Do you remember that old steam tube that I made out of some 4" PVC pipe? It melted and sagged, which prompted me to make the plywood steam box. Well I figured out how I can reuse it. I put it on the bench and cut it into 3" lengths to use as cutworm collars for our tomato plants. We normally wrap some cardboard from cereal boxes into circles to make the collars, but they don't last very long, and we have to make new ones each year. The 4" diameter of the pipe is just the right size for cutworm collars. So I got out the old saber saw and cut it up.
The Old, Bent PVC Steam Tube
Take a look at this cross section. I think the pipe suffered a lot from the steam temperatures. So cutting it up is a good thing. We can use these collars for years because they will not rot. Waste not; want not. Besides, it lets me bury my mistake out in the garden.
That is Not a Round Pipe Anymore
Enough of that. I want to get back to making a hoop out of that bent board. If you recall, I had split the end of the board while sawing off the ends and had glued the split together. The glue has now dried, so I took off the clamps and started making a heel block for it. I am going to use the bending form as a jig for making the hoop. I can clamp the board to the form and slowly bend it into shape in order to keep it under control. Using several clamps of different types, I managed to bring the two ends together by loosening and tightening the bar clamps.
Got Some Clamps Going
This proved to be a tricky thing to do. The clamps kept slipping off the hoop and the whole thing would spring apart. The problem is that I was clamping with the cauls against round surfaces, and the cauls would slip off. The clamp has to be exactly centered on the hoop or it will not work.
But I finally got it stabilized, and here are the two ends held together by the clamps.
The Ends Are Brought Together Using the Clamps
Here is what the joint looks like from inside the hoop. It isn't a perfect joint, but I think I can make this work.
The Ends From Inside the Hoop
Now that I have figured out how to join the ends together in a controlled fashion, I have decided to make a new heel block that has been fit to that particular joint. The one I made last time was made estimating the curvature of the joint. This one will be fit to the joint itself. I turned another 1 inch scrap of pine over on top of the joint.
Another 1 Inch Board is Marked
Here is the curve of the end joint marked on the board.
The Actual Curve is Marked on Another Heel Block
I did not take that project any further today because I thought of another refinement I want to try for bending the boards, and I need the bending form to try it out. I have noticed that at the very end of the bending process the board cools down and becomes quite difficult to bend. I thought that maybe I could get a slightly better bend on the last end if I steam the board a bit longer. So I am going to try steaming the board for 20 minutes per side instead of 15 minutes per side. Here are the numbers.
- Start the steamer at 14:55
- Full steam and insert board at 15:25 - 30 minutes to start
- Turn the board over at 15:45 - 20 minutes on first side
- Pull out and bend 16:05 - 20 minutes on the second side.
When I turned the board over, I flipped it end to end like I did last time. After steaming both sides, I pulled it out and wrapped it around the form. Here are the photos after the bend.
The Board Bent Smoolthly
Another Angle of View
The Overlap of the Ends
This one bent a bit more easily. I think that the extra time is a good thing. According to the book, for a steam bend you should steam the wood for three quarters of an hour per inch of thickness. So I should only have to steam my 1/4" wood for a measly 11 1/2 minutes to do the bend that I am doing. I was already steaming it for 30 minutes total. But I think that maybe the book number is based on a more powerful steam generator than the one I have. My little wallpaper steamer does not put out a whole lot of steam. So I need to immerse the wood in the wimpy steam a lot longer. I did not do that sooner because I have read that steaming the wood too long will dry it out and make it shatter. I did not see that happen after steaming it for 40 minutes.
This looks like a good bend.
