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-   -   Breadboard ends... (https://www.contractortalk.com/f13/breadboard-ends-420477/)

Robie 07-17-2019 10:16 PM

Breadboard ends...
 
Has anyone ever gone against conventional wisdom and made sure breadboard ends were bisquited and glued along the whole width of a panel and seen it hold up without some signs of stress?

Talking about 4' x 8' x 2" counter top.

Breadboard end was installed so the glued-up boards couldn't move...like it was a solid extension of the glued up boards.

I've always made mine so the boards could move in and out with the seasons.

But a guy I know says...It'll be fine all glued up so nothing can move.

Thoughts?

Idothat 07-17-2019 11:04 PM

Id say no , gluing solid cross grain will not hold up in the long term, especially at a 4 width. If the joint fails in a manner that it releases without splitting the countertop, you got lucky.

pinwheel 07-18-2019 01:54 AM

All well & good as long as you keep the exact same humidity 100% of the time. But that's not gonna happen & when the wood looses moisture, it's gonna split.

rrk 07-18-2019 06:14 AM

I know someone who has an island top 40" wide like that every winter it splits when the heat is on and in the summer it looks fine.

Deckhead 07-18-2019 06:18 AM

Works great for these types of things.

https://festools-online.com/201350-f...RoCfAQQAvD_BwE

BlueRidgeGreen 07-18-2019 07:10 AM

Funny you should ask.

I did one exactly of those dimensions last year.

Walnut.
Beautiful.

I was concerned about it.
But.....I guess we did something right.

Ive visited it over the past ....15 months(?) many times.
Last week in fact.

It never showed even a millimeter of movement, through humid Virginia summers (last year it rained like every day), nor did it move after going from that to really dry forced air heating conditions.

I was very pleased.


Sent from my iPhone using Tapatalk

Leo G 07-18-2019 07:42 AM

Quote:

Originally Posted by Robie (Post 7581841)
Has anyone ever gone against conventional wisdom and made sure breadboard ends were bisquited and glued along the whole width of a panel and seen it hold up without some signs of stress?

Talking about 4' x 8' x 2" counter top.

Breadboard end was installed so the glued-up boards couldn't move...like it was a solid extension of the glued up boards.

I've always made mine so the boards could move in and out with the seasons.

But a guy I know says...It'll be fine all glued up so nothing can move.

Thoughts?

(Troublemaker)

I have a tiger maple coffee table that I glued solid with breadboard ends. It's been nearly 2 decades and it hasn't moved or cracked/split. But it is also only 22" wide.

Most of them I do a tongue and groove and pin them with a wood dowel so they can move.

Deckhead 07-18-2019 12:34 PM

There are tricks that you can do to make it successfully, it just takes some extra skill.:thumbsup:

Always cool to see a quality carpenter do something when people say something cant be done. Common practice isnt always the best method.

Deckhead 07-18-2019 12:46 PM

Quote:

Originally Posted by BlueRidgeGreen (Post 7581977)
Funny you should ask.

I did one exactly of those dimensions last year.

Walnut.
Beautiful.

I was concerned about it.
But.....I guess we did something right.

Ive visited it over the past ....15 months(?) many times.
Last week in fact.

It never showed even a millimeter of movement, through humid Virginia summers (last year it rained like every day), nor did it move after going from that to really dry forced air heating conditions.

I was very pleased.


Sent from my iPhone using Tapatalk

No way he was talking about something you built. That would be cowardly to try to talk bad about something you did without outright confronting you. I'm sure he would have just said, BRG did "x" what do you guys think? Hes not such a pussy he wouldnt just say your name.

Maybe he was hoping to be able to learn some of the tricks you applied to do it.

Robie 07-18-2019 02:20 PM

Yeah, that's it.

hdavis 07-18-2019 03:44 PM

I actually like the question.

The classic case is in door panels which are supposed to float, but they got glued in with paint or finish.

Some will crack, but Not all.

I don't know if any database where you could look up all the relevant wood properties and calculate an answer. Certainly some of this brings up kiln schedules, once the surface if the wood could be in tension or compression before doing anything with it.

Plywood does fine, so it isn't a bummer that it will or won't split.

Leo G 07-18-2019 03:52 PM

Wood Shrinkage Calculator:

http://www.woodweb.com/cgi-bin/calcu...ator=shrinkage


The relationship between moisture content (as well as the equilibrium moisture content “EMC”) of wood and relative humidity can be studied and approximated for a given temperature. It is clear that for each value of relative humidity “h”, there is a corresponding value of EMC. Therefore, EMC can be plotted as a function of relative humidity. True for most of North America, 30% to 50% relative humidity corresponds to 6% to 9% EMC. The EMC values of solid wood are generally greater than wood composites.

For a reasonable estimation of the true target EMC at any value of relative humidity and temperature, the following equation may be used:

EMC = [ -ln (1 – ϕ) / 4.5 x 10-5 ( T + 460 ) ] 0.638
where

ln = natural logarithm

ϕ = relative humidity expressed as a decimal

T = temperature in F


https://www.wagnermeters.com/moistur...sture-content/

Leo G 07-18-2019 04:23 PM

Humidity, Temperature, Wood Moisture Content, and Wood Movement
Basic technical information and an extended discussion of the way wood expands and contracts in response to changes in temperature and humidity. November 13, 2009


From Gene Wengert, forum technical advisor:
From time to time, there are postings that involve the movement of wood. Here is some information that may be helpful. Wood does not shrink or swell in use except if its MC changes. Its MC changes when the RH changes. (Of course, if the wood is at the wrong MC when first put into use, it will adjust to achieve equilibrium with its environment and therefore may shrink or swell initially quite a bit.) Temperature alone does not cause any significant size change in wood. Heating does causes moisture changes to occur faster.

The basic relationship between MC and RH is given below, with a third column for the equilibrium moisture content (EMC) which is a property of the air.
0% RH = 0% MC = 0% EMC
30% RH = 6% MC = 6% EMC
50% RH = 9% MC = 9% EMC
65% RH = 12% MC = 12% EMC
80% RH = 16% MC = 16% EMC
99% RH = 28% MC (approx.) = 28% EMC (approx.)

Note that most heated homes and offices will run 6% EMC in the wintertime and even a bit lower. In the summertime, 9% EMC is common. Outside in most of North America, the outside is 12% EMC, summer and winter. In coastal locations, 16% EMC outside is common.

When air is heated, its RH drops unless moisture is added (that is, the air is humidified). For example, if it is 30 degrees F outside and 100% RH = 28% EMC; snowing or foggy perhaps) and that outside air is brought into a home or office and heated, the following will be seen:
Heated to 40 F will result in 68% RH and 13% EMC.
Heated to 50 F will result in 47% RH and 9% EMC.
Heated to 60 F will result in 34% RH and 7% EMC.
Heated to 70 F will result in 24% RH and 5% EMC.

Note in the above that a home with plants, cooking, bathroom showers and so on will add moisture, so these values might be a bit low, but not much. Of course, using a humidifier will increase these values; offices are not humidified too often, although such higher humidity would help keep static off of paper used in high speed copy machines, etc.

Because purchased wood is often around 9% MC (actually too high, but that is reality for some folks; I suggest 7.5% maximum MC) and a shop can run around 5% EMC, some folks are tempted to increase the shop air to about 50% RH. Indeed this will eliminate problems in manufacturing, but it actually only postpones the shrinkage until the customer gets the wood in his/her dry home or office. Do not over-humidify a shop.

Checking and recording on paper the MC of wood you are using and the RH of your shop using fairly inexpensive instruments is a prudent thing to do. It provides documentation to prove that you did the right thing regarding MC so that subsequent MC problems are not your fault - assuming you would not use wood that had incorrect MC readings and that you would not keep a shop at the wrong RH or EMC. (Sometimes this approach is called CYA.)

Once a piece of wood or a wood product is put into a fairly tight container, including wrapped in plastic or into a closed truck or trailer van (that is, liquid water cannot get in and there is little RH exchange with the outside), the MC will not change in transit or storage, regardless of the temperature. For 100 pounds of wood to change by 2% MC will require the addition or loss of one quart of water...that is a lot of water to be brought into a container by merely exchanging a small amount of air with the outside. It would involve bringing in more than 1000 cubic feet of humid air and this is just for one 100 pound piece of cabinetry, furniture or flooring.

http://www.woodweb.com/knowledge_bas..._Moisture.html

DaVinciRemodel 07-18-2019 06:02 PM

Quote:

Originally Posted by Robie (Post 7581841)
Has anyone ever gone against conventional wisdom and made sure breadboard ends were bisquited and glued along the whole width of a panel and seen it hold up without some signs of stress?

Talking about 4' x 8' x 2" counter top.

Breadboard end was installed so the glued-up boards couldn't move...like it was a solid extension of the glued up boards.

I've always made mine so the boards could move in and out with the seasons.

But a guy I know says...It'll be fine all glued up so nothing can move.

Thoughts?

Will the guy you know stand behind the method?

The piece seems a little big for a solid glue-up.

Like Leo, I've done some smaller pieces that way - plus I'm in a desert climate.

Deckhead 07-18-2019 07:26 PM

Quote:

Originally Posted by Robie (Post 7582137)
Yeah, that's it.

Nice. Glad we cleared that up.

When I get to my computer in the morning I'll post the link that I use for all my scientific side research on wood. It can get you really stuck in a time suck looking at different tests and studies.

Biggest thing for moisture loss and gain is a complete end grain coverage and a board with no grain run out which concentrates the moisture loss on the end grain. It can be done successfully but has to be carefully selected and then some steps need to be taken in the process to allow movement as a whole...

Robie 07-18-2019 07:53 PM

Quote:

Originally Posted by DaVinciRemodel (Post 7582237)
Will the guy you know stand behind the method?

The piece seems a little big for a solid glue-up.

Like Leo, I've done some smaller pieces that way - plus I'm in a desert climate.

Dunno. When I spoke to him, he thought his method was how it was done.

I explained it wasn't but...he knew better.

Robie 07-18-2019 08:23 PM

Quote:

Originally Posted by Deckhead (Post 7582261)
Nice. Glad we cleared that up.

When I get to my computer in the morning I'll post the link that I use for all my scientific side research on wood. It can get you really stuck in a time suck looking at different tests and studies.

Biggest thing for moisture loss and gain is a complete end grain coverage and a board with no grain run out which concentrates the moisture loss on the end grain. It can be done successfully but has to be carefully selected and then some steps need to be taken in the process to allow movement as a whole...


Please explain those steps.

I have searched and searched and am unable to find one article that states gluing a breadboard end to a solid panel, tight, with no allowance for movement is "a method".

Morning Wood 07-18-2019 08:36 PM

For something 2 thick I tend to leave the end grain exposed. I just sand the crap out of it and finish it along with the rest. I think it looks cleaner that way.
But, if I was capping the end grain I think Id definitely allow for movement.

Deckhead 07-18-2019 08:54 PM

Quote:

Originally Posted by Robie (Post 7582327)
Please explain those steps.

I have searched and searched and am unable to find one article that states gluing a breadboard end to a solid panel, tight, with no allowance for movement is "a method".

If I had an owner who absolutely insisted on having it all glued I would do the following. Selection of wood is the absolute here. It all has to be close in moisture content from the beginning.

1) select wood that has little to no grain run out, or buy it wide and rip it so there is no grain run out.

2) make a tenon out of the end grain on the end of the glue up. And cut mortise to fit in the end board.

3) rub all the end grains with acetone and then coat with a thin coat of epoxy

4) sand the end grains with 120

5) attach breadboard with a flexible epoxy and an added silica (g-flex with silica strands works well)

6) absolutely no mechanical fasteners within six inches of the end of the top. And preferably floating machanical fasteners throughout the top.

The key is to reduce the moisture loss/gain in the glue up. That's what sealing the ends helps with. The other thing that is of utmost importance is allowing the wood to move together. As long as it's a really solid connection, and you have the end grains sealed on the end board, it will move together. The biggest deal isnt glue up with as much as it is the end board width.

The T/R percentage is a big factor and if you're using a really wide end board you are going to have more movement opposite the glue up, which will promote the splitting. If however, everything can move at once it SHOULD stay together.

Also I would not seal the bottom side as that could create a serious desire for cupping and split the glue up.

I've done it this way a few times and it seems to be working. I did some similar on outdoor stuff and it still hasn't split or opened up. It can be done, it just has to be done with forethought and even then isnt fool proof. You have to know the wood your working with pretty well.

Robie 07-18-2019 08:59 PM

Quote:

Originally Posted by Deckhead (Post 7582103)
There are tricks that you can do to make it successfully, it just takes some extra skill.:thumbsup:

Always cool to see a quality carpenter do something when people say something cant be done. Common practice isnt always the best method.

Quote:

Originally Posted by Deckhead (Post 7582351)
If I had an owner who absolutely insisted on having it all glued I would do the following. Selection of wood is the absolute here. It all has to be close in moisture content from the beginning.

1) select wood that has little to no grain run out, or buy it wide and rip it so there is no grain run out.

2) make a tenon out of the end grain on the end of the glue up. And cut mortise to fit in the end board.

3) rub all the end grains with acetone and then coat with a thin coat of epoxy

4) sand the end grains with 120

5) attach breadboard with a flexible epoxy and an added silica (g-flex with silica strands works well)

6) absolutely no mechanical fasteners within six inches of the end of the top. And preferably floating machanical fasteners throughout the top.

The key is to reduce the moisture loss/gain in the glue up. That's what sealing the ends helps with. The other thing that is of utmost importance is allowing the wood to move together. As long as it's a really solid connection, and you have the end grains sealed on the end board, it will move together. The biggest deal isnt glue up with as much as it is the end board width.

The T/R percentage is a big factor and if you're using a really wide end board you are going to have more movement opposite the glue up, which will promote the splitting. If however, everything can move at once it SHOULD stay together.

Also I would not seal the bottom side as that could create a serious desire for cupping and split the glue up.

I've done it this way a few times and it seems to be working. I did some similar on outdoor stuff and it still hasn't split or opened up. It can be done, it just has to be done with forethought and even then isnt fool proof. You have to know the wood your working with pretty well.

Pretty sure your method wasn't done.

In fact...I'm sure of it.


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