Mjolnir Pen - Stacked Leather and Metal Rings With Cast Urethane Hammer Head

I started making pens on the lathe a few years ago and always enjoyed the experimental side of it. There are so many different materials you can use to make pens. Of course, there are the different species of wood and epoxies, and resins and in my case leather and metal. I had the idea to make a Mjolnir (aka Thor Hammer) Pen a while ago, but I didn't want to use wood I wanted to use leather to try and mimic the actual prop used in the movies. And I also knew I wanted to include the metal ring details as well. After some trial and error, I finally came up with a process to make them that works most of the time. I say most of the time because I usually do have some failures, but I'll speak to those later and how to possibly avoid those. If you are curious as to the process, I came up with please keep reading.

Wood Lathe

3mm Leather Straps

3/4-inch Wide Brass Bar or equivalent

3/8-inch Brass Tube

1x30 Belt Sander

4x32 Belt Sander

Utility Knife

Cutting Mat

Drill Press

Water

Paper Towels

1/2-inch Electrical Conduit

Electrical Tape

3/8-inch Aluminum Washers

Vice Grips

Scrap 1/4-inch Wood or MDF

Sand Paper 120-3000 grit

3/8-inch Bolt with Nut

Bench Vice

4-inch Hand Screw Clamp

12-inch Clamp

3/8-inch Brass Rod

1/2-inch HDPE Scrap

Paste Wax

Epoxy

Mixing Sticks

Mixing Cups

Hammer

Scale

Mini Torch

Executive Pen Kit

Executive Pen Turning Bushings

Pen Turning Mandrel

5 Minute Epoxy

Acetone

Portable Bandsaw

Pen Barrel - Trimmer

Carbide Lathe Turning Tool

Super Glue - Thin

Plastic Scraps or Packing Tape

Meguiar's Plastic X Polish

Blue Tape

Spray Gloss Laquer

5/16-inch Punch

3/4-inch Scrap Wood

Clamp

Pen Press

3D Printer

Filament

Silicone for Mold Making

AlumiRes Casting Resin

Rubber Bands

Baking Soda

Filler Primer

Black Spray Paint

Rub-n-Buff Silver

I used some 3/4-inch-wide leather straps that were about 3mm thick. I used 120 grit sand paper to rough up both sides of the leather, my assumption being that this will help when it comes time to epoxy the leather to itself. I used a 3/4 inch wide brass bar to measure out 3/4-inch squares of leather and cut them with my utility knife. You will need 24 pieces.

I learned this trick from Jimmy Diresta aka @jimmydiresta in one of his tips videos. I need to make a 3/8-inch hole in the center of all the leather squares. I didn't have a 3/8-inch leather punch, but I did have a 3/8-inch brass tube. Using my 1 x 30 inch belt sander I sand a taper in to one end of the brass tube. As the sander is running, I touch the tip of the brass tube to the sanding belt at about a 45-degree angle (the angle is not important as long as it creates a bevel) while rotating the tube at the same time. This creates an edge that will be sharp enough to cut through the leather.

Next, I chuck the brass tube in my drill press and place a leather square on a scrap piece of plywood and drill a hole. I do this for all 24 squares. The center piece that is drilled out will sometimes clog the inside of the brass tube, so you may have to remove the tube and push out the clog. Also depending on how fast you are drilling the squares the brass can get pretty hot from the friction so be careful not to touch it.

*Bonus tip - This will also work if you need to drill holes through multiple sheets of paper.

With all the holes drilled next I put all the leather pieces into a warm cup of water to soak for about 20 minutes. This will help make them less rigid and more pliable for shaping, which is the next step in the process. After the pieces have soaked, I remove them from the water and pat them dry using some paper towels. They will still be wet, just not dripping wet. In order to shape the leather pieces, we have to mold them into the shape we want and secure them in that state until they dry. I use a piece of 1/2 inch electrical conduit tubing and tape each square to it using electrical tape. I set this aside to dry usually for about 2-3 days to make sure they are completely dry. The longer you let the soak in the water the longer they will take to dry.

Once they are dry, I cut the electrical tape and make sure they have all taken the curved shape.

Since the leather has a radius now the once 3/8-inch hole is slightly distorted and is no longer 3/8 inch so using the same brass tube as before I ream out the holes in each one to make sure they are exactly 3/8 of inch wide.

For the metal accents I use 3/8-inch aluminum washers. I ordered 3/8- inch washers but they are slightly undersized, so I use a small pair of vice grips and a 3/8-inch drill bit and drill out the holes to make sure they are 3/8 of an inch. You will need 5 washers for each pen blank.

Like the leather the washers are sanded to add some texture for the epoxy to grip on too. This makes for a better bond. I use a scrap block of wood with the diameter of the washer slightly drilled out so that I can use it to grip each washer while I sand some texture into it. I use 120 grit sandpaper for this part.

Also like the leather the washers will be shaped but in order to do that we have to grind off some of the diameter. I place the washers in a bolt and secure them with a nut then I use my 1x30 belt sander to make a flat spot on two sides that are parallel to one another. The last picture shows what the washers look like after grinding.

In order to bend the washers into the curved shape I had to make a jig of sorts. I took a piece of 1/2 inch conduit and using my Porta band saw cut it length-wise. I use the cut half to hold the washer in place and then put that on top of a solid piece of 1/2-inch conduit and use my bench vise to press it into shape. As you can see in the first picture if I had not sanded down the sides of the washer it would not have fit in the conduit half pipe. By sanding the sides of the washers the fit snuggly and securely in the half pipe. I repeated this process for all 5 washers.

Here again the piece has been distorted and so has the hole so I have to drill out each washer to 3/8-inch. I use my hand screw clamp, that I made, (How to Make Handscrew Clamps : 14 Steps (with Pictures) - Instructables) to hold the piece while I drill each one out. This can be tricky you don't want to squeeze the hand clamp too tightly because you may end up deforming the washer so be careful and take your time. Also you do not want to do this while holding the washer with your hands as it will most likely be ripped out of your hand by the drill bit.

Now it is time to prep for the glue up. I have a 12-inch bar clamp that I have drilled out 3/8- inch holes in the two squeeze pads. I will be using a solid 3/8-inch brass bar as well as some scrap pieces of HDPE that also have 3/8-inch holes drilled in the center. The fourth picture shows what the glue up will look like this is just a dry fit to make sure everything lines up and all the pieces slide on to the 3/8-inch brass bar. The last pic shows the arrangement of the leather and aluminum pieces. (6 pcs. of leather, 1 metal washer, 3 pcs. of leather, 1 metal washer, 3 pcs of leather, 1 metal washer, 3 pcs. of leather, 1 metal washer, 3 pcs. of leather, 1 metal washer, 6 pcs. of leather)

Since all the pieces will be assembled on to the rod to help line them up you don't want the rod to stick to the epoxy. In order to prevent that I coat the brass bar with paste wax. I also coat the HDPE with wax. This will not keep the epoxy from sticking but it will help once the epoxy cures.

I usually use Total Boat epoxy for this but I didn't have any more, so I just used what I had on hand. Whatever epoxy you use just make sure it has a long working time at least 45 mins or so. I mixed up the epoxy per the instructions, in my case it was a 1:1 ratio by weight. Once I stirred the epoxy for a few minutes I dumped all the leather pieces into the cup and stirred them around to make sure they were completely coated. I let them sit in the epoxy for a good 5 minutes. The goal is for the leather to soak up some of the epoxy, be forewarned the epoxy will not completely soak into the core of the leather. What we are after is just a good soak that will penetrate the outer surface layer of the leather. This should be enough to bond everything together.

After the leather pieces have had time to soak we slide them on to the brass bar per the arrangement in step 11. Make sure that the pieces are curved in the same direction and that the washers are also lined up in the same orientation. Otherwise, when you go to turn the pen blank it will look wonky and unsymmetrical. Once all the pieces are slid on to the brass rod I insert the brass rod into the clamp and squeeze it together as tightly as the clamp will allow. I set this aside and let it cure for at least 24 hours.

After the epoxy cures I remove the brass rod from the clamp and knock off the HDPE pieces. Sometimes they slide right off other times they need a little help from a hammer. Now its time to get the brass rod off. In order to do this I have a 1/2-inch hole drilled in my work bench that I place the rod into. I usually give the rod a few whacks with a hammer to see if the rod moves. If it does not I use a mini torch to heat up the brass rod which helps soften the epoxy then I give it a few taps with a hammer until the brass rod drops out from underneath my bench. Sometimes the rod just drops out, other times I need a punch to continue hammering the rod out. Once the brass rod is out I let the epoxy continue to cure for at least another 24 hours.

I use a chrome "Executive Pen Kit" from Rockler for these pens. I think they look the best as a handle for Mjolnir compared to others. These kits come with a 3/8-inch brass tube that has to be glued into the pen blank. I prefer to use 5-minute epoxy as the glue for the tubes in these pen blanks. When you insert the brass tube try to center it in the pen blank as best you can. The pen blank should be over-sized, lengthwise. Also wipe away any overflow epoxy with Acetone. Also make sure you don't get epoxy inside the tube. I set this aside to dry overnight.

Once the epoxy dries I trim off the excess using my Porta band saw (How to Make a Portable Bandsaw Table : 14 Steps (with Pictures) - Instructables). Next I use a barrel trimmer to trim the edges flush with the brass tube.

Since I use carbide lathe tools for turn these pens I like to remove as much excess material as possible before the actual turning happens. Basically, I load up my pen blank into my pen turning mandrel with the correct pen bushings and take it to the Porta band saw and trim off the corners. The pen bushing act as my guide on how much I can cut away.

Next, I load the pen mandrel on to my lathe. I take very shallow passes with my square carbide bit lathe tool. You don't want the lathe tool to catch or it could ruin the pen blank. The initial goal is to just get it to a concentric shape and remove all the rough edges.

Once the pen blank is round, I start to remove material one section at a time. I do not ride the tool rest side to side while trying to cut material away. I just make straight cuts at 90 degrees to the pen blank. I keep doing this until I am happy with the shape of the blank. Going slow and easy is best.

When I am happy with the shape of the pen blank, I move on to sanding. I start with 120 grit and go all the way up to 3000 grit. This is all dry sanding at this point. I do not wet sand the leather because it is still porous and will absorb moisture which will ruin any finish we try to apply later.

After the sanding comes the finish coat. I like to use thin CA glue or super glue for this. I use a scrap piece of plastic to apply each coat of super glue you can also use packing tape to protect your fingers. The goal at this stage is to get a good heavy coat of clear finish that can be sanded down. Ultimately, we are trying to make it water-proof.

I use a heat gun to help speed up the drying process after each coat. I apply anywhere from 5-6 coats of CA glue at this stage.

Once I think I have built up the protective coating enough I sand it smooth starting with 400 grit sandpaper then work my way up to 3000 grit. This time it is a wet sand. I use Windex to wet the sandpaper. Then I use Meguiar's Plast-X polish to buff the pen blank. I apply the Meguiar's with a foam pad and remove it with a microfiber towel. I do this until its nice and shiny.

Next, I apply 6-8 coats of glossy lacquer to the pen blank. Here again we are building up the coating so that it can be sanded and then buffed to a smooth glassy finish. It's the same process as the CA glue, spray a coat of lacquer, use the heat gun to dry it, then spray another coat, use the heat gun to dry it, this is done over and over. Once you think you have enough coats of clear on the pen blank you wet sand it again starting with 400 grit sandpaper up to 3000 grit sandpaper. And lastly, I use the Meguiar's Plast-X to buff the pen blank.

The pen blank may be stuck on the bushing because of the CA glue finish, if this happens to you just use a razor to score the edge of the bushing where it meets the pen blank to cut through the CA glue. You can carefully sand off any residual CA glue that may have built up on the edge of the pen blank.

The pen kit comes with a pen clip attached to top ferrule. I prefer the look of the pen without the clip, so I remove it. To do this I first take a scrap piece of plywood and drill a 3/8-inch hole right next to the edge of the plywood. Then I clamp that to the edge of my work bench and place the ferrule into the hole in the plywood. Next, I use a 5/16-inch punch and hammer apart the ferrule and top ring. You will end up with 3 pieces, feel free to keep or discard the pen clip.

I use a modified aluminum bar clamp as my pen press. The first thing I do is reassemble the top ferrule with the top ring where the clip used to be, these are all press fitted together. Next, I insert the top ferrule into the pen blank, then the tip is installed on the pen blank. Next, the spring and pen refill are inserted into the pen body. Then the transmission is screwed into the pen body and the top cap is placed on to the pen body.

This is a twist pen, so you twist the top of the pen to expose the tip and vice versa to retract the tip. At this point the pen is complete.

Now it's time to move on to the hammer head of Mjolnir. I found a 3D model (Thor Mjolnir Hammer Bic Pen by effektz - Thingiverse) on Thingiverse of a Thor hammer pen which I had to scale down in order to make it fit the pen kit I used. You can 3D print the hammer head then paint it and be done but I noticed that the print can be too light which may not support the weight of the pen and can be easily tipped over. So instead, I 3D printed the model then made a silicone mold of it so that I could cast solid hammer heads that would be nice and heavy.

In order to not make this already long Instructable even longer I will leave a link to an Instructable that I wrote that goes into detail on making and casting molds. Epoxy Resin Screwdriver/Nut Driver From Silicone Mold Making to Casting Resin Parts : 18 Steps (with Pictures) - Instructables

This is my hammer head mold. I use curved wood and rubber bands to hold the mold together, the curved wood pieces help apply even pressure to the sides of the mold. It is a one piece cut mold. I learned a lot from Robert Tolone's YouTube channel on making one piece cut molds I highly suggest you check him out if you are interested in mold making.

I use a fast cast product to make the hammer heads in this instance I found a heck of a deal on some AlumiRes so I used that for this particular casting.

AlumiRes is mixed in a 1:1 ratio and this stuff sets up really fast. The bottle says you have a 2-minute working time but I think it's closer to 1:30 before it starts to set. Make sure you have all your molds ready before you start mixing any fast-setting resin otherwise you could end up with a cup full of resin. It can be demolded in 10 minutes. The smaller mold in the picture is just there to catch any leftover resin. I try to minimize waste.

After 10-15 minutes the part is rock hard and ready to be demolded. If you are not sure if its ready to demold you can always just check your mixing cup to see if the resin in there is hard.

I take the casting to my Porta band saw and remove the bung left from the over pour.

Since I didn't use a pressure pot to cure the resin I end up with some bubbles. To fix these I pour some CA glue on to the area with holes and sprinkle some baking soda on the CA glue. The baking soda/CA glue combo will harden immediately. I use my 4x32 belt sander to clean up that face of the hammer head. You may have to do this several times to fill all the holes. The smaller the hole the more difficult it is to get the CA glue into the actual hole to fill it. In this case you want to try and fill the holes with baking soda then drip the CA over the baking soda. And sometimes large holes require multiple attempts to build up each coat. While this sounds a bit tedious it can be done fairly quickly since there is zero drying time.

I don't mind some imperfections as I think it adds character to the finished piece.

Once I am happy with the look of the hammer head I will spray 2-3 coats of filler primer, depending on how well it is filling the imperfections. I may or may not sand in between coats it just depends on how the piece is looking. Each casting is different and will require different levels of preparation. I do make sure to lightly sand the last coat of primer with 600 grit sandpaper to get a nice smooth finish.

When the primer is dry and cured, I will spray paint the entire surface of the hammer head with black paint. I usually only need 2 coats to get good coverage. I will usually set that aside to dry for a few hours or overnight.

Lastly, to give the hammer head its classic metallic look I use silver Rub-n-Buff. I make sure to wear gloves because it's a bit messy. Rub-n-Buff is very easy to apply, you just wipe it on and rub it to get a bit of a shine to it. It's hard to mess up, if you rub too much off you can just re-apply it. I also try to leave some of the black areas black which I think look better. Rub-n-Buff is a pigmented wax and has to be allowed to dry. So, once I am happy with the look I will set the hammer head aside to dry. This can take a day or longer depending on how heavy a coat you used. Once it dries your hammer head is done.

While this pen takes quite a few days to make, mostly due to waiting on drying and curing times, I think I turns out really nice. Thank you for taking the time to read my Instructable I hope you find it helpful and maybe even a little inspiring.