Flame Straightening done right

[bebeaux]

After reading another thread about flame straightening/shrinking and the incomplete understanding of the process that some had, I thought this website would be instructive. Free advertising removed is the best in the business, and the damage they can correct using torches and come-alongs is nothing short of miraculous. Having used some of these techniques with varying degrees of success, one thing I can say for certain is that while the torch alone can move some metal, the process is way faster using mechanical means(winches, come-alongs) to hold the work in tension/compression.

Another good resource is the AWS publication C4.4 Recommended Practices for Heat Shaping and Straightening with Oxyfuel Gas Heating Torches.

I used this method years ago to bend a 1/8" wall 2" x 4" tube for a custom brush guard/bumper for a friend's truck. Here's a time lapse video of the process

And here's the brush guard...

 

[jlpservicesinc]

This method works very well..  Using ice cubes can expedite the process as can shooting cold at directly at the spot..  The colder the metal around the area the faster the shrinking..  Really kinda neat how the metal will move outwards upsetting itself then when cooled contracts pulling back even more.. 

[anvil]

"Macbruce" here on IFI did a good series on flame straightening heavy plate.

[Nobody Special]

On ‎2‎/‎23‎/‎2019 at 5:42 PM, jlpservicesinc said:

This method works very well..  Using ice cubes can expedite the process as can shooting cold at directly at the spot..  The colder the metal around the area the faster the shrinking..  Really kinda neat how the metal will move outwards upsetting itself then when cooled contracts pulling back even more.. 

Used to use something similar with dry ice to pull small dents and dimples out in sheet metal.  Put it (or often enough, park it) in the sun on a hot day, then run dry ice over it when it was good and hot.  Pulls small rock dings out of a car nicely.