I was looking at the Kee Klamps for a quick project out in my garage this past weekend when I found this really pretty cool bed on one of their suppliers' blog: http://simplifiedbuilding.com/blog/?p=172
The thing I was wondering was how do you make large radius bends in steel pipe in your garage or backyard? Do you need really fancy equipment to get a good arch like that?
Your typical pipe bender maxes out at a fairly small radius.
But experiment with this. dig a trench in the grounded about 3 pipe diameters deep by 3 pipe diameters wide. Cut your pipe about 18" overlong. Fill the bottom third of the trench with charcoal, fill the pipe with charcoal, put the pipe in the trench and cover with charcoal. Lighter fluid (generous), a match, and come back in the morning. Your pipe should now be relatively short.
Hammer one end shut. Fill COMPLETELY with sand. Hammer the other end shut so no sand can leak out. Now, when you hammer, you want the flat spot to be at least 3" thick. Half inch hole in each hammered end.
Now, knock yourself out trying to blacksmith this bastard into shape. Or, try this. Eye bolt in each hold. Heavy steel chain NOT NYLON STRAP!!! in the eyebolts. Think like making Iron Man's Longbow. You'll need some kind of turnbuckle contraption in the middle to put the whole thing into tension. Tension the chain until you get the radius you want.
Dig a trench so you can charcoal fire your arc under tension. Hopefully in the morning you now have your piece. When you do the second firing, carefully monitor the fire so that is gets evenly and progressively hotter from the ends to the middle.
The purpose of the sand is to provide support to force the metal to stretch smoothly as opposed to buckling in the middle. That's why you want the tube full of tight packed sand, not just loose sand. Water DOES NOT replace the sand.
If you're feeling adventurous, you can skip the first firing. But then you will have made Iron Man's Longbow, and God help you if the chain/connection gives way and you're standing in the wrong spot....
The best bet, and probably the cheapest, would be to find a nearby iron works. They'll have a fairly large and crazy expensive rolling bender. That's about the ONLY way you're going to get such a perfect smooth arch. The benders muffler shops have won't do it. You're looking for someone with something like <A HREF="http://www.ercolina-usa.com/er50h3.htm" TARGET="_blank">this</A>.
It also looks to me that it shouldn't be too hard to fabricate one. I'm thinking I'd like to put together a simple greenhouse with an arched top. I can also picture other furniture concepts, parade floats, and interesting projects that might be possible with a bender rig.
I'm still getting my first foundry set up. It won't be capable of casting iron, but I should be able to cast aluminum and make the frame and pulleys. Hmmm. Sounds fun to try. So many projects, so little time....
rwo, glad to hear that you are setting up a foundry. I'm a sculptor and have had a foundry for years, matter of fact used to build melt furnaces and kilns for others. If I can help in your process let me know. I have used both castable refractories and a lot of ceramic blanket over the years. For smaller furnaces I like the ceramic blanket, but I know that the fibers probably are bad for breathing. Are you going to fire it with propane? I was given two induction power supplies that I wish that I knew more about to modify into a melt furnace. I would be interested in what your building. kentsmithstudios@msn.com
I am not sure if you are close enough that this would help, but I have a set of rolls that I use for rolling sheet and plate. I have also rolled square tubing with then with good results. kent
I am not sure that this would help, but I have a set of rolls for forming sheet and plate. I have used them for forming square tubing with success. If your close to the Denver area your more than welcome to use them. You could build a set using three cast iron v-groove caster wheels. I see these in the grainger catalog and probably fastenal. kent
I'm in Ohio. My immediate project with the kee klamps will use straight pieces. I'd like to install an attached greenhouse, and one design possibility is to use kee klamps and large radius bent pipe. I'm really not sure I'll have time to do this before winter sets in.
At this point I decided to start with a very small electric foundry with the goal of melting bronze. After several iterations I've gotten the foundry up to 1100 deg. F over the course of a day. (My goal is 2000 deg F.) I am using castable refractory. I'm going to try adding more insulation to see if I can get it to heat up faster. If that doesn't work, I may try to install a blow torch or propane burner of some sort. If I can't figure out how to do that, I'll scrap the whole thing and start over with a waste oil burner.
I've been working on it (sparingly) since January when I get an odd moment here or there. I'm really determined to make it work even if it takes me another year or two. I've been documenting the whole process and if I achieve my goal, I'll post it all to a web page.
With the electric foundry already about capable of melting aluminum, I could fabricate at least the smaller parts. Since I'm pretty focused on bronze casting, I'm not going to let myself go too far off on a tangent with a side project of building a large radius bender for my greenhouse until I'm sure I'll actually have time to build the greenhouse.
rwo, sorry to not get back to you, we were out of town this weekend. My small furnace that I used to use for bronze casting was made out of a section of a steel oil drum with 2" on low density concrete and 2" of ceramic blanket and 2 burner ports. I uses a small radial vaned blower and a 20 Lb propane bottle to fire it. It held a #16 crucible, about 50 Lbs of bronze and would bring it up to 2400 F in about 45 minutes. it worked great for years, but I made a larger furnace for a project a while back and stopped using it. kent
I have built two greenhouses using a new tool I found on ebay. Its a manual bender just for bending greenhouse hoops, it works great only draw back is it is fixed radius, but good news it bends the hoops fast and cost only $89.00 or so on ebay. Its called a greenhouse tubing bender however I checked their webside recently and they are running a sale there for $54.99 I think it was. www.lostcreek.net I guess no one ever thought of it before because its just to simple and I love simple.
I think Lindsay's Technical Books has a book on how to make a "pipe bender" that might do what you want, though depending on how big and how beefy your pipe is, their design might not cut it for you.