View Full Version : I'm coming unglued!
08-25-2001, 07:26 AM
Seriously! The project that's going to take me through the next few weeks is refinishing the cabinetry removed from the interior. Having everything out of the boat provides a once in a lifetime (we hope) opportunity to refinish everything.
On many of the pieces, portions of the glued joints are seperating. Not the whole joint, just one end. Murphy's Law being what it is, it's not any of the small, square, easily clamped pieces that need work.
Is there a practial way to touch up/reglue only the areas that are seperating without completely pulling apart whole piece? Some of the glued joints terminate in very fine (1/4" to 1/2") trim and the glue is still holding strong there. I'm afraid if I pull the joint apart completely, I'll do permenant damage.
08-25-2001, 09:37 AM
A glue joint that has started to fail will only continue to fail. Generally speaking, you'll be happierbreaking/sawing the joint apart, jointing the mating surfaces flat again and regluing. I cannot visualize the complicated construction you describe, but if it's a round surface you're trying to clamp, you can clamp square blocks on either side of the joint and clamp to them to draw the joint together. Good luck.
08-25-2001, 09:58 AM
The only way to effectively deal with a delamination is to make a new one. Opposing that, the one sound argument might be for leaving them alone. How bad are they?
08-25-2001, 10:19 AM
Have you detirmined why these pieces failed?
Knowing the cause may reveal the answer to regluing the whole join or a simpler repair.
08-25-2001, 12:05 PM
What kind of joints are these? Some type of failure are fixable w/out disassembly. It depends on the problem.
08-25-2001, 12:38 PM
Seems the story of my life, I agree with disparate opinions too often.
I was a bit hasty, and I don't actually know the proper techniques for dealing with repairs of this sort. My experience is that without disassemly glue failure repairs almost always fail again, shortly. Could well be a matter of inherent problems with the original technique.
Best of luck
08-25-2001, 01:20 PM
Gluing to the failed surfaces of a glue joint will give glue stuck strongly to the surfaces to which the glue did not stick in the first place.
Don't do that.
You don't know why it failed.
If you can slip a piece of 80 grit into the joint and scrub it back and forth, and thus sand both surfaces clean, then whatever remains should be gluable.
Unfortunately, not all glues will stick to other dried glues. For example, I think it unlikely a flexible epoxy adhesive will bond to a cured film of aliphatic resin glue, although it should to a cured film of resorcinol or some other epoxy adhesive.
Rigid epoxy adhesives are not always the best choice for cabinetry, as the different coefficients of thermal expansion and coefficients of [moisture-content-in-wood] expansion will cause such rigid glues to fail more readily.
I recently had occasion to measure the range of mechanical expansion for teak, from fully hydrated to fully dehydrated (it is fairly linear up to the fiber saturation point and little change beyond that). For two apparently identical pieces, I found,
expansion parallel to the direction of the grain: 0.47% and 0.53%
expansion perpendicular to the grain, one axis, 2.9% and 2.1%
expansion perpendicular to the grain, second axis, 5.4% and 3.7%
Wood is not the same, even from piece-to-piece.
Joints too tight (i. e., glue line too thin) combined with glue too rigid combined with sufficient humidity variation will give a sufficient shear force to fail the joint. Thermal coefficient of expansion may be 0.2% in one direction and 1% in a perpendicular direction, similarly giving differential changes in dimensions which can fail a glue joint, if it be too thin and the glue too rigid.
This is true of any wood, but some situations are more forgiving than others. Design of the structure which allows some movement as flexure of the elements can relieve joints of some stress. More flexible types of woods may also be preferable. Wood well-aged, so it does not tend to warp with further ageing, will give more stress-free joints. Wood pieces cut so they fit perfectly with no clamping needed to bend or force things into alignment will give more stress-free joints.
For example, if the cabinetry were teak, fabricated in a very dry shop in the winter where it was fairly cool, glued with very fine glue lines with a really stiff epoxy adhesive such as WEST, and then installed in a boat that sat in a very warm, humid environment, I would expect to see glue-joint failures.
To take the joints apart with less likelihood of damage to the wood, heat the wood with a heat gun. Teak should stand 150-180 deg. F briefly, once or twice, with negligible loss of its oils and resins, and the hydration/dehydration process is fairly reversible. I did some temperature cycling tests on teak, which is how I know. After disassembly, sand the glue-joints clean, soak briefly in water and let air-dry a few days to restabilize the wood at the ambient humidity before further work. If you have a Wagner moisture-meter you can measure the moisture content of the teak before you start to mess with it, and ensure it is hydrated back to about the same vicinity before reasembly.
08-25-2001, 03:02 PM
I should have included pictures this a.m. This is the most complicated piece.
It is pine and I believe it to be original to the boat which makes it German knotty pine. This piece is approximately 25" x 50" at the maximum and covers the water tank forward and serves as a seat and place to throw gear. There are four seams running lengthwise. The seams are fine towards the top where the piece narrows and the only problems are at the widest portion. The seam that runs just to the left of the access hole for the water tank is opening in the first five or six inches. Approximately 5" to the right is a seam that is open as far as the access hole and would allow enough movement as the Chemist suggests to sand the surfaces.
I expect the seams are giving way because they are 45+ years old and although I've tried to treat them with kid gloves, dismantling everything is taking its toll.
It may be more obvious in this picture.
A complication though is that the right edge is not square and will be very hard to clamp.
This is the underside and in the past someone placed a support piece across the joints.
The picture quality is a little poor because I was trying to make them download faster.
[This message has been edited by Concordia41 (edited 08-26-2001).]
08-25-2001, 03:19 PM
That's a wild raggedy assed edge on the right side. Is this the vaunted German craftmanship we've come to honor? I might have left it the same way, depending on the circumstance, and apparently they were correct, as its still there.
Okay, in this case I would do one of two things, leave it alone or resaw it, and reglue it. I don't think re-gluing in parts is going to work on a piece like this. It wouldn't hurt anything, but as I said above they, 99% of the time, come un-glued again.
My 2 cents.
08-25-2001, 03:32 PM
Jack - It's hard to tell about this piece. Someone could have tried to whittle it down for some reason or another, but as far as the German craftmanship goes, some things are amazing. Others horrifying. In dismantling the hanging locker when I removed the top trim pieces, there was a wild variation in the boards. Nothing that would have ever shown, but none the less, more like I'd expect from myself, not the Germans. There was a good quarter inch gap in places not related to the boat flexing or moving. And yes, I'm certain this was the original German work because on the reverse of may of the boards is our Abeking & Rasmussen #5005 and penciled notations in German. But even at her worst, she's head and shoulders above anything I'd expect to buy today...
08-25-2001, 03:49 PM
Like the doctors say, first do no harm. It may be that you will have an easier time and greater security if you through-bolt the entire assembly instead of taking it apart and regluing it. The lumber looks thick enough to through-bolt without too much trouble. Alternatively, if you're not wedded to the using the original pieces, then you could make a new one from plywood, using the original for the shape and the bevels, and painting it when you're done. (You could also make the edges cleaner, to keep Ish happy.) I don't have great confidence in those 45+ year old glue joints, especially as they are not supported by any cross pieces. Both of these solutions will be quicker and more reliable than trying to reglue the originals.
That's my $.02.
08-25-2001, 03:53 PM
My vote is coming down on the side of leaving it be. With the question and proviso that only if it's still sound. I don't see, from the pictures, anything untoward.
Perfection is best achieved in love making.
08-25-2001, 07:53 PM
I'm with Jack.
If the piece has opened up that far,but over time has not opened more,you could fill with a color matched furniture putty and finish.
The rest of this post is a test.Testing my skill at giving directions w/o much reference,and your ability to follow this crazyness.
Using picture 3.the left straight edge is 1
the right angled edge is 2
the top(facing up) is 3
the bottom(resting on the table) is 4
If you want to glue,those odd angles are not a problem.Cut a wedge that when lined up against the angled(2) edge,the outer edge of the wedge is parallel to the(1) edge of the piece being glued.Be sure the wedge is the same thickness as the piece being glued.
sandwich the wedge between two flat pieces(parts a and b) of about 1'x6"so that these pieces extend over (3) and (4).Fasten a and b to the wedge so that the outside edge of the wedge and the ends of a and b are flush.Now slide the wedge/a b combination piece over(2) the angled edge of the piece.a and b should now be laying flat against 3 and 4.
clamp a and b to the piece,making the piece a part of the sandwich just like the wedge.
now you can glue and clamp by placing bar clamps from the out side edge of the wedge contraption to side 1.
Be sure to clamp the piece to the bench if possible,to prevent it from curling.
[This message has been edited by dasboat (edited 08-25-2001).]
[This message has been edited by dasboat (edited 08-25-2001).]
08-25-2001, 11:38 PM
From the furniture shop*GRIN*
If I were trying to reglue, I'd do what the chemist suggested - work some sandpaper inside the joints to cut away any old glue. I've also used a single hacksaw blade wrapped with tape at one end (to hold onto)
Then take a vacumn cleaner and hold it under the joint while applying glue from the top- this will get glue all through the joint.
I'd try clamping that piece with bicyle inner tubes. I get them from the bike shop when they can't repair them - cut the stem out to make a long strip and wrap it around stretching as tightly as possible- several wraps will give tremendous pressure.If one isn't enough use two or three. But do try clamping it down flat so it doesn't curl while banding - the inner tubes do create a lot of force.
Or just fill the cracks with a soft putty and leave 'em alone *Grin*
And good luck
08-26-2001, 06:29 AM
The cause of the glue joint failure could very likely be the crosspieces in the assembly you referred to. As the Chemist has stated wood moves different in different directions. The thing to avoid in good cabinetwork is “cross grain construction”. Those supports may be preventing the larger piece from moving back and forth during seasonal changes in humidity. When reassembling it would be wise to elongate the screw holes out near the edges of the large panels to allow for this. The analogy is a raised panel door that has been glued to the stiles and rails of the door from improper painting, causing the panel to split apart during a dry winter.
08-26-2001, 07:44 AM
Thank you all. Based on your responses, I think I will leave all but the worst areas alone. As it's all cabinetry and not structural, it's mainly cosmetic. I just want to do what I can while it's out of the boat. I can also add more structural cross pieces as it's reassembled.
Sanding between the pieces and the wedge and bicycle innertube ideas are just what I needed as I'm plunging into new territory here. Based on earlier research, I had them throw some Resourcinal in the last Jamestown order. Let me go get busy...
08-26-2001, 09:52 AM
I come from a cabinet background, as I designed custom kitchens and baths, before health issues had me retire.
Feel free to send me pics and any questions you might have, as I still have all my professional conatcts. If I don't have the answer these NC craftsmen will surely have the answer.
I have collaborated on several boat projects with my former boss, who also happens to be a sailor, as well as an artist and an artisan. So if you need any additional pieces or cabinets to add to the original, he is fully capable of not only replicating style, but matching aged coloring in the proper species also.
08-26-2001, 01:48 PM
Whenever I've run across things like this in furniture and cabinetry, the open joints have been caused by the wood movement. First try to stabilize the pieces -- get them into an evironment the same as they were in before. If they're drying out, they'll split. If they're taking up moisture they'll split.
If you fix them and reinstall, they could dry out/take up moisture again and give you the same problems.
For handling the opened joints, other than taking the joint apart and re-gluing the only fix I've found to work consistently is to clean the open joint out and use a hypodermic syringe to inject your choice of an appropriate adhesive. Clamp or not, depending on your adhesive's requirement.
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