Introduction: How to Chisel Aluminum Flashing Into Any Design or Sculpture
I work as a sculptor and have a lot of trouble making models of proposed pieces that can reflect the aesthetic a finished stainless steel sculpture will present. An additional problem is that I often use complex geometries enclosing empty spaces. I could easily solve this problem with a 3-D printer but do not have the funds to buy one -cough!, vote for me so I can win one, cough!- (the tab is on the top right of this page).
One of the ways I have made-do is by chiseling Aluminum flashing. It is a lot easier than you think and can be made on the cheap.
Step 1: Map Out Your Design
Here I drew one side of a hand I am currently working on. I clearly mark-out, with heavy line-weights the bands that will form to "positive" aluminum bits of the sculpture. The "negative" spaces in-between will be what we cut out. You will use a chisel because as you can see from the drawing, the "negative" spaces in-between are completely surrounded by the "positive" spaces and will not be able to be cut with shears.
NOTE: The first few times you do this you might want to take a sharpie and go over the "positive" parts you want to keep. This will help you keep things strait as to what you are cutting out and what you are keeping. You will see this method in some of the images on the next few steps.
The dotted lines surrounding the hand is where I will cut out the whole image using shears (see below).
Step 2: Commandeer Aluminum Flashing
Aluminum Flashing can be found at any hardware store; it is used for a number of construction needs, but mainly in roofing where it is bent and tarred as a waterproof barrier between masonry and asphalt roof tiles.
You can buy an entire roll for about $5 to $10, depending on the width of the roll. You can also find some that have a gold-metalic finish on the inside!
If you are on a budget, you can probably find some in your basement or attic as well.
Step 3: Tape, Paste, or Stick the Design to the Aluminum Flashing
I like to cover the whole underside of my design paper in Acrylic Medium (the best friend of any painter) then stick it to the flashing; it keeps the image down on the flashing, even after you have a lot of cuts, and can be easily peeled off.
You could also draw directly onto Contact Paper and stick it to the flashing. Glue is another possibility but be careful, the impermeability of the Aluminum Flashing has its limits and glue might be a pain to get off later.
I have used simple tape (painter's tape) as well but this can be a pain if you are constantly re-taping once you start making headway into the chiseling-out of the negative spaces.
If you are a baller, you can draw directly onto the flashing with a sharpie. Iso alcohol will take any excess off when you are done.
Step 4: Let Dry, Gather Chisel Materials
I like to let the Acrylic Medium dry over night but really you can start right away, just make sure the drawing doesn't shift once you start cutting.
A set of 3 chisels is more than enough. They should have strait ends and be SHARP. Dull, chewed-up, or beat-up ends will not cut properly; they will only bend/maul your piece. Pre-sharpened chisels are more than sharp enough. You can buy a simple set of 3 straight-end, pre-sharpend chisels at any Hardware store, like the one's pictured for about $10; the sizes are usually 1", 1/2", and 1/4". If you want curved cut-outs you can use curved chisels that fit OR you can just cut with the straight-ends, then snip the curves with shears as best you can.
You will also need a cutting mat or a piece of scrap plywood you do not mind destroying.
A mallet, tally-whacker, hammer, or any blunt object (I sometimes use a 2x4) will drive the chisel through the flashing.
Step 5: Get Yourself Setup to Make Your Life Easy
A lot of metalworking involves the 90/10 principle, where you are spending 90% of your time just setting-up and preparing for the interesting parts (like actually welding) that seem to be over all too quickly. The chisel method is simple to set up and has a nice long work time BUT if you do not get yourself set up in a good way things will be problematic.
I like to work in a direct line with an underlying table leg. When I don't, the chisel tends to "bounce" more, or not cut all the way through the aluminum.
I also like to work with at least two chisels in my hand, so that I can quickly switch between sizes as I go.
Good lighting is always a must as well, especially if you will be cutting small areas.
Step 6: Start Big, Work Your Way Small
Put your safety glasses on; jagged bits of aluminum in the eye is not a good time.
Start with the largest section(s) and with the largest chisel. As you work you way through the piece and get the hang of it, you can get into the smaller and smaller areas or sides.
REMEMBER: Always hold the chisel upright and perpendicular to the piece/cutting mat. The beveled edge should be to the inside of your cutting area. Strike with the mallet/hammer with good pressure straight down. Hammering the chisel at an angle could cause you to slip off the piece and/or shift the design. This tends to be an adjustment for people used to chiseling wood, where glancing-blows are the norm.
I like to press down in the corners a little more and start each section here. You can work your way towards the middle from the corners in the big sections. This progression will give you sharp corners/turns and manageable interiors.
Step 7: Chisel All Interior Sections, Then Snip
Once all the interior sections are chiseled and removed, take your shears and cut out the overall image along the dotted line. I tend to leave this as the last step because I like the added structure to the flashing while I am chiseling. If you cut out the shapes first with the shears, you have a better chance of tearing intersections just from the pressure of the chisel.
Step 8: Peel Off Drawing/Template, Hammer Defects, File Jagged Parts
Because I have only done this for maquettes (sculptural models), I have not really filed any of my cuts. If you want a more finished piece, a small metal file can smooth any jagged areas or corners.
I will, however, hammer the entire cut sheet. Dimples, Puckered areas, bends, or creases sometimes form during the chiseling process. These can be made uniform just by lightly tapping the whole piece with a hammer. You don't need an anvil, just the cutting mat or plywood sheet you were working on.
If you want to get really crazy, an orbital sander can be used to on the piece as well. Sanding the aluminum tends to give it a more "brushed" or matte finish, however, so this is why I shy away from it (I like things shiny).
Step 9: Bend, Shape, Combine, And/or Finish
The awesome thing about using chiseled Aluminum Flashing is that once you have your design cut, you can then bend, shape, and manipulate the whole object very easily. In the example shown above, I molded the sheet to my hand, then combined it with a second, additional sheet, that follows a semi-opposing geometric pattern.
Step 10: Make It Your Own
The example piece was for a public sculpture where lighting would be a critical aspect. So, for the model, I added a cycling LED system to light the interior of each hand (I chiseled 4 sheets, then bound them along the edges with wire). The video shows how the light will effect the geometries and shadows.
I am sure you'all will come up with some interesting versions. PLEASE POST your projects. I am curious to see them.
And of course, please hit the vote tab at the top so I can win a 3-D printer, if you need more persuasion, I intend on installing the 3-D printer at my school so students can use it too.