Can Airstream skin aluminum be annealed?

[ahatzung]

So, I have to say that I have been utilizing this forum for several months now, and every question that I have had regarding the restoration of my airstream has thus far been answered by a quick search through previous discussions.

I now have a question that I have been unable to find a definitive answer to. Can the skin of my 1967 Airstream Caravel be annealed?

I have two large, deep dents and a lot of dimpling on the upper portion of the front end-cap, which I would like to repair. I have no experience with repairing aluminum besides the 20+ hours of research I have done on the issue. From what I have read and viewed so far, annealing makes the process of hammering and repairing dented aluminum a much easier and faster process. I have read in this forum that the skin is most likely made of 2024 aluminum, which I have read is very difficult to anneal by an amateur, such as myself. This is because the temperature zone between annealing and melting for 2024 aluminum is very small (400 degrees, 800-1200).

Does anyone have experience with this process? Is it very difficult to pound out dents and dimples without annealing?

I'm bent on doing all the work involved in restoration myself and would like to get started on this repair before winter arrives so that I can re-rivet the skins (replace old pop rivets used by PO for repair of the skins), get new insulation in and get the interior panels back in place so I have a warm place to work through the cold months up here in Minnesota.

Thanks in advance!

-Drewski

[Inland RV Center, In]

Originally Posted by ahatzung

So, I have to say that I have been utilizing this forum for several months now, and every question that I have had regarding the restoration of my airstream has thus far been answered by a quick search through previous discussions.

I now have a question that I have been unable to find a definitive answer to. Can the skin of my 1967 Airstream Caravel be annealed?

I have two large, deep dents and a lot of dimpling on the upper portion of the front end-cap, which I would like to repair. I have no experience with repairing aluminum besides the 20+ hours of research I have done on the issue. From what I have read and viewed so far, annealing makes the process of hammering and repairing dented aluminum a much easier and faster process. I have read in this forum that the skin is most likely made of 2024 aluminum, which I have read is very difficult to anneal by an amateur, such as myself. This is because the temperature zone between annealing and melting for 2024 aluminum is very small (400 degrees, 800-1200).

Does anyone have experience with this process? Is it very difficult to pound out dents and dimples without annealing?

I'm bent on doing all the work involved in restoration myself and would like to get started on this repair before winter arrives so that I can re-rivet the skins (replace old pop rivets used by PO for repair of the skins), get new insulation in and get the interior panels back in place so I have a warm place to work through the cold months up here in Minnesota.

Thanks in advance!

-Drewski

All the side and roof metal is 2024T3.

Annealing it is basically out of the question.

If the metal is creased, the dent can be smaller, but will always some what show. If the dents are from hail, in time they will for most part disappear, since the metal is tempered stress relieved.

The segments are made with a much softer aluminum.

Small dents, as an example from hail, will not disappear since the segment metal is stretched.

Andy

[SteveH]

I have no expereince or knowledge in this are whatsoever, but this is a very interesting thread for you:

http://www.airforums.com/forums/f381...eat-84029.html

[Belegedhel]

I don't think annealing is the way to go. First, you have dimples, or noticeable dents because the metal has been stretched. Annealing, if it could be done in a controlled fashion (which is very doubtful on such thin material), would make the metal easier to work, but you still have the problem of trying to "shrink" the part of the skin that has been stretched, and that is going to be pretty tough. The other drawback of doing anything to affect the temper of the aluminum is that it would then be left softer than ever, and that much more susceptible to future denting.

Some people on the forums have had luck getting dents out by having an assistant hold a bag full of lead shot on the exterior of the trailer as an "anvil", and then using rubber mallets or curved body working tools on the interior to beat the dent (mostly) out. They still usually end up with a noticeable ripple, and if the aluminum has been creased, then it will be very hard to get that crease to go away altogether. Aerowood (search for his "Full Monte" thread) made a metal roller on a handle to achieve the same thing with less hammering.

The people who just can't tolerate the imperfections replace entire panels, the rest of us accept them as part of life. Its easier to live with if the dents are not around eye level and the trailer isn't polished to a mirror finish.

Good luck.

[Splitrock]

I watched a video of a guy rolling a dent out of an aluminum car body by using a roller and a heat gun. I tried it on my trailer rear segment and it worked. I pushed the dent out with a couple load jacks and then used heat and the roller to finish up the repair. When it was warm enough it just rolled out with almost no pressure. Cold, it wouldn't even move at all . . . even with pressure.

The repair isn't perfect but a casual observer can't find it. I have to show the guest where it's at. Maybe when I strip the clearcoat it'll stand out more. Next summer we find out.

[SteveH]

Originally Posted by Splitrock

I watched a video of a guy rolling a dent out of an aluminum car body by using a roller and a heat gun. I tried it on my trailer rear segment and it worked. I pushed the dent out with a couple load jacks and then used heat and the roller to finish up the repair. When it was warm enough it just rolled out with almost no pressure. Cold, it wouldn't even move at all . . . even with pressure.

The repair isn't perfect but a casual observer can't find it. I have to show the guest where it's at. Maybe when I strip the clearcoat it'll stand out more. Next summer we find out.

How much heat did you use? What was the heat source?

[JimGolden]

Once you crease a piece of aluminum, that's basically it; because you stretch it.

With steel you can sometimes use shrink dolleys and body hammers to shrink the steel,but that doesn't work as well with aluminum.

With aircraft, you basically drill out the rivets and replace the entire panel. That is probably your best option as well.

I know it's not the answer you wanted to hear....sorry. That's one bad thing about these trailers....you ding one and you replace the panel. But, it's not really that hard to do; just a lot of boring monotonous work.

Best of luck!

[Splitrock]

Originally Posted by SteveH

How much heat did you use? What was the heat source?

I used an electric heat gun. I didn't save the video but it was easy to find on you-tube. I just followed the video. Applied heat until I could feel the metal give with the roller.

I'm happy with the way it turned out.

[SteveH]

Originally Posted by Splitrock

I used an electric heat gun. I didn't save the video but it was easy to find on you-tube. I just followed the video. Applied heat until I could feel the metal give with the roller.

I'm happy with the way it turned out.

Thanks.

[ahatzung]

I also don't have any experience with auto-body work but this video is what sparked the annealing question.

Are the other methods used in the video pertinent to dent removal in an airstream?

This guy makes it look SO easy!

Kirkham University Aluminum Fender Dent Repair - YouTube

Thanks for all the input. I guess I wont try anything crazy...

[Wabbiteer]

They show that fender part being machine drawn in another video - metal is described as 0.062" thick and 3003-T0 alloy stock designed to be worked and formed from the start - the alloys AS used over the years is selected for rigidity and tempered for fatigue resistance, both of which would be compromised by annealing.

Interesting to note:

2024 alloy: Annealing is done at 750°-800°F for at least 2 hours at temperature, followed by slow cooling in furnace. This will anneal 2024 from a heat treated condition. Annealing 2024 between cold working operations may be done at 650°F for 2 hours, followed by air cool (the aluminum will work harden at/around the work area).

Also: 2024 is an age-hardening aluminum alloy and responds to heat treatment to accomplish the strengthening (aging). The T4 condition is attained by a 920°F heating followed by a cold water quench and aging at room temperature. T6 is attained by the same 920°F and quenched followed by a 375°F for 10 hours and air cooling.

Speedy Metals

Temperature indicator 'pens' are available, they are similar to a wax color pencil or a paint stick marker that change color once their design temperature is reached. Welding supply shops will have sources in their catalogs.

My opinion is its too easy to drill rivets and replace sheets/segments to try any of the above on a large scale - but for a tinkerer it may be a tempting option, as in it can't be any worse than it already is

[Splitrock]

PDR ( Paintless Dent Removal ) Aluminum Heating Times and Temperatures - Tutorial.mp4 - YouTube

DF-900 AluSpot Aluminum Repair Station Demo/Preview - YouTube

The paintless dent aluminum repair videos showed me how heat works to allow the aluminum to be moved. The trick for me was to move the aluminum and remove the memory. I tried a crayon but in the end I just used the roller to feel the softening of the metal.

This was the first time I tried to remove a dent in aluminum. I've done steel body car repairs and repainting and it's a lot the same . . . but different.

[judithd]

Who do we go to if we need to have panels replaced? We are in Texas right now, but plan to head out to Arizona or California. We backed into a drive way and hit a large tree branch. It creased, big time dent on top. Looks like we will need to have panel replaced and perhaps more than one. It is ugly, but thank goodness there doesn't apper to be anything leaking. Any ideas?

[Wabbiteer]

We backed into a drive way and hit a large tree branch. It creased, big time dent on top. Looks like we will need

judithd : This deserves its own thread!!!

[slowmover]

Originally Posted by judithd

Who do we go to if we need to have panels replaced? We are in Texas right now, but plan to head out to Arizona or California. We backed into a drive way and hit a large tree branch. It creased, big time dent on top. Looks like we will need to have panel replaced and perhaps more than one. It is ugly, but thank goodness there doesn't apper to be anything leaking. Any ideas?

Go see the guy in Post #2 above.