I am in the process of building a bankers dory. The Bill of Materials
calls for Marine Glue.

My partner wants to use an epoxy instead. Anyone been down this road
before?

wrote:

I am in the process of building a bankers dory. The Bill of Materials
calls for Marine Glue.

My partner wants to use an epoxy instead. Anyone been down this road
before?


The newsgroup has..many times. What it boils down to, as far as I am
concerned, is what species of wood you intend to use.

White oak doesn't glue up well with epoxy. Epoxy works with mahogany and
pine, for example.

If you are going to glue white oak you might try resorcinal. It's water
resistant - not totally waterproof.

I think that before epoxy was popular, "marine glue" generally meant
resorcinal.

--
Saville

Replicas of 15th-19th century nautical navigational instruments:

http://home.comcast.net/~saville/backstaffhome.html

Restoration of my 82 year old Herreshoff S-Boat sailboat:

http://home.comcast.net/~saville/SBOATrestore.htm

Steambending FAQ with photos:

http://home.comcast.net/~saville/Steambend.htm

I think he's just amused by our quasi-religious rants on the arcane
topic of glue and wants to get it started again.

gregg wrote:

White oak doesn't glue up well with epoxy. Epoxy works with mahogany and
pine, for example.

If you are going to glue white oak you might try resorcinal. It's water
resistant - not totally waterproof.

I think that before epoxy was popular, "marine glue" generally meant
resorcinal.


Works for me.


Lew

Normally I use epoxy and a suitable filler to make it thick (gap
filling) or make it stick to horizontal surfaces so it wont run. How
ever I did find this interesting recipe for marine glue on a search of
the web....

"This composition is said to be composed of 1 part indiarubber, 12
mineral naphtha or coal tar heated gently, and 20 parts of shellac,
mixed with it. The composition is now usually employed to stop the
seams of decks after they are caulked. The old fashioned plan was to
use white lead putty for the stopping and indeed it is at this present
time occasionally used the objection to it is that it dries as hard as
a cement and cracks, the result being that water gets into the
caulking, rots it, and then leaky decks are the consequence. Moreover,
hard putty is very difficult to get out of the seams without damaging
the edges of the plank, and then in re-stopping ragged ugly seams are
the result. Marine glue, on the other band, can easily be renewed, and
the edges of the plank remain uninjured.

In using marine glue the following practice should be observed : In
driving the oakum or cotton thread (the latter is sometimes preferred
as it can be laid in finer strands, a matter of consideration if the
plank is closely laid) into the seams, the caulking iron Should be
dipped in naphtha and not in oil, as, if the sides of the plank are
touched with the latter the glue will not adhere ; naphtha, on the
other hand, dissolves the glue and assists in closely cementing the
seams. The plank should be quite dry when the glue is applied, or it
will not adhere to the sides of the seams. The glue should be
dissolved in a pot, and applied by lip ladles used for paying, two
being kept going; or the glue can be melted in the lip ladles. Great
care must be taken that the glue is melted slowly, as if it be melted
over too fierce a fire it will be spoilt. A little of the liquid glue
can be usefully mixed with the other as it assists in keeping it
dissolved. The glue that runs over the sides of the seams should be
cleaned off with a broad sharp chisel and remelted. It is not
advisable to scrape the surplus glue off the seams, as it cannot be so
removed without leaving a ragged, unsightly surface."

Now, as you are making a dory, of the style of a Grand Banks dory is
it possible that you will be using pine planks? Epoxy works well on
plywood, thin strips, and anything that is encapsulated and will not
expand and contract, such as do planked boats. However, if the
required "marine glue" is to be used to laminate or construct
structural members, than it will surely do the job, but don't try to
use it to edge glue planks together on the bottom or the sides. If you
are going to go with epoxy, don't use the hardware version tub stuff,
get the industrial strength stuff. I use G1 or G2 Epoxy depending on
what I'm gluing up, unless I am encapsulating, then I use West Systems
slow cure, because I'm old and never did move fast.
http://www.vexcel.ca/eg2epoxy.htm
http://www.westsystem.com/

That's my two cents worth.

Shawn

wrote in message
ups.com...
|I am in the process of building a bankers dory. The Bill of
Materials
| calls for Marine Glue.
|
| My partner wants to use an epoxy instead. Anyone been down this
road
| before?
|

"gregg" wrote in message
...
wrote:

I am in the process of building a bankers dory. The Bill of Materials
calls for Marine Glue.

My partner wants to use an epoxy instead. Anyone been down this road
before?


The newsgroup has..many times. What it boils down to, as far as I am
concerned, is what species of wood you intend to use.

White oak doesn't glue up well with epoxy. Epoxy works with mahogany and
pine, for example.

And glueing white oak with epoxy has also been covered a few times in this
newsgroup. It works good as long as you sand the oak across the grain. I
have never had a joint fail.

If you are going to glue white oak you might try resorcinal. It's water
resistant - not totally waterproof.

And it requires an absolutely tight fit and high clamping pressure.
Better stick to epoxy.

Meindert

"Mungo Bulge" wrote in message
...
[...]

Epoxy works well on
plywood, thin strips, and anything that is encapsulated and will not
expand and contract, such as do planked boats. However, if the
required "marine glue" is to be used to laminate or construct
structural members, than it will surely do the job, but don't try to
use it to edge glue planks together on the bottom or the sides. [...]

So what marine wood adhesives allow a little movement and creeping (other
than the fascinating historical recipe glue)?

Tim W

Meindert Sprang wrote:

"gregg" wrote in message
...
wrote:

I am in the process of building a bankers dory. The Bill of Materials
calls for Marine Glue.

My partner wants to use an epoxy instead. Anyone been down this road
before?


The newsgroup has..many times. What it boils down to, as far as I am
concerned, is what species of wood you intend to use.

White oak doesn't glue up well with epoxy. Epoxy works with mahogany and
pine, for example.

And glueing white oak with epoxy has also been covered a few times in this
newsgroup. It works good as long as you sand the oak across the grain. I
have never had a joint fail.

I have.

I did the sanding thing you are talking about when I made some laminated
ribs with White oak. They failed - right on the glue line. I suspect the
bending stresses of being under sail flexed the ribs and caused them to try
and slide along their length. But I don't know that for sure.


If you are going to glue white oak you might try resorcinal. It's water
resistant - not totally waterproof.

And it requires an absolutely tight fit and high clamping pressure.
Better stick to epoxy.

I've also used 3m 5200 successfully. Though you better not ever want to
remove the piece.

--
Saville

Replicas of 15th-19th century nautical navigational instruments:

http://home.comcast.net/~saville/backstaffhome.html

Restoration of my 82 year old Herreshoff S-Boat sailboat:

http://home.comcast.net/~saville/SBOATrestore.htm

Steambending FAQ with photos:

http://home.comcast.net/~saville/Steambend.htm

The plank problem on banker dories is that they (the planks, garboards
especially) are very wide at the ends.....in excess of 12 inches on large
dories. If any glue is put between the laps the results will be disasterous
unless you are using plywood to "plank" the dory. I have built dories
using pine. A little 3M 5200 in the laps will help keep a dory from
leaking; even so, the fits have to be pretty good. Old time dory
construction called for NOTHING in the laps; that called for really good
woodwork and they still leaked.
Dave

) writes:
I am in the process of building a bankers dory. The Bill of Materials
calls for Marine Glue.

My partner wants to use an epoxy instead. Anyone been down this road
before?


When was the design published? Is it a reproduction using historical
materials?

Dories are traditionally held together with mechanical fasteners, ie nails
or screws. When wood gets wet is swells and closes the gaps so the boat
doesn't leak. On some boats, although I don't think on dories, the cracks
between the wood was stuffed with something that would also swell up when
it got wet and seal the cracks better. It's a bit tricky because if the
gaps are too small the wood fibres will get crushed when they swell and
lose their ability to close the gaps.

Up until the 1930's all sorts of things were used to try to stop leaks on
boats. They were usually called "calking" or "bedding" but not "glue".
Glue is supposed to be an adhesive, ie holds things togehter. Glues used
to be proteins, "glue" and "gluten" being from the same latin root. So
it's the protein in wheat flour that makes four-and-water paste stick, the
protein in milk which makes casein glue, the protein in skin and scales
that makes fish glue, and the protein in hooves and hide that makes
animal glue. None of the glues is very waterproof.

In the 1930's two new adhesvies were made from (petroleum?) chemicals,
urea formaldehyde and rescorcinol. Urea formaldehyde is generally called
"plastic resin" glue. It is water resistant but will break up if heated,
say in boiling water. It is called "cold waterproof", and sometimes
"weatherproof". Resorcinol adhesvie is waterproof. Both of these are thin
glues which have to be applied to pieces which fit closely with no gaps
more than 1/8 inch. They both dry hard and brittle. When sold as "marine
glue" the urea formaldehydde is a dry powder mixed with some wheator rye
flour to thicken it. Weldwood is (or was) a popular brand. I used a
different brand on one small plywood boat (Dogskiff) in combination with
wood screws. Where the parts didn't fit well I mixed in some sawdust for
extra thickener. It worked fine. There are some limitations like having to
be above 70 degress to cure. I was building indoors in winter and threw a
tarp over the boat and put a space heater underneath to "cook" the
plastic, a common practice. I've never used resorcinol but have read
accounts of others who have. The plywood motor torpedo boats and the
plywood aeroplanes (Mosquito light bombers) used in WWII were glued with
urea formaldehyde.

Epoxy (epoxides) is one of the post war chemical adhesives. ("Glue" should
probably be reserved for protein adhesives). Epoxy is waterproof and very
strong. The drawbacks are cost and toxicity. Cost is always an arguable
point and there have been many arguments about it. It becomes less of a
factor on large boats for which epoxy can be purchased in volume.



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