cutting Aluminum Patterns

[donf]

Hi All;
Have completely strip my trailer and trying to replace the plastic ceiling end
pieces with aluminum sheets. I don't appear to be a very good pattern
maker. To make matters more complicated, I hope to cover the whole inside
with Birch. It seems like when I cut the corner pieces, like where the ceiling
meets the walls, it never fits. I finally figured out it can't be a straight cut.
Thanks for your time and efforts.

Don
Davis, Ca

[Tinsel Loaf]

When you are replacing an outside panel, you put the new panel over the old panel to get hole placements and edges. The inside shape would seem to be the same. Make a pattern of the outside panel because the inside curves should be pretty close match. You could tape and thick heavy paper over the outside panel and use it to cut the and make the fit inside. Then when you are ready cut the actual material you will use. Ta DA !

[dwightdi]

On a late model trailer, like yours, the ends are complex curves. That means they can not be duplicated or covered by simply using flat sheets of anything. You will need to lay in alot of small small dummy ribs and then tape paper between each of them until you are happy and then cut the edges of them with a knife when they are still taped to the ribs. This is not a small job. The large panels in the straight part of the trailer will also take some triming to get the edges right.

[donf]

Thanks all, somehow I didn't think this was going to be easy. Nice way to spend the winter though.

Donf

[jcferguson]

Hi Donf,

I did the inside skin of my trailer pretty much in the manner you describe, I have images and descriptions on this thread:

http://www.airforums.com/forum...tml#post183930

I didn't need to make extra ribs for the curved ends in my 62' trailer since I worked over the top of the fiberglass endcaps with my birch plywood. For the main body, I removed the aluminum, reinsulated, rewired, resealed, and then replaced with the plywood. I then made new trim for the windows. It was a long process but I like the results. I would worry a bit about weight with both birch and aluminum layers unless you use 1/16" ply when you go over the interior aluminum (which might be a good idea - easy to form and install). I have the patterns for the 13 panel endcaps if you want paper copies - they might need some tweaking to fit your trailer (or might not work at all if the curve is different enough) but they worked in both the rear and front of mine and those areas are fairly different. As Tinsel Loaf says, if you make paper patterns out of tarpaper or red rosin paper you can tape them into place to fit before cutting your aluminum or birch.

Carlos Ferguson

[Tarheel]

You can "Torture" plywood and force it into a compound curve. For metal it is best done my making more smaller panels. What is happening here is that you are trying to put two different shapes into the panel and that cannot be done without stretching the material. Templates are the only way to go.