Expansion - I need an education please....! - Page 2 - Woodworking Talk - Woodworkers Forum
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post #21 of 30 Old 01-06-2018, 12:27 PM
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This has been a terrific thread, thank you for the information...one more question, how do these principles affect plywood? Not that I'm looking to side glue a plywood panel table top or anything, but I am curious...


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post #22 of 30 Old 01-06-2018, 02:06 PM
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Originally Posted by Avickers89 View Post
This has been a terrific thread, thank you for the information...one more question, how do these principles affect plywood? Not that I'm looking to side glue a plywood panel table top or anything, but I am curious...


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Plywood is layers of thin wood stacked on top of one another with each layer perpendicular to the next. Thinking about what was discussed above - panels will grow/shrink across their width. Each layer is usually 1/32 to 3/32 thick, depending on the plywood. If you took only one of those plies by itself and measured it as its moisture content increased and decreased, you would see that individual ply grow and shrink. Now sandwich that ply between two perpendicular plies. You have 3 plies and a balanced sheet. Each of the plies stops the next from expanding and since the ply is so thin, it doesn't have the mass to break the bond of the glue joint with the ply on top of it. Having said that, plywood is considered dimensionally stable. While sometimes plywood may warp, it won't grow/shrink with changes in moisture.

Above I mentioned a balanced sheet. If you look at various types of plywood, you'll notice the outside faces of the plywood both have grain that runs the same direction and that there is an odd number of plies in the sheet. If the plies weren't balanced, and the top face ran vertically and the bottom face ran horizontally, and then you change the moisture content of that sheet of plywood, the plywood would warp like crazy. Panels expand across their width. Balanced plywood balances out the expansion equally on both faces and stops itself from warping. Unbalanced sheets would have the outer layer expand across its width and since there's not an equal opposing force on the opposite face of the sheet, it will grow and warp the sheet.

Let's take it one deeper. Let's say you want to build a table. You decide to use 3/4" plywood on the bottom and you have some 3" x 3/4" tongue and groove flooring that you want to use for the top. You glue the flooring to each adjacent piece and to the plywood and get everything laid up beautifully. You come in to the shop the next day and find that the whole thing warped. What happened? You just created an unbalanced sheet. The flooring on the top became bonded to the plywood. It expanded and the plywood couldn't stop it from moving. The only way to counter that is to put the same thickness and same grain direction material on the bottom of the plywood to once again create a balanced sheet.
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post #23 of 30 Old 01-06-2018, 07:24 PM
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LET's stop this now..... I made the comment....I'm sorry you took it harsely. YES, I didn't go back and research you or your past posts PRIOR to me posting or speaking (lesson learned NEVER post when tired!!!!) I just took the number....I have since read and found most are re tools and other various things (as you stated) BUT not much with working wood on the first page or 2 listings of posts started.

I'LL TAKE MY LASHINGS!!!!!

Sanchez explained the wood design and movement better than any I've ever read as a plain simple to understand.

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post #24 of 30 Old 01-07-2018, 08:51 AM
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New2woodwork, here is a book I own myself and have recommended to others multiple times. It shows a lot of basic joinery and different ways to do each. It also has a very good write-up about wood movement, and many other very useful topics.

The Complete Book of Woodworking: Step-by-Step Guide to Essential Woodworking Skills, Techniques and Tips https://www.amazon.com/dp/0980068878..._pAHuAb2V9SBMQ

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post #25 of 30 Old 01-07-2018, 08:55 AM
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We have lost this young member.

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It's very easy to rack up posts on forums - questions, responses, on going threads (what did you today etc.)



Yep, correct there

Perhaps it would have been better if you had not answered the thread at all.



Post count does not make one an expert nor does it make one knowledgeable of all the aspects of a very in depth hobby (which is what it is for me).

From machinery and tools, to wood types, to finishing, to wood turning... An endless amount of information most of the experts here have taken YEARS to absorb and are willing to share in their spare time!

I happen to greatly respect the experts and the amount of knowledge they are willing to share with people like myself.

They have given me an incredible amount confidence based on the sharing of that knowledge and their insight into the many aspects of this hobby and the many foolish questions I have asked over the past 1.5 years!

It is a hobby for me, not a job and I've been at this on and off for 1.5 years.

I have not made a table top, never heard of Breadboard before this thread, and still have no clue what a Farm Table is unless it's a table on a Farm!



If you are indeed here to help, then perhaps starting a response with "and probably sound rude" is not the most appropriate way to offer assistance!

Feel free to direct to me another thread that discusses what a Breadboard is and I'll read it and in your words "observe" it - there is no other that I could find.

Research... I looked up breadboard before asking the question - I got pages and pages of electronic circuitry results which made absolutely no sense.

So I asked a question...!!! EXCUSE ME FOR ASKING!




Too late!

If I ask too many DUMB questions, my apologies to all - I'll stop asking questions here and find another place to ask for guidance.

You really PISSED me off here @Tennessee Tim
I sent and received PMs from him. He is gone. Too bad, so sad. If a new member can't ask the most elementary questions without getting a tongue lashing from a senior member, then you can't really blame them go being offended to the point of leaving the forum. The response should not be to question the question or the questioneer, but simply to answer it.
"What the heck is a breadboard" was the question and unless you've been a woodworker were we use that term unlike 99% of the rest of the world, it will be confusing. Of the 5 breadboards I have, none of them have "bread board ends", so I get where he's coming from. Not everyone, in fact most folks who ask a question here have not researched it beforehand. Call it lazy, call it the new world of millenials, call it frustrating, it gets to me also. When I end up doing the research often I learn a bit more myself, but not always.
Well it's too late now for this member who said he may just drop in at times... we'll justy have to see what happens.
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The answer to your question will only be as detailed and specific as the question is detailed and specific. Good questions also include a sketch or a photo that illustrates your issue. (:< D)
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post #26 of 30 Old 01-07-2018, 12:09 PM
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I sent and received PMs from him. He is gone. Too bad, so sad. If a new member can't ask the most elementary questions without getting a tongue lashing from a senior member, then you can't really blame them go being offended to the point of leaving the forum. The response should not be to question the question or the questioneer, but simply to answer it.
"What the heck is a breadboard" was the question and unless you've been a woodworker were we use that term unlike 99% of the rest of the world, it will be confusing. Of the 5 breadboards I have, none of them have "bread board ends", so I get where he's coming from. Not everyone, in fact most folks who ask a question here have not researched it beforehand. Call it lazy, call it the new world of millenials, call it frustrating, it gets to me also. When I end up doing the research often I learn a bit more myself, but not always.
Well it's too late now for this member who said he may just drop in at times... we'll justy have to see what happens.

I will email him I liked him, not everybody knows everything, hell I have been doing woodwork for about 50 years, I did get out of it for a while, not out of it just not letting it consume all my extra time, that was already taken when I opened my own bidness, but when i first heard bread board a couple years ago I was wondering WTF it was too
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post #27 of 30 Old 01-07-2018, 02:53 PM
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He said he'd take his lashings............
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post #28 of 30 Old 01-07-2018, 06:31 PM
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won't a good seal multiple layered finish to both sides of the table top to a breadboard style table top reduce or stop the expansion due to variations of humidity over time.?
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post #29 of 30 Old 01-07-2018, 08:06 PM
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Originally Posted by woodnthings View Post
I sent and received PMs from him. He is gone. Too bad, so sad. If a new member can't ask the most elementary questions without getting a tongue lashing from a senior member, then you can't really blame them go being offended to the point of leaving the forum. The response should not be to question the question or the questioneer, but simply to answer it.
"What the heck is a breadboard" was the question and unless you've been a woodworker were we use that term unlike 99% of the rest of the world, it will be confusing. Of the 5 breadboards I have, none of them have "bread board ends", so I get where he's coming from. Not everyone, in fact most folks who ask a question here have not researched it beforehand. Call it lazy, call it the new world of millenials, call it frustrating, it gets to me also. When I end up doing the research often I learn a bit more myself, but not always.
Well it's too late now for this member who said he may just drop in at times... we'll justy have to see what happens.
Unfortunately, such is the nature of many members on many forums. They have some amount of knowledge in their little world, and it makes them feel good to criticize & belittle someone trying to learn. The challenge is to learn to ignore them & listen only to the more helpful members.
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post #30 of 30 Old 01-08-2018, 10:33 AM
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"What the heck is a breadboard" was the question.


I don't think the op realized that he referenced a thread about breadboards and E&C.



not the first time I've seen responses a little less than friendly. should be a good lesson to all of us to remember that we are brothers (and sisters) in the woodworking industry.
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