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Discussion Starter · #1 ·
Anyone know how to form aluminum sheet? I want to make a fan shroud for the Benz and just want to roll the edges over a wood buck.

I think I need to heat it with a torch... aneal it? So the metal will bend not crack. I did some searching on youtube. Any good ideas?

Mike
 

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Hi Mike , I may be able to help..... :) First step is to purchase the correct aluminum sheet. What your going to need is 1100, or my favorite 3003 H13 or H14.This type of aluminum is very maluable and weldible . Now after you have your piece cut and ready for your buck, you will want to anneal it.
To anneal aluminum you will need a oxy acetylene torch. Now when ready set your flame very sooty. When that is set you want to paint your panel as if it were a paint gun and covering the entire work area. When your panel is covered or blackened
You need to change your flame to a neutral flame were your cone has a nice clean burn but not hot were it melts thinner metals on contact.
Aluminums melting point is right around 1200 degrees and close to that is the annealing process...... Now that you have your torch set and panel blackened you want to move around the panel some what briskly at an even distance until you see the the panel appear. Again move around not staying in one spot so not to over heat the panel.
When your panel is mostly clear, you may see some areas that are slightly yellowed this is as far as you want to go....
NOW ! ! Allow me to explain what happened so you better understand the process. When you blackened the panel with soot, it was actually carbon. Carbon it what make the aluminum hard. Releasing that carbon is what makes it soft. If you look at the number 3003 the ( 03 ) is the percent of carbon in the panel from the mill. 3 % is a small amount but will make it more difficult to make compound bends or what I like to refer to as 3 dimensional bends.
Now don't be surprised as you are working your panel, you will feel it starting to resist. This is we're the panel becomes hardened again. Now not carbon hard but what is known as work hard. This is when there are tiny shapes in small areas causing the panel stress. Look at it like a flat roof span, weak and soft and easy to move with little effort. Now add small bumps or truss shapes threw out the panel it becomes more difficult to move. It's not a chemical hard it's a work or structural hard.
So this is when you may have to anneal your panel once more or soften some of your structural bumps. Usually when this happens in panels as you are free hand shaping without a buck we go back to the wheeling machine or planisher.
So as you are forming around your edges you will notice the areas are going to start to thicken. This will happen when you are gathering more amount of material in smaller areas. This will also happen when you create tucks which is when you also gather more material in one are to cause a shrink, these areas will look like and often called ruffles. I will get some pictures from here to better explain.
I guess my long winded explanation is only so you really have a greater idea of exactly what's going on when you are working your panel. ;)
 

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Discussion Starter · #4 ·
Thanks Steve. I am just rolling the edge over, about a half an inch, so should I anneal the first couple inches to be safe? Then what to do to keep it hard? Is there another treatment that will add the firmness back to the aluminum?

I'll post picks of what I am making.

Mike
 

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Mike when your done with the panel you do nothing..... The panel will remain firm and the work will structurally work harden itself and the panel will be no weaker. You will see also when your done, and remember the edge over the buck will actually have more material along the edge.
Also Mike I'm sure you already thought of this but I like to make my panel a bit longer so I can cut back a bit on the edge to clean the panel up.
 

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Discussion Starter · #6 ·
I'm not sure that I did it right, but it's done. Even after annealing it was very difficult to form so I ended up just doing a 90 degree bend. It's about 1/8" thick, so it's pretty beefy. I am using the full width brackets that are on the fans to give it more sturdiness. Here are a couple shots.

I marked it and needed an 11 1/2" hole so I found that my 13" trim rings that I had from my Cal-Look bug from the '80s has the same size inner.


Trimmed out the holes and it fits tight!


After bending over the lip. Not as fancy as what I had in my mind, but it actually fits tight against the face of the radiator and should force all the air to come thru.


Side view. Now all that is left is to bolt it all together and install it with new mounting screws.




Mike
 

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Looks good Mike, but is it going tight against the radiator? If it is, then the solid portion of your shroud will actually block air flow to that area. Usually need a minimum of 1" clearance from solid surface to the radiator core to let air flow through.
 

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Discussion Starter · #9 ·
It's about 5/8 to 3/4 inch away from the rad fins. My thinking was that the shroud would aid in flow over just having the fans only on that side. The stock fan had a shroud and I'm attaching this shroud to the same mounts.

Mike
 
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