First. Thanks Uncle Doss.
Second. So I have still been toying with the bender. I thought I would update this for anyone who really wants to make this, since some interest has developed. I don't want someone left out in the weeds when their hoops don't work out.
What triggered this is that my second hoop was a disaster. I struggled to compress it enough. I actually ruined a piece of pipe when the swagged end buckled. My 3rd hoop made me realize something was wrong. My 4th hoop gave me redemption that im on to something.
This will be a ongoing update as I have now bent 4 hoops (I guess 4.5 since I had to fix half of #2). Only 9 more to go.
One of the issues to deal with is the "spring back" of the pipe. That is the tendency for the pipe to recoil back. The pipe simply wont stay 100% percent where you bent it. Its just the nature of Alloy Metal.
I have the solution, and the solution creates a second problem. Seems thats how things go for me. I'll cover both starting with the first issue.
The solution is to make your radius tighter then you actually need. I subtracted 1 foot off of my measurements. So, for a 12 foot wide house, the radius is 6. As you recall from above, I said:
"Step 6.
Continue measuring up the length of the long 2x4 until you reach 6 foot. Now add 1 extra inch. 6 foot because this is your radius, plus 1 inch because you measured in 1 inch in the previous step. See photo 4."
Nix that 6 foot. I changed that to 5 foot. So now you are drawing out the arc for a 10 foot circle, instead of 12. This may seem really drastic, but in the real world, you still have to compress the pipe a bit to make it slide over the rebar pounded into the ground. You can thank "spring back" for that.
Right now, I can only comment on a 12 footer. Other sizes of houses would be trial and error. But I would guess that 20 foot wide house would probably need roughly 2 feet taken off the radius. But again that is only a guess.
Now the second problem. Because we have monkeyed around with the radius, there is a tenancy for the ends of the pipe to curve in on itself. I have included a pic below and you can see this for yourself.
The solution is to leave approx 6 inches of pipe sticking out of the bender, when you bend your pipe. 4 inches might work just as well. The original MFR of the Hoop Bender states the same. To mark the pipe and leave 6 inches sticking out. I couldn't figure that out for the life of me as to why. Now I understand.
Now, for a small upgrade to the building process of the bender itself. Switch out the string with a piece of 1x2 pine, or something similar. Drill a hole in the end for a pencil to barely slide thru. When you draw out the arc, it is far more accurate.
Ill keep updating this as I bend more hoops.