Introduction: Scrap Aluminium Polar Bear
This instructable is on how to make a bear out of a solid piece of
aluminium, using basic filing techniques. It uses tools which most people would have in a garage or workshop, and the processes are easy to do. I like to consider it as a fairly versatile project, it can be a small afternoon activity for someone who is just starting out doing metalwork or a larger project for someone with more expensive tools such as milling machines and band saws.
I have used lots of pictures to explain how to do some steps as they are quite difficult to describe (I have tried my best).
You will need,
Items in Bold:
A set of large files (round, half round, and flat, files are the main ones used, any other files could be used as well).
Needle files (small files) In the same shapes as the large files.
Sandpaper in Corse and fine grades. I work with scrap sandpaper so I don't know the exact grades but the more range you have, the better. Also polishing paper or a polishing wheel is needed to get the shiny finish.
An automatic center punch is easier to use in this case as it is for decoration, but a normal one will work as well(with a hammer) .
A dremel is useful for sanding and polishing the parts that are trickier to reach, but it is not necessary. I used a hand drill with dremel tool pieces so this can be done as well.
Pencil and Scriber (an old center punch can be used instead of a scriber).
A Piece of aluminium plate at least 10mm thick
Finding a piece of material the right size is quite easy, simply chose a length and divide it by 2.9 to get a width and divide it by 2.2 to get a height ( this is a rough calculation of average proportions). For this particular size I just drew the profile on a piece of 13mm plate.
The exact dimensions do not matter too much, as the bear can be any size you want. For me, this usually depends on the material that is available.
Here are the dimensions for some of the bears I have made.
132 x39 x61mm (5.2 x1.56x 2.41 In)
52 x 20 mm x 25mm (2.05x 0.8 x1 In)
34x 13x 14 (1.34x 0.51x 0.6 In)
26x 10x 12 (1.03 x0.4x 0.5 In)
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Step 1: Process Overveiw
The process is
quite long but it can be split in to ten steps.
1. Cut out the 2 dimensional drawing.
2. File it down to the lines.
3. Cut the head to a thinner width.
4. Split the legs from a 2D profile into 4 separate legs.
5. Round all the edges into each other.
6. File tail nose and ears into shape.
7. More rounding.
8. File out large scratches.
These steps are explained further in the next steps.
Step 2: Marking Out
The first step is to draw the side view of the bear on the piece of material. You may have to prepare the surface if it is not smooth enough to draw on. The shape here could either be copied or printed off and traced from one of the pictures onto the surface of your piece of material. It may be easier to trace the picture in pencil and then go over it with the scriber (you can see in the first picture how faint the lines are).
Step 3: Cutting the Underside of the Head
These next steps cover cutting out the side profile. If you have a band saw that cuts metal then it would be much quicker to use this than to do it by hand.
First we need to cut out the section of material under the head. I have outlined the shape in the image so that it is easier to see the material being removed (the black section). Hold the piece of material vertically in the vice and cut along the underside of the head( picture 2) .Then turn the piece of metal about 70 degrees and make the other cut Picture 3 is a bit blurry but shows the angle. You should have a roughly rectangular offcut. Picture 1 shows how your piece should now look.
Step 4: Cutting the Legs Gap
The first part of this step is to cut down the inner side of each leg. Then cut out as much of the material as possible by making vertical cuts between the two legs cuts and then file the remaining material out using the thin edge of the flat file( if it doesn't fit you may have to use a smaller square file).Eventually the gap should be completely flattened. This section will be the belly.
Step 5: Cutting Behind the Back Legs
A small section needs to be removed from behind the back legs. This can easily be cut out using two simple cuts with a hacksaw.
Step 6: Cutting the Back
The next step is to cut out the section of material above the back (from the tail up to the ears).This will require two cuts, one behind the ears and the other down the length of the back. It is best to do the one behind the ears first so that there is less chance of accidentally cutting into them. Hold the bear upright in the vice and make the cut. You can make a cut to the same depth in front of the ears. Then turn it 90 degrees and make the longer cut. This should remove a long thin slither of material . The section in front of the ears can be cut out by turning the piece so that the head is facing up and making a vertical cut downwards to remove a small piece of material.
Step 7: Filing Down to the Lines
The side profile is now cut out. Some parts will need to be filed down to the lines, but because there are no exact dimensions, it does not matter if they are not exactly on the lines. You will need to round the corners of the back down to the line. If the pieces of material are large enough then use the hacksaw to remove as much as you can.The picture shows the basic outline.
Step 8: Cutting the Head
Once you are happy with the outline, it is time to remove the extra material
from the sides of the head.
The head is thinner than the rest of the body so we will remove slightly less than a third of the total width from each side of the head (one of the pictures shows the parts being removed colored in black marker pen).
Hold the material in the vice and cut vertically down each side. Then turn It sideways by 90 degrees and cut out the section of material. Turn it 90 degrees to the other way and do the same on the other side.
Step 9: Tapering the Shoulders
The shoulders will be thicker than the head. The width of the shoulders now can be tapered into the head so that there is a smooth change from one to the other. I do this part by holding the bottom half of the bear in the vice at about 30 degrees from the horizontal (see the first picture).
Step 10: Splitting the Legs
If you look at the pictures, you may notice that this step was done a bit later on than I have put it here. I have decided to put it here so that all the steps that are about rounding are kept together.
Now It's time to make the gap between the legs. This time we will be splitting the width into three sections and removing the middle part. Depending on where your vice is and how much space you have on either side of it ,it may be easier to hold the material by the nose and tail instead of the sides. I do not have much space in my garage so the vice is up against the wall and I cannot stand to one side of it.
Once you have cut down the middle you can start filing out the remaining material. As long as your line is in the center, It should be fairly easy to use the short side of a rectangular needle file to remove some more material and increase the width of the gap to the desired size. you may be able to use a square needle file if the gap is big enough.
Step 11: Rounding the Underside
The underside of the belly can be rounded. How much you round these parts will also affect how fat the bear looks. I like to make mine a bit fatter than a bear might normally be, but it is a matter of preference. Unless you have a dremel with some small sanding disks, it is quite hard to round the inside edges of the legs. It is possible to use a long strip of sandpaper and pull it back and forth between the legs to remove the material but I found this quite hard to do.
Step 12: Rounding the Back
The back of the body should be rounded into the head, sides, bottom and tail section. The best way to hold the bear for this step is by the sides with the part that you are rounding hanging over the side of the vice. The back should curve smoothly into the sides. If they are not curved enough then the bear will still look a bit blocky. To round the bear simply file at an angle and rock the file. There is a short video that may or may not play properly of me rounding an edge if you are unsure.
When I am doing this step I do it at the same time as rounding the sides and putting in the curves were the legs join the body. This is to make sure that the curves blend evenly.
Step 13: Creating the Tail
To make the tail start, hold the bear with the rear facing up and the feet pointing towards you.Then file down about one millimeter leaving a strip of material from the top to the bottom of the back ,finishing almost between the back legs.
Step 14: Creating the Nose and Head
Hold the bear with the head pointing up. You will probably need a small square file for this part. File the very tip of the nose on one side and repeat on the other side until there is a rectangular section of material (see the picture). File down the other sides till there is a square. Round the corners of the square until it is round or slightly oval.
One of the pictures shows the start of a nose being formed on a larger bear.
Step 15: Rounding and Shaping the Sides of the Body
Between the front and back legs, the sides should dip in slightly. You can use the curved edge of a half round file, to make these dips. The marker pen in the pictures shows were the dips are and how they blend into the rounding (sorry about the poor quality). It is best to hold the bear sideways in the vice for this step.
One of the pictures here is one I found about polar bear fatness. The top view shows the contours that can be made when blending the legs into the body in this step.
Step 16: Rounding the Outside of the Legs
This step is a little tricky to do with a file. If you have a dremel (or a drill and some small sanding drums) then I would recommend using that. If you do not then a medium size file is best. A half round file can be used (use the curved edge).The first Picture shows the angle that you need to hold the file at. It should be almost vertical.
Step 17: Ears
This step will use a needle file with a triangular profile to make a groove in the middle of the block. If you don't have a triangular file or are making a larger bear than the one shown here then a rectangular needle file will do as long as the thin edge has cutting teeth. If you are fortunate enough to own a wedge shaped needle file then you can use that as well. The ears are one of the more fiddly parts to make so take your time with them. For the first part of this step, hold the bear sideways in the vice so that the head is sticking out from one side. File the ears down to the height that you want them. Do not round the front of the ears as they will stay flat. File the front and back edges till the ears are in the right place (not too far forwards or too far back). There are no specific dimensions as the size depends on your preferences. The backs of the ears can be rounded, or you may chose to taper the whole back so that the ears are triangular from the side. Taper the sides of the block so that it is slightly thinner at the top than where it joins to the rest of the head. When you look from the front of the bear it should be a trapezium. Make the groove go right down the top of the head but be careful as you may have to use short strokes with the tip of the file to avoid putting file marks in the back. Your bear should now have two separate ears.
Step 18: Filing and Removing Scratches
I start this step using fine needle files to remove all the large scratches. A lot of material will have been removed in the last few steps and there may be some cuts that are quite deep. It is okay to hold the bear in the vice for this step but remember to put something on the vice jaws to stop the bear getting more scratches or dents. Some people use a piece of cloth but I find that this gets in the way of the files and is very annoying, so I stick a few pieces of tape on the vice jaws. Duct tape or another type of tape that is quite thick and robust works.
Step 19: Stamping the Eyes
Hold the bear in the vice with the head pointing towards the ceiling. You should be able to mark two small points above the nose. Stamp these points lightly with a center punch. If you have an automatic center punch it is less fiddly but a normal center punch will work. If you are happy with where they are then stamp them harder so that they are properly visible. Do the first stamp lightly so that if you aren't happy with where they are you can just sand them off and do them again. Make sure you put tape on the vice jaws or use soft jaws to protect the bear from dents.
Step 20: Final Sanding and Polishing
From this point I don't put the bear in the vice any more. If you have a vice with a set of rubber jaws then you could still hold it in them as it would make it easier. I have put pictures of the grades of sandpaper that I use. If you don't know the sandpaper grades and are just using some scraps like I do then use the one that looks the most coarse first. Then test one that looks a bit finer. It should replace the scratches that the last piece of sandpaper left with smaller fainter ones. I like to go over my bear twice with each piece of sandpaper. The first time I press harder and then I go over it again using lighter strokes. Then I use a finer piece and do the same. I keep working till I have reached the finest grade of sandpaper that I have.
I don't have lots of grades of sandpaper so I use new pieces first and then worn out ones of the same grade as they act like finer grades. If you have a dremel then it is easier to sand between the legs. If you don't, there is an easy alternative to this by simply folding a piece of sandpaper over the edge of a small scrap on metal or plastic plate. You can fold it over a steel rule. The ruler is likely to be too thin so you may have to fold a couple of pieces over each other.
I have a few pieces of polishing paper which I use after sanding. Wire wool is very messy and leaves little bits of metal everywhere so I don't use it often. Before I give the bear its final polishing, I like to wash it off with water and dry it to get rid of any metal dust. Then I polish it with a piece of ordinary notepad paper. It works well for polishing (something I discovered in a really boring English revision session) and is good if you don't have access to polishing wheels. It may take some time to get through the last stages of polishing and you may have to go back to sandpaper if you find scratches that you missed earlier.
Step 21: Finished
The bear is now finished. I like to store my pieces in an airtight container (like a Ferro Rocher chocolate container). I find they make quite a nice gift for people which is why most of the ones that are shown here I don't actually have any more.
There are lots of things you could add or change to your polar bear. If you had a milling machine, this could be made larger without too much work (I am working on it) . Although the title says Aluminium polar bear, You could use brass, steel or even Perspex. Anything that polishes well (not mild steel) will work. Neodymium magnets could be added to the feet to make a fridge magnet by drilling a hole and gluing a magnet in. I have added lots photos of various bears at different stages(most are finished pictures of diffrent features and angles. Some are of a larger one that I am making using a mill.
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