Steam Bending Help

[Mike Cutler]

Hey folks.

I'm looking for some advice from real life experience bending wood. I've google searched SMC and the web,and have found a lof of info. Maybe too much info which is contributing to the confusion. Addtionally most of the tutorials are making parts for boat or chair backs, and arms.

Specifically I am building a Bow Front vanity with a granite top for our bathroom. This project will require that wood be bent to a radius of 32".
I need one piece that will have a cord length of 40" and the 32" radiuis for supporting the granite top. This one can be done as a bent form lamination, but I would like to steam bend the layers, let them dry, and then laminate them to minimize spring back.

The rails on the doors however will be solid 4/4, and maybe 5/4 . they also will conform to the front of the cabinet, so the 32" radius is what they will be bent to.

In my searching I have found that all of the net info recommends 1 hour per inch of thickness, yet Tage Frid recommends 1 hour per 1/4" of thickness in his book. Which is actually correct?

The other recommendation is to use Qsawn material and bend parallel to the grain? I believe that it is meant that once the piece is bent that the actual Qsawn face would be the edges of the rails on the doors, ergo as viewed from the butt end the grain would run parallel to the face.:confused:

One more question;
Can I route the profile for the frame and panel door construction into the rails prior to bending.

I plan to use bending plywood for the door faces, or do my own face panel ply glue-up and bend it to form.

The Vanity will be painted, so the species of wood isn't as important as the ease of bending, the predictability of spring back, and the ease of painting.
Any recommendations on material selection would be welcomed.

TIA
Mike

[Rob Parsons]

Mike, I have a little experience with steam bending. I have built oval shaker boxes and a bow arm Morris chair.

How long to steam? I steamed the 1" thick arm for the Morris chair for one hour. The general rule of thumb that I've heard is one hour per inch. That means 1 hour at the target temp.
However, when I steam the 1/16 - 1/8 shaker box material, that guideline doesn't really apply to such thin material. And the shaker boxes are bent to some very small radii. So I steam them 30-45 minutes.

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The more uniform the grain, the higher the probability of success. Wild grain would be more challenging to steam bend.

The quartersawn face of my bow arm is on the top of the arm.

Hope this helps.

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Here's a previous link about steaming.
http://www.sawmillcreek.org/showthread.php?t=98898

[Ben Hatcher]

When I steam bent the skirt for the table in my avatar, I had to steam the 1/4" laminates for about an hour befor they'd bend without breaking. I put them in the form and still got a bit of springback. When I did the final glue-up, however, there was almost no springback.

From what I've learned, kiln dried wood does not steam very well. It takes longer, like in my case, and doesn't ever become as pliable as air dried. My steam box was a one time use deal made of MDF that I sat on top of a stock pot on top of a gas turkey frier. It worked well enough for the job at hand. As expected, it was completely ruined afterwards.

Don't be afraid to just try something. You're not going to ruin the wood. If you don't steam it long enough, it won't bend. If you steam it too long it isn't as if it will dissolve on you.

There are other ways to get a bowed front. Have you ever tried kerf bending? You make a series of kerf cuts on the back side leaving ~1/8" on the face side. The number and spacing will depend on the arc you're trying to make. You can either fill in the kerfs with epoxy, or glue a thin piece to the back side to set the curve.

[Chris Padilla]

slice it up on a bandsaw and bend it that way

[dan petroski]

i bend 1"x1" for Windsor chairs and go an hour on the steam. I'm guessing you will be about 4 wide so go maybe a little longer on the steam. i watch the vent hole and when your getting good steam out i start the time from that point.
i'm no expert but i hope that helps

[Mike Cutler]

Thanks for the tips and tricks folks.

Rob.
Your reply answered a few questions I had, especially concerning grain orientation. I may build something similar to the "Steamdog". I liked that.
Thank you for the pic's. A big help!

Ben.
I had pretty much decided on the technique you outlined in your first paragraph for the support piece under the granite top. I wanted to avoid kerf cutting for this piece because it technically is providing support for the granite top, and I wanted it as strong as possible. I also need to be able to attach the other support members to this piece to support the granite.

Chris

I've tried some "dry" bent laminations with some junky walnut and they've come out pretty good. (I have a ton of air dried walnut to play with. (Unfortunately it's no good for furniture though:()Which would work for the support piece, but not for the door rails. Id like the door rails to be solid.

Dan
Thanks for tip about watching the venthole.


I'm going to do some experimenting. I have a lot of air dried walnut and cherry to play with, and maybe I'll rip a red oak log down and try that.