Curtiss Jenny Restoration

Welcome! We hope you enjoy following the restoration process of a 1918 Curtiss JN4D Jenny. Once completed, the aeroplane will be flown and displayed at the Candler Field Museum in Williamson GA (30 miles south of Atlanta). You can contact me below by clicking on "VIEW MY PROFILE"

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Location: Peachtree City, Georgia, United States

Friday, April 13, 2007

Steam Bending

"Now, what does this contraption do again?" my wife asked me.
"It's supposed to make a lot of steam," I replied.
"The kids want their slide back."

Guess I should have asked them first.

Anyway, the above picture was my first attempt at steam bending the 1 1/2in. X 1 1/4 in. ash longerons. Using my new steam kettle, I turned the gas grill on high and waited for results. Sure enough, a little steam came out of the open end. Great! This steam bending would be a piece of cake, I thought. Nothing to it. Just let it steam away for an hour for each inch of wood thickness and slip it into the form.

Well, after an hour and a half, I pulled the ash strips out. They were barely even wet! I could even touch them with my bare hand. Hmmm. Something was not right.

I called my friend John Gaertner in Virginia. Always willing to help, he listened to my tale and made a few suggestions from his experience steam bending skids for a Wright Flyer reproduction. "You need more heat," he told me. "A lot of heat! You want the steam to exit the drain holes like it was coming out of a locomotive."

Taking his advice, I called Nate Hammond. He quickly borrowed his Dad's Turkey Deep Fryer. The burner was capable 55,000 BTU's. "That ought to do it," he reasoned.

So, the gas grill was moved back into it's usual spot on the porch and the Turkey burner put in it's place. Boy, did it ever make a lot of steam! I stuck the ash back into the "Ivey Steamer" and went back into the shop to work on other things. I had an hour to wait.

After about an hour, I decided to check on the progress. Steam had stopped coming out of the box, even though the pot was boiling like mad. Something was wrong. After scratching my head, I finally figured it out.

There was a low spot in the hose and it filled up with water! The steam could not get through.

You can see it in the photo above.

After adjusting the hose, the steam started to flow. I steamed another hour and pulled out the longerons. Quickly, I put them into their forms - one upper and one lower.

We'll see how they hold their shape after drying for 24 hours. Some things I learned:

-make sure you have a full propane tank.
-check the water level often. (yes, I ran it dry once!)
-use the heaviest blocks for your formers. Even though the ash was steamed, I still had to put quite a bit of pressure on the clamps to follow the shape. I probably should have used heavier blocks, like Paul Dougherty mentioned. Mine worked, but bigger would have been better in this case.

More soon



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