Resorcinol glue

[Egon]

Question: Does the powder have a shelf life?:confused::confused::confused:

Thanks.

[Mrleft8]

Oh yes.... If it just sort of clumps up and looks like sour milk when you mix it, it's gone bad. I found this out right in the middle of a huge glue up.... What a mess!

[John Boone]

It always looked more like dried blood to me :D

Here's a link that might be useful.

http://www.dap.com/docs/tech/00030205.pdf

Don't get it in your eyes! Don't ask me how I know :eek:

[kc8pql]

That's why it's not a good idea to buy that dusty can from the local hardware store. Go somewhere that sells enough of it to have fresh product on the shelf.

[SchoonerRat]

I've always shied away from Resorcinol. I heard long ago that environmental conditions needed to be nearly optimal for proper cure, but mostly I just don't like the color. It makes glue joints jump out and bite you.

[Egon]

Thanks for the replies. The year old can I tossed in the scrap wood box will remain there.:D

[Mrleft8]

There's a "made on" date on the can. If you're going to use it all, then a year is OK. I can't remember what they said when I called the company, about shelf life, but it was more than a year... The can I had was about 10 years old...

[Thorne]

The Weldwood powdered "plastic resin glues" have a shelf life of 1 year, but I thought that rescrcinol could be stored longer.

Updated - just looked at the resorcinol data sheet pdf, it says shelf life is "1 year minimum".

http://www.jamestowndistributors.com/userportal/woeimages/00002710.jpg http://www.jamestowndistributors.com/userportal/woeimages/00002696.jpg

[patrick.blanchard]

When visiting w/ the company engineering support, he said 1 yr. That's the 'official' shelf life and the length probably has a lot to do w/ liability for the company (my opinion not the engineer's). I purchased some cans from one vendor and it had the same batch number printed on the lid as did my cans from a wholesaler. It's possible that Dupont runs a huge batch and then ships out to distributors. In reality the '1 yr.' shelf life is probably a lot longer, and who really can say. If stored properly then it seems to reason the shelf life is much much longer.

Since we are on the topic of this glue, I'll share more details of my discussion w/ the engineer.

This is the only glue available that can maintain it's tremendous strength anywhere humans can take their boats on earth. It's not that hard to maintain proper gluing conditions and w/ a simple wood hygrometer you can be assured your wood is within the range of moisture before gluing. If the wood is wet or too dry, it's easy to bring the wood to the proper range in a day or so.

The 0.005" glue line is the toughest one. The engineer simply said - don't overclamp.

I discovered a tiny strip of construction paper (find some that measures 0.005" using a micrometer) placed here and there will prevent overclamping and a thin glue line. I tested this out over a few weeks, did some research on construction paper materials, measured glue lines after cutting into them on the band saw, and the paper strips work very well for me. No more guessing about clamp pressure and for big timber w/ warps, the glue line is consistently 0.005".

The use of any nail w/ copper is a bit worrisome. There is a warning on the bulletin about no exposure to copper alloys. This is the main reason for my call into the company. Copper will prevent proper curing of the glue. So, w/ nailed edge planks, SS316 is the preferred alloy. Also, copper based wood preservatives may interfere too - but these may be safely applied after a week or so of curing.

Lin Pardey has an excellent essay on modern adhesives well worth the price of his book on traditional boat building.

Resourcinol glue is easier for me to apply than any epoxy. I get a bad enough migraine when around epoxy that it makes me lie crying in a fetal position in some corner for a week. Also, I don't like woodworking in a hazmat suit. With a little bit of air circulation during the mixing of resourcinol, I can't even smell it. And when I do smell it, it's not bad. I use cotton gloves while working which are very comfortable. I use an old Elmer's Glue bottle for laying the bead of glue and easily have over 1 hour work time before the final clamp. The glue will thicken during work, but it is the loss of moisture and not the chemical curing - so don't mistake air drying of the glue for the chemical curing of the molecules.

Hope this helps.
patrick

[Thorne]

From Bob Smalser's many posts on the subject in this Forum, temperature requirements are also critical -- he suggests using old electric blankets wrapped around the work to keep temps in the required range (70+ degrees F?).

My one experience using the plastic resin glue was not a good one, but I'm pretty sure it was the temperature requirement over cure time that I failed to meet. These glues are not as forgiving as epoxies and polyurethanes -- follow instructions carefully!

[Wayne Jeffers]

. . . That's the 'official' shelf life and the length probably has a lot to do w/ liability for the company (my opinion not the engineer's). . . .
Or, it may be the desire of the company to sell you another can sooner than would otherwise occur.

This is certainly the case with many (not all) pharmaceuticals.

Wayne

[patrick.blanchard]

From Bob Smalser's many posts on the subject in this Forum, temperature requirements are also critical -- he suggests using old electric blankets wrapped around the work to keep temps in the required range (70+ degrees F?)...!

It's a matter of how much of a hurry I'm in when waiting for the glue to cure. The engineer mentioned it will cure at below 70F, but it takes longer. Over 100F will be faster, but the end result is the same - the most durable and dependable glue line possible on earth. No other gluing system can match it.

[spirit]

Anyone planning to use resorcinol glue should read Larry Pardey's Appendix C ("Superior adhesives for the millennium") in his elegant tome "Details of Classic Boat Construction," Pardey Books, 1999. He believes that "winter-grade" resorcinol is a far better adhesive than epoxy, and he makes clear that this adhesive can be used at temperatures as low as 50 degrees F, with gaps up to 1/16 inch, or with tight clamping pressure if desired.

The article can be downloaded from http://www.cpadhesives.com/media/ClassicBoatAppendix.pdf

This is not the same resorcinol as Weldwood, Borden or DAP, which Pardey calls "summer-grade resorcinol."

[patrick.blanchard]

This is not the same resorcinol as Weldwood, Borden or DAP, which Pardey calls "summer-grade resorcinol."

I could not find the gap filling kind he discussed, so I am using DAP. Also, I don't understand the chemical difference between the two (besides the gap filling capabilities and temperature difference).

[Egon]

:DAgain, thanks for all the information. It has been very helpful.:D

[Fishpot]

I have made hundreds of wood decoys using many kinds of wood. These are working decoys. Used several different kinds of glue. 2 part resorcinol is the only one that has NEVER failed. You can imagine the treatment working decoys get. Some of them are over 40 years old and still in 1 piece. And you can imagine the conditions of manufacture too. Way back we learned to just mix some sifted sawdust in the resorcinol and you could even fill small gaps in uneven fit situations. In boats I have used it to repair even old growth cypress and "carolina juniper" aka white cedar. Bait heavy and have a long soak, Fishpot

[David G]

It's been many years since I did my research on resorcinol, but I do remember a good bit of it, so I'll add a couple things about shelf-life. First, I've used it when it was several years old with no issues, so it can last longer than the nominal 1-year specified. Second, in my talks with the tech folks at DAP, I remember them mentioning two major factors which affect shelf life. First is moisture. The more moisture that reaches the stored material, the quicker it becomes unusable. Second is temperature cycling. The greater the temperature swings, and the more of them, the quicker the glue apparently ages.

So - what I took away from it was this: pour the glue, then close the container... soon and well; store the glue in conditioned space if at all possible. Don't leave it in the garden shed to bake in the summer and freeze in the winter.

[W Grabow]

"Resourcinol glue is easier for me to apply than any epoxy. I get a bad enough migraine when around epoxy that it makes me lie crying in a fetal position in some corner for a week. Also, I don't like woodworking in a hazmat suit. With a little bit of air circulation during the mixing of resourcinol, I can't even smell it. And when I do smell it, it's not bad. I use cotton gloves while working which are very comfortable. I use an old Elmer's Glue bottle for laying the bead of glue and easily have over 1 hour work time before the final clamp. The glue will thicken during work, but it is the loss of moisture and not the chemical curing - so don't mistake air drying of the glue for the chemical curing of the molecules."

I have used resourcinol that was several years old and used it at temps of 60-70 degrees with no loss of properties. I do store it carefully and don't try to fill gaps with it. I built one boat using only resourcinol adhesive.
I also use epoxy, but it scares me. I approach it like I am doing surgery: gloves, mask with organic filters, glasses, all items pre-positioned, initial dry run. Recently I was wearing a new pair of levis while using epoxy. Afterwards, although there was no visible spot on the pants, I developed a red itchy spot on one leg. Despite washing the pants twice, the redness and itch quickly returned when I put the pants back on. Had to throw them away. Epoxy is great, but very toxic. So I use a variety of adhesives to minimize my exposure.

[tom arnold]

I am wooden aircraft rebuilder and am required by the FAA to use resourcinol in my work. I have a single situation where I cannot apply the extreme clamping pressures that is traditionally required (50#/in.sq.) for our purple glue without collapsing a wing structure (not good) and was excited to read Spirit's post and referrel to the "Adhesives for the Millineum" by Larry Pardey. I was especially delighted to read that extreme pressures were not needed and that it even had gap filling properties. I promptly bought some cascophen resourcinol from Aircraft Spruce, the only distributors I found in the US, and read the instructions that came with it.

I was also shocked when, in reading the spec sheet, there is nothing, absolutely nothing about lessened pressures required. Cascophen requires the same high pressures that all resourcinols need. I called the manufacture and talked to both the sales and the lab technicians and they told me that the information I was operating on was not accurate and to do so would give a very weak joint as the high pressure is critical to the bond. Where is Mr. Pardey getting HIS information? It is not even remotely close to the manufacture's lab tests and product design standards.

I was really sorry as I am now back at ground zero and a little wiser about experts.

[andrewe]

Tom A, I also started with recorcinol gluing repairs in aircraft.Mostly Jodels and DHs+ homebuilts and autogyros. And was puzzled by the references to 'gap filling' in recent posts. Assumed things had moved on, but have not bothered to check spec sheats as I no longer use the stuff.My boat building is composite ply, so epoxy is the way. Nice to hear that the info is the same. Larry P is not keen on epoxy, perhaps overly.
A

[Captain Blight]

Apparently Ærodux 500 will fill gaps of about 2mm with no loss of strength, and does not require the very high clamping pressure that Cascophen or Dap will. But I believe this is the only resorcinol for which this is true, and I further believe it's not readily available Stateside.


We really need to convince the WBS to become the US Distributor. Would be a win/win situation, I believe.

[Bob Smalser]

Are Your Glue Joints Repairable?
http://www.sawmillcreek.org/showthread.php?t=21822




General Notes on Glues and Goos

Resorcinol: The marine standard. If you can get 70 degrees F or higher for an overnight cure and consistent and high clamping pressure with no gaps, you won’t go wrong using it. Likes wood at 10-15% EMC, according to Navy tests. Long open time. Repairable with epoxy. Ugly red glue line.

Marine Epoxy: The repair and restoration standard. Bonds well to a wide variety of materials, and usable in almost all flexibility and temperature conditions. Needs no clamping pressure, only contact…fills gaps well. Likes wood below 12% EMC. Repairable with itself, joints can often be broken apart for repair with using heat. Clear glue line and can be dyed to match the wood. Controllable open time with different hardeners. Slightly permeable to water vapor and there are reports of failures in fully saturated wood and with White Oak. Very sensitive to UV, requiring protection.

3M 5200: A rubbery, polyurethane sealant in various colors with adhesive properties sometimes used as a glue. Fails as a glue under water saturation without high clamping pressure, and without the proper strength testing I couldn’t do here, it’s not recommended as a stand-alone marine glue. Repairable with epoxy.

Liquid Polyurethane: Gorilla Glue, Elmer’s Probond, Elmer’s Ultimate, and others. Versatile in temperature and bonding wet wood with moderate open time, these glues aren’t rated for below waterline use but initial use shows potential as a marine glue. Likes high clamping pressure and fits similar to resorcinol…it won’t fill gaps. Will successfully glue green wood at 30% EMC. Repairable with epoxy. Noticeable, yellow-brown glue lines.

PL Premium Construction Adhesive: This polyurethane goo shows promise as a marine glue with further testing and use. Works like 3M 5200 but cures and behaves like liquid poly. Appears to bond well to everything epoxy does, and more where epoxy and liquid poly won’t, perhaps because of a higher isocyanate content…it bonds to difficult surfaces only cyanoacrylate super glues will bond to. The only general-use glue I’ve found that will bond difficult aliphatic-contaminated surfaces. Appears flexible to temperature and moisture content with gap-filling ability, but as a construction adhesive, its open time is shorter than liquid poly. Appeared to like high clamping pressure, and unlike other glues, wouldn’t bond at all without at least some. Repairable with itself and epoxy. Glue line as in liquid poly.

Urea Formaldehyde Plastic Resin Glue: The old interior furniture standard, and in older marine applications that required well-blended glue lines. Still preferred by many, as it is a no-creep glue easily repaired using epoxy. Long open time, it needs tight fits and 65 degrees F or higher for an overnight cure…it doesn’t fill gaps. Best glue line among them all and moderate water resistance still make it useful for protected marine brightwork applications. A relatively brittle glue and UV sensitive, it requires protection….but its brittleness is an aid to reparability, as joints can be broken apart for repair. An inexpensive powder with a short, one-year shelf life.

The Titebond Family of Aliphatics: Convenient. No mixing, just squeeze. Short open times, fast tack, and short clamping times. Flexible in temperature and to a lesser extent in moisture content, but the bottled glue can freeze in unheated shops. A flexible glue, it has been reported to creep under load, sometimes several years after the joint was made. The latest “Titebond III” appears to be a stronger glue than its two predecessors. Difficult glues to repair, as they won’t stick to themselves and no other glues will except cyanoacrylates, which are too brittle for general use. Epoxy and fabric aren’t bonding to aliphatic glue lines in marine strip construction, compounding repair difficulties. While not definitive, the new PL Premium appears to bond well to Titebond III residue and is worth pursuing by those repairing old white and yellow aliphatic joints.

[tom arnold]

I have a question regarding Patrick Blanchard (previous poster) use of .005" paper strips to "prevent overclamping" of a glue line. I do not understand how that works and he has no email as I tried to PM him. Is this a common technique? Can anybody explain it? Many thanks in advance.

[Feazer]

I will throw in my .02 cents here about Resorcinol.

The product is moderately hygroscopic and therefore will try to suck up atmospheric moisture resulting in product that fails to blend or mix properly (lumpy )

Phenol-Resorcinol is the glue preferred by the U.S. Navy and a product that has been tested to death with white oak, plywood you name it. Bottom line is nothing performs as well with oaks and the tannins that reside in them. Temps are critical for proper cure and in controlled atmospheres like the Navy ship builders are able to maintain they look for apprx. 90-100° but around 70° is the recommended low cut off. Clean reasonably tight joints or faying surfaces and well controlled clamping pressure are necessary to achieve full performance with this glue. The glue line is distinctive unlike epoxy but to my eyes that red glue line means QUALITY .

[Torna]

(cough cough) Aerodux 500/Prefere (http://www.chemical-supermarket.com/Aerodux-500-Medium-Speed-Cure-p102.html) $192 per 1/2gallon!

[keyhavenpotterer]

Winter Grade Resorcinol

The winter grade small gap filling resorcinol adhesive Larry Pardey refers to in Classic Boat Construction as Aerodux 500 is available. It is now called Prefere 4050 F Resin Solution and is mixed with Prefere 5750 Liquid Hardener.

There are three advantages of Prefere resorcinols for boat builders over other resorcinols.

1. The resin comes as an already made liquid (not a powder) and is simply mixed with the resin in a one to one ratio.
2. The fast setting resin denoted 4050-F (for fast) can be used at lower temperatures than other resorcinols for use when boatbuilding in a cold shed or to achieve a faster set at higher temperatures to work quickkly or so you dont have to run heaters for so long in the winter or maybe the glue job can be now done during the higher ambient temperature during the day.
3. The resorcinol can have fillers added for minor gap filling.


The "normal" Prefere resorcinol is called Prefere 4050 -M (for medium setting)

From the data sheet

1. Pot life in hours for Prefere (was Aerodux) resins at different temperatures in degrees

4050 F

1.5 hrs @ 20C/68F
4hrs @ 15 C
6hrs @ 10 C
9hrs @ 5 C

4050 M

1hrs @ 30 C
2hrs @ 25 C
3hrs @ 20 C
5.5 hrs @ 15 C

2. Assembly time

4050 F

0.5hrs @ 15 C
0.75hrs @ 10 C
1.5hrs @ 5 C

4050 M

0.5hrs @ 25
0.75hrs @ 20
1hr @ 15 C
1.5 hrs @ 10 C

3. Clamping times

4050 F

0.5hrs @ 30 C
1.5hrs @ 25C
2.5hrs@ 20C
5hrs @ 15C
7hrs@ 10C
24hrs@ 5C

4050 M

1hrs @ 30C
3hrs @ 25C
6.5hrs@ 20C
8.5hrs@ 15C
15hrs@ 10C

4. Clamping pressure required

0.6-1 N/mm2 for softwoods
0.8-1.2 N/mm2 for hardwoods

5. Moisture content of wood to be glued

Max range 6-25%. Optimum 12-16%

6. Viscosity when mixed - tomato paste/ peanut butter. China clay or fine chalk can be added for minor gap filling or to increase viscosity.

I purchased mine in November 2009 from

Alansons
7 Flowers Hill
Brislington
Bristol
England
UK
BS4 5JJ

Tel 0117 971 1364
Email sales@alansonsuk.com
www.alansonsuk.com (http://www.alansonsuk.com/)

They are an adhesive supplier. They also keep Aerodux 306/308 adhesives if your looking for these also.

I purchased 5Kg of adhesive (2.5Kg Resin/ 2.5Kg Hardener) for £70 approx £14 per litre. This is half the price of Epoxy typically£25/ litre in UK. If you want Aerolite 306 once made up it works out at £6/ litre if you buy 5litres or so. As with all adhesives the more you buy the (much) cheaper it gets. Balcotan polyurethane from another source is the current fashion in laminating is £40/ litre and is dosent have the proven durability that Resorcinol now has proved. So Resorcinol the daddy of all adhesives is the second cheapest, beaten only by Aerolite. Resorcinol glue line is much thinner so less adhesive will be used in any glue job than epoxy increasing cost savings. It can be wiped off with a wet sponge before cured unlike epoxy. Most epoxy smells and can lead to sensitisation, resorcinol much less so. Larrys words are still correct. Each glue has its place, but if your looking for "winter grade Resorcinol" its still available.

Its made/ owned by Dynea. They are based in Finland but the adhesive is made certainly in different parts of the world it seems though they dont seem to be big in US. They do have a distributor in Canada it appears.

UK agent

Dynea Uk Ltd
Denbigh Road
Mold
Flintshire
CH 7 1 BF

Tel 01352 757657

My sealed resin tin was purchased in November 2009 the Expiry says August 2013. The Hardener tin says Expires March 2011. It says on the sheet it lasts at least 12months once opened.

Another retail source in the UK is

John Burn
74 Albert Road
Stechford
Birmingham
B33 9AJ

Tel 0121 508 4144

www.johnburn.co.uk (http://www.johnburn.co.uk/)


The 4050 -S (S for slow) is for working in very hot summer conditions - it gives longer open time and is for use if your boatbuilding in these conditions.

I hope this helps those looking for it http://www.woodenboat.com/forum/images/icons/icon7.gif.

[keyhavenpotterer]

In the UK £70 buys 5 litres Winter Grade Resorcinol and there's 3.79 litres to your US gallon (4.5litres to a British Gallon). At todays exchange rate of $1.66 dollars to a pound, I've therefore bought 1.32 US Gallons of Winter Resorcinol for the equivalent of $112 dollars.

So a half Gallon of Winter Grade Resorcinol is US$42 dollars from Allansons in the UK exc. shipping or $84 dollars per US gallon, a quarter of the cost in the above link.

Dynea North America (in Canada) has been sold and renamed to Arclin, Arclin North America head office, 5865 McLaughlin Road, Unit 3, Mississauga L5R 1B8 Ontario Tel: + 1 905 712 0900

The Arclin website lists adhesives including resorcinols. Anyone looking stateside could investigate price/ availability from here, or look to ship from UK though may be difficult as uncured they are flammable.

[Bill Perkins]

For a review of the former Aerodux 500 see WB March/April 1999 page 119.

[Carlsboats]

I can add to this Larry Pardey's comment that Aerodux 500 not only holds across a gap -- ordinary resorcinal resin glues don't do that well -- but also successfully glues teak and oak, neither of which does well with epoxy. As noted in other posts, resorcinol resin joints are permanent and waterproof --really waterproof. My test of that is a white oak keel, laid up with two-by-sixes glued flat sides together, making a timber about 6" X 20"X 24' long. Two and a half tons of lead hangs off that structural keel. The keel was laid up in 1964, and the glue joints are still holding tight. I don't know of any other adhesive that could be trusted to do that job.

[GJBan]

It looks like there are two types; A one part system that I remember years ago and now a 2 part system. The one part system was mixed with water and worked fine on boats. I am not familiar with the two part system. I want to use it on battens with white oak frames.

[David G]

GJ,

See Mr. Smalser's post above - #22, and Thorne's post #8.

What you call the *one part system* is called Urea Formaldehyde Plastic Resin adhesive in Mr. Smalser's list - the first image in #8.

What you call the *two part system* is what Mr. Smalser calls *Resorconol* - aka Phenol Formaldehyde adhesive - and the second image in #8.

[Bernadette]

ive had a 20lt drum of resorcinal stored (and still using whats left of the glue) since about 2005. its still good. we live in the tropics and just have to work quick with the glue if say, we are laminating a long mast section. other than that, there is no rush. we often perform a "glue line test" which is with an offcut of the glued material we try and split the timber through the glue line. it always fails...the timber will pull away from the glue line. many years ago, resorcinal was stipulated by lloyds of london as 'the' glue to use.
we just use a vapor/particle filter on a face mask if preparing a large volume of glue to prevent inhalation. otherwise its just a matter of being extremely cautious with the powder.

[Emma56]

I like this Reorcinol www.cpadhesives.com (http://www.cpadhesives.com) Very helpfull people ,:) I have had a few gallons of resin in the basment for a couply years .. No problem . I keep the powder in the frige.

[Bruce Hooke]

I have made hundreds of wood decoys using many kinds of wood. These are working decoys. Used several different kinds of glue. 2 part resorcinol is the only one that has NEVER failed. You can imagine the treatment working decoys get. Some of them are over 40 years old and still in 1 piece. And you can imagine the conditions of manufacture too. Way back we learned to just mix some sifted sawdust in the resorcinol and you could even fill small gaps in uneven fit situations. In boats I have used it to repair even old growth cypress and "carolina juniper" aka white cedar. Bait heavy and have a long soak, Fishpot

It should maybe be noted that while decoys certainly live a pretty rough life, one thing I'd guess they don't experience is high structural loads on the glue joints. This is, of course, not true of most boat parts. So, I would be hesitant about using techniques like thickening the glue with sifted sawdust without some more solid data...

[jonboy]

I have a question regarding Patrick Blanchard (previous poster) use of .005" paper strips to "prevent overclamping" of a glue line. I do not understand how that works and he has no email as I tried to PM him. Is this a common technique? Can anybody explain it? Many thanks in advance.


Quite simple, and a technique used for centuries with animal glues in classic joinery... principle is you don't want to squeeze out all the glue under clamping pressure....ribbons of paper provide a (slightly compressable) physical barrier to prevent total closure and exudation of almost all glue....say, edge joining a pair of butt jointed boards 20mm thick....strips or ribbons of paper every 100mm linear, paper about 5mm wide, prevents the boards closing totally and provides a glue gap of five thou " .010mm
some glues need a mass of glue in the joint , tho' not necessarily as much as a 'gap filler.'

[Breakaway]

Does the paper in any way weaken the joint? Or since its cellulose mosty, does it become amalgamated (?) with the glue/wood?

[Sailor]

That's exactly what I was thinking.

[David G]

One of the reasons to use animal glues - hide glue, et.al. - is reversibility.


One old antique restorer told me that the paper lines aid reversibility in two ways. First, they weaken the joint a bit (which, BTW, means that they must be accounted for in your plans). Second, they help ensure a slightly thicker, more consistent glueline by making over-clamping harder. Since these glues tend to be brittle, a thicker glueline will mean that the two parts are more likely to separate (during the demolition leading up to repairs) IN the glueline, as opposed to breaking out chunks of the wood itself. I've followed his thinking over the years, with good results.

[Breakaway]

thank you David G

[patrick.blanchard]

Does the paper in any way weaken the joint? Or since its cellulose mosty, does it become amalgamated (?) with the glue/wood?

The construction paper strips soak in the resorcinol and are saturated. If there is weakening it won't be as much as glue starvation with a tight laminate bend, the alternative.

This construction paper strip technique was used two years ago on kiln dried white oak 3/4" strips and overclamped. The glued board was tossed outside and has weathered rain, sun, hot dry wind, bare soil (all kinds of critters) for two seasons. The glue line is stronger than the white oak and there was no rot in the oak. It took a sledge hammer to break it. I don't believe all the talk about white oak not taking glue. Epoxy maybe, but not resorcinol. You don't need to fiddle with the pH of the white oak either.

It is difficult to find large timbers for classic boat construction. I invented a "triple sawn timber", using kiln dried white oak, sipo tenons and resorcinol. Take 3 4/4 x 12" kiln dried white oak (or any hardwood or combination of woods for that matter) and plane to 7/8". Lay your board for grain and knots for your final timber, taking advantage of the grain. When finished, label the center board sides A and B, respectively. Cut the center board mortise (I use the Festool tenon tool and sipo tenons) through. Place the center template and mark the side boards internally and cut the mortise to just under 7/16" depth. Use resorcinol and construction paper strips for gluing. My clamps are 50 lb lead pigs on the top board. Final thickness is just over 2.5". Continue laminating up for as much height as needed, using a new through-cut mortise template and a final cap board. You never see the tenons if you lay them properly according to your loft.

You have a very very strong triple sawn timber for double sawn frames, keels, knees...anything you need for classic wooden boat construction. You also use almost all the wood so it is eco friendly(er) than most other techniques. Also, the tight bends with thin strip lamination have always worried me (hence the construction paper strip technique) for frames and backbone. I cannot think of a stronger timber than one constructed in the triple sawn timber described above.

This triple sawn timber technique can be scaled for whatever timber you need, big boat or little boat. For example, my Lynaes dinghy keel will have a central white oak layer with 2 outer layer hackberry boards for the 11 foot keel.

You must glue in the summer if outside like I am (under a greenhouse). It's the only way to get bigger timbers. Electric blankets do not soak enough heat into the larger timbers. I've used Aerodux and think it is overrated. You just have to wait for the right season.

Just a note on the bigger timbers and keels... It is probably better to make a triple sawn timbers according to the plans and then bolt them accordingly. Anything wider than 12" will require width lamination. For a 14" wide timber I would alternate a 9" wide and 5" wide timber, flipping the join line for a 4 " overlap. This way I can use the inexpensive and plentiful Kansas white oak from the sawmill down the road. It is not easy to find 14" wide boards and those usually have soft wood on the edges. For long lengths, stagger the joins within the 3 layers as recommended in the expert text books on lamination. Bed and bolt the timbers for the keel. I think it would be foolish to laminate an entire keel of a moderate cruiser for example.