Introduction: Foam Creations: the Mahi-Mahi

About: Custom Fishing Rod Builder from North Carolina. I love too make things, build things, fix things, etc. Check out my Social Media pages for more information.

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Ok this is my 4th foam creation I have done, but only the second one I have shared with you. Foam is very easy an somewhat fast and cheap to work with once you know what you can and can't do with it. You can pick crafting foam from your local hobby/craft store. I purchase mine, a 1 foot by 2 foot rectangle, from a Local "Mom & Pop" store for $9.99 USD. The big commercial box hobby/craft store around here sell them for $14.99, so shop around. You can use the packaging foam, but it is much harder to work with or (what I am going to use next) use the insulation foam.


It is expensive any way around it. It is expensive to preserve a real fish and it is expensive to replicate a fish you have (hopefully) released. I believe in catch and release, but I have always wanted to get a fish on the wall. And on top of that, I can't afford to pay a company, a business, an individual, etc. to make this catch. So I decided to take the matter into my hands and make it with foam.

Be sure to check out my other instructable, Foam Creations: The Hook right here=>

Step 1: Step 1: Find Your Inspiration, the Piece of Foam, and Your Tools

The supplies I used were...

  • Safety, Respirator mask, gloves, glasses, not really a dangerous job, but there will be a lot of dust and sticky stuff your hands will get into
  • Crafting Foam
  • A hand saw I made from a used wooden sponge-brush handle with a used jig saw blade epoxied into the handle, I call it my "shank"
  • Sand paper, I used all grits from 60-240
  • rotary tool preferably with a flex shaft
  • wood glue and white glue
  • Mixing containers
  • Clamp
  • Quick Epoxy
  • Razor Knife
  • Metal Wire Hanger
  • China Marker
  • Can of Insulation
  • Plaster of Paris
  • Popsicle Sticks for mixing
  • small to medium size brush or sponge-brush
  • airbrush, first time using it, so I bought cheap=>
  • Compressor for the airbrush
  • Acrylic Paint in the colors (lows and highs) of your creations
  • Acrylic Paint Thinner and/or Window Cleaner (blue kind)
  • Mod Podge, For this project I used the Super Gloss
  • Hardware to hang the creation

I wanted to make a beautiful Mahi-Mahi (Dolphin, Dolphinfish, Dorado).

I made a rough outline of the fish I wanted on a roll of paper, bulletin board paper. You can use a projector if you can to project the image onto the paper to trace.

I then took a razor knife and cut out the out-line.

Using two slabs of crafting foam stacked on top of one another, I fitted the outline.

I marked the outline on the foam slabs using a china marker.

Step 2: Step 2: Cut Out Creation and Fuse Slabs Together

After tracing the outline onto the slabs, I cut the pieces out using my "shank". I didn't put the piece together yet because I figured it would be easier to cut with two separate pieces.

Save your scrap pieces!! All will be used whether in this creation or the next.

Once cut, I took a metal wire hanger and cut it into desired lengths to use as internal supports. I lined up the pieces on to the creation to see where they would best fit. (Don't go at an angle, it is a pain to line up the 2 pieces together, just go in straight). As I was fitting the pieces of foam together I used epoxy to seal the wire into the foam. Epoxy will not eat the foam away so you will be fine. Do use any kind of solvent based adhesive like contact cement, it will eat it away!

I then mixed my first patch of Plaster of Paris (PoP), wood glue, and white glue. When mixing PoP for these types of projects I like to think of the viscosity as pancake mix. Not runny, but not clumpy pancake mix. Mix ingredients in a container and spread onto the seam of the two slabs on one side and the sides, then let dry. Flip and do the back side.

I ever so gently clamped the two pieces to make sure the dried perfectly. Be careful not to tighten too much or you will break your creation.

Step 3: Step 3: Base=> Double D's (Depth and Details)

Using the China marker, I marked what areas of the Mahi-Mahi needed to be reduced and what needed to be kept out.

I used my shank to cut the majority of the foam off and maintained the rolls and bends of the piece with the rotary tool with a sanding attachment.

If you are worried about exposing a metal wire support, and you forgot where they were exactly, use a light on the back side of the foam to see the shadow of the wire.

Step 4: Step 4: Coat Those Double D's (Depth and Details)

I wasn't satisfied with the depth of the Mahi-Mahi. My goal was to make it look as real as possible. So I took a piece of the cut scrap and shaped it into a fin.

I still wasn't satisfied, so I wondered how can I add more depth, more jump-out, more 3D to my project.

Use Can foam insulation. I caked the Can foam insulation all over the main parts that need to protrude outward. Tip=> better to put a lot on and cut off whats needed then put on a little, start shaping, and find out its not out enough.

Make sure you save the details, I made sure the eye of the fish was more inward then the main part of the body.

I cut the can foam with my shank and smoothed it with elbow grease sand paper and with the rotary tool.

I mixed my next patch of PoP and glue to coat the entire fish. This patch I used more PoP then glue, but it was still present. Make sure to apply a light coat onto the back of the piece. Also Make sure no foam is exposed, because your paint (depending on the ingredients) could eat the foam away.

Sand piece when dry and/or reapply when needed.

Attach hardware to the back. I used to keyhole hangers in the back of the fish that were epoxied into the fish.

Step 5: Step 5: Sand Smooth Apply Colors and Present It to the World

After I have sanded and smoothed the Mahi-Mahi to it's final state. It was time to add some life to this fish.

I had many options how to color this.

I could of brush it, spray paint it, color penciled it...marker?...Crayon? but only one style and technique came to mind. Airbrush! Yes it could be expensive, especially for someone starting out and has never done it before like me, but I was determined to figure it out.

I bought my airbrush from harbor freight. It was a very small investment, because I already had a compressor which I added a moisture filter to and gauged the PSI to the proper alignments of airbrushing (below 50 PSI).

Now I need paints, I had a ton of the little acrylic paints in the plastic tubing. They are way too thick to spray. I had to figure out how to thin them. I went my hobby store and found a small bottle of acrylic paint thinner. It worked like a charm. Mix the special thinner and paint till you get a viscosity of milk. I also found out blue window cleaner, like windex, can also thin acrylic paint. For all you need to learn about airbrushing, research online! If you want me to make an instructable on how I airbrush, feel free to leave me a comment so I know you are interested.

I started with black, spraying the outlines of the fish. I then worked into a base coat of yellow. Using a combination of blues and greens, I finished my project to the color I wanted.

Lastly I coated the fish with Super Gloss Mod Podge in the baby blue bottle.

Overall, it was a success and I am very happy with my results.

Step 6: Step 6: Thank You! and Video

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