Need some advice on bending rail.

[Shawn Morley]

So I have a curved railing to do, I am the second trimmer on the job, the first trimmer broke the bending rail while trying to make the radius. So I was thinking I would steam them first, problem is I got the material and it has several finger joints in it. Question is, can I steam bend something that has finger joints in it and I'm unsure what kind of glue they used to joint them.

Material is Clear Alder 10ft long.

Any input would be greatly appreciated.

Thanks, Shawn

[Lee Schierer]

No offense, but my guess is that you may be the second, but won't be the last trimmer on this job.

Steaming a finger joint will likely soften the glue enough that it will fail. Depending upon the radius, the joints may or may not fail or the wood itself may fail. To penetrate the thickness of a standard hand rail you are going to need to steam for a long time and will have 60 seconds or less to get the piece formed once it is removed from the steamer.

I wish you luck my friend, let us know how it turns out.

[David Helm]

If you have access to a shaper cut the bend out of larger material, or laminate it in the bend. Then shape the profiles.

[Richard Wolf]

Curved rails are always difficult, maybe I can give you some tips.

1) Forget steam, you will never work fast enough and the finger joints will fail.
2) I assume it is a tight curve, so you will need a lot of L braces to support the bend. Try it dry first, clamp one end and slowly start to push or pull the other side around your forms. Give the wood a chance to move a little at a time. If it will almost go around it will work better with glue as a lubricant. I forgot to mention that you should wrap all your lams together with shrink wrap.
3) If that's not going to work your next chance is to make each lamination thinner and make more of them, The problem is the outside laminations with the profile can't be made much thinner, but they most likely are not finger jointed so will be stronger.
4) If that's not going to work, you will have to make you own thin laminations and bend up a solid rail. There are lots of router profiles that will come close to what you need so you should be able to match the profile fairly closely. As long as you don't have to meet up to another rail, you would be surprised how you can fool the eye.
5) You could also build the rail out of wide material and band saw it to shape and then route the profile as above.

This is all assuming this is a balcony rail and not a rake rail which will make the routing thing impossible for you.

Let me know if you have any questions I can help you with.

Richard

[Shawn Morley]

No offense, but my guess is that you may be the second, but won't be the last trimmer on this job.

Steaming a finger joint will likely soften the glue enough that it will fail. Depending upon the radius, the joints may or may not fail or the wood itself may fail. To penetrate the thickness of a standard hand rail you are going to need to steam for a long time and will have 60 seconds or less to get the piece formed once it is removed from the steamer.

I wish you luck my friend, let us know how it turns out.

Well, my thought was the finger joints would fail as well which is why I wanted more opinions. According to the manufacturer of the bending rail we can steam it for hours and the joints won't fail, they even went as far as to say they will give us new material and pay two hours of labor if it does fail.

It is a slight radius which is why I was surprised to hear that the wood cracked when it was dry. We made the landing treads for the stair and had no problem with them, but then again I was able to supply my own material.

We'll see what happens. I'll let ya know.

[Richard Wolf]

A slight radius should not be a problem. But like bending pipe, you need to support in at many spots along the way. Also, wrapping the rail with plastic wrap will help a lot.

Richard

[neal jack]

A slight radius should not be a problem. But like bending pipe, you need to support in at many spots along the way. Also, wrapping the rail with plastic wrap will help a lot.

Richard
totally agreed

[Shawn Morley]

After looking at the material again, we decided to try it dry and did so without issues. It's all in place and looks great.

Thanks for the advice.