Steam Bending

[Julie Mo]

Since I already had the steamer, all I had to do was make a box.  So I took some scrap wood and roughed one together.

 

The box is about 30" long, overall, enough to take the longest pieces of the model I'm working on.

 

I placed rod inside, made from a painted wire hanger, spaced 5" apart.  This keeps the wood raised so the steam can get to all sides.

 

I placed a plank in the box and left it for a little over 10 minutes.  Rule is 1 hour of steaming per inch of thickness.  I should also have a meat thermometer in there so I know the box reached 200⁰ but these are such small planks, I didn't think it was necessary.

 

I pulled the first plank out and pinned it to the hull.  After about 20 minutes, I removed the pins to check the shape.

It kept the shape pretty well.

 

Turned 180⁰ you can see the shape it held a little better

 

I really only needed the steam bending for the stern end, near the keel, but I wanted to see how it worked for the entire length. I was pretty pleased.

 

I have a 23 gauge pin nailer that shoots headless pins as short as 3/8",  If I was nailing to the frames, I could probably do an entire side in a day, maybe both sides.  The plank was very pliable but still had enough rigidity that it wouldn't sag between frames.

 

The only downside is the steamer I have is designed for much thicker wood.  So it was a bit of an overkill for the amount of steam it produced.

[Roger Pellett]

Over the past 20 years or so I have restored or rebuilt four wood/ canvas (Old Town type) canoes. All of the have required replacing steam bent cedar ribs and planking And ash stems. On my first canoe I rigged up a system in mt driveway using a camp stove. While it worked fine, it was a hassle to set up and after I had dismantled it I usually discovered a couple of cracked ribs that I had missed and would have to set it up again.

 

A work colleague who had been remodeling his house offered me a Wagner Power Steamer, intended to steam off wallpaper. This thing produces steam by heating electrically so I can use it indoors, and the steam is hot! The coupling at the of the steam hose mates with a 3/8in npt male pipe nipple screwed into a threaded flange mounted on my steam box. If I need to steam a piece of wood it is a simple matter to hook this and to put it away when I'm done.

 

Several years ago, WoodenBoat magazine reviewed a specially built steamer. It looked exactly like my Wagner Steamer.

 

Roger Pellett

[allanyed]

Julie

 

What kind of wood is the planking?

 

Thanks

 

Allan

[Julie Mo]

Allan, my guess would be basswood.  It is from an Amati kit.  Amati only refers to as "hardwood" planking.

 

Roger, the steamer I am using is made by Earlex.  Rockler sells the same thing.  They also have free plans for building a steam box.

 

Yesterday, I laid 5 rows that were steamed first.  They laid down much better than the dried planks and there was almost no clinker effect.  On the other side, I had dipped the ends of the planks, where the twist was most pronounced, into boiling water for a few minutes.  This worked very well for the end but did nothing for the rest of the row. 

 

If I had a way to keep the planks in place other than pinning from the underside, steam bending would be the way to go.  But I'm almost done with the 1st planking so I'll look into an alternative method on the next build.  The 2nd planking on this model is so thin, steam bending would be overkill.

[Roger Pellett]

The Earlex steam generator looks just like my Wagner unit.

 

Roger Pellett

[Julie Mo]

For anyone not following my build log, here is a summary of today's steam bending:

 

I steamed 3/32" thick planks of sapele.  First time steaming sapele.  Wow!  This stuff is resilient to steam bending!

 

First round, I steamed the planks until I thought it was time.  Then I banded them to the keel

 

A couple of hours later, I removed the banding.  Barely a whimper.  The planks pretty much sprung right back.

 

So I cooked the Davey Jones out of them, something like 1.5 hours, and they finally looked ready to comply.  They are now banded tightly to the hull.  Tomorrow, we'll see...

[Julie Mo]

Again, if not following my build log, here's pictures of the progress:

 

Glued up laminate:

 

Comparing to the hull:

 

Comparing to the drawings:

[rdestefano01]

They say when you soak planks in water they swell then shrink when dryed.  Does that happen with steam also?

[jbshan]

They say when you soak planks in water they swell then shrink when dryed.  Does that happen with steam also?

Yes.  Wait until the planks are cool and dry before gluing in place.  Clamp hot, glue dry.

[bluenose2]

Hello Les here. I agree with jbshan. For those of you who don't want to build a steamer unit, here's what I did. I purchased a 4 foot piece of plumbing pipe available at any home or plumbing store. I ripped it in half length ways to create a half pipe. Purchase 2, 4" end caps and glue on. Now you can fill with boiling water or whatever witches brew you can come up with to soak your planking. Note the harder the wood the longer the soaking time. This is when you can form the planks into any jigs you have made.  Be aware that wood will shrink when drying. Hope this helps.

[hornet]

I built something similar to what Bluenose2 describes. It works well. I ended up putting a tap in one end for easy draining because the Admiral got somewhat sick of me spilling water all over the floor.

 

 

 

Cheers

 

Steve

[bluenose2]

Les here. You bet hornet. The war department got upset when I sloshed water all over the upper deck. Have added a drain so no more lashes. At least for this one.

[Guest]

These look cool!  What is your steam source?  A tube connected to a kettle of water or something more sophisticated?

[hornet]

I use a plank bending tool. It heats up like a soldering iron. I have had it for over 30 years. It came from aeropiccola - not in business any more.

 

Edited September 24, 2016 by hornet

[marktiedens]

Yes,hornet - I have one of those too. Marvelous tool - I have bent strips as large as 3x8mm with it.

 

Mark

[Julie Mo]

I use the this.