UV rated varnish to combat the UV problem but theres not way around the heat issue. Every epoxy is different and each manufacturer has their own proprietary blend. I believe you get what you pay for, so I'll keep buying brands that I've heard of and just live with the slightly larger cost. It's a great adhesive but it's not perfect. I buy my epoxy from Jamestown Distributors and have been satisfied with my purchases. I have used System Three Silver Tip epoxy epoxy and Total Boat classic 5 to 1 epoxy with good results.
Titebond III wood glue is also being used extensively in this build. I actually called the company's tech support line and discussed this glue with one of their engineers. This glue really is amazing stuff. It's very strong, nearly waterproof, fairly inexpensive (compared to the previous two) and comes premixed. It's not rated as a structural adhesive or recommended for below the water line usage but those warnings are really there for liability reasons. As it was explained to me, "we're not going to sell a $2 bottle of glue and guarantee peoples lives in open water" It's hard to find apples to apples comparisons of strength tests for each of these glues but it appears titebond is not as strong as the aforementioned adhesives. Regardless, all three are stronger than wood and the wood will fail before the glue line will. This glue is plenty strong for structural applications, especially in assemblies not under continuous loads and supported by mechanical fasteners. For example, all the frame gussets are glued with TBIII and backed up by 5/8" bolts. TBIII is flexible and will handle shock loads well. Perfect for a boat being abused by waves or accidentally run aground.
TBIII virtually eliminates the need for plastic resin glue. TBIII is stronger and more waterproof than plastic resin. Plastic resin also requires 70 degree application temperatures and you have to mix it. TBIII can be used down to 45 degrees and comes premixed. Plastic resin might be needed for more complex glue ups where more open time is required but otherwise I'll stick with TBIII. Both plastic resin and TBIII are made with essentially microscopic plastic balls floating in water. When they dry the plastic parts bond to each other and the wood. This bonding process requires a minimum temperature to take place. Since both glues are essentially liquid plastic that is how they develop their water resistance. I buy Titebond III at Home Depot They regularly have specials and I bought my last batch as a 2 gallon pack for $43.
I'm using lots of different fasteners, screws, bolts, drifts and threaded rod. I was shocked at how hard it was to find cut thread, galvanized wood screws. Cut threads are the old fashion looking wood screw where the shank of the screw is the same width as the threads. Modern wood screws have threads wider than the shank. Cut threads are beneficial in boat construction because they essentially plug the hole they make with their shank and provide more strength in shear conditions. Silicon bronze cut thread wood screws are easy to find but the prices vary widely so shop around. The best place I found for galvanized cut thread wood screws was Tacoma Wood Screw Products They are significantly cheaper than silicon bronze but more expensive than big box store screws.
I'll be using various size galvanized bolts for stuff all over this boat. So far I've used the Bolt Depot to buy my bolts online. The prices were great and shipping was reasonable and fast. I also needed 18" drift bolts for various parts of the keel. Drift bolts are another item that is kind of hard to find since there is not much demand for these types of fasteners. I bought galvanized drift bolts from Portland Bolt and Manufacturing Company. They were very high quality and custom made to my specifications but they were expensive. If I had to do it again I would try to find galvanized bar stock and make my own, there really is nothing to them.
In order to install some of these fasteners you'll need some really long drill bits. These can be hard to find as well. I bought some 40" drill bits from Associated Industrial Distributors with an auger tip. I'm told many boat builders prefer a "naked" tip drill bit, but I like the auger style. Associated Industrial Distributors had the best prices I could find and the quality of the product I received was excellent. I've only drilled a couple holes with them but they sliced through my Douglas Fir keel like a hot knife through butter.
The keel requires some really long bolts, some over 3 feet long! Since you will not be able to find bolts this size at the big box stores I had to order bar stock and make my own. I used hot rolled mild steel. Hot rolled takes galvanizing better and is easier to cut threads on. Once I cut each piece to the proper length and thread each end I'll send them off to the galvanizer for waterproofing. I bought the bar stock from Online Metals and was happy with the product. The thing to watch out for when buying heavy things online is the shipping costs. Online metals had very reasonable shipping for my 50+ pound order. It's always cheaper to have them cut down from their stock length of 10' or 20'. Even though you'll probably pay a cut cost, you'll make up for those in the savings on shipping. If you live in a decent size metropolitan area you'll be able to find a steel supply house where you can buy direct. I chose to order online just because it's so damn easy!
I'll update this page as the build progresses. It took a lot of research to find the materials I needed at the prices I was willing to pay. Hopefully this page will save some of you some time on your project!
It's going to be awesome bro !!!ReplyDelete
I bookmark this great advice for my own future project. Thank you!ReplyDelete
Are you concerned about the longevity of galvanized fasteners in a salt water marine environment? Seems to me Stainless Steel fasteners would be preferred. My experience with fresh water small boats is that galvanized fasteners don't last long...especially below the water line.ReplyDelete
I cannot speak for Scott, but according to George Buehler on page 31 of his "Buehler's Backyard Boatbuilding for the 21st Century" book he states: "Personally, I don't use stailness much, and never in fastening hull planking. I don't trust it, you see. As mentioned earlier, only the 300 series is suitable around salt water and you can't be positive what you're getting these days, with so much of this sort of thing being imported from the Orient. Also, electrolysis sometimes makes it do weird things, and it's expensive, although not as bad as bronze." Then on page 32 he says "For all permanent screwing or bolting, I always use hot-dipped galvanized steel fastenings. They're stronger than bronze, more flexible and predictable than stainless, and by far the cheapest. ...Most commercial boats and many yachts are galvanized-fastened. ... if you live in a city, buy regular bright-steel screws and bolts and take them to a galvanizing joint that has a centrifuge, which will dip and spin them dry so the coating doesn't clog the threads and slots." I assume Scott is doing it the Bueler way based on this recommendation but can't say for certain.Delete
what kind of plywood are you using?ReplyDelete
Titebond III link is deadReplyDelete
Thank you so much for such an informative piece of information :)ReplyDelete
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