# Glue Failure, what happened??



## nbanks (Feb 5, 2021)

Hi all-

I had several glue joints fail today and was hoping you could help me diagnose the issue. I am laminating 2-3 pieces of roasted red oak to make an outdoor bench and the laminations were clamped overnight. Titebond III was applied to one side and MANY clamps applied (mostly parallel clamps, about 12 clamps per 36? bench leg). Every leg failed, either partially or fully (pics provided). My basement shop is climate controlled and the glue is less than six months old.

What happened? How can I fix this??

Nathan

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## prazbotta (May 20, 2020)

It almost looks like there is a finish on the oak. Did you put anything on the oak faces prior to glue up?
That or maybe you got a bad bottle of glue? I used the same glue on my cedar porch post wraps, and I know my glue was in pretty bad shape (thick and gummy), and it is still holding great.


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## OnhillWW (Jan 10, 2015)

I can't say for sure but things to consider:
How dry was the wood i.e. moisture content?
How flat were the boards prior to glue-up? Were they cupped?
I would have applied glue to both faces and always to squeeze out, did you do that?


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## nbanks (Feb 5, 2021)

The glue is new and looked fine. The wood was measured between 4.0% - 5.0% RH (similar to other wood in my shop that's been sitting for years). The wood was bone dry (also an effect of the roasting process). The boards were dead flat as well, and one of them moved a bit after the glue-up (shown in the pic). After rough milling I let them sit for two weeks and NO movement (another positive effect of the roasting process). I applied glue to both faces on the structural components (arms and legs) and only one face to the more decorative components. I used a lot of glue though, and rubbed it in pretty good. I don't think the joints were starved (or squeezed out) from too much pressure. I think this is a roasted oak / Titebond III incompatibility. But I'd like to know WHY (email sent to Titebond).


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## nbanks (Feb 5, 2021)

There was no finish on the toasted oak. It was right from the planer with fresh knives.


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## Tony1212 (Aug 26, 2013)

> ... I think this is a roasted oak / Titebond III incompatibility. But I d like to know WHY (email sent to Titebond).
> 
> - nbanks


Titebond III gets very brittle and hard when it dries. In your pictures, the glue looks webbed/stretched, like the boards were separated prior to the glue fully drying.

How long did you let it dry before removing the clamps?

When you took the clamps off, did the board immediately fall apart?

Was the glue still gooey, or quite hard when you removed the clamps?

If it was gooey after clamp removal, is still gooey (bad glue) or did it harden up?


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## OnhillWW (Jan 10, 2015)

I am unfamiliar with toasted Oak, I googled it but only got results regarding wine and spirits barrel construction. You may be correct about the compatibility between the oak and your glue. Your glue could be off spec or old, try to date the glue by contacting the manufacture with the lot number. Also I never glue off the planer, everything gets hit with 120 - 180 grit before it sees glue, knocks down any wash boarding and adds a bit of "tooth" prior to glue up,

The planer can have a tendency to burnish the surface


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## Unknowncraftsman (Jun 23, 2013)

My guess is. Wood was not prepared correctly wood was bowed clamps were used to close the joint. Small gaps are acceptable if they can be closed by hands.
Good Luck


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## nbanks (Feb 5, 2021)

The wood was definetly flat when I clamped. I should have toothed the wood as well. I still think there's something going on with Titebond III and roasted red oak. This video shows the same result, wish I saw it earlier!

https://www.woodworkerssource.com/blog/wood-conversations/video-heres-what-roasted-oak-lumber-is-all-about/


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## controlfreak (Jun 29, 2019)

Was the wood used in another project at some point in its life where it could have absorbed an oil or other penetrating product or finish?


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## nbanks (Feb 5, 2021)

I let the glue dry at least 3 hours (but most of the pieces dried over night). The glue is hard-ish but still stretchy in the thin sections. It wasn't wet or gooey when I removed the clamps. The worst failure occurred not when I first removed the clamps, but after sitting over night and "moving" apart.


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## nbanks (Feb 5, 2021)

More pictures:


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## OnhillWW (Jan 10, 2015)

Re the video. If the process makes the wood more hydroscopic then I would think it could have an affect on certain glues. Also, one failed joint (TB III) does not make a test for me, I would have tried another to be sure, maybe he did but he didn't state that.


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## nbanks (Feb 5, 2021)

Note, the boards in the pictures above are artificially separated using a plastic wedge.


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## OnhillWW (Jan 10, 2015)

Usually TB III cures to a darker color than that so maybe the glue is bad or cures differently because of chemicals in the toasted wood??
Can you resaw on the joints on a bandsaw to salvage the wood?


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## nbanks (Feb 5, 2021)

I think I have these options:

1) Resaw the BAD lamination joints and reglue with polyurethane glue
2.) Resaw ALL lamination joints and reglue with polyurethane glue
3.) Pour thin epoxy into the joints and reclamp
4.) Push polyurethane glue into minor separations and reclamp (major failure will need to be resawed regardless).

Not sure if resawing will leave me with enough thickness. You guys recommend table saw or band saw? Should I get a thin kerf ripping blade for the TS?

Thanks for all the help!


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## bruc101 (Sep 13, 2008)

i saw that happen to a friend several years ago and not saying this is your problem. He glued the boards using opposite grain rotation like yours look.

When I glue up boards face grain to face grain, and I do many a year for table and island legs. I never glue them with opposing grain. Never had a failure in many years. I have four sets of legs in the clamps now for farmhouse tables.

He tried that and his legs stayed together. You might also have some bad glue, I had that issue one time with a new gallon of TB3 and found out later, humidity and wet weather caused it to fail.


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## Lazyman (Aug 8, 2014)

Is the wood roasted or torrified?

I think that wood glue will only set as the moisture is wicked away by the wood. Based upon how the glue sort of stretched out, the glue in the picture was obviously still wet when you removed the clamps. I think that water resistance is one of the attributes of roasted and torrified wood. You can test this by putting a drop of water on the surface and see if the wood absorbs it before it just evaporates from the surface. The shinier it looks the less likely it is to absorb moisture. You may have to scuff it or something to make the surface absorb water and leave it clamped for a several days or use another glue that doesn't rely on "drying" for it to set.


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## JCamp (Nov 22, 2016)

I had that happen once several years ago. I think it was due to me using to much glue. I separated the pieces and let dry then scraped them clean and glued up again using less glue. That worked for me. I've never had glue go bad but just because you got it 6 months ago doesn't mean it didn't set in a warehouse for 2 years before hand. Just to be sure you might try a different bottle of a different glue from somewhere else on the next try. And yes if you resaw get a thin blade if your are already worried about loosing the thickness. 
Also I know it's aggravating so just try to be calm and not kick yourself. Wood is a wonderful product that has a mind of its own at time. Sure there are some things that can be done to minimize the result but just because it acts out doesn't mean you did anything wrong. Just get back on the horse… or in this case clean it up and reglue


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## Lazyman (Aug 8, 2014)

BTW, you can check the code date to see if your TB glue is expired. I have had TB 3 go bad before the code date (+ 2 years) so I only buy it in the smallest bottle and only when I need water resistant joints.

EDIT: one more thought, You may not need to resaw it to separate the joints. Since the joints obviously failed, a heat gun or even a blow dryer may be all that is needed to finish breaking it apart. I've used heat to break PVA blue joints and heat will soften the glue pretty effectively, especially when you already have a gap. Heating a putty knife to slide into the joint will help as well.


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## RichT (Oct 14, 2016)

I've found that gluing boards face-to-face is chancy. If you are going to try it, make sure the growth rings are in the same direction, not opposite one another like photo #2.


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## OnhillWW (Jan 10, 2015)

I wouldn't try to pour into the void, that would make the joint epoxy to TB III. Resaw, replane or sand ( 60, 80, 100, 120) then go with poly or epoxy .

I feel your pain.


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## nbanks (Feb 5, 2021)

Should I resaw the joints that look good? Or just the visibly bad (separated) joints?


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## putman (Jan 1, 2019)

I have not used "toasted oak", but I always apply TB to both surfaces to be glued.


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## CaptainKlutz (Apr 23, 2014)

Can get roasted oak and maple from Woodworkers Source (WWS) mentioned above. Had a long conversation about laminating it to make thicker sections, as I wanted 8/4 stock for tool handles and moldings. They suggested against face lamination. Roasted wood doesn't absorb water well, and it absorbs it really slow. Hard to get moisture out of the center of large joint.

If gluing straight out of thickness planer, and the surfaces are burnished smooth, it is harder for water to reach glue fibers too. They suggested using epoxy laminating resin with a rough surface (80grit rough), to get away from the need to remove moisture in making large mechanical bonds. And the result will end up with very visible glue lines.

Have only used roasted red oak once for small box AKA 'test' project. Made edge glue joints only with TB II extend; my normal warm weather adhesive. The brittleness of the wood made using router difficult, as had to strictly cut with grain. Any cuts against grain resulted in massive explosion of splinters, with narrow pieces breaking apart entirely. Didn't like that it made shop smell like a BBQ on fire after cutting, or milling it. Still waiting on WWS to obtain some roasted 8/4 maple stock, before I play with roasted wood any further.

Not sure of your roasted wood source, but it has become popular for outdoor siding. Most of the outdoor sellers of roasted wood use an oil coating to help improve longevity. So check your source.

FWIW - In AZ, can not laminate boards with only one side coated with PVA glue. The glue skins so fast due low humidity that one side always has poor adhesion on long lamination. Can usually tell when this happens by width of glue joint. A double wet joint will be narrower than single wet joint. Most of my lumber stash is sub 4% moisture, and occasionally even have to wet the wood before applying glue to slow down evaporation and get near normal working time.

Your process description would have ended in failure for me in AZ. 
Must coat both sides of joint. Use 4×4 or 6×6 wood beam to spread out the clamping force on each side of face lamination, so you can get away with less clamps and narrow glue line. On woods that are slow to absorb water, will let clamps rest for at least 24 hours before removing parts with PVA; and that is with average shop temp of 80-90° and sub 30% humidity. 
Considering you work in a cool, damp basement; might need a week in clamps and still not be able to dry out enough glue moisture? At least that is my SWAG.

YMMV


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## therealSteveN (Oct 29, 2016)

Easiest way to figure it out that just takes the time to glue 2 2×4's together using that same glue. I wouldn't even plane them, just glue them. If they stay together as you had them clamped the "toasted" part of the oak is the issue.

I imagine toasting = heat of some sort. Probably altered the grain structure, pores, something that didn't allow the glue to penetrate the pores.

If it is manufactured glue, I don't see it as the problem. Now something you mix, well that could have issues if mixed wrong.


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## nbanks (Feb 5, 2021)

Response from Titebond:
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Your joints below look like they are wide open. I assume that these are joints you pulled apart? The glue looks stretchy in the pictures which would indicate it did not dry properly.

Note on roasted wood (Thermally modified wood): heating causes the wood to carbonize. The carbonizing gives the wood better resistance to moisture. This carbonizing also causes the wood's chemical properties to change and decreases adhesion of most adhesives. The higher the heat treating (carbonizing) the lower the adhesive bonding. Also, since the wood is more moisture resistant, water-based wood glues such as Titebond III will dry slower.

Cleaning with acetone is preferred over mineral spirits for cleaning wood surfaces.

If you have questions about the quality of the glue, take some unmodified wood and glue it with the Titebond III in question. Clamp overnight and break with a hammer. It should give a high amount of wood failure.
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## 1thumb (Jun 30, 2012)

TB response is interesting and makes sense. Lesson learned. Roasted wood needs poly glue


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## EdDantes (Aug 24, 2018)

I like Unibond 800 for laminations like this. Rigid glue line and better gap filling. Not sure how it would interact with the toasted wood, though.


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## Unknowncraftsman (Jun 23, 2013)

See what happens when you mess with Mothers nature. Wood is not supposed to last forever scientists think they are smarter the nature apparently not. 
I've seen this lesson played out in my roofing carrier. Every year or two some new man made material would come out. It's going to change the industry what a break though.
They all failed for various reasons. 
I've have not had good a experience using time bond 3 on outdoor projects especially on exposed glue line or joints.
Good Luck


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## MadMark (Jun 3, 2014)

Looks like incomplete coverage over a slightly non porous surface. Was the oak planed or sanded prior to use or wsa it used full thickness?


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## 1thumb (Jun 30, 2012)

> Looks like incomplete coverage over a slightly non porous surface. Was the oak planed or sanded prior to use or wsa it used full thickness?
> 
> - Madmark2


Non porous because it was roasted and toasted


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## nbanks (Feb 5, 2021)

Yeah it was nonporous. I have glued up 10 samples and will follow up tomorrow on the results.

1. Roasted oak with TB3 (same situation that failed)
2. Roasted oak with TB3 with good prep (sand, acetone, water)
3. Roasted oak with TB2 and no prep
4. Roasted oak with epoxy
5. Roasted oak with old polyurethane glue (gorilla)
6. Roasted oak with new polyurethane glue (Titebond)
7. Roasted oak with thin CA glue
8. Roasted oak with thick CA glue
9. Poplar with TB3
10. Poplar with TB2

I used rub joints on all. Face grain with about 1"x1" glue surface. Not scientific but I will learn something and pass it on to the forum.


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## nbanks (Feb 5, 2021)

I broke my 10 test samples, and the most wood failure (strongest joint) occurred with the Titebond III, which is in complete disagreement with my initial hypothesis (TB3 was a bad choice for my application). The new polyurethane, epoxy and thick CA glue also performed very well for these small samples. The "old" polyurethane glue did the worst, followed by the thin CA glue. I did not notice any appreciable difference between the "prepped" TB3 and the "unprepped" TB3 samples (reminder: prep included sanding at 150 and cleaning with acetone). I have three more large samples for polyurethane, and both prepped and unprepped TB3. I will fill you in on the results.


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## putman (Jan 1, 2019)

When using the TB3, did you apply to both surfaces before clamping?


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## Lazyman (Aug 8, 2014)

Using rub joints instead of clamps could be at least part of the cause of failures. I would bet that you will get better results using clamps.


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## Loren (May 30, 2008)

> Using rub joints instead of clamps could be at least part of the cause of failures. I would bet that you will get better results using clamps.
> 
> - Lazyman


I haven't done much with rubbed joints but my concern about face joints is that when the moisture hits the face of the board it can cause cupping. I had to do some face joints for a client in a hurry a year or so ago and mail ordered about 40 of the cheap 6" bar clamps from Harbor Freight. Man, all that glue was a mess. I put cardboard on the floor to pick it up.


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## nbanks (Feb 5, 2021)

> Using rub joints instead of clamps could be at least part of the cause of failures. I would bet that you will get better results using clamps.
> 
> - Lazyman


I only used rub joints for the test samples. My project was clamped (and failed). The test samples were rubbed and passed. I am back pointing to "bad / old glue", poor prep, and insufficient clamp TIME (only 8 hours).


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## MadMark (Jun 3, 2014)

*Loren:* Using too much glue is a waste and makes a mess. The key to gluing is 100% *uniform* coverage. Just running a wavy line doesn't ensure complete coverage even with clamps.

Only one surface needs to be coated with PVA (Elmer's yellow, TiteBond-III, etc). Spread it evenly edge to edge by using a piece of scrap clear plastic. This allows you to see the layer and easily control the thickness and placement of the glue.

Don't rush. Work quickly but deliberately. Most projects have several things to be glued, but not all at once. Placing a piece and letting it tack before moving on is lots easier and neater than trying to align several slippery pieces at once.

Clamping forces spread out at a 45° angle so the clamps should be spaced the boards width apart. Counterintuitively, wider boards require fewer clamps further apart, it's narrow pieces that need *lots* of clamps.

After an hour the bond should be set and ready to come out of the clamps. The bond will strengthen overnight but only an hour is needed between stages, especially if clamped. If you're joints are falling apart after an hour, either the glue has gone bad, or the material is wrong (waxed, painted, scorched, etc.)


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## tomsteve (Jan 23, 2015)

> 2. Roasted oak with TB3 with good prep (sand, acetone, water)
> 
> - nbanks


thats not good prep to me.
sand with 120( or coarser), wipe/blow off, shake glue bottle, apply glue evenly and not heavy to one surface, clamp.


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## splintergroup (Jan 20, 2015)

> 2. Roasted oak with TB3 with good prep (sand, acetone, water)
> 
> - nbanks
> 
> ...


I really like the silicone spreader I got from Rockler a while back when I needed something to hit the free ship mark.
Toothed to spread out the glue evenly on large surfaces.

A plastic mastic spreader (for tile/vinyl flooring) also works perfectly. Usually I'll just toss it in a can of water when done (if I remember) so it can be reused without doing a lot of dried bugger picking.


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## nbanks (Feb 5, 2021)

> *Loren:* Using too much glue is a waste and makes a mess. The key to gluing is 100% *uniform* coverage. Just running a wavy line doesn t ensure complete coverage even with clamps.
> 
> Only one surface needs to be coated with PVA (Elmer s yellow, TiteBond-III, etc). Spread it evenly edge to edge by using a piece of scrap clear plastic. This allows you to see the layer and easily control the thickness and placement of the glue.
> 
> ...


Oddly enough I have had success the last set just by extending the clamping time to ~18 hours. Yes, the glue is almost two years old so it may require a longer clamp time. And Titebond (the company) responded to an email and also said that TB3 on roasted wood needs extended cure time. Just though I'd share, as your comment was my position before this failure.


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