Wooden doors laminate stop from bending?

[Samer]

Hi everybody ,
Does anyone know  how to stop wooden doors (solid laminate) from bending ?
I did laminate Rimu wood slices = 450 x100x19mm , i did check all pieces edge = 90 degrees exactly, joined them all with domino and glue up all together with pva glue and then left it overnight on parallel jet clamps. after a couple of days after installed on the cabinet the door started to bend outwards .  [eek]

 

[Samer]

Some pics

 

[Samer]

Pictures door

 

[junk731]

Samer

Looks like from your pics its the wider flat sawn boards that are warping. The quarter sawn appears straight. I'm not familiar with the wood your using but did you check the moisture content and did you allow the wood to climatize before and after cutting and planing. You may want to consider using narrower quarter sawn for your door panels and use the flat sawn cut narrower for the supporting structure.

John

 

[Alan m]

if they dont straighten. let them bend as much as they want for a few days.
then cut kerfs in the back , force it flat or a touch more. then fill the kerfs with cascamite etc. then veneer over it .

 

[mattfc]

first questions was how newly cut were the strips you joined. would tends to curve round to the shape of the "rings" running through it. Whne you re-saw you will often get the wood bowing with the rings quite quickly. The way normally to try and miniminse this, so if you look from the top (will try and who the shape with text) you do this "un"rather than "uu" or "nn" so they even themselves out. Make sense?

 

[Timtool]

i'm not certain but it appears that you didn't systematically alternate the growth ring direction. And the sections that are glued together are quite wide, really risky to do that, if they are not perfectly dry it will warp.

either make new doors with less wide strips of wood and make sure you alternate the growth rings so the eventual warping cancels itself out.

Or you could reinforce the doors at the back with rails, or cut the top and bottom of the door and place a rail there with tongue and groove joint.

 

[Rob-GB]

As Mattfc says regarding growth ring direction, though also, smaller section size would help (450x50x19) if quarter sawn is hard to get or consider "breadboard ends" as one would make thin table tops or...breadboards. These act to restrain any cupping.
The main cause for this problem is through shrinkage by drying out, hence the notes on moisture, and it works like this;
Cut a tree down and you will see the growth rings in both stump and trunk, they are concentric, some wider or darker than others but each journey outward from the centre. When boards are sliced off one after the other across the log (and along the length) the majority of them will have concentric rings that are longer along one face than the other, these growth rings will dry at the same rate but the longer ones will lose more moisture than the shorter ones over their length and contract/shrink at a greater rate causing the movement (cupping). Adding moisture to dry wood has the opposite effect, pretty much, and from your photos one can not specify the main cause...end grain shots would be better showing how this timber has cupped etc. Again, Rimu as a species is not one I am familiar with so a botanical/latin name may shed some light on it's attributes.

Rob.

 

[mattfc]

this link has some more detail and pics to demonstrate
http://thewoodwhisperer.com/avoiding-cupped-panels/

here is an exaggerated picture re alternating the grain

 

[mouppe]

Same thing happened to me in my early woodworking days. If you want the clean, solid wood look as opposed to a frame and panel door, you may have to go with a veneered door, or select really stable quartersawn wood.

 

[semenza]

Hi,

Same finish inside and outside?

Seth

 

[Samer]

Thanks all for the comments,
Rosemberger i didnt check the moisture, will study about that
SRSemenza  i did use this oil in all cabinet http://www.supremeoils.co.nz/haarlem-oil.html  very good oil and smell good too
will let the door on clamps to get back straight then will make a grove on bottom and top of the door , and glue same hard wood , soon i finish i will post back .
Cheers ....

 

[Captainwrinkles]

Hey Samer,

I worked for Danske Mobler for 6 years back in the day. All the Rimu doors we made had 2 "braces" screwed onto the backside of them to reduce the bowing/twisting/cupping your dealing with. Basically a piece of Rimu about 30mm wide by 19mm thick and about 70mm shorter than the width of the doors. I think that a small bead of glue was applied along the middle of the piece and screwed at each end to the backside of the door. This seemed to reduce the movement of most of the doors.

But then again, all the doors were sealed and finished with lacquer, not oil. so maybe that was the big factor to stop movement.