|
"Marine Glue"
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? |
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. -- ------------------------------------------------------------------------------ William R Watt National Capital FreeNet Ottawa's free community network homepage: www.ncf.ca/~ag384/top.htm warning: non-FreeNet email must have "notspam" in subject or it's returned |
Epoxy is Marine Glue. There are several other kinds of marine glue, but epoxy is the best. Gorilla glue will work, but only if you make perfect joints, because it loses a lot of strength if you start using to fill a small void and glue at the same time. Gorilla glue also has a short shelf life after its been opened, it reacts with air. Polester resin will work but is not as elastic or strong as epoxy. There are a lot of good epoxies out there, but I've had my best luck so far with West System. I have had no problems with getting the last 10 oz's out of a gallon like some epoxies. Also the the pump spouts that automatically measure are well worth the money. They will save you money down the line, because you will be able to quickly measure out and mix small batches when you are just gluing a small piece. Or mix a little more real fast because you didn't have enough the first time. Or not add too much hardner and have your cup of mixed epoxy go hard before you use it. On 8 Jul 2005 15:16:36 -0700, 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? |
|
On Sat, 9 Jul 2005 10:30:30 +0100, "Tim W"
wrote: "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 Hi, Have a look at Sikaflex 221, and their tech info. cheers, Pete. |
| All times are GMT +1. The time now is 09:47 AM. |
Powered by vBulletin® Copyright ©2000 - 2025, Jelsoft Enterprises Ltd.
Copyright ©2004 - 2014 BoatBanter.com