Introduction: Model Fish

This instructable is a sub-project of a larger shamelessly plugged automata aquarium project.  In this step I will walk you through the creation of a paper mache model fish that can be articulated to swim. The first part of the project describes how to make the fish model, you can end your project after this section if you wish.  The second part of the project describes articulating the fish so that it can "swim."

There were several requirements for this fish that makes it unique.  It had to be light, durable (as I am highly clumsy and it was likely to fall a couple times) and I had to be able to make it look decent and somewhat fish like.

A further bump in the road was that the perfect material for most of these requirements was paper mache.  Here's the rub,I have never been able to make a paper mache model look nice, unless you count the balloon pinatas in kindergarten. However, I have quite a bit of experience with sculpting from clay.  An idea turned into a unique recipe for paper mache clay that is a bonus part of this project.

Building the Fish Body: Steps 1-7 show how to model the fish.  If you wish to simply build a cool fish model, you can stop at step 7.

Articulation: Follow all of the steps, except for step 7, in order to make an articulated swimming fish model.

This was part of a project for the spring 2012 Things That Think class at CU Boulder.

Step 1: Materials and Tools

Materials:
   -Tissue Paper
   -Toilet paper
   -News Paper (Not Glossy)
   -Wood Glue
   -Flour
   -Bleach
   -24 Gague Wire
   -Aluminum Foil
   -Masking Tape
   -Acrylic Paint
   -Clear Craft Glue
   -Beads (optional)
 
     
Tools:
   -Stove
   -Pot
   -Blender
   -Old Nylon
   -Wire Cutters
   -Pliers
   -Paintbrush
   -Wax Paper or Glossy Advertisements (optional)

Step 2: Rip Up Paper

You need at least 5 unpacked cups of shredded paper.  
   -Use the tissue paper, toilet paper, and newspaper in nearly equal proportion, with a bit less newspaper.
   -It does not actually matter what color the tissue paper is, the bleach will help whiten it up.

Now rip the paper into tiny pieces, mine were about the size of my pinky nail. The smaller the pieces better.
 
The ripping will take a long time.  Don't try to take a shortcut and cut the paper.  DO NOT CUT THE PAPER.  To make a strong bond in the clay you want to have the longest fibers in the paper possible.  Cutting chops up and shortens the fibers, whereas tearing only pulls them apart and makes them more inclined to break apart and form strong bonds.

Step 3: Boil and Puree

The title pretty much says it all.

Put all of the torn paper into a pot along with about 3 cups of water, or enough to allow for the pieces to move about in the pot.  Then add four tablespoons of bleach into the mixture.  The bleach is to prevent any molding and make your piece last longer.

Bring the mixture to a boil, then set it to simmer, covered, for around 30 minutes, or until the mixture looks like the second picture.

Once the pulp has been thoroughly broken down in the boiling transfer the mixture to a blender and puree until smooth.

Strain the resulting goop through the old nylon until the water is mostly gone and the goop is a ball. 

Step 4: Mix and Make Clay

This is a purely personal and dependent mixture.  I can't give you any specific measurements for ingredient amounts.  Just mix until it feels like a good bread dough.   You will use your hands for all the mixing, they are the best tools.

Add flour to the pulp mixture in order to absorb most of the remaining liquid.  Then add a good amount of glue to the dough.  I ended up using around 2 1/2 cups of flour and 1/4 cup of glue.  Add the flour slowly, kneading between each addition until smooth and malleable and a good clay consistency. 

Step 5: Build an Armature

Find an image of a fish that you would like to model and print it out.  It will be much easier to make the armature if you can find images showing the fish in multiple angles.  In the armature you will be creating the ROUGH shape of the fish, so it does not have to be perfect.
The best way to start it is to align the wire with the outline of the image.  Make sure to tie off the wire to make it a continuous shape.

Now do a similar step for the other angles of the fish.  

Combine the two wire outlines  to create a 3D skeleton.  Image 2.

Cover the wire skeleton in aluminum foil to create a smooth and solid base.  I had to fill the wire skeleton with some crumpled up newspaper in order to provide a platform for the aluminum foil.

At this point you can add some rough details for the fish in the aluminum foil. I did the upper fin ridge in this case.

Step 6: Cover and Sculpt the Fish

Cover the armature with a base layer of the clay.  

Once you have the base layer you can begin to sculpt the details of the fish.  I did as much smoothing on this step as possible.

Now let the fish dry FOREVER.  Actually it is only 24-36 hours in Colorado on a gorgeous 75 F day.  It will take longer if the temperature is colder or if there is humidity.

Step 7: Sand and Paint (No Articulation)

If you are finishing the fish model here and not continuing on to articulate the fish, this is the point where you finish.

Sand the fish model down until it is smooth and the right shape to make you happy.

Now paint the fish to either look like the model fish or in whatever colors suit your fancy.

Add any bits or baubles to the fish that will enhance your ideal of the fish.  

Step 8: Articulation Steps

The following steps will instruct you on how to articulate your fish model.  If you have made it this far, you should have skipped step 7.  However, if you happened to follow step 7, never fear, you can touch up the paint job at the next painting step.

Additional Materials:
   -Acrylic Sheet/basswood
   -Hot Glue
   -Brads
   -Crimp Beads
      
Additional Tools:

   -Cutting Tool
     -The Laser Cutter was very useful, but it is possible to do it by hand or with a dremel.
   -Hot Glue Gun
   -Pliers
   -Wire Cutters

Step 9: Sand and Cut the Fish

Sand the fish model down until it is smooth and the right shape to make you happy.

Now cut the fish up into two or three pieces (you may add more or less cuts depending on the size of your fish model).
I used the dremel with a cutting tool to make the cutting a bit easier.  You may use a hand saw at this point if you don't have a dremel.  Be forewarned that the dried compound will be extremely hard and unwilling to be cut.  

Pull out the armature and stuffing so the fish is hollow.

More sanding.  Sand down the edges of the cuts to make them nice and smooth. I did not like the ragged nature of the cut edges, so I ended up doing quite a bit of sanding.

Step 10: Now You Get to Paint

It is now your turn to paint the fish.  If you painted before, touch up the paint job now.

Now paint the fish to either look like the model fish or in whatever colors suit your fancy.

Since the inside of the fish can be seen as it swims, it is wise to paint the inside a solid and dark color.  This will make the inside less distracting and will keep the eye on the fish itself.

Add any bits or baubles to the fish that will enhance your ideal of the fish.  On the pictured box fish I added beads for the eyes.  Sequins would also be fun.  Also, tissue paper makes very nice fins that move nicely.

Step 11: Articulation Joints

For the moving pieces cut, either from an acrylic sheet or wood, enough pieces to have two for each joint.  I needed 8 joint pieces in total.  The pieces will have to be scaled relevant to the fish that you made.  This is where quite a bit of trial and error at this step. The pieces need to allow for free movement of the fish parts between each other.  The fish parts should not collide with each other for a smooth swimming motion.

I ended up with pieces cut from acrylic on a laser cutter that were 1/4 inch by 3/4 inches with a .4mm hole a short distance from the end of the piece.

Once you have the right size glue it in place with hot glue so the pieces align with one piece above the other.   The hot glue allows you to build up places where need be.  There were some parts where I had to build up a base quite a bit.

Step 12: Connect the Fish and Finish

Now that all of the joint pieces are in place, connect them by putting one of the large headed brads through the two holes of the related joints.  i.e put the brad through the bottom two joint pieces to make a full hinge type joint. It will create a safer fish if you put the head of the brad on the outer part of the joint.  

Once the brad is in place, put a crimp bead on the long headless piece of the brad.  Leave a small amount of space between the joint pieces so that they don't rub against each other in the final connection.  When everything is lined up on the brad, crimp the bead down so that it is going nowhere.  Cut off the remaining piece of the brad above the crimp bead.

Repeat this on all of the joints until fully connected.

You can mount the fish onto a post in order to play with the swimming motion.

You are now done and have a fully articulated fish.  Have fun with it!


(video to come)

Comments

author
poofrabbit (author)2012-04-03

This is cool, I may have to give this a try!

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