Marine glue for wood boat

I am in the process of starting a wood boat project,and would like to know if anyone has ever used 5200 for constructing a boat out of cypress wood.?This boat will be lapstrake on oak frames...Thanks for any help...I always used welwood resorcinol glue on plywood in the past.

 

Welcome to the forum.

3M-5200 is a adhesive/sealant, not a glue. Though it has very good adhesive properties, it's also pretty flexible compared to real adhesives or glues.

With lapstrakes, the goo of choice on traditional builds is polysulfide, not the polyurethane used in 3M-5200. 3M-101 is a common choice, but again, this is just a sealant, with some adhesive qualities. On a traditional lap build the goo in the lap is just a gasket and not the thing that hold the boat together.

If this is a "glued lap" style of build, the only choice is epoxy in the laps. These types of builds, use a wholly different set of design parameters, compared to the traditional plank over frame lap build. In fact, if designed properly the glued lap method, can eliminate the frames entirely. This save a lot of weight, but more importantly also a lot of building effort, plus the epoxied laps, insure it'll stay water tight for decades. A glued lap doesn't need any fasteners in the finished product also, further insuring longevity.

 

Hi,
Just saw this post & it caught my eye. Not many folks do lapstrake any more, so it's neat that you are.
I'm not sure as to your experience level, but it'd pay to do some studying on boat construction with epoxy, as at times, oak can be a little trickier than some woods to glue to. Though when done right it's as strong & has as long a life as anything else.

If memory serves, there are a few articles in the WEST System magazine "Epoxyworks" on the topic. Look in the 'Epoxy Techniques & Materials' section @ www.Epoxyworks.com
Ah, and System Three Resins has some good info as well. Ditto on WEST System's main site. Plus you can download their book on boatbuilding for free. It's a classic, & I've owned the hard copy for a few decades now too..

I applaud your building a boat from the keel up (or down). It can be a lot of fun, & I surely learned more than I ever imagined I would.

 

I have a glued lapstrake underway currently.

 

What 'Cypress' are you using? Not sure we have your species this side o' t' Pond, but maybe. May be someone could guide you on the exact type. The available ones ie grown, in the UK are not generally used in boat construction. However Cypress is a bit of a generic species definition like Cedar!! and which exact one matters with boats on the whole. Might be better with modern 5 ply (gaboon) as it will resist splitting in the middle of the plank better.

American white oak? Again if it was our European oak it would be pretty hard but durable. Trad construction in UK was often larch on oak.

2nd PAR for modern lapstrake/clinker builds, use epoxy. Far superior in cohesive strength, (compared to resourcinols and most other w/proof adhesives) so you can keep things a bit lighter.

 

Thanks folks for your replies...The cypress ,is a 5/8ths finished plank that will be beveled over and attached to the oak timbers(ribs)...its a simple old style Banks Dory....I have built marine plywood boats in the past,and they were fastened with bronze screws and Weld Wood resorcinol Marine Glue(Purple looking 2 part) which bonds like steel... I am not sure what kind to use on a solid cypress boat...I need a name of a glue, so I can research its properties, thanks for any help..The original plans called for "white pine",but that wouldn't work for a southern built boat..Juniper was my first choice, but trying to find enough to build a boat seems impossible...

 

Welcome, newbies.

I used to build with Weldwood Resorcinol Glue but it is hard to find nowadays. I have gone over to West System 105 epoxy and am very satisfied with the results.


On this side of the pond in the American South, when we call something cypress, it is our common Southern Bald Cypress.

Cypress has some problematic properties which have been discussed elsewhere on the forum, the weight per board foot not being the least of them, though it has worked well for me as stringers. I like Western Red Cedar and Douglas Fir(for stringers). Douglas Fir marine plywood is also at the top of my LOM.

http://en.wikipedia.org/wiki/Taxodium_distichum

http://en.wikipedia.org/wiki/Taxodium_distichum#mediaviewer/File:Baldcypress_range.jpg

 

Up until the last twenty years,Juniper hulled Shrimp Boats were used in the Gulf with great success...When I was younger,my dad had a 25 ft Shrimp boat built out of "Black Cypress"...planked and caulked hull...lasted longer than our shrimping venture...We would pull the boat yearly and re-caulk it...The system on the bottom will be tongue and groove,and lapstrake sides. So you think 105 West is the answer?

 

WEST System is good stuff, & has the advantages of a well known name, as well as being one of the early pioneers in terms of using epoxy for boat building.
They have a number of formulations, which is more or less another way of saying curing speeds, based on ambient temperatures. And also make some slightly more exotic blends for "professionals", known as Pro Set. Most of which are designed to be post cured, & achieve higher physical properties, thusly.

In addition one of the other big names is System Three Resins. Who in addition to having a product line designed primarily for wood/epoxy construction, make a sister line aimed more at cored composite construction. Phase Two I believe it's called.

Gurit aka SP Systems is another huge one. Although at least as far as most of the small scale marine industry, they're primarily European in terms of market orientation.

There are also MAS, Raka, East System, & a few others out there, including some which I just discovered on here the other day. http://fiberglasssupplydepot.com/Epoxy.html?objects_per_page=50

Various makers "tune" the properties of the resin to match the application. Meaning that they'll have it chemically formulated to have stretch & flex characteristics closely matching the reinforcing material which it's being used with. Be said material; wood, fiberglass, carbon fiber... And it pays to look into these properties of the resin, in addition of course to it's cure rate vs. the temperatures where you'll be using it.

Also, one other primary thing to look at is it's viscosity. As some resins are very thin (runny) for applications such as infusion & vacume bagging. While others are thicker, & lend themselves better to being applied by hand, hand layups, use on vertical surfaces, etc. Or even some semi-super specialized formulations, which cure ultra clearly & are designed for things like mirror finish bar top coatings.

Obviously this is an abridged info list about epoxies, but it's a place to start, in terms of doing some research on what's out there on your own. And most of the companies have both electronic, & hard copy information available on what they sell. In addition to how-to documents, & videos - and data bases there of.

 

We have a 20' sloop built by Paul Rollins circa 1987. Weight is around 3000 lbs with an 800 lb lead shoe. The hull is lapstrake, planking is plywood with Boatlife polysulfide in the laps and copper rivets. No frames; structural bulkheads about 2' forward of the transom which also serves as the forward end of the lazerette, midships which also serves as the aft end of the cabin, and about 4' aft of the bow.

No indication of any structural problems so far.

 

Here's a link to an epoxy comparison test which I ran across a while back, after I "discovered" East System epoxy, & was curious as to how it compared to the other brands with which I was familiar.
http://www.oneoceankayaks.com/Epoxtest.htm
It's a place to start, but do your own digging, until your mind's at ease.

 

The Glue used by the designer is Bostik 920....and I don't think they make it anymore...Ca. doesn't allow it! Anyone know a Bostik supplier?

 

Uncivilized, that epoxy test is sited often, but is full of flaws and assumptions that simply aren't very helpful, not to mention doesn't include the "usual suspects" in the discount portion of the industry. Folks using MAS, West System and System Three, simply haven't performed the research yet and are seemingly willing to pay 2 to 3 times as much per gallon, as products that have the same physical properties.

 

So,what would you use for an adhesive?...Remember its cypress planks with tongue and slat groove...and the side are clinker....

 

You are describing traditional construction, not glued plywood.

Clinker/lapstrake planking from boards (rather than plywood) should be mechanically fastened throught the laps and to the frames/ribs. Copper rivets and galvanized clench nails are two methods for the laps. As PAR mentioned anything in laps should be a gasket rather than and adhesive. The planks need to be able to move a bit relative to each other or they may split with major changes in moisture content. Traditional clinker/lapstrake construction generally relies on a good fit and swelling of the planking to prevent leaks.

Planks can be screwed, riveted or nailed with ring shank nails to the frames/ribs. No "goo" is needed between the planks and frames/ribs.

Bottom planking will change width with moisture content changes. If you try to glue it together into a single slab it will probably crack. Anything in the joints needs to be very flexible.