W. Oak & Epoxy: What the Mfg's say....

[BrianY]

I thought this might be of some interest to the group:

The lack of any consensus of opinion in the never ending discussion about gluing white oak with epoxy caused me to wonder what the epoxy manufactures had to say on the subject. On 10/26, I sent the following email to West Systems, System Three, Raka, MAS, Progressive Epoxy Polymers (Paul Oman) and US Composites:

Greetings.

I am taking a poll of various well-known epoxy manufactures regarding the suitability of epoxy for gluing white oak. I am asking each manufacturer the same question:

What is you position on the advisability of using epoxy for gluing laminations of white oak for structural applications (i.e. frames) in wooden boat building? If it is O.K. to do, are there any special precautions or steps that should be taken to prepare the lumber for gluing?

I'm sure you've been asked this question many times before as it is a point of much debate in amateur wooden boat building circles. I intend to compile all of the responses I receive and report the results on the WoodenBoat internet boatbuilding discussion forum. I am not associated with WoodenBoat in any way. I am a participant in the forum and an amateur boat builder. This subject comes up on the forum every few months and there is a huge amount of speculation and conflicting information out there. I thought it would be useful to get the actual opinions from the actual epoxy manufactures and share the info with the group.

Thanks for your help,

Brian Yankee

Here are the responses I received:

From Larry at Raka:

Generally Oak or any other hard or oily wood will glue just fine if these following steps are taken: (1) Course sand all gluing surfaces (2) wash with acetone to rmove any oils (3) this may be not necessary but will not hurt and that is to thin the mixed epoxy with 5% laquer thinner or denatured alcohol and apply your first thinned coat to the gluing surfaces, this will assure what surface penetration is possible. (4) apply a thin coat of regular mixed epoxy to all gluing surfaces (5) apply normal filler thickened epoxy and lightly clamp.
Most people don't have a problem as long as they very course sand and skip some of the steps but if all the steps are followed, there never seems to be a problem.

From Paul Oman/Progressive Epoxy Polymers:

HI Brian

don't know of anything special about white oak. Gluing with epoxy, however can be tricky....

The bond is just a surface bond with epoxies (you might prime a wood with a solvent thinned coat of epoxy for a wee bit of penetration) and it is very easy to squeeze all the epoxy
out of the joint when clamping it. So... issues are surface bond only and care not to starve the joint of epoxy. (one fix its to put grooves in the wood to be jointed together. As a person with unlimited epoxy on hand, I do glue a lot of things with it, but think I would learn (or test) more traditional glues if I had them available.....

From W. Kern Hendricks at System Three:

Epoxy adhesives like System Three's T-88, SilverTip GelMagic, and MetlWeld are suitable for bonding white oak providing that the oak is prevented from deep moisture cycling once bonded. This can best be accomplished by epoxy coating the joined wood. System Three's General Purpose and SilverTip Laminating epoxies are not recommended as they are designed to be coating and fiberglassing resins suitable only for bonding softwoods and other porous materials.

The bonding area should be lightly sanded with 80 grit paper. Clamping pressure should be kept to the minimum necessary to close the joint. The joint should be allowed to cure for several days before it is highly stressed.


From JB Currell at MAS:

We are asked this about once a week. Here is our answer.
When gluing white oak:
1. sand with heavy grit sand paper leave surface rough.(30 grit) wash with lacquer thinner 2. pre coat both surfaces to be glued with our low viscosity or FLAG resin and slow or medium hardener. Let set for 2-3 hours at 65-70 degrees f 3. Mix another batch of resin. Using Colloidal silica, thicken resin/hardener mix to a pudding consistency .
4.glue the parts together before the original coating sets to a hard surface, using the thickened material between the surface you've precoated.
5 Clamp and let cure.
note: do not over clamp and squeeze out all the glue.

This is the protocol used by Triad boat works in Marion Massachusetts.
They restore Concordia sail boats and have used this method successfully for over 10 years. It is primarily used for laminating new frames I hope this is of help.


I have not gotten any response from West Systems or US Composites. I will post them if/when I do.

FWIW : I have asked the System Three reps at the last two WoodenBoat shows and the MAS rep at the most recent show about white oak and epoxy and they all looked at me like I was nuts to even worry about it. They all reported no problems with the combination.

[JimD]

Not surprising. Once a couple or three years ago a new member of the forum happened along one of the many recurring posts on the subject and couldn't understand what all the to do was about. Said he'd never heard of an epoxy/oak problem anywhere but this forum, as though it was an idea that had taken root here somehow and had persisted to the point where it was taken as common knowledge.

[pcford]

Not surprising. Once a couple or three years ago a new member of the forum happened along one of the many recurring posts on the subject and couldn't understand what all the to do was about. Said he'd never heard of an epoxy/oak problem anywhere but this forum, as though it was an idea that had taken root here somehow and had persisted to the point where it was taken as common knowledge.
Why, then, do extremely competent professional boat repair guys that have never read this forum report problems.

If you believe that the above post and the answers from the epoxy formulators conclusively believe there is not a problem with white oak and epoxy, I've got a bridge I'd like to sell you.

And it ain't lack of sanding prep.....or too much pressure....or moisture cycling.....do these guys ever actually work on boats? Would not know it from the answers.

[JimD]

pcford. I dunno. Dunno what to believe.

[pcford]

pcford. I dunno. Dunno what to believe.

Once again......

If you want to see for yourself......

1. get some white oak. make several samples from several piece of white oak. Some green, some old, etc.

2. abrade mating surfaces with 60 grit.

3. mix epoxy.

4. put samples and epoxy together. use NO pressure.

5. let set in an appropriate environment for a week.

6. test glue joint. watch some of samples fail at the glue line when chisel is applied and tapped with 10 oz. hammer.

Do that and then come back with your results. Don't believe me or anyone else.

[JimD]

I've epoxied oak on a real boat in a couple places. Had no problem. When I was making some changes and had to take a piece of oak off I had to take a hammer and chisel to it. The joint did not fail. On the other hand I have no reason to doubt those competent builders who have had it fail on them. So it goes.

[pcford]

I've epoxied oak on a real boat in a couple places. Had no problem. When I was making some changes and had to take a piece of oak off I had to take a hammer and chisel to it. The joint did not fail. So it goes.

As I said in the above post "watch some of samples fail at the glue line" Epoxy/will not fail 100% of time. But, it will, at least with the epoxies which I have used, fail some of the time.

Feeling lucky?

And another thing. Why do you suppose that other professionals and I would want to mislead you in this matter?

But you can find out for yourself.

[JimD]

No, I've never been very lucky and for that reason I wouldn't epoxy glued oak on a critical structural part of a boat. Can't think of any reason you'd want to mislead me and didn't think that you did. I think my first post is not coming across as I had intended.

[Mike Vogdes]

Thanks Brian, its about time somebody asked the horse.

I have been using WEST system for more than 25 years and have had very few problems with this product.
Granted I don't laminate white oak very often but I have in the past.

About 8 years ago I built a set of roof racks for a friends high top van using what I had laying around. It was a 3 pieces laminate sprung with a camber to match his rooftop, I wound up using 2 pieces of white oak with a piece of mohagany in the middle, everything was wiped down with laquer thinner befor epoxy, the hardware was regular steel flatstock fabricated to fit the gutter around the van, anyway, my friend kept the van for a few years and used the racks for his kayak and never removed the racks from the van while he owned it, he has since sold the van to a boat yard crew who routinely use the racks with virtually no maintenance. Everytime I see this topic come up I think of those roof racks and wonder how much longer they are going to last befor something gives. This van lives at the Jersey shore in a rather harsh enviroment.

Granted, this is not a boat but it surly is a case of extreem use and abuse.

[pcford]

Thanks Brian, its about time somebody asked the horse.

I have been using WEST system for more than 25 years and have had very few problems with this product.
Granted I don't laminate white oak very often but I have in the past.

About 8 years ago I built a set of roof racks for a friends high top van using what I had laying around. It was a 3 pieces laminate sprung with a camber to match his rooftop, I wound up using 2 pieces of white oak with a piece of mohagany in the middle, everything was wiped down with laquer thinner befor epoxy, the hardware was regular steel flatstock fabricated to fit the gutter around the van, anyway, my friend kept the van for a few years and used the racks for his kayak and never removed the racks from the van while he owned it, he has since sold the van to a boat yard crew who routinely use the racks with virtually no maintenance. Everytime I see this topic come up I think of those roof racks and wonder how much longer they are going to last befor something gives. This van lives at the Jersey shore in a rather harsh enviroment.

Granted, this is not a boat but it surly is a case of extreem use and abuse.

Good.....one data point. You will notice that nobody has said that epoxy will never work with white oak.

[BrianY]

I thought of another question that might generate some useful data on this issue: For only the folks out there that have had direct personal knowledge of or experience with white oak laminates glued with epoxy in real wooden boats, how many failures of the laminate do you know of? I'm not talking about test samples (although that information is certianly useful). I'm talking about actual applications in actual boats?

[Bayboat]

Nice, useful contribution, Brian. You might also have consulted Smith & Co., who manufactures & markets a special epoxy for gluing white oak and teak as well as other oily woods. It's called Oak & Teak Epoxy Glue. The literature includes a lengthy list of woods for which the epoxy is compatible. The list includes just about any wood you would want to use for boatbuilding. www.star-distributing.com
I've had good results with it, but not long term so far. I still use resorcinol for laminating oak stems & frames.

[pcford]

Nice, useful contribution, Brian. You might also have consulted Smith & Co., who manufactures & markets a special epoxy for gluing white oak and teak as well as other oily woods. It's called Oak & Teak Epoxy Glue. The literature includes a lengthy list of woods for which the epoxy is compatible. The list includes just about any wood you would want to use for boatbuilding. www.star-distributing.com (http://www.star-distributing.com)
I've had good results with it, but not long term so far. I still use resorcinol for laminating oak stems & frames.
I have never used epoxies that are specifically formulated for used with white oak. Industrial Formulators also makes one.
They may possibily solve the problem. I'd be interested in anyone with experience with them.
As you mention, Smith's makes one. Makes me a little uneasy because they make the supposed miracle product CPES. However, most of the excessive promotion of that product comes from fanboys here and not the manufacturer. As I see it, Smith's makes CPES as a stopgap measure for rotten architectural elements on houses.

[sdowney717]

It only takes 2 failures to convince me that its no good gluing white oak.
That is my own glue failure when I tried and everyone else's failure when they tried.
How would you like your hard work to split apart on you just when you need ot to hold togther and probably will at a most inoportune moment.