Thursday, March 22, 2007

The Road to Bending pt.3



Finally to the steambox! There are many ways to make an effective steamer. My choices have been guided by cost, availability and flexibility. My box is simply 3/4" CDX, set on an angle to drain and a Lee Valley steam pot. It is easy to see some sort of magic need for an airtight chamber, but remember this isn't a pressure device, just steam. I have had some pretty leaky cobbled boxes (folks at Williamsburg last year may remember!) and they work fine. I think that it's much more important to focus on sizing the box properly. While the steam pot I use is amazing, I still built my latest steambox to be just large enough to accomodate my largest bend, no more. You can see in the photos that I have a second (unused) tube to the box. I used to have two pots hooked up (I managed to burn the old one out), but have found that one is plenty. I have dowels across the bottom of the interior to support the workpiece and aid in circulation. In the photo of the door you can see the tongue joint that I used on the sides, it works great in this application. although screws, caulk and a butt joint would fit the bill! Steamers are one of those tools that need not be overbuilt, largely because your needs will have you redesigning it from experience soon enough. Two more important points, don't bother to paint or seal the wood and have an easy means of adding water to the pot. A pot like this, even though it shuts off automatically when dry, should be allowed to cool before refilling. So constant monitoring of the water supply will ensure not having any delays in the process. I simply pull the rubber hose out of the end of the aluminum insert to add more. And, oh yeah, always wear gloves when working with steam, it can burn you easier than you think!

9 comments:

Philip said...

Peter, Thank you for running this very useful BLOG. It is appreciated, by many folks.
I wondered if you have any vent holes for the steam to flow out of the box, or do you force it to stay inside until it cools to a water and drain?

Peter Galbert said...

Thanks,
The only hole is a weep hole in the bottom at the low end to drain the water.

Anonymous said...

Peter, is there any need to use an additional kettle when steaming 7-8' long settee arms, such as one towards each end?

Peter Galbert said...

My steam box isn't long enough to do a settee in one pass. I actually bend one side at a time. For the few times a year that I need to bend a settee, it is worth the smaller steamer. I simply hang one half of the bend out of the end of the steamer, plug it with a towel and proceed to bend as normal. Then I can either wrap the unbent portion and wait a week or so to bend the other half, or crib up a regular arm bending form outside my steamer so that the unbent part is inside and then wrap the whole thing on my settee form.

Peter Galbert said...

Sorry, maybe I didn't answer your question. If you have a long box, you might consider two steam pots, just think of the investment in time and material you have in the workpiece and a second pot seems like a small investment to ensure a safe bend.

Kevin said...

Peter--

Thanks very much for talking about your steambox set-up. Can you provide the approx dimensions of the box? In addition, do you just add water to the kettle slowly over the length of your steaming time (i.e. continously, little-by-little) or do you wait until it is running close to empty to add a lot? I would think the former as you want to keep the steam up without losing momentum.

Thanks again. This is the best Windsor resource out there right now. I need to figure out how to come take a class with you.

Kevin

Peter Galbert said...

Kevin,
My box's interior is 3 1/2" X 4 1/2" and 60" long. This is large enough for all of my chairs. I try to fill the pot completely at the beginning of each steaming to avoid refilling. I would not refill slowly a little at a time. The pot is designed to boil water lightning fast and I just add an extra fifteen minutes if I have to refill it. It will depend on your own set up how long it takes to get back up to heat.

Kevin said...

Peter, thanks for the further input. I will try your set-up in the near future. Most of my wood are air dried ash logs that I quartered up and have stacked around my shop over a year ago. There was no way I could use all of it when I took the tree down and rather than watch it rot outside, I brought it in (60" lengths for the most part). It's not as easy to work now obviously, but with a sharp knife, I get a beautiful finish. I did take down a smaller hickory late fall that has been covered in snow so it should be fairly fresh, but with the temps rising now, I better get to it quick. Anyway, with my air dired ash, I presume I will need to steam longer anyway, that is why I was wondering about refilling the kettle. How long do you typically get with a full pot?

I really appreciate your continued advice.

Kevin

Peter Galbert said...

Kevin,
Check the pot often, at least every 20 minutes or so. If you are steaming air dried stock, you will have to refill one or more times. I would consider steaming it for 45 minutes to an hour. Extra diligence in following the fibers and growth rings will help the bend succeed as much as extended steaming. If you do get to bending the green hickory, consider coating the end grain after you've bent it. Hickory has dramatic shrinkage in the tangential plane and likes to check. I don't use it for bends often because I tend to have white oak on hand, but it is a fantasic wood to work green and almost heroic in its strength. Good luck