Submitted by: Unknown
Science, how does it work?
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DIY: Home Dent Repair
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He heats it up, expanding the metal, then with the spray he cools off the near side. The near side contracts, but the far side of the metal is still hot, so it doesn’t. And that bends the metal back into place.
High School Science wins again!
It’s not metal… That part there is plastic.
The problem isn’t the dent–it’s the microscopic cracks that are in the clear coat which will result in the paint flaking off in about a year or two. The clear coat is not just there to make the car shiny. It is there to protect the paint, which is going to come off that bumper any day now.
That’s not the bumper, it’s the rear door of the van, which is metal.
It works because metal deforms with heat and cold. The canned air gets really cold and causes the metal to contract–reverting it to its factory-molded shape. My uncle owns a custom paint/body shop and I learned this trick from him years ago. Works great for hail damage!
Please esplain!
Simple. Take the inner pannel out, and have a friend sit in the vehicle. When you give him the signal, have him bump the dent out from the inside.
^BEWARE OF TROLL
Naah, his picture’s a purple face. He’s legit.
Supposedly the expansion/contraction from the heat/cold will pop out the dent. I’ll have to try it to see if it works.
It works by the heating and then rapid cooling of the metal. The heating is done such that the metal is at a uniform temperature through its thickness, then the fast cooling caused by the compressed air rapidly expanding creates a tensile stress on the outer (colder) surface of the sheet metal. The stresses applied over an area creates a force, which then fixes the dent.
It is the speed at which you heat or cool that makes the difference.
The hair dryer heats up the metal of the vehicle, making it more plyable, and by blowing the cool air on it, it contracts back to it’s original state.
Not just “cool air”, but “can of cold” – when you take a can of compressed air and turn it upside down, you get VERY cold gas. It’s a poor-man’s liquid nitrogen tank.
Also, the heat hast little do to with making the panel “plyable”, that little heat has NO such effect on metals. However, it does allow for a much larger margin in temperature.
It’s a very effective way of not having to spend ages dressing the dent out, and then trying to get a colour-match with the paint! It won’t work if the panel is creased, or the metal is stretched.
All Toyotas are made out of Shape Memory Alloy now.
I have a book printed in 1929 called “The Key to Metal Bumping” that shows this exact same fix using an oxy-acetylene torch to heat the dent and the area around it and then you put a cold, wet sponge directly in the center of the dent to pop it back out. The only problem is the heat cooks the paint off.
Although this is awesome and easy to do in your driveway.
Mmmmyeeeeeahhhhh…. “Who you gonna call? MYTHBUSTERS!” I’m feeling sceptical about this. A torch or something else that really heats the metal up, sure. A hairdryer? No. That ain’t gonna make any difference. You might as well breathe on it.
The heat will just dissipate through the metal.
That’s not a hair dryer, it’s a heat gun.
http://en.wikipedia.org/wiki/Heat_gun
Yeah, sure, glossy magenta, common plastic, aqua green triggered, heat gun.
Come on pal, that’s a hairdryer.
Nope. It’s just a cheap funking hair dryer.
That’s not just “a hair dryer” but a Heat Gun that’s putting out 1400-F plus air no open flames.
You still have to be really careful not to start blistering the paint or melting the plastic car emblems, but it will work the same as a torch if you have the proper touch.
Oh, and get a can of real Freeze Spray or a CO2 fire extinguisher with a modified nozzle.
That’s not a heat gun he’s using. I have the same hair dryer it’s a Conair quiet tone 1875
Actually a hair dryer can put out a good bit of heat, and we don’t know how long he’d been doing it. It really doesn’t take that much heat to create a reaction like this.
You’d be surprised. A few weeks ago my father fixed a huge dent in my fender using a hair dryer. Saw it with my own eyes.
It works we did it on small dents in aircraft in the USAF. You heat the metal to expand it and the Rapid Cooling, causes it to shrink and can help pull it back to to original shape. It’s not a sure thing but when it does work it saves you a LOT of time.
You can use crushed ice inside a bag of any fabric, like cotton, and wait some time… also you may need to repeat the process… It work’s!
But that apostrophe between ‘work’ and ‘s’ does not!
That’s not real kludging when the dent is so small you can’t really see it. And all dents add personality to your vehicle. Shameful.
Yeah! The dents on my F350 don’t make it look beat up and run down at all, they add personality. I am going to slide off the road in the snow again just to add more personality to it!
I am also not overweight I am just big boned.
If I do this 50 times, will it remove that same number of hail dents?
I have a similar question, and I’ll go find out. Although I’ll probably have to use a butane torch as I don’t own a hairdryer. Word of advice, never park under an oak tree in the fall.
Old trick known to older Body Shop People. In the 40′s 50′s and 60′s if a car had a big dent (like a caved in roof from a roll over) they would heat the dented area with a blowtorch and when red hot, throw cold water on it and “Pop” the dent would pop out. Of course it was body shop work and they could then paint it. Relieved a lot of banging with hammers to knock out dents.
This is very common down south after hail storms. Wait till it gets very hot outside, then put a small cube of dry ice in the dent, it pops right back up.
I don’t care how common it is, it’s still bad for the paint D: .
No worse for the paint than any other traditional dent pulling method. If you heat the area properly, then any heat damage to the paint can be buffed out since it’s more than likely just discoloration of the clear coat anyway.
Now if you leave a heat gun in one spot for a prolonged period, then yes, that is terrible for the paint.
Great for a small dent, but that sort of working makes the metal more brittle, too. The rapid expansion and contraction causes tiny defects, so if the car gets hit again, it’s more likely to crack in that spot rather than bend.
QUICK! If I don’t get there soon someone should submit it to mythbusters.
it’s only a toyota mini-van, who cares about the paint?
Thermal expansion FTW!
hell yeah its magic
fixed buckys dent.
That’s plastic, not metal.
EPIC WIN!!!
Towlie says dont forget to bring a towel ! Wanna get high?
I once pulled a huge dent out of my door using a toilet plunger
Ugh…this is some of the dumbest fixes ever – the only thing popping back in tho the factory position is the paint.
The dent in the metal stays, so all you’ve achieved is loosening the paint from the metal effectively hiding the actual dent from sight.
The paint will eventually flake off, revealing the dent and probably also some rust, since the paint wont come off all at once.
This is NOT a fix, it’s a kludge akin to peeing in the pants.
Cheers, WHEN I appreciated a put up hugely. It will be attractive to determine someone making a specific thing worthy of reading.