Grain orientation for bending laminations?

[Michael Weber]

I need to laminate 1 1/2 inch wide strips of cherry around a half circle with a 10 inch diameter. What is the proper or best grain orientation to minimize breakage. Assuming I will be using flat sawn 6/4 cherry would the laminations come from the edge of the board? Or would the proper thing to do be to rip off 1 1/2 inch pieces and then cut the laminations from the face of the wood? Hope that makes sense. I was planning 18 laminated pieces each 3/32 inch thick. Thanks, Mike

[Brandon Shew]

Cut the laminations so the grain runs lengthwise. I would cut off the edge/side of the piece, but you could cut from the face if so desired.

[Michael Weber]

Cut the laminations so the grain runs lengthwise. I would cut off the edge/side of the piece, but you could cut from the face if so desired.
Thanks Brandon. So your saying it doesn't really matter which orientation is used and one is no more likely to break than the other? If so, then I'll just make the strips from thinner stock and save the 6/4. Mike

[Tom Veatch]

... Or would the proper thing to do be to rip off 1 1/2 inch pieces and then cut the laminations from the face of the wood? ...

Yes. The annual rings will then be essentially parallel to the face of the lamination - flat or plain sawn appearance and the lamination will be more flexible.

Slicing laminations for the edge of a flat/plain sawn board will result in the annual rings being essentially perpendicular to the face of the lamination - quarter sawn apperance and the lamination will be less flexible.

The difference in flexibility may or may not be significant with 3/32 laminations on a 5" bend radius. Gut feeling is that's pretty thick unless you're working with green wood.

[John Fry]

I agree with Tom. I think you are better to use the flat sawn laminations. Another rule that helps in bending wood, whether laminating thin strips, or steam bending is this;

"Heart side inside, sap side out"!

I also agree that 3/32" thickness is probably too thick for a 5" radius, especially if you are using kiln dried wood. Try it as a test before you cut all your laminations, but if I were doing this lam, I would probably try to get down under 1/16".

18 laminations @ 3/32" is well over a 1-1/2" thick. What are you making?

[Michael Weber]

I agree with Tom. I think you are better to use the flat sawn laminations. Another rule that helps in bending wood, whether laminating thin strips, or steam bending is this;

"Heart side inside, sap side out"!

I also agree that 3/32" thickness is probably too thick for a 5" radius, especially if you are using kiln dried wood. Try it as a test before you cut all your laminations, but if I were doing this lam, I would probably try to get down under 1/16".

18 laminations @ 3/32" is well over a 1-1/2" thick. What are you making?
Thanks John, Tom and Brandon for your input. I should be able to go to 1/16 with no problem. And, since the orientation doesn't matter I can get the strips from the face of thinner stock and save the 6/4. This is for the backrest for a childs chair. The laminated assemble will serve as the backrest and rear legs so the length of the strips is going to be around 6 feet long including the arched top and 1 1/2 inches square. Thanks again for sharing your knowledge.
Mike