Front Door

[Boxy]

I'd like to glue 10mm t&g mahogany to plywood for an outside door.
Will the glue prevent expansion and movement as the seasons change?

 

[Bradshaw Joinery]

It wont, Your probably best to just pin them on, or glue the board to both sides of the ply, to prevent it from warping. Definitely not just one side, it will bend like a banana. Put some expansion gaps in too.

 

[Boxy]

Yes I'll do both sides.
Surely the glue will hold it fast being only 10mm thick?

Hardwood flooring is glued down over wide areas. So how come it doesn't move as humidity levels rise and fall and heating turned on and off?

If it was just tacked on then surely rain will penetrate easily?
I'd like a door that is sealed, solid and water proof for many years and has the beauty of natural hardwood.

 

[Racers]

Hardwood flooring is glued with glue that allows movement so the boards can expand and contract, and the underfloor is just about unbendable so resists the forces.
If you pin the boards on to the plywood the door will only be as strong as the ply, there are reasons that frame and panel door are made they way they are.

Pete

 

[Max Power]

Why do they need to be 10mm thick ? You would encounter fewer problems if yo made them 2mm or so

 

[Boxy]

I'll have 25mm ply in the middle and 10mm mahogany on both sides. That makes the door 45mm thick. So should be pretty beefy.

2mm sounds thin.
Does anyone know the maximum thickness off a mahogany veneer when gluing to plywood that will remain stable?

Thanks again.

 

[andersonec]

5mm.

This guy makes engineered flooring boards up to 12" wide with 5mm timber stuck onto 18mm Birch ply, he cuts his own timber and finishes it to 5mm, there is no movement on a 12" board, they are glued on with PU glue.

http://www.billinghaysawmill.co.uk/

Andy