Introduction: Restorin Old Rusty Hammer and Casting Aluminum Handle for It
A while back I found this old hammer for a couple euros from flea market. The head seems quite ok, a little rust and a lot of cement stuck on it. The handle on the other hand was pretty loose. The head moved like and inch up and down... So I had to change it. Othervise the handle was in good shape, maybe I'll repurpose it on a smaller hammer or something.
I thought I'd do something more creative this time than just a restoration. First thing that came to my mind was to do kind of a pop-culture vikings/northmen inspired look for it. I also wanted to practice polishing so I came up with this "Mjölnir" look. Aluminum handle with thick leather wrapping and polished head. I'm pretty satisfied with the results. This was only my second casting project and I haven't done that much polishing either. Wrapping the handle without glue was also my first try. Only the casting had some minor issues, which was expected but I learned a ton, which is why I do these things. Now I just need to learn to carve some runes...
Step 1: Preparing the Head for Polish
I started by removing the handle. It turned out to be quite easy because the handle was so loose. I removed teh screws and put the head in a vise and just hammered the head out using a rebar as a help. In the pictures you can see that either the wood on the handle has word off or the handle was made way too small to begin with. I', guessing the latter.
The head had some medium light rust on it which probably would have come off well with a wire wheel but it was also covered in cement which didn't come off that easily. I figured that, in theory vinegar as acid should dissolve cement which I believe is a base. So I submerged the head in vinegar. This seemed to work well. Most of the cement had fallen off in few hours. I used a wire wheel to remove the rest of the rust and cement which were not very loose and came off easily because of the vinegar treatment. I also found a makers mark from under the cement. It wasn't visible in the beginning. Sadly I didn't find out who made it...
Step 2: Polishing the Head
Now that the head was cleaned up a little I could see that there wasn't too bad dents and pits in the head so I didn't have to start wit super rough sanding belt. I took I think 120 grit belt which I used to flatten the sides of the hammer head, except for the area with makers mark which I didn't want to ruin. I ended up using a file to flatten the bottom as well as possible.
After the sides were flattened I used a rough scorching pad disk on an angle grinder. My local harware store has these available in rough, medium and fine grits, but I don't rally know more about them. I've noticed the medium grit is unnecessary to use between the rough and fine as that also yields a mirror surface. Therefore after going through all of the surfaces with the rough pad I changed to fine. When polishing, if possible, you should try to change the polishing direction when you change to finer grit. This way you can see when you have polished off all the lines from the previous grit.
After the finer scorching pad, I changed to wool flap wheel on a drill press. I used a metal polishing compound on the wheel. That removed all the lines that were left from the fine pad. Sometimes you might need to use also a rougher and finer polishing compound, and they usually come in the same package. However as with the pads I've noticed that often the rougher compound is unnecessary. After the polish I ended up with almost pretty much perfect mirror finish. There is just something very satisfying in three dimensional items with mirror finish...
Step 3: Casting the Handle
I wanted to make an aluminum handle. Casting is a simple way to get a good fit for the handle (wood isn't that hard either but this is almost effortless), but metal handle will be harder for your hands when you use the hammer. In this case I made what any artist would do, I chose the one that looks cooler... However to dampen the vibrations I designed the handle with thinner section to wrap with leather.
I cut the rough design with a hot wire from styrofoam. Then I used belt sander to further sculpt the shape I wanted. If you are not experienced in casting, like me, It's a good idea to leave a little extra foam on the model as aluminum is easy to sand down and the surface can always end up with some imperfections.
I made the handle from three parts, pommel, the handle to be wrapped and the thicker part of the handle that will be left unwrapped. By using three separate parts it was easier to sculpt the parts but harder to keep them lined up with each other. After sculpting the parts I used hot glue to put them together. In addition to these parts I made a sprout for pouring the metal and "cap" on top of the hammer to seal it from the sand and to attach an air tube to.
After the whole thing was assembled I put it in a wooden box an buried it in casting sand. I used a wooden stick to press the sand tightly against the mold the get the best possible surface. I made funnel from old steel can. You want to have rather high funnel/sprout because that will increase the pressure in the mold (like water tower). This will result to better casting and will enable you to cast larger objects, e.g. in this model without enough pressure the aluminum would not have made it all the way to the hammer head. As I was covering the model with sand I also added a plastic straw to the "cap" of my mold to be used as an air tube. If there was no air tube. Some air would be trapped in the mold and the casting would fail.
Before the actual casting I still poked some air holes trough the sand along the handle with a barbeque stick. I also burned most to my sprout because it would only slow the aluminum downs as I pour. The casting sand packed around the sprout will hold it's form and I will have just a pouring hole left.
After preparing the mold I heated up the aluminum in my furnace and poured it in the mold and hoped for the best. After letting the aluminum to cool down I took it out from the sand and noticed it was quite successful. The top half of my mold seemed to have some pits. I think my air holes might have been blocked somehow as the aluminum only came out from one of them. Next time I'll use larger air holes.
Step 4: Finishing the Handle
I cut off all excess aluminum, sprout, "cap" and the aluminum that went in to the air holes. Then I continued by sanding most of the pits off the surface with an angle grinder and belt sander. I had to leave some pits on the other side (seen in last picture as the handle would have gone too thin if I sanded those down.
Then I did the same polishing process for the handle that I did with the hammer head. I didn't polish the thinner part of the handle as I would wrap it and the cast surface will be hidden.
I cut a strip of buffalo hide to wrap the handle with. I clamped a metal ruler to a board with the leather under it to get straight enough strip. Leather will always stretch so it doesn't have to be exactly straight. Then I cut a piece of string and folded it once and taped it on the handle as in the pictures. I wrapped the leather by first wrapping the leather on top of itself and then moving down the handle so that each layer of leather was half way on the previous layer so that I had a nice thick handle. The string that was left under the wrapped leather is now used to pull the other end of the leather under itself. I pulled the end of the leather strip trough the loop in the string then I shortened and started to pull the string from the other end. After a while of struggling I manged to pull the end of the leather strip under itself and the string out from the other side. I think this is a nice way to wrap the handle as now I don't have the ends of the strip glued in place or anything like that. Now we have a finished hammer ready to be used... or put on a self because I have hammers that are in worse shape to use instead.
Thank you for taking the time to read this instructable. Check out the video also and my other projects as well if you liked this one.
4 years ago
Since I'm not a novice to casting I understood the procedure but felt you were lacking in handle casting procedure, great project, just needs more description.
4 years ago
Cool project but I'd be careful about putting your handle to heavy use. Cast aluminum is on the brittle side given the nature of the material. You might end up with a stub in your hand and a 5 lb missile heading for who knows where. The reason ash and hickory handles have been used for centuries is due to the straight, solid grain pattern of the wood being free of defects that could cause the handle to have a weak spot.
4 years ago
DUDE! I love this! When you use it what is the shock through the handle like compared to wood? If it isn't too bad I have a few hammers I might do this too.
4 years ago
This looks great! Did you put anything on the head to inhibit rust? It would be a shame if surface rust showed up after all that work.
4 years ago
The hammer looks fantastic. How bad is the vibration when you use it since you went with a solid metal handle?