Cutting a curve vs. steam bending

[rcnewcomb]

We have a project to make some mouldings for the gothic arches surrounding stain glass windows for a church restoration.

I know I can cut the curves on the 'bot, however, I'm concerned about the strength and change of wood grain as I cut along the curve.

Has anyone done steam bending of mouldings and what are the pros and cons of cutting a curve vs. steam bending a curve.

Note: I''ve only done a little wood bending so this would be new technology to me.

[gerald_d]

You say it is a restoration....were the originals cut or bent?

[lto]

Randall,

This post caught my interest as I have significant wood bending experience. Steam bending can be a great solution in many cases, but not all. I would not recommend steam bent for exterior moulding because of potential moisture problems. You may want to also consider laying up a laminate arch. Do you have a drawing or picture?

Steam Bending;
http://www.barevillewoodcraft.com/

[rhfurniture]

I used to do a lot of stack laminating for such things - You build it up with short lengths 1/3 of the finished thickness bevel butted at the ends with overlapping joints - like building a 3 course brick wall in a curve - then bandsaw and machine it. Sound as a pound.

[mikejohn]

In medeval Gothic buildings they found timber that had bent during growing, and used this for their arches.

But as the United States was created at about the same time as plywood, I guess that 'Gothic' windows were made with modern materials
.

...Mike

[gene_marshall]

We just did one of these for a church here in bayhead NJ.
We cut them out of sapele mahogany... and used the curve of the grain as mike suggested.
we used a stlye and rail door set to make the interlocking corners.
Came out sweet, I'll try to get some pix on our site.
Good luck
Gene

[edp]

We do a lot of elliptical and true arch work on georgian style windows in teak, cedar, and mahogany. Have never had any problems stack laminating these - on really large work when the shop is busy I cut everything on the bot, but for "normal" sized windows with arched top fanlights we just make our patterns on the Bot. It is well worthwhile to glue up with epoxy for any and all exterior work - the added expense is not an issue when there are no comebacks caused by glue failure. The largest we have done was a 10 foot radius 4 x 8 mahogany beam on a tennis pavillion that rafters sat on - No problems after 5 years exposure in the tropics.

[rcnewcomb]

The arches will be interior and are quite small. But since the originals were cut from white oak and not bent we will follow a similar method.

Our initial cut was fairly close. Since I now have the shape in PartWizard I'll just tweek it a bit and we can proceed with cutting 16 of these.

The final thing to figure out is how to match the profile that was cut in the originals. It is basically a 30 degree angle with a flat bottom.

I've attached a photo of the original and our initial test cut.


5166

[terryd]

Maybe? just maybe? you should profile these parts before you cut them out. Jigging, holding etc are already accounted for. My humble opinion based on having done hundreds of pita parts like this. BTW Pita means Pain in the a**

[rcnewcomb]

Thanks, Terry. We had concluded the same thing. Our motto has been: 10 fingers in, 10 fingers out -- another good day at the shop.