Replies

1. 
   philip_r | Apr 25, 2000 04:13am | #28

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   a side from drilling and blasting or attaching a heighly explosive to the side of your rebarb::::: all-tho' that would be a great big kick to see it think i have done that very job make
   a stationary box to hold one end of the the stick close to a pole or tree .lay it in ..the box grab it and bend the dang peice or with those lovely legs of yours just dance on it a while
   love ya mean it

2. 
   Guest_ | Apr 26, 2000 02:50am | #29

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   Phillip is new to typing. I am glad to see him. He makes me look good. Back to bending rebar... I like my conduit benders because I can bend the bar to any angle by myself if I must. Multiple bends ,anywhere in the bar, not much problem...

3. 
   PE_Jim_Nation | May 13, 2000 04:56am | #30

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   If your bending rebar very much get yourself a rebar bender. Less than 200 bucks. Don't heat it to bend, you never know what strength you have then. To AE, when I was in AF RED HORSE in 'Nam we used WP the way you describe it. Thermite is actually hotter than WP but doesn't attach itself the way WP does.

1. 
   ArcWood_ | May 13, 2000 02:33pm | #32

   *When you are cutting trees down for the house site leave a stump a little better than waist high. Cut a slot across the top wide enough for your rebar and an inch or two deep. Trim the stump so the slot is 8" long to make steps in the footer.

4. 
   Guest_ | May 13, 2000 02:33pm | #31

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   Anyone have a good way to get nice tight 90 degree bends on rebar in the field? Thanks - Jim

1. 
   Guest_ | Apr 14, 2000 05:54am | #1

   *hey crazy,I was installing some #4 bars a while back and needed some 90s. I scratched my head a while and looked around and noticed the trailer hitch on my truck. I slide the bar between the ball and ball mount and used the bumper for support. I bent the bar around the ball and got supprisingly good results. Someone makes a tool for this purpose but my ball and bumper work fine for me.

1. 
   Guest_ | Apr 14, 2000 06:04am | #2

   *hey k - yeah, the bumper ball works good. I did that for years too, but my new van doesn't have a hitch yet, and I need to bend some. I'm thinkin' maybe two pipe wrenches, or a piece of pipe and a pipe wrench, something like that.

1. 
   Guest_ | Apr 14, 2000 07:37am | #3

   *Jim,I use a couple of lengths of black iron pipe. 1/2" pipe for #3, 3/4" for #4, etc. You can get by with 2' lengths but the bending gets easier with longer lengths of pipe. Never bent #5 or larger - may require 3' or more. You can get a good, tight bend with this technique. The only thing you can not do is multiple bends in the same length. Most of the time I am bending bar for footings and one bend in a length is all ever I need. For cutting, I use a metal blade in my circular saw. Rebar cutting and bending tool is over $300. I came into my pipes and the blades cost less than $4 at Lowe's. For occasional use, no contest.Steve

1. 
   Guest_ | Apr 14, 2000 08:30am | #4

   *Tell the truth JclB. You got no faith that your new chevy or ford or whatever you flavor is will hold up to a couple of sticks of rebar ;-)

2. 
   Guest_ | Apr 14, 2000 01:08pm | #5

   *I use my conduit bender for up to #5 rebar.

3. 
   Guest_ | Apr 14, 2000 10:03pm | #6

   *A rebar cutter would be a novel idea and will bend a 4" radius, if you need it tighter than that use a torch/rosebud to heat and bend.What are you? a whimp? bend it in your hands and impress your friends.............lolOur rebar supplier has pre-bent corners that you tie in etc......or bend thembefore you get there.Don't try this unless it is a last resort, find a pinch point on a back hoe, truck box/hoist frame, loader bucket and insert and bend...I deny any knowledge of this post and it's inherent danger.So you got a new van, does it have dark windows, carpet on the floor and walls with a water bed in it?..................

4. 
   Guest_ | Apr 14, 2000 11:01pm | #7

   *crazy legs, Best bet, by the pre-bents. But, if you have a small number to bend or a lot different lenghts as in a sloping retaining wall, feild bending makes sense. I bought a 10' 3/4 pipe from the plumbing supply. Attached 25" to a 12' 2x6 with "U" clamps. I back the truck over one end of the board. The 25" is the shortest over lap for 5/8 re-bar, thus saves some measuring. The remainning 7'11" is plenty of leverage for bending the re-bar. I use a cheap carborumdum blade in my saw to cut lenghts.

5. 
   Guest_ | Apr 15, 2000 12:37am | #8

   *Jim:For 1/2" (#4) or less use your foot and other appendages to "form" the rod. For larger - use the pipe method that Steve H suggests above - just about any old pipe will do as long as it's 1) large enough (diameter & length) and 2) it's strong enough. Or - hey - next time I'll have try combining the trailer hitch with the pipe - yea!! That's the ticket!!I got a friend from upstate NY. Talks a little different than most Carolina boys. Whenever he says "re-rod" I always like jerking his chain: "Re-rod - what inthehell is that??!!"

6. 
   Guest_ | Apr 15, 2000 05:54am | #9

   *Tool Rental Store. Jeff

7. 
   Guest_ | Apr 17, 2000 03:02am | #10

   *Jim Bob I use the pipes in my pony clamps like steve said it works great at and cost is small.

8. 
   Guest_ | Apr 18, 2000 07:32am | #11

   *Jim,What ever is on site.I've used the pinch points on equipment, holes in the steel forms, bumbers and pintels, and for some tricky bends the lug nuts on the front axle of a dump truck, and for multiple bends made a jig out of ply and 16d nails and a torch to heat the bar.DaveThe ply was toast though. :-)

9. 
   Guest_ | Apr 18, 2000 02:05pm | #12

   *I've notice several references to using a torch to heat up the rebar to bend it. I've always been under the impression that reheating weaks the rebar. It's a fast way to fail an inspection around here.

10. 
    Guest_ | Apr 19, 2000 08:44am | #13

    *Don't know why. Common rebar is soft steel, no temper. It is no different than bending it as it rolls out of the mill. Remember steel has grain like wood. Heating it to bend it is akin to steaming lumber.I can see if you are using Epoxy coated bar. And in some bridgework I have seen Hi tensile steel bar used, Usually that is square around here. What does your inspector say about field bends in general?AE

11. 
    Guest_ | Apr 19, 2000 02:27pm | #14

    *I do agree that reinforcing bars are mild steel (at least the ones I've seen all have a strentgh of 60 or 75Kpsi.)I've read about high strength bars so they do exist somewhere.I don't think all the mild steel bars are of the same hardness. I've had bar that was easy to cut and others that were just about impossible to cut. Maybe some are cold rolled and other's hot, maybe for some reason they quench temper some.As for the torch bends, it's not allowed because shape bends weaken the steel. There's alot of stress (and probably cracking) where you make a sharp bend, evey if you heat the metal first, you're stretching the outside of that bend to 3 or four times it's original length and giving the bar a weak spot. In fact, you've created a week spot where there's an unusually high concentration of stress to begin with.The rules are (I had to look these up): for rods #2 through #7: bend diameter must be at least 7 times the bend diameter. For #8 and #9: D=8dFor #10 - #18 (never seen anyhing this big): D=10d.b I'm not an engineer but I play on on the internet

12. 
    Guest_ | Apr 20, 2000 06:23am | #15

    *As for the #10's that is 2-1/4" and I have seen those in bridges. The largest I have ever whitnesses is a #28, They were in a concrete boxed beam bridge going up in Germany in the 80's. They were set with a crane and had sheet metal "buckets" set in the concrete 2" from them. As part of the design all we Engineers had to do was to put White Phosphorus Grenades into the buckets and run. The grenades would generate enough heat to melt the bar and cause a failure.All that to protect from the Communest Horde.AE

13. 
    Guest_ | Apr 20, 2000 12:53pm | #16

    *What is a White Phosphorus Grenade? We love thermite around here, is it some fancy modern replacement for thermite? Can you send me some?

14. 
    Guest_ | Apr 21, 2000 03:11am | #17

    *Heat 'em with a blow torch. Thats what we used to do in the structural steel shop.blue

15. 
    Guest_ | Apr 21, 2000 03:39am | #18

    *Rebar is made from scrap. It is what ever it was; hard, soft, etc. On stick can have hard to cut and easy to cut sections. True story. A number of years ago a Mexican mill across the border from El Paso used some US source scrap to make rebar. The scrap included some very radioactive material from a powerful X-Ray machine. The good news was the stuff was sold to a US construction firm with a contract at the DOE lab at Los Alamos in New Mexico. When it was delivered the alarms went off. They had some trouble finding the source of the radiation as the alarms were intended to detect radioactive material going out of and not in to the lab.

16. 
    Guest_ | Apr 21, 2000 03:46am | #19

    *I vote for thermite. WP is nasty stuff. The 4.2 mortar was originally designed to deliver it and other chemical munitions. It does not, however, generate enough heat to burn through metal. Key bridges (those with tactical significance) in what was once West Germany had chambers for demolition munitions. Bridges in some key locations had the charges in place. Don't ask me how I know.

17. 
    Guest_ | Apr 21, 2000 05:42am | #20

    *...just a follow up...I formed a small addition this week and had to bend just a few #4 bars (20 or so). You guys who suggested the two pieces of 3/4" pipe were right on. You guys who haven't tried it, should. I'll be keepin a couple short lengths in my truck from now on.

18. 
    Guest_ | Apr 21, 2000 08:24am | #21

    *Way back when White Phosphorus was developed to start fires and mark areas. That was in WWII and it was used the same way up thru the Vietnam war. Yes very nasty. When it was used in the past it was blown apart. It Burns so hot it will melt thru steel. When contained it burns even hotter. Thermite is an improved method of doing the same thing. Different material but used alot the same way. Mostly for illumination. The main difference is Thermite can be extinguished if you starve it for oxygen gas. It can be done. WP draws oxygen from any state, liquid, gas solid. From water, the air or your cells in your body. Either way it will burn once ignighted. Period.I know we all think about building thing solidly and with a high level of quality but I also see how to destroy the very same thing.Go back a few posts.b "If it can be built I can blow it up."Not just a catchy phrase my primarry job in the Army.AE

19. 
    Guest_ | Apr 21, 2000 11:51am | #22

    *Crazy Legs, Glad that worked out for you.

20. 
    Guest_ | Apr 21, 2000 01:58pm | #23

    *Thermite actually gets its oxygen from itself. Needs no external oxygen.Thermite is aluminum and ferious oxide.When burned, it producs only aluminum oxide gas (which off gasses) and pure iron. Al + FeO2 --> AlO2 + Fe + heatBesides being used by you guys for demo. It's used alot for welding.Train track sections are sometimes joined by placing a ceramic mold around the track joint, pouring in thermite, and lighting it with a magnesuim strip that has to be lighted with a blow torch.I know a guy that got some thermite to try it out, he tried to burn a small mound of it on his draft forge to see how hot it really got. He says it was a mound about the size of a quarter. It burned right through the 1/4" steel plate and then dissapeared through the concrete floor of the shop.

21. 
    Guest_ | Apr 22, 2000 05:17am | #24

    *Didn't realize it produced oxygen upon burning. My question is how come we can extinguish it in water?Are there perhaps different compounds??Welding... Is that what is used for underwater welding?Now you have sparked my interest.AE

22. 
    Guest_ | Apr 22, 2000 06:22am | #25

    *Thermite, as I understand it, can't be extinguished with water. Water won't cut off the oxygen since it doesn't need any and the reaction produces so much heat that you can't pull the heat away fast enough to stop it with water. In fact, I don't think there's a procedure for stopping the reaction. Maybe it can be done but I don't know how.I've never heard of it being used for underwater welding but that doesn't mean it isn't.Usually, this stuff is used to weld very big and heavy pieces of steel. I've heard of it being used to weld plates together so that the entire surface of the plates is uniformly welded. A dusting of thermite is laid between the sheets, you light the stuff (can't be done with just a flame) and let it do it's thing.I've read that the stuff reaches 6000°C. Who knows if it's true?The only trade name I know of is CadWeld. I think this product is doped with plain old iron to weaken the reaction.There was actually a discussion about this stuff here maybe last summer.

23. 
    Guest_ | Apr 22, 2000 08:39am | #26

    *I have seen thermite grenades snuffed out in water. Perhaps as you say they are not pure. I have used Cadweld for welding steel pins on finger damns on bridges. never knew what was in them. Learn something new every day.AE

24. 
    Larry_"The_Home_Hack" | Apr 22, 2000 04:03pm | #27

    *In my younger years I would have used my little brothers head. Now I have a son for that. :o)