Proper method for dent recovery

The guys all have good points. there aren't any really heavily stretched spots there. You can work a lot of stretch into it if you beat on it too much. A broad head hammer or slapper gives minimal stretch since it strikes a lot larger surface with each blow but you have to have a fair sized dolly with the right contour as was mentioned to back it up. If you have a porta-power, that helps a lot. A shrinking disk only shrinks the little puckers you have left after whacking on it. That would keep shrinking to a minimum too. If you shrink to much then you have to beat that out too and that's what I mean about chasing your tail.

Guys that specialize in this stuff can fill the imperfections left over with prime & sand if there are any. Experience is the only way to get to that level.
 
Porta-power? You mean the hydraulic device? I am not familiar with that except for large displacement dents where you can stretch a door or fender that has been shortened by collision damage.
 
You can hammer beside the Dolly say 2" this is the of dolly method ,or you can hammer direct on the dolly,After getting most of it up you can hammer direct on dolly for heavy creases but not to hard .Ted
 
I would start by using the off dolly method to straighten the panel out as much as possible. Put the dolly underneath the low spots and apply upward force. Then hammer on the high spot, this will bring down highs and bring up lows without stretching. If you do this, and then get the shape back, and start to have oil canning, that will tell you that the metal has stretched, and there is now too much material, and will need to be shrunk.
 
cretin said:
I would start by using the off dolly method to straighten the panel out as much as possible. Put the dolly underneath the low spots and apply upward force. Then hammer on the high spot, this will bring down highs and bring up lows without stretching. If you do this, and then get the shape back, and start to have oil canning, that will tell you that the metal has stretched, and there is now too much material, and will need to be shrunk.
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Great advice, that means to me that an assessment of stretch needs to happen after the hammering. What ever stretch has then occurred would then require shrinking.

I appreciate all the replies and help guys.

Ken
 
cretin said:
I would start by using the off dolly method to straighten the panel out as much as possible. Put the dolly underneath the low spots and apply upward force. Then hammer on the high spot, this will bring down highs and bring up lows without stretching. If you do this, and then get the shape back, and start to have oil canning, that will tell you that the metal has stretched, and there is now too much material, and will need to be shrunk.
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Excellent and to the point.
The high mild creases are made up of metal bent beyond the elastic limit which lock the low below it's high crown former position. The low "wants" to go back to high crown but is locked down. Cretin's technique will free the low and done carefully will require little filler if any.
Working this less than severe damage will be good practice.
 
Cretin has repackage what I others have said ,While there' are some good suggestions above ,This is just the way we were taught . Heat shrinking has been mentioned several times ,for a novice I would leave this as a last resort you can create more problems than you could deal with .A badly damaged panel may need heat shrinking, but going by the photos its light damage ,If you get oil canning in a low crown panel such as a roof it really needs stretching not so much shrinking so the tension holds the panel to one side .I suggest you use the porter power with you left arm and move it around on the low spots while tapping the high spots on the top .then if you get oil canning I would work that error with the file slapper (picture attached )lightly slapping on the dolly moving back forth ,this will hold it in tension .at this stage you may be able to use your arm and push up .Ted
 

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Roter makes some good points
rotorwrench said:
The guys all have good points. there aren't any really heavily stretched spots there. You can work a lot of stretch into it if you beat on it too much. A broad head hammer or slapper gives minimal stretch since it strikes a lot larger surface with each blow but you have to have a fair sized dolly with the right contour as was mentioned to back it up. If you have a porta-power, that helps a lot. A shrinking disk only shrinks the little puckers you have left after whacking on it. That would keep shrinking to a minimum too. If you shrink to much then you have to beat that out too and that's what I mean about chasing your tail.

Guys that specialize in this stuff can fill the imperfections left over with prime & sand if there are any. Experience is the only way to get to that level.
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I agree with GM about the heat ,Assessment needed and this comes with Esperance
G.M. said:
The metal may or may not be stretched. I would get two guys inside and put the back of your shoulders up against the roof and push it up. Most of it should pop back up.
It may be a little wrinkly around the edges which will have to be straightened.
I would avoid heat on a large metal panel as it can warp. G.M.
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I would think using something as powerful as a porta-power for something that needs little pressure is asking for creating more problems, especially for a novice metal worker. If my understanding is that the issue is the slight creases that remain at the edges after a large panel deformation is pushed back is accurate, the pressure from beneath while using a spoon or slapper would be fairly slight.
 
A guy can use a 2X4 cut to a wedge length as long as there is a crowned head to push against. A porta-power just makes it to where you don't have to cobble stuff together like a lot of us do. A person wouldn't want to go to jacking to hard on it. They just need to apply pressure. It's just another tool if you have one.
 
As stated all that is needed in a case like this is to hold pressure upward on the roof.
I have used this method on a few roofs over the years.
 

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First off do NOT!!! use heat at this point. You can only make matters worse. Heat is a very last resort thing unless you really know what you are looking at in the metal.

Get yourself an aluminum can and press in until you get the two points sticking out. Notice the can is not shorter on that side.
Now massage the points out and get the can back in shape.
It is still short on that side because the wrinkles are making the metal shorter.
The fix is to stretch the metal by reducing the wrinkles.
The points are a function of the high crown surface of the round can. The points are locking in the dents.

Another thing to try.
Get an 8x11 piece of paper.
Lay it on a table after tearing about 1" in the middle of the side.
Now take the two sides with the tear between your fingers and slightly overlap the edge.
A nice oil can pops up.
You can fix that by making the rest of the paper shorter along the middle or just release the very very slight shrink on the edge.

What you have on the roof are some spots that go into the high crown area.

You need to work with careful hammer dolly hits to release the bends in the high crown area and get the roof as level as possible. You must be careful to not stretch the metal while doing this.

The above will get the roof better, but not done.

Next you really really want to get a shrinking disk.
This will bring out the creases and very slight high spots and help you bring everything level.

You should be able to bring that roof out to level where a couple of coats of a higher build primer will be enough to make it perfectly level.

No torch shrinks are needed to fix this problem. In fact, a shrink in the high crown area could make it MUCH harder to fix.

BTW, a shrinking disk will only create heat on the slightly raised spots. This is a very special form of shrinking that quickly takes out the small stuff created with your hammer and dolly work.

I suggest you do some research on the web. You will also find some links on my webpages down below.
 
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