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Gluing Info

picture framing clamps by MasterClamp 2021

David Waldmann

Herder of cats
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Feb 6, 2002
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Vermont Hardwoods
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Saw this on a FB group yesterday. Fascinating info.

Myth #1 totally blew me away.

Myth #2 was exactly as I expected (only because I had already watched Myth #1) until about 75% of the way through when he showed that a "perfect" miter was not required as far as strength goes. Totally unexpected.

Highly recommend both videos.
 

Greg Fremstad

MGF, Master Grumble Framer
Joined
Sep 4, 2002
Messages
971
Location
Eugene OR
I wonder which direction a mitered joint would fail. Bending across the joint as shown in the videos is not how frame joints fail in my weak opinion. Think of the weight of the glass-art-backing package pushing down on the bottom rail of the frame when hanging on the wall. I feel that this is the direction of force in a frame. I find it interesting that wood expands/contracts across the grain but hardly any along the long axis. Some food for future testing.
 
picture framing clamps by MasterClamp 2021

Rick Hennen

CGF, Certified Grumble Framer
Joined
Dec 7, 2017
Messages
106
Location
Jamul, CA 91935
Business
Rian Fabrication Services
I have created extra long liners - 12 ft up to 18 ft so far - out of 15MM and 18MM Ultralight MDF by mitering the ends of 2 lengths and edge gluing the miters together. I always figured that cutting the miters instead of gluing 90 degree edges gave me a longer glue seam and as a result it would be stronger. Been doing this for over 20 years and have never had one fail.
 

David Waldmann

Herder of cats
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Joined
Feb 6, 2002
Messages
8,098
Location
Chester, Vermont USA
Business
Vermont Hardwoods
I have created extra long liners - 12 ft up to 18 ft so far - out of 15MM and 18MM Ultralight MDF by mitering the ends of 2 lengths and edge gluing the miters together. I always figured that cutting the miters instead of gluing 90 degree edges gave me a longer glue seam and as a result it would be stronger. Been doing this for over 20 years and have never had one fail.
MDF has a pretty homogenous structure, unlike solid wood. So I bet that a scarf joint WOULD be stronger in MDF.

Speaking of which, occasionally we have made pieces over 16' (generally the longest commercially available length) by doing an approximately 15° scarf joint. While it always feels dicey, we have run said material through a saw and planer and it has always held together. Not sure how an end-grain joint would fare, but it also would be really hard to clamp an end-grain joint on a 20-24' piece...
 

Rick Hennen

CGF, Certified Grumble Framer
Joined
Dec 7, 2017
Messages
106
Location
Jamul, CA 91935
Business
Rian Fabrication Services
MDF has a pretty homogenous structure, unlike solid wood. So I bet that a scarf joint WOULD be stronger in MDF.

Speaking of which, occasionally we have made pieces over 16' (generally the longest commercially available length) by doing an approximately 15° scarf joint. While it always feels dicey, we have run said material through a saw and planer and it has always held together. Not sure how an end-grain joint would fare, but it also would be really hard to clamp an end-grain joint on a 20-24' piece...
How did you arrive at 15 degrees for your scarf cuts? Of course the other consideration to these longer lengths is the shipping costs.
 

David Waldmann

Herder of cats
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Feb 6, 2002
Messages
8,098
Location
Chester, Vermont USA
Business
Vermont Hardwoods
How did you arrive at 15 degrees for your scarf cuts? Of course the other consideration to these longer lengths is the shipping costs.
We typically start with WAGs and modify if needed...

Not sure we ever shipped anything that long - it was most likely local delivery/pickup.
 

alacrity8

SGF, Supreme Grumble Framer
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Joined
Sep 22, 2009
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1,304
Location
Albany, NY
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We typically start with WAGs and modify if needed...
images



Huh?
 
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Keencut Ultimat Futura Precision Mat Cutter
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