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Forum topic by beekman001 posted 01-07-2018 02:51 AM 1396 views 0 times favorited 16 replies Add to Favorites Watch
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beekman001

9 posts in 327 days


01-07-2018 02:51 AM

I’m considering making an exterior door along the lines of this

I’m intending on face gluing the boards into appropriately wide stiles then using a domino joiner to put in the rails for the window openings. Flattening the door is of little concern as I have access to both a 36” wide thickness planer and 48” wide belt sander.

This brings up a few questions:

1) I learned long ago to always make a cheap trial unit. In this case I’ll be using 2×3s. The door will be well sealed with a coat of epoxy primer then painted. What kind of performance can the person who gets the trial version expect? What problems should they look out for?

2) I intend on routing out the back side of the window openings and holding the window glass in place with molding from the back. Is a bead of silicone caulk going to provide sufficient water proofing?

3) for my “real” unit, I was intending on using Ash. What kind of sealing should I apply to the end grain other than the epoxy primer?


16 replies so far

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cabmaker

1740 posts in 2930 days


#1 posted 01-07-2018 02:47 PM

can you explain what you mean by face gluing appropriately wide stiles ?

View a1Jim's profile

a1Jim

117204 posts in 3698 days


#2 posted 01-07-2018 02:56 PM

My father-in-law was a sash and doorman for over 65 years, what he use to do is take short pieces of wood(10-12”pieces) and finger joint them together and apply a 1/4” veneer on both sides, this made a very stable door eliminating any bowing or twisting, he made some doors that were 12’ tall and 5’ wide this way.

-- https://www.artisticwoodstudio.com/videos wood crafting & woodworking classes

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beekman001

9 posts in 327 days


#3 posted 01-07-2018 02:56 PM

Cabmaker, Like This:

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John Smith

1314 posts in 284 days


#4 posted 01-07-2018 03:03 PM

what part of the country do you live in ?
what direction will the door be facing ?
will the door be under a porch ?
I would use tempered double pane glass.

.

-- some people are like a Slinky - - - pretty much good for nothing. But still make you smile when you push them down a flight of stairs.

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Knockonit

450 posts in 323 days


#5 posted 01-07-2018 03:09 PM

Well I live in Arizona, hot dry and not a friend to woodl

When i built my front door (42’‘x 7ft x 2-1/4’’ thick)

I used a piece of 3.4 marine grade plywood and laminated knotty alder to it, of course plywood was let into the side and top and bottom styles, put a speak easy type window in it,
Been up about 6 years now, simple stain job with a few coats of satin urethane, it is on the north side of house, is protected by entry, however in summer does see a smidgen of sun, but at present it holds up well.
Some of the alder did dry out some, mostly at mortise and tendon of frame, but did fill with epoxy, as it happened.
I let it dry in shop for a few months before installing.
Used ball catches up and down on latch side,
all in all turned out awesome, lots of compliments on door,
Outside is a almost harringbone T&G type finish, inside is a different pattern.

good luck, i enjoy building doors, just remember, they shrink, move ect, pending on the weather, especially if its not sealed properly.
Rj in az.

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beekman001

9 posts in 327 days


#6 posted 01-07-2018 03:12 PM

John:

what part of the country do you live in ? Philadelphia so fairly wide extremes with high humidity.
what direction will the door be facing ? The ash version will face south west. Others I don’t know.
will the door be under a porch ? The ash version will, others I don’t know.
I would use tempered double pane glass. Agreed o found a place in my area which can make argon filled double panes.

View jerryminer's profile

jerryminer

944 posts in 1562 days


#7 posted 01-08-2018 05:50 AM

I think the issue you will have with this door—as designed—will be that the width will change fairly significantly with the seasons. a typical entry door system will not tolerate more than about 1/8” variation in width. I think you will see more variation than that with this door. Wood moves.

A better approach, IMHO, would be to veneer a stable substrate (ply, mdf, or even particle board)—with solid stiles and rails at the perimeter. (That’s the way the “big boys” (i.e. manufacturers) build their doors.)

-- Jerry, making sawdust professionally since 1976

View clin's profile

clin

920 posts in 1117 days


#8 posted 01-08-2018 06:51 AM

I think jerry is on to something concerning the width changing. Gluing up a bunch of smaller boards doesn’t change the fact that wood changes a lot across the grain. Even a 1 percent change in dimension is not out of the question and on a 36” wide entry door, that’s about 3/8”. There’s a reason traditional doors are made with frames with inset panels. The bulk of the frame width is in the direction of the grain for the rails. So the width doesn’t change that much.

Looking at a table, quarter sawn Ash (the best orientation you could use) changes by 0.17% per % change in moisture content of the wood. I don’t think a 5% change in the moisture content of the wood is out of line, and 10% or more could happen depending on the humidity changes you have. 0.0017 5 = 0.85% 36” = 0.31”.

If it were oriented flat sawn, the change is 0.26% per percent moisture change so this would be 0.0026 5% = 1.3% 36” = 0.468”

But according to Jim, his father-in-law had success with something similarly constructed with veneers on it. So maybe there’s a reason that wouldn’t be that much of a problem.

Perhaps having inside air on one side and outside air on the other reduces the humidity extremes the wood sees. Obviously the wood finish would affect this. But I think that just slows the changes in moisture content rather eliminating them.

-- Clin

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a1Jim

117204 posts in 3698 days


#9 posted 01-08-2018 03:09 PM

Jerry is right wood still moves across the grain but far less when it’s quarter sawn. I considered my father-in-law a woodworking genius, he did work for Disney land and numerous movie stars that no one else knew how to do.

-- https://www.artisticwoodstudio.com/videos wood crafting & woodworking classes

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Mario

181 posts in 3517 days


#10 posted 01-08-2018 03:28 PM

I build a lot of custom doors, for the AZ weather, follow JimĀ“s advice, ash is not a very stable wood to be used in solid rails and stiles

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beekman001

9 posts in 327 days


#11 posted 01-10-2018 05:07 PM

Clin—Where are you getting your table & calculations? The one I found from the forestry service, seems to indicate that my design would change around 0.1199” in width and 0.0113” in thickness.

to review: My door will be made of 24, 1.5” thick flat sawn ( illustration of saw terms ) boards face-glued ( illustration of face ,edge, and end grain ) to achieve a 36” wide door.

Given that design most of the expansion along the width of the door will be along the radial direction of the grain and most of the expansion along the thickness will be in the tangential direction.

The expansion formula is D(delta) = D(initial) C(X) (M(final)-M(initial))

Per the chart on page 4 my maximum moisture content variance, M(final)-M(initial) in Philadelphia is 1.8 (min 11.2, max 13)

for Douglass Fir (2×4’s) my C® = 0.00165, C(T) = 0.00267
for White Ash my C® = 0.00169, C(T) = 0.00279

Since no board is every really fully flat or quarter sawn, and these values are fairly similar, I’ll be using the following values:
C® = 0.00185 because there’s some tangential expansion but not much
C(T) = 0.00279 as a worst-case

so,
my width expansion would be 36 1.8×0.00185 = 0.119
my thickness expansion would be 2.25×1.8×0.00279 = 0.0113

Is there anything wrong with my reasoning about the grain direction or math here?


I think jerry is on to something concerning the width changing. Gluing up a bunch of smaller boards doesn t change the fact that wood changes a lot across the grain. Even a 1 percent change in dimension is not out of the question and on a 36” wide entry door, that s about 3/8”. There s a reason traditional doors are made with frames with inset panels. The bulk of the frame width is in the direction of the grain for the rails. So the width doesn t change that much.

Looking at a table, quarter sawn Ash (the best orientation you could use) changes by 0.17% per % change in moisture content of the wood. I don t think a 5% change in the moisture content of the wood is out of line, and 10% or more could happen depending on the humidity changes you have. 0.0017 5 = 0.85% 36” = 0.31”.

If it were oriented flat sawn, the change is 0.26% per percent moisture change so this would be 0.0026 5% = 1.3% 36” = 0.468”

But according to Jim, his father-in-law had success with something similarly constructed with veneers on it. So maybe there s a reason that wouldn t be that much of a problem.

Perhaps having inside air on one side and outside air on the other reduces the humidity extremes the wood sees. Obviously the wood finish would affect this. But I think that just slows the changes in moisture content rather eliminating them.

- clin


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clin

920 posts in 1117 days


#12 posted 01-10-2018 08:01 PM



Clin—Where are you getting your table & calculations? The one I found from the forestry service, seems to indicate that my design would change around 0.1199” in width and 0.0113” in thickness.

to review: My door will be made of 24, 1.5” thick flat sawn ( illustration of saw terms ) boards face-glued ( illustration of face ,edge, and end grain ) to achieve a 36” wide door.

Given that design most of the expansion along the width of the door will be along the radial direction of the grain and most of the expansion along the thickness will be in the tangential direction.

The expansion formula is D(delta) = D(initial) C(X) (M(final)-M(initial))

Per the chart on page 4 my maximum moisture content variance, M(final)-M(initial) in Philadelphia is 1.8 (min 11.2, max 13)

for Douglass Fir (2×4 s) my C® = 0.00165, C(T) = 0.00267
for White Ash my C® = 0.00169, C(T) = 0.00279

Since no board is every really fully flat or quarter sawn, and these values are fairly similar, I ll be using the following values:
C® = 0.00185 because there s some tangential expansion but not much
C(T) = 0.00279 as a worst-case

so,
my width expansion would be 36 1.8×0.00185 = 0.119
my thickness expansion would be 2.25×1.8×0.00279 = 0.0113

Is there anything wrong with my reasoning about the grain direction or math here?

- beekman001

I think you’ve got it. Remember I said if the moisture content changed by 5%. I have no idea what yours would be. But, I won’t argue with the table you have that says 1.8% seasonal change. I live in in Albuquerque NM, and the range according to the Forrest service table is 4.3%. I think you are fortunate your humidity is much more constant than ours, if certainly higher.

You may see something different though based on the fact that it is an entry door (or I assumed that’s what you meant be exterior door). Usually your indoor air is much drier so I don’t know if that would make it better or worse.

I know that just muddies the waters.

As for wood grain, I would use the worst case calculation. That way you know if that’s good, you won’t have a problem.

And of course as Jim said his father in law had no issues making doors similar. So it seems you would likely be fine with your relatively stable humidity and some second hand experience conveyed by Jim.

I grabbed the value for ash off this page, though misread the flat sawn as 0.0026 instead of 0.027.

http://www.finewoodworking.com/2013/08/29/calculating-for-wood-movement

-- Clin

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jerryminer

944 posts in 1562 days


#13 posted 01-10-2018 10:19 PM

You sound convinced that your shrinkage rate is within tolerances. It’s your door, so go for it. But…

I would double check your EMC numbers. I just did a quick search for humidity swings in Philadelphia and got a RH variation from 54 to 78. At 70 deg.F this translates to an EMC of 9.9 to 15.3, a variation of 5.4, not the 1.8 that you calculated.

Not trying to rain on your parade, but there is a reason that plank doors were largely abandoned on favor of frame-and-panel doors in relatively tight-tolerance situations.

-- Jerry, making sawdust professionally since 1976

View a1Jim's profile

a1Jim

117204 posts in 3698 days


#14 posted 01-10-2018 10:58 PM

Come on guys, you know any job can be analyzed to death, sure it’s good to do some research, but your doors not going to the moon, doors were made out of wood for centuries they worked then and they work now. Just start as smartly as possible, use dry 1/4 sawn wood, good joinery and use the small pieces finger jointed together with veneered edges and faces or not, time to start milling wood! Enjoy!

-- https://www.artisticwoodstudio.com/videos wood crafting & woodworking classes

View clin's profile

clin

920 posts in 1117 days


#15 posted 01-10-2018 11:05 PM



You sound convinced that your shrinkage rate is within tolerances. It s your door, so go for it. But…

I would double check your EMC numbers. I just did a quick search for humidity swings in Philadelphia and got a RH variation from 54 to 78. At 70 deg.F this translates to an EMC of 9.9 to 15.3, a variation of 5.4, not the 1.8 that you calculated.

Not trying to rain on your parade, but there is a reason that plank doors were largely abandoned on favor of frame-and-panel doors in relatively tight-tolerance situations.

- jerryminer

Jerry, I wonder if the difference is because you calculated EMC using relative humidity at a constant temperature of 70 deg F. Since the relative humidity is seasonal, I would think the temperature should reflect this as well. I don’t have the formula handy, but I suspect this might explain your calculation of 5.4% compared to 1.8%.

Also, I didn’t see where Philadelphia had 54% to 78% humidity swings during the year. Did you use daily swing by mistake? The door of course would not react much to humidity changes during a single day.

This brings up another good point. The forest service data is based on monthly averages. While this is no doubt better to use than daily swings. Wood will react significantly in a few days. We’ve all had a door that sticks when it rains (until we fix it of course).

So a week of rain will be a lot higher humidity than the average as would a week of dry weather. So it could be the monthly values are a little forgiving. And slightly more change should be allowed for. This of course is also where the wood finish makes a big difference. Finish won’t prevent changes, but it will sure slow it down.

-- Clin

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