Black art of heat staightening. Advise needed

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I am building a set of nerf bars for my new rig.   Apparently I got this too hot during welding, and warped the damn things.   I used 3" square with a 3/16" wall thickness turned on a 45.  It pulled upwards after welding in the flat steps.   My question is when trying to heat straighten, do I heat the opposite point, or down the sides below the flat step.   Any help would be greatly appreciated.   Thanks agin for lookingMiller BobcatHarris cutting outfitMiller spectrum 625 plasmaVariety of shopmade tools
Reply:Heat the high side of the rainbow. And from there, it is truly an art of feel, sight, and luck.  but flip it over so the steps are down, and heat the highest point, and a bit of the surrounding. Don't go nuts, you can always reheat if needed. Let it cool and check for straightness
Reply:Just put them on.You can theorize, well actually you don't even know the theory of it, then you have to put the pen to the pad and develop a skill. This is not a simple thing to do.
Reply:Heat the long side as said. Sometimes you can just run a bead on the back side too. Do a little then check it or you'll go too far. You can also straighten them by putting the crown up and smacking it with something heavy. For that I would set it on a couple 2x4s on each end and smack it in the middle with a 4x4 or something else that won't dent like a hammer. I have better luck that way than the heat method.Yeah, I know, but it'll be ok!Lincoln Square wave 255Miller Vintage mig30a spoolgunThermal Dynamics Pacmaster 100xl plasmaSmith mc torchEllis 1600 band saw
Reply:I am known by several to be damned spiffy at heat straightening. What I would do is flip it over, supported at the ends and use a small rose bud or cutting torch to heat a series of 1"-2" lines down the opposite corner and use a siphon blow gun with water to cool each strip as you do it. After you have done all this, let it cool to near ambient and reevaluate. Sent from my iPhone using TapatalkUsing Tapatalk
Reply:Originally Posted by Nashvegas WelderI am known by several to be damned spiffy at heat straightening. What I would do is flip it over, supported at the ends and use a small rose bud or cutting torch to heat a series of 1"-2" lines down the opposite corner and use a siphon blow gun with water to cool each strip as you do it. After you have done all this, let it cool to near ambient and reevaluate. Sent from my iPhone using Tapatalk
Reply:I don't know the specs but as they sit now .005 run out is too much.
Reply:Continuous chain attached to each end or desired location to pull from.  Turn high side up, place jack in center of high point and apply pressure to chain.  Apply heat as you apply jack pressure if needed. Jack will push down while chain is pulling up.  May have to build brackets to set jack on since tubing is at 45 degree.Used this method numerous times on the dreaded arch!  Just find way to keep chain attached and not slip from ends.Sometimes multiple pulls may be required.
Reply:Thanks for all the input.   I was thinking along several of the ideas that some of y'all presented.   I am just glad to hear I wasn't to far from what needed to be done.   Thanks again for y'all's timeMiller BobcatHarris cutting outfitMiller spectrum 625 plasmaVariety of shopmade tools
Reply:Thanks againMiller BobcatHarris cutting outfitMiller spectrum 625 plasmaVariety of shopmade tools
Reply:Originally Posted by Nashvegas WelderI am known by several to be damned spiffy at heat straightening. What I would do is flip it over, supported at the ends and use a small rose bud or cutting torch to heat a series of 1"-2" lines down the opposite corner and use a siphon blow gun with water to cool each strip as you do it. After you have done all this, let it cool to near ambient and reevaluate. Sent from my iPhone using Tapatalk
Reply:I learned how to do it balancing  automotive and heavy duty driveshafts, but 5 thou is tight! If you can hold that, my hat's off to ya! I've also straightened a LOT of odd shaped/designed pipe and tubing rails and off-road accessories as well. The theories may be the same but the practice varies wildly from one hand to the next. The only real no no from all I've been taught and picked up is don't overheat the steel. Sent from my iPhone using TapatalkUsing Tapatalk
Reply:I've always TRIED to keep the ambient light low and go no further than a dull red. Sent from my iPhone using TapatalkUsing Tapatalk
Reply:Here is a pic of the jack and chain method. I used this to straighten a back blade I had. Should have thought of this myself, it very easy to control with this method. Thanks for reminding me kuzineddie.Yeah, I know, but it'll be ok!Lincoln Square wave 255Miller Vintage mig30a spoolgunThermal Dynamics Pacmaster 100xl plasmaSmith mc torchEllis 1600 band saw
Reply:That's pretty slick there welderj, would work well with a porta-power too, I'd think!Sent from my iPhone using TapatalkUsing Tapatalk
Reply:Originally Posted by Nashvegas WelderThat's pretty slick there welderj, would work well with a porta-power too, I'd think!Sent from my iPhone using Tapatalk
Reply:Nice. Sent from my iPhone using TapatalkUsing Tapatalk
Reply:Just throw a half inch piece of bar underneath the ends of the cut out piece and clamp it down to the welding table with the shims holding up the middle. Go easy and release until you figure out how much stretch you are affecting. Ten minute repair, tops.
Reply:Originally Posted by welderjHere is a pic of the jack and chain method. I used this to straighten a back blade I had. Should have thought of this myself, it very easy to control with this method. Thanks for reminding me kuzineddie.
Reply:Originally Posted by ExcaliburLooks like a good way to take a jack handle to the happy sack!
Reply:Originally Posted by 7A749I knew a guy that worked in the shipyards back in the '70's and described a similar method used for straightening deck plates. One guy in front with a rosebud heating, a guy came right behind him with a torch they had modified to spray a mixture of water and air. The sprayer guy would hit the heated spots and pop dents out and straighten things up.He said it was something you had to see to believe. Guy wasn't a BSer so I know he wasn't blowing smoke.It would be neat to see.
Reply:It is pretty cool. Sheet metal is the most drastic/immediate. It actually makes a solid pop noise when the dent pulls most of the time. Thick stuff is cool too though, when an end is unsupported, you can literally watch the metal move. Sent from my iPhone using TapatalkUsing Tapatalk
Reply:I welded a reinforcement strap to the bottom of my sliders when I built them and ran into the same issue. Heat straightening works, and works well. Don't be afraid of the process. I had never done it before, and I had excellent results. Try to find a temp gun, or use temp sticks to make sure you're in the correct heat range. After you do a few patterns, you'll learn to judge temp by material color. I read this:http://www.fhwa.dot.gov/bridge/steel/02.cfmDecided on which pattern I wanted to use, then just went for it. Here's my results:Before (using other slider as a straight edge reference)DuringAfter
Reply:Originally Posted by Bray DI welded a reinforcement strap to the bottom of my sliders when I built them and ran into the same issue. Heat straightening works, and works well. Don't be afraid of the process. I had never done it before, and I had excellent results. Try to find a temp gun, or use temp sticks to make sure you're in the correct heat range. After you do a few patterns, you'll learn to judge temp by material color. WellI read this:http://www.fhwa.dot.gov/bridge/steel/02.cfmDecided on which pattern I wanted to use, then just went for it. Here's my results:Before (using other slider as a straight edge reference)DuringAfter
Reply:Originally Posted by welderjWell done! And thanks for that link! I've used heat before a few times, but never liked it because I wasn't any good at it. With this link I'll try it some more, should be able to make it work better. This is what's good about the internet, so much info is so easy to get now. Back in the day I would have had to find someone who knew this and ask, which would be much harder. Thanks again for a great link.Bray D thank you for the link, you just filled my future reading time  Pls educate me what does slide on these sliders i just can't figure-it out
Reply:They are rock sliders/rocker panel guards for an off-road rig of some sort. Prevent impact and snag damage along the bottom of the body between the wheels and keep from hanging up on rocks. Sent from my iPhone using TapatalkUsing Tapatalk
Reply:I have talked to guys at Truck shows who have taken the dents out of old dump bodies that way .
Reply:They SLIDE over the rocks. Sent from my iPhone using TapatalkUsing Tapatalk
Reply:It's a cool *** process gxbxc. I do it frequently building handrail. Sent from my iPhone using TapatalkUsing Tapatalk
Reply:Thank's nashvegas for the clearer picture
Reply:No prob Bird... I've built a few sets, nothing as elaborate as what these are though. More fun to use than build!Sent from my iPhone using TapatalkUsing Tapatalk
Reply:Mine are really more like running boards or steps to make it easier to get in an out of my lifted truck.    I had to work late tonight, so I am hoping to give this a whirl tomorrow night.   Thanks again for all the info.   I will post Picts with progress.here are some Picts of a set I built on my last rigAttachment 846911Last edited by jw3; 09-17-2014 at 09:50 PM.Miller BobcatHarris cutting outfitMiller spectrum 625 plasmaVariety of shopmade tools
Reply:Did you know the three kinds of off roaders ,(1) the mechanic ,(2) the rich,(3) the now walking . if you can't fix it stay in the driveway.
Reply:I've been the wrench and the walking.    Damn shame I will probaly never be the rich.   I think that's why we are having this conversation.   LolMiller BobcatHarris cutting outfitMiller spectrum 625 plasmaVariety of shopmade tools
Reply:Ahhh... The black art of flame straightening. Ok, so I have done a bit of this and like a few others have said, it is not that hard if you take the right approach. In the ornamental/commercial railing field, flame straightening was a regular thing for me when building long straight sections of rail. Hell, for that matter flame BENDING was a regular thing as well when building curved rails. (which is quite common in this field) Either way, the rosebud was attached to my torch more than the cutting head.I have worked in places that have all the big boy forming equipment, and in others that was like walking into the stone age. In the case of ornamental iron, the couple of shops that I worked in was primitive in the forming department, and most contraptions were made from structural steel out in the yard. Kinda like one of thoseresidential/light commercial structural shops that "also" does rails. Anyway, some nice rails were made, and with the excption of a old set of rolls for forming spiral staircase top bar, most bending involved the torch in some way, shape or form.That said, the way I approach flame straightening is to start with determining how it is/was bent (kinked or curved). In the case of railings, and a seemingly good analogy, you have industrial style pipe rails that have horizontal rungs as you would see in a factory/industrial setting, and you also have pipe rails that you have in more urban office park settings that have vertical pipe pickets (1/2"-3/4" or the like) spaced every 3-1/2" - 4". So a pipe rail that has no vertical pickets might display a "kink" at every post that the top bar intersects with. The latter picketed pipe rail will also have these "kinks" at every post, but will have an ALSO have a "bow" that spans between vertical posts where the all of vertical pickets are welded. When you create spans of railing 20'-60' or longer, this can become quite cumbersome and can quite frankly become crooked as a dogs "heeem"..Heavy clamping and strategic placement of welds (constantly clamping, weld a little, un-clamp, flip, clamp, weld a little, etc) "could" be performed to minimize all of this bending from happening in the first place, but when you have however may thousand feet of rail to build, this quickly becomes un-feasable. Unless you have some sort of super fab jig table, you do modest clamping, tack one side, weld the other first, then the tacked side, and deal with the straightening when its all welded, connected and cooled, "which is not really as hard as one might think".As others have said, heat the top of the rainbow, go easy on the heat, cherry red colors should be for hard kinks only, and more a broad spectrum for the sweeping bows, heat then quench with water to draw the bow or kink out.  A lot can be done by eye, but of some applications where there is a near by edge to reference, such as a nerf bar as compared to the rocker panels of a jeep for instance, you can start with putting a straight edge against the object in question, and note the points of reference with soap stone. Feel free to write notes at the points of reference "kinks or sweeping bows" on the steel to notate where to heat and how hot to heat. That way if you don't get all of them the first time through, you already have things marked and can come back to straighten the scragglers on the second pass. The aim is to NOT create an opposing bow or kink from applying too much heat. I would typically vere away from straightening one spot at a time, rather I would work in reverse order heating/cooling all marked spots, then narrow down to individual problem spots"if any".UUGH, there were a coupla more paragraphs in this original post, but got shredded trying to post via a tablet. Anyway, thats a lot of how I approach flme straightening as it applies to long straight objects with welds between.. Hope it is of some assistance to somebody who likes to create.-Niche
Reply:Originally Posted by snowbirdBray D thank you for the link, you just filled my future reading time  Pls educate me what does slide on these sliders i just can't figure-it out
Reply:No cage?No HELMET??Naughty naughty......zap!I am not completely insane..Some parts are missing Professional Driver on a closed course....Do not attempt.Just because I'm a  dumbass don't mean that you can be too.So DON'T try any of this **** l do at home.
Reply:Originally Posted by zapsterNo cage?No HELMET??Naughty naughty......zap!
Reply:I see the cage now but sorry.....No helmet no excuse.Tip over and clank your head on a rock........Stupid things can and will happen even to the best of us....Speed has no bearing in this....zap!I am not completely insane..Some parts are missing Professional Driver on a closed course....Do not attempt.Just because I'm a  dumbass don't mean that you can be too.So DON'T try any of this **** l do at home.
Reply:Zap you've worked hard to build the reputation of a hard a$$ uncaring Masshole. Are you sure you want to throw it away trying to save one jughead from traumatic brain damage.
Reply:Absolutely....zap!I am not completely insane..Some parts are missing Professional Driver on a closed course....Do not attempt.Just because I'm a  dumbass don't mean that you can be too.So DON'T try any of this **** l do at home.
Reply:You guys are funny. I see your point, but there's also a time when a guy can be overly cautious. Every hobby has its inherent risks. I don't wear a helmet when I drive to the grocery store either.
Reply:Well gentleman I have another question.    If after trying heat and bottle jacks this damn thing still hasn't moved, am I correct to assume that I need to apply more heat?    Any advise as to how much heat.  Thanks again.   Normally I can work my way through most things, but this one is whooping my tail.Miller BobcatHarris cutting outfitMiller spectrum 625 plasmaVariety of shopmade tools
Reply:It's been a few days ,do those stone bar/running boards need straightening yet?
Reply:No just the straightening from the first screw upMiller BobcatHarris cutting outfitMiller spectrum 625 plasmaVariety of shopmade tools
Reply:Originally Posted by jw3Well gentleman I have another question.    If after trying heat and bottle jacks this damn thing still hasn't moved, am I correct to assume that I need to apply more heat?    Any advise as to how much heat.  Thanks again.   Normally I can work my way through most things, but this one is whooping my tail.
Reply:Lotta "tell" here, and no "show"You gotta problem, and there's always a solution for a problem.This is an old build from some time back.  The bumper hitch on my 1 ton.First off, this was the finished product.Nice, and straight, ready to go on the truck.  BUT IT DIDN'T STRAIGHTEN ITSELFLet's start out with something approaching the same type of problem you're having.  Mainly a warp in some flat.Welded the ball tab to a piece of 3/8 flat (or maybe it was 1/2 flat), and despite using a strongback during the welding process, it pulled the flat like a banana.So, now that you got something resembling a pretzel, it's time to have some funThe piece is placed with the bow up between two supports.  Heat is applied to the top of the bow, and the weight of the piece, when the heated area cools, pulls it as it shrinks, and straightens it out.  This particular piece was also peened as it cooled to increase the shrinking effect.  Peening relieves stored stresses in the metal.It's important to stress that this didn't straighten itself magically by heating alone.  The weight of the piece supported like it is, combined with the peening, made it happen.  YOU NEED EITHER STRESS RELIEF, OR AN OPPOSING FORCE.  This is called upset, and results by restriction of movement in the surrounding metal.  The same principle applies when straightening sheet metal, but in that case the restraint is provided by the metal alone.PEENING MEANS HITTING IT WITH LIGHT TO MODERATE FORCE, DEPENDING ON THE THICKNESS ETC.  IT DOES NOT MEAN BEATING THE LIVING **** OUTTA THE THINGNow for some more types of straightening.........."Any day above ground is a good day"http://www.farmersamm.com/
Reply:Same build, different problem.  The tubing pulled while it was being welded.Again, I placed the piece between two supports in such a manner that the bow was upwards, and the weight of the piece could act as the opposing force during shrinking.In this case I just wanted a small smoogie  So, instead of spraying a high volume of water on the heated area to cool it, I used a wet rag.  A gentler bend this way.The final result.  Good to goThe outside radius of the bow is heated, along with the adjacent sides of the tubing.  You can use a pie shape heating pattern with the small point of the wedge furthest away from the outside radius.Do this all the time, take time to TRY to explain it, but mostly it falls on deaf ears.  Feel like a broken record sometimes"Any day above ground is a good day"http://www.farmersamm.com/
Reply:Thank you farmersamm.   The Picts and description helps tremendously.   Again thanks for your timeMiller BobcatHarris cutting outfitMiller spectrum 625 plasmaVariety of shopmade tools