Teak glue

[Scott B.]

as noted in a previous posting, some of the teak on my CD25 is showing minor signs of splitting along the grain, probably due to its age (30 years) and lack of oil which i intend to do as soon as it is out of the water. However, before i apply any oil, I want to repair the splits. I am not in the mood for replacing entire pieces (toe-rail, hatch slide). Any suggestions on the proper glue to use? I have tried Titebond III with little success. I am using Gorilla glue for other home improvements and am tempted to use it. It sticks to everything. used in the proper amount, it wont show too bad.

[Ron M.]

Polyurethane glue,(Gorilla) is fine for exterior use.I have used it laminating my bowsprit and for scarf joints on toe and rub rails. It expands quite a bit curing, but for any good glue job you need a tight joint to begin with, so..... gap filling ability is of little importance.
Epoxy thickened with silica is good also.Then there is the old stand by.....
Resorsonal, a great exterior glue......but be careful, it cures purple.
Clean your splits of dirt and debris and dry clamp to see how tight you can get them. When satisfied hold the joint open with wedges or toothpicks and use a glue injector to get the material into the split, then clamp for the proper duration, clean up what you can before it cures.
________
159 S

[aja]

Most polyurethane glues hold up to UV rays pretty well. You'll have to clamp it together, as Ron had mentioned, however.

Epoxy has terrible UV resistance and your boat is in the sun all day every day. I guess it would be Ok for the short term.

[rtbates]

I use Gorilla glue for just about everything, including glueing teak. The only thing I can add that's in conflict with the advice so far, is to NOT clean up excess till it's fully cured. IF you try to clean it up as it cures you will drive it into the grain and make getting rid of it much more difficult. I've learned to just let it expand and it will form a bubble that is only attached at the joint. I then use a sharp chisel to lift it from the joint by prying under the bubble at right angles, Then run the chisel point along the seams.

wet one or both surfaces before applying.

[marka]

the reason teak is so difficult to glue is the oil in the wood. the popular wisdom is to wipe the glue surfaces with acetone to remove the oil just prior to gluing.

[John Vigor]

The only structural glue I would recommend for exterior wood-to-wood construction is resorcinol. Let me quote from one source:

"PRF (resorcinol) adhesives are mainly used in the production of load-bearing timber structures where a maximum of weather resistance is required. With a proven track record such as this, these adhesives have developed a long and successful history of use in plywood laminating, boat building and wood aircraft construction. Unlike the epoxy family of adhesives, PRF’s are completely UV-resistant, outlasting epoxies in high-weather-exposure applications almost ten to one."

Resorcinol adhesives are represented by such products as:
Weldwood Resorcinol (DAP Products)
Aerodux-500 (now called Prefere’)
G-1131 (also called Penacolite or Cascophen)

Epoxy is badly affected by the sun's UV rays and starts melting at relatively low temperatures. Lin Pardey risked expensive lawsuits when he took on the West System epoxy company in his book on boatbuilding, and listed the reasons why epoxy is unsuitable for wooden boatbuilding purposes when exposed to sunlight and heat. He used resorcinol for his home-built boats that circled the globe.

Epoxy has gained such a popular following that it has almost become blasphemy to criticize it, so I don't expect to make any converts here, but at least the combined intelligence of this board should be aware of resorcinol's superior qualities. We might also ask ourselves a simple question: howcome marine plywood is glued with resorcinol, not epoxy?

I built five marine ply dinghies with Aerodux and Cascophen and found those resorcinol glues very easy to work with. If I'm not mistaken, the teak tillers supplied with the smaller Cape Dories were also put together with resorcinol, and mine, at least, is showing no signs of delamination after 25 years outside in all weathers.

You might want to read a relevant piece from the Pardey's website:

http://www.landlpardey.com/Tips/2007/April.html

Cheers,

John Vigor

[tartansailor]

That is absolutely correct. The trick however is to get the
stoichiometric relationship correct; that means a good scale.

Dick

[Sea Hunt]

Richard:

This is a family viewed website. On behalf of all of us who have young children and/or grandchildren, please refrain from using language such as "stoichiometric".

Thank you.

[John Vigor]

Sea Hunt:

I am astonished (a) that you know the meaning of stoichiometry and (b) that you would admit it in public. No decent-living person ever gets to hear that word in the kind of general conversation that epitomises the family values you pretend to espouse.

Those of us with clean minds, who now come upon the word for the first time, can take a highly educated guess as to its meaning. Like Gaul, it is divided into three parts.

The last part, metry, refers of course to measurement. The first part, stoic, refers to people who don't mind doing without life's luxuries, and who are prepared to suffer as long as they can boast about it to their friends. The middle part, hio, refers to something that shouldn't be discussed on a nice bulletin board like this one.

I mean, the upshot is that those who mention stoichiometry as part of their lifestyles are admitting that they go around measuring the hios of stoics. And in public, too.

Disgusting behavior, Sea Hunt. As I said, I'm surprised you even knew about it. I think I'm going to write to Sarah and see if she can get it banned.

Any more loose talk like this and I shall take it upon myself to see that you are drummed out of the Cape Dory fellowship.

I remain, amazed and disgusted,

John Vigor

[Markst95]

I tried glueing a crack in my combing with gorilla glue and it didn't work, came apart. I sanded out the glue and used epoxy with microballoons(it matched the color better then colloidal silica) and it seems to be very strong. Covered with Cetol teak.

[Russell]

I will second using epoxy. For this kind of repair I use teak sawdust as a filler for color matching, works great. BUT if you leave your teak unfinished epoxy will turn yellow in the sun.

[Oswego John]

When I have to glue up a cracked piece of wood, first I generally drill a small hole in both ends of the crack. Doing this tends to relieve the pressure on the crack so it won't continue along the grain.

Before refinishing the wood, I sometimes tamp wood putty or filler of a close color into the drilled hole, using the head of a finishing nail as a tamper.

It always amazes me to discover that a word I had always considered, for years on end, to have a mild and innocent meaning would, in reality, possess a vulgar significance.

Up till this point in time, I had always believed that the word hio (yech, forgive me ) was a metallurgical prefix for silver.

Have a good one,
O J

[Sea Hunt]

Mr. Vigor:

For the record, and I say this with the utmost amount of jest that I am able to muster after not being able to sail (or dive) today because of really inclement weather , I am not the offending party referenced in your post. My post was directed at the author of the offending word (which I shall not here yet again repeat) and was intended to deter the miscreant from further offending usage.

That said, I will soon want to try to "scarf in" (I think this is a safe family OK'd word) some teak on the starboard rub rail and toe rail of S/V Tadpole. If I understand your initial post correctly, I will use one of the three referenced adhesives to connect the new teak to the old teak. There appears to be one screw within the area that I must cut out (another boat hit me while on my mooring - no idea who). My plan is to use the adhesive to bond the teak wood to teak wood and epoxy to bond the wood to the hull. I will then reaffix the screw and put on a teak "bung"( ) over the screw. Does this seem OK

[tartansailor]

First, John, thank you for coming to my defense.

Second, It seems that someone flunked the analytical section of Chemistry 101.

My integrity has been put in question. That is intolerable.

May I respectfully refer my scientifically challenged friend
to a good dictionary, if you have one, and if not try google
before defaming one's reputation.


Dick

[John Vigor]

My plan is to use the adhesive to bond the teak wood to teak wood and epoxy to bond the wood to the hull. I will then reaffix the screw and put on a teak "bung"( ) over the screw. Does this seem OK

Yes, resorcinol would be the best glue for the teak-to-teak bond, in my not-so-humble opinion. Swipe the teak with a cloth wetted with acetone just before you apply the glue, to get rid of the teak's natural oils. I am never sure how much this helps, but I've seen plenty of professionals do it and I dare say it can't hurt any.

I wouldn't use epoxy to bond the wood to the hull. I'd use 3M 5200. It's waterproof, unlike epoxy, and plenty strong enough.

And yes, do put a bung over the screw. You can buy 3/8" teak bungs ready made, or you can buy a special little bit to put in an electric drill and make your own bungs from scraps of teak. Some people like to fix the bung in place with a dab of varnish. I prefer a dab of epoxy, even if it is a nuisance to make up such a tiny batch.

Make sure to line up the grain of the bung with the grain of the wood before you tap it in place with a small hammer. Don't knock the bung all the way in. Leave a little protruding. Most of us remove the protruding part of the bung, once the varnish or epoxy has set, with a sharp chisel, leaving just a small sliver to be sanded down level with the rest of the wood, but be very careful.

Rather take off too little with the chisel than too much. Quite often the chisel will lift off a chunk of the bung from below the level of the surrounding wood, and then you're in trouble. Start all over again.

Cheers,

John Vigor