How 2 hammer out your fenders - save the A-line, save the fender

[DMZ73]

It's all about push and pull. I would definitely recommend removing the skin where you can, safely and get it back rather than the slidehammer. They do tend to pucker the metal a bit, but you just need to weld it together. NO big deal. Stud welder does the same thing.

How to hammer the fender A-line:

Tape the A-line, scribe it with a permanent marker where you need it to go. Hammer down the highs using a dooly block behind it. If you don't have a solid dolly block, use a piece of hardwood. It will work just fine. IN fact, you can even form it to the shape you need to hammer (bandsaw)

Where I have some of the arrows, or, better yet, the concave part of the fender form to the A-line break-over, I use a hardened-steel chisel. As wide as you need to coin in the line. Backside, and front side, nice and slow. An even pace makes sure that the metal does not get over-worked.
Some precise blows help straighten the line.
I take my time and make sure I follow my scribed line, making sure I don't go too far. When I start refining my blows, and begin to smooth out the blows, I back the metal with a small dolly, similar to the shape I am after.

Hope this helps. I will re-illustrate the step-by sterp soon. I am beat.

Dan
More to come. I wish I could make a video.

[Street_Challenged73]

Great thread, DMZ73!   I'd love to sharpen my metal-working skills some more.  I've used a stud gun welder before and trust me, they're worth it compared to having to drill holes into the metal, then using the slide hammer, and finishing up with welding the holes.  I've never used the heat-shrink method before, but I've done alright with both the hammer-on as well as the hammer-off techniques to pop dents out.  Just out of curiousity, what was your technique for straightening out that crease in your front fender?  The reason I ask is my Challenger's driver's side quarter panel is tweaked right along the body line and I'd like to maybe try to get it reworked a little better myself before I bring it back to the shop for the final prep. work and paint.

Here are the two areas that'll need attention:

[DMZ73]

Man, that one is EASY compared to what I just did.

I used a cold chisel to help get the A-line back. I used it like a punch, gtting direct force to the area that needed to go in a specific direction, obviously blocking where you can. THose low spots you have that are really close to the A-line-
Hammer them from the backside, with a small 1" chisel, with a few direct hits/blows  on the chisel (use a dead blow hammer) use medium to light force to hit, and push that dent/pucket out,then  planish a little from the front side, dolly-blocking the back side with care. You are not looking for the "ping" you are looking for the lower sound. Ping is stretching, then other sound is not.

I will try to post a few more pics tonight, specifically showing the method.

I hope this helps.

Dan

[Street_Challenged73]

Thanks for the response.   I've just never tried screwing around with it 'cause I don't want to over-stretch the metal then have a larger mess than what's there.

[DMZ73]

Did ya try it yet? It's easy, a slow and steady pace wins the race.

I have kids and an attached garage, so my "hammer time" is restricted to when the kids are out.

Dan

[Street_Challenged73]

I haven't tried it yet, but I planned on messing around with it some this weekend. (after I work on the daily beater, though. )

[b5blueaar]

for final restoration of the body line, stretch a string along the line (stretched strings are straight) and mark with a pencil by carefully tracing along the line.
then sand up to the pencil line from below and down to the line from above, leaving the line on.
you will end up with a perfectly straight body line.

anytime metal is permanently bent, it stretches.
to remove the stretch, heat up a 1 inch diameter circle red hot (as quick as possible with a very hot torch), place a shrinking dolly behind the spot (while still red) and smash with a shrinking hammer. it helps to have someone to hand the torch to quickly so you still strike while red hot.
The effect is to draw metal into the center because you cool the center with the dolly and hammer. (also, serrated shrinking dollies and hammers also help to pull inward, but mostly its just the cooling effect, it can be done with a smooth hammer and dolly) when metal cools, it shrinks. Each time you do this, the metal shrinks a little more and eventually it will pull the panel tight.
 With this technique you can shrink metal to its original shape, removing all tendency to "oil can".

when the panel is truly flat, the dolly will "ping" and your hammer will bounce away as if you hit an immovable object. any other sound without the bounce and its not flat yet (your still moving metal). The dollys sound and the hammer bounce will tell you when its flat. the metal talks to you.

Also, you only have to hit (or pull if using a pulling tool) lightly if your hitting in the right spot.
If you find yourself hitting hard and nothing is moving, then your not hitting in the right spot. You dont need a bigger hammer. A body hammer will move any metal that is not locked by stress.
dont pound harder when nothing moves, that spot is locked up by stress from somewhere else. find the stress, remove it, by hitting lightly and then the locked up metal will be free and will move very easily. again, the metal tells you if it wants to move or not. forcing it will just cause more stretching.
when the metal gets to where it started, (its original shape) the dolly pill ping, (always use a dolly behind the hit) the hammer will bounce,  and that spot is done. the sound tells you when its done.

dont be afraid to try, you can always redo it. you can always shrink it back and try again. just listen to the dolly its tells you all you need to know.

[DMZ73]

Very well put!

The metal talks, so listen for the sounds and watch closely. The metal moves when it is free of stress. Find the stress points and you are golden.

Shrinking is still an artform I have not yet mastered. Since I don't have anyone helping me, I can only guess that your technique for shrinking is superb.

Dan