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Thread: Wood Movement
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4th November 2013, 06:03 AM #16... and this too shall pass away ...
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Thanks, Pete.
The only thing that surprises me a little about all these discussions is that one seems to need to allow for movement even when a frame and panel construction method is used for the sides of the cabinet. I thought that given the web frame was glued to the stiles only that it would not be necessary to allow for movement.
We live and learn.
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4th November 2013 06:03 AM # ADSGoogle Adsense Advertisement
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4th November 2013, 06:57 PM #17
that is my preference
One more question ... If I make veneered MDF panels with (say) 45 mm stiles and rails rather than edge banding (which I dislike) is it OK to dado/biscuit and glue the web frames to this panel and glue up all the web frame joints; or do I still need to allow for movement?
you can dado/biscuit, glue, screw web frames to an MDF panel
the "proper" or traditional way is to form divided tenons on the ends of the panels. For the moment I can't recall the proper term, but think of a tenon in the shape of an E with very wide horizontal strokes -- the corresponding mortice would have three pockets, two of which would be oversize. Only the centre portion of the tenon is glued, the other two can them expand and contract in their "pockets"
strictly speaking this is true, but there are advantages of always using a similar construction in that you are less likely to forget and glue a M&T when you should leave it floating
also, the panel in a F&P construction is usually too thin to screw drawer runners toregards from Alberta, Canada
ian
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4th November 2013, 07:14 PM #18... and this too shall pass away ...
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Gentlemen,
Thank you one and all. All my questions have been answered.
You have once again demonstrated the value of the brains trust at this board.
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4th November 2013, 11:53 PM #19
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5th November 2013, 12:05 AM #20
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6th November 2013, 09:01 AM #21
"So far " is the key phrase! You are begging for trouble gluing anything across a substantial amount of cross-grain. I know mortise & tenon joins involve cross-grain glueing, but the distances involved are usually short, and so don't develop quite the same amount of stress as a runner glued across a wide panel. So far, either there has not been a deep-enough moisture cycle to rip them apart, or the glue you used is still flexible enough to accommodate the stresses, but eventually, in 99% of cases, it will give up & let go sometime down the track.
In my own early days & ignorance of sound woodworking principles, I did all kinds of "wrong" things, and it seemed like I'd gotten away with it, too, for a few years, but one by one my sins came back to haunt me. In one case, it was more than 10 years after I'd built a pine cupboard before the mouldings I'd glued gross-grain along the top & sides let go, but let go they did. (The time taken might have had something to do with the sheer amount of glue I used back then... ).
I apologise if I was one of the people who have brought this to your attention, John (but I'm sure it was the other Ian ). We have caused you sleepless nights waiting for the sounds of rending wood & drawers collapsing in the dark! It's like the bloke I read about in the paper on the weekend. He asked for a test, then when he got a diagnosis of possible cancer, he wished he'd never asked for the test in the first place! At least a busted drawer runner is relatively easy to fix, & will have an excellent prognosis if done right.
Cheers,IW
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6th November 2013, 08:11 PM #22... and this too shall pass away ...
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Ian,
No need to apologise ... grateful for the advice. The good news is that my furniture is either in my house or my kid's houses, and they got theirs for free. So, let them stay awake at night waiting for that sickening, tearing sound. I will sleep like an innocent.
If and when they fail, I will fix or replace them (built properly this time). In the meantime, I am having fun in my workshop.
It seems that I may have had dumb luck on my side. Most of my stuff was Wau beech in the beginning, because I was getting it very cheap. Then I moved on, mostly to cedar and NG Rosewood. These timbers are low shrinkage and fairly stable in service ... but dumb luck only extends so far ...
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7th November 2013, 08:43 AM #23
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7th November 2013, 12:05 PM #24... and this too shall pass away ...
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Awww ... guys ...
Until recently I was blissful in my ignorance. Now I know better. I promise I'll be a good cabinetmaker in future. But can we please stop with the horror stories? I have pieces 10 years old that have survived just fine ... so far ... (no, Ian, don't say it). I intend to ignore the fact that they are all at risk and to pretend that they are fine until that tearing sound happens.
Elephant? What elephant?
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7th November 2013, 01:18 PM #25
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7th November 2013, 01:38 PM #26... and this too shall pass away ...
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7th November 2013, 01:44 PM #27... and this too shall pass away ...
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7th November 2013, 02:06 PM #28... and this too shall pass away ...
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A wild theory
Here is a wild untested and unsupported theory developed in my never-ending pursuit of over-engineering.
About 30 years ago I built a timber double carport. I wanted a clear span, and because I was as poor as a church mouse, needed to be able to make it myself at low cost. I needed two beams to span the 6.5 M carport, the rear beam was supported by a post, but I wanted no posts in the middle or front of the carport.
I decided to make laminated beams out of 3X2 inch oregon pine. The beams were curved. I made them by putting a 60 mm block in the middle, bending the first member over this and nailing it to the carport floor at the ends. Then I built it up to about 10-12 inches thick using 308 glue and screws. Then I put some bolts through the lot (told you I was good at over-engineering). I made the first beam and was delighted. You could park a battleship on that beam and it would barely flex.
Sadly, I used all the 308 glue on one beam, and it was as dear as poison ... so much so I could not afford to buy any more. I stumbled around the hardware store until the owner decided to give me some advice. He recommended another glue he assured me would do the job admirably, but at a fraction of the cost.
I made the beam ... with an early version of what we now call construction adhesive ... and discovered that this glue moves ... a lot! Under a very light roof, that beam flattened ... lost it's 60 mm curve entirely ... stopped only when the bolts hit the sides of the holes and locked everything into place. Drove past it recently. It's still there and still flat.
So, here is the question. If instead of leaving some joints without any glue at all we were to use construction adhesive on these joints, would the glue be flexible enough to move with the humidity? Would it move enough? Would it harden with time and lose its flexibility? I note that some manufacturers claim their product remains flexible ... but how flexible?
OK guys ... be honest ... but be gentle. I'm feeling a little sensitive after having all my wood movement sins exposed to the entire universe and I am just bouncing ideas around at this stage.
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7th November 2013, 02:55 PM #29
You are stuck in a sticky situation
If you were born before glue was invented then your gonna have many sleepless nights. Listen to moi, there are other ways to hold 2 pieces of wood together. Glue is not the only answer.Visit my website at www.myFineWoodWork.com
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7th November 2013, 03:22 PM #30... and this too shall pass away ...
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One of my kids just suggested that you were correct; that I was indeed born before glue was invented.
I intend to scratch his name off the escutcheon with a rusty nail ... immediately after I write him out of my will and burn all the photos of him. That's almost as bad as my daughter, who, in Year 1, asked me if I knew Jesus.
Wongo, you are, of course, quite correct. For instance, I recall helping my dad make furniture held together with wedges when I was a kid. Flat packs were around long before Ikea got into the game.
Pourtant, allez-vous élaborer?
au revoir!
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