Rabbet for mirror frame

Hello, all.
I am making a mirror frame (yes, I did a google search). I plan to make it for a 36" x 48" x .5" mirror using some free wide pine flooring that came with my house. I plan to use half-laps for the corner joints with gorilla glue, and will use a piece of hardboard for the backing that will not be inside the rabbet I make for the mirror.
Here is my question: given the mirror's dimensions, how much extra space should I allow for dimensional change of the wood? Should I just cut a rabbet that will allow exactly a 36" x 48" x .5" mirror, or should I allow slightly more space? I am a newbie, and would appreciate any advice y'all could give.
Thanks in advance.
-Barry K.
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Dimensional change will be negligible because wood shrinks and swells perpendicular to the long grain. In a picture frame wood movement will have very little effect on your design.
However, I would make the rabbet opening a total of 1/8" or so larger in each dimension than your mirror, just to make it easier to install the glass.
Jay
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"BKeane71" wrote in message

Wood movement should not be much of a factor providing your frame is not ridiculously wide ... just allow enough room for easy installation of the glass: 1/8th all around should be ample.
Consider pegging the half-lap joints with a contrasting wood for extra strength and appearance.
--
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Hummmm....half inch glass, 12 sq. feet of the stuff....about 75 lbs worth of mirror. One heavy dude to hang on the wall.
Larry
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WHOOPS!
Sorry, folks. After posting, I realized that the thickness dimension was incorrect. It should read 0.25 inches, not the .5 inches. Whooo, that would be one heavy mirror, eh?
Thanks.
Barry K.
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: : Sorry, folks. After posting, I realized that the thickness dimension was : incorrect. It should read 0.25 inches, not the .5 inches. Whooo, that would : be one heavy mirror, eh?
A tip. General practice is to paint the faces of the rebate with a matt black paint.
This helps to avoid showing a reflection of the inside of the rebate.
Jeff G
-- Jeff Gorman, West Yorkshire, UK Email address is username@ISP username is amgron ISP is clara.co.uk Website www.amgron.clara.net
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snipped-for-privacy@aol.com (BKeane71) wrote in

Still gonna be somewhat heavy. Make certain you think through the provisions for hanging/securing the piece.
Patriarch
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Thanks...that's a very good tip!
-- DaveinFLL =========================It's not the heat, it's the humidity! =========================(..Think the humidity's bad? You should watch us vote!)
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