Undenting firewall

[digidocs]

Somehow I got a pretty reasonable shiner in the firewall. What should I try to work it out? I have pretty good access to both sides.

Thanks for the help,
David

[aarvig]

I'd replace it.

[digidocs]

No reason to replace---at worst it's a cosmetic defect. Would be nice to reduce/remove it if possible though.

[comfortcat]

You firewall pass-thru goes near there.

Build on.

Dkb

[Larry DeCamp]

Use your flat faced riveting tool (actually it has slight curvature to face) and flat riveting anvil. With VEEERY low pressure, move the tool over the "outy" with the backup bar behind. If you are patient, you will end up with a flat firewall that has an area of "dulled" finished that may respond to polishing..Larry

[BillL]

The crease is the most difficult one to address, I would back up any impact tool with some very smooth, hard wood. Maybe even cover it with some leather. Metal on metal , like hammer or spoon on dolly will stretch the metal.

The short answer is that it if you have to ask how, you won't be happy with the result. I know what to do, but the skill to do it, even after years of practice, always escaped me. The real challenge is that is flat, no crown.

Here is an expert: http://www.tinmantech.com/html/kent_white.php

There is even a place to ask questions. Kent is AMAZING. I have seen his demos at OSH. Please let us know what you find.

[bret]

Aren't you going to cover it with a fire barier of some sort any way?

[rvbuilder2002]

Amazing results can sometimes be accomplished on damage like this.
The problem is it takes a lot of experience to have the skills to do so.

A couple tips if you decide to try...

Never use impact tools (hammer, rivet gun, etc.) if your goal is a flat surface. They stretch the metal and it will not be as flat as it could be. In instances were a compound curve is desired, they are helpful because stretching is needed but that is not what you are after here..

To repair bends like you have, you need to find ways to cause a reverse bend directly along the line where the bend exists. It sometimes requires cutting a shape from hardwood that matches the shape of the bend in a particular area. Add a radius to the edge that is similar to the bend radius of the crease (in areas where the crease is very light you need to be using something with a large radius. In areas where the crease is sharp, you use something with a much sharper radius), and slowly massage with finger pressure in the direction that will reverse the bend. Start with the worse area first, and keep expanding the work area as the area with similar bend radius grows. You can also use radiused tools like wooden spoons or custom formed wood blocks and slide them along the peak of a crease while applying pressure.

A stainless firewall is actually tougher to do this on than an aluminium skin because it is so soft and will easily bend beside the crease while you are removing it. Because of that you will not be able to remove it 100%, so I recommend that after doing the best you can, you hide it by removing the gloss of the firewall by applying a machine turned finish (Google it or search the forum). I have done it a few times just with a 2" diam scotchbrite pad and disk, hand held in an electric drill. Everyone will marvel at your custom firewall finish and probably never see the faint remnants of the crease.