Tail and Tutorial: Rogue Siren

Modeling the Tail: Lopti of Some Like it Blue

This is not an inexpensive project, and it is very time consuming. Custom silicone tails start at around $2000, after this tutorial, you will understand why. Materials alone can cost over $1000, they will be covered in the next step.

Expense alone is why I wouldn't recommend this as your first mermaid tail. Try a fabric or neoprene tutorial first. Swim in a monofin. Figure out if mermaiding is for you!

These tails are heavy! Depending on how thick you cast your scales and fins (more on this later), you could end up with a tail weighing 35lbs or more! Not only are they heavy, but they bind your legs and feet together. Be sure you are a confident swimmer, and have a buddy before attempting to swim in one.

They also take a lot of care! This will be covered at the end, but the overall effect is worth it! These are the most realistic and fully swimmable tails you see around! The final texture and feel is just like a fish.

WARNING: Tailmaking is addicting!

Looking for more info on mermaiding? Check out Mernetwork. It is an amazing resource.

Step 1: Materials

Materials:

Oil-based, sulfur-free clay (5 lbs of Plastalina or Monster Makers is recommended)
Plaster or fiberglass resin (you should need around 2 gallons of resin OR 50 lbs plaster)
Fiberglass matting
Vegetable oil (to clean fiberglass molds of clay)
Original Dawn dish soap
Spray bottle
Isopropyl alcohol
Krylon Lacquer
Platinum Cure Silicone (Smooth-On's Dragonskin 10 medium is recommended: 2 gallon units should suffice)
Silicone Solvent (Smooth-On's NOVOCS: 2 pints)
Silicone Pigment (Jacquard Pearl Ex and Smooth-On's Silc-Pig are recommended)
Sil-Poxy (not necessary, but recommended)
Mixing cups
Plastic spoons or sticks for mixing
Power Mesh (swimsuit lining: 1-2 yards)
Thread(and needle)
Sewing/fabric pins
Small plastic/vinyl tubing
Latex-free, vinyl gloves
Tracing paper
Tape measure
Scissors
Airbrush or disposable Paintbrushes
a Monofin (the next section will cover monofins)

Step 2: Picking a Monofin

A monofin is what will make your tail really move through the water. This fin will go inside the "fluke" of your tail. It will be sandwiched between two layers of silicone and will be where you put your feet. The monofin you pick can change the overall effect your tail has moving through the water. You will want to decide where you will be swimming most. If you will only be swimming in pools, you can use smaller, softer monofins. If you want to swim in the ocean, against ocean currents, you will need a much stronger fin.

Pictured (from left to right): FINIS Trainer, FINIS Shooter, FINIS Foil.

FINIS makes many high quality monofins. They come in different kinds of rubbers, plastics and fiberglass.

The FINIS Foil is a great beginner monofin.

It is made entirely of rubber and has a smaller blade. It is softer and not recommended for ocean swimming. It is great for maneuverability, flips and turns. Not speed or power. Using this fin will give your tail a very soft and "floppy" fluke. *The heel straps are known for being thin with the potential of snapping.

The FINIS Wave/Rapid is a step up.

They are made from a harder plastic with a larger blade than the Foil. They can easily be cut to shape with sharp scissors or a dremel tool. The ridges can sometimes pose a problem of being visible. You can sand them down a bit, however it will decrease the strength of your fin. This monofin provides more power than the Foil, while still allowing for maneuverability.

The FINIS Shooter and Trainer have fiberglass blades.

The FINIS Shooter has a shorter blade than the Trainer. These blades are much stiffer than the previous mentioned monofins. They provide for great speed and power, but are best for different types of kicks. The Shooter is great for fast, small kicks for butterfly stroke. The Trainer is good for larger kicks. Both provide decent maneuverability. The Shooter will give a "floppier" look to the fluke. The Trainer will provide more stiffness.

The FINIS Competitor is the monofin often used by professional freedivers.

It has a large fiberglass blade meant for ocean swimming. It provides little maneuverability, but the greatest speed and power. It requires a great deal of muscle to really master this fin. It will give your tail a very stiff fluke. It is also the most expensive monofin listed here.

My personal favorite is the Triton, Hydra and Minos monofin by a French company.

They can be quite difficult to source in the US. The shipping often costing more than the fin itself. They have a large Polypropylene blade with Polypropylene stiffeners on each side. The blade itself is smooth and slightly transparent, lending itself well to a silicone tail. It provides wonderful propulsion and maneuverability.

There are many monofins to choose from!

You may want to modify your monofin's shape. If you do, be sure you do not cut the monofin into a point! Sharp corners can cause the fin to snap. More info on cutting a monofin can be found here.

Step 3: Sculpting and Molds

Materials:

Oil-based clay
Plaster or Fiberglass Resin
Original Dawn dish soap
Spray bottle
Fiberglass matting
Latex-free, vinyl gloves
Tracing paper
Vegetable oil*
Toothbrush*

*materials only needed with fiberglass resin

Scales

There are many different ways to create your scales for your mermaid tail. Scales can come in all different shapes and sizes. Use reference photos and decide on something you like. Be creative.

Individual Scales

This is the method I use for my tails. It is very time consuming, but produces wonderful results and no seam.

Sculpt your scales individually with about a cm or more between them. Sculpt different sizes. As many or as few as you like.
Build a wall around your scales with clay.
Mix water and Dawn soap in a spray bottle and lightly mist your clay with the mixture. Allow to dry completely.
Use gloves. Mix your plaster or resin according to their individual instructions and pour it over your scales. Lay a thin layer of matting on top. Make sure it is soaked in the plaster or resin, but not too close to the scales to leave an imprint.
Once hardened, clean the clay out of your molds. You can use vegetable oil and a toothbrush to clean out fiberglass molds.
You will need hundreds, if not thousands of scales to finish your tail. You can cast scales in silicone using your mold (more on this later), and repeat steps 2-5 with the silicone scales to create more molds. Be aware that your molds will contain less and less detail as you recast.

Scale Sheet

This is the most common method used to create silicone and latex tails. One mold is used to create two "sheets" of scales, a front and a back, that is seamed together at the sides. You can cut scales from craft foam and layer them into a sheet of scales, or you can sculpt the scales from clay like the previous method. The "sheet" will need to be as tall and wide as your own leg measurements. If it is not tall/wide enough, it will require you to cast multiple sheets and fit them together like a puzzle which produces a weaker and less attractive tail.

Fins

These are optional and totally dependent on your design. Keep in mind, the larger and more fins you have, the more silicone it takes, and your tail will be heavier and may cost more.

Sketch out your fin design on tracing paper.
Fold the paper and trace your design. Unfold your paper.
Sculpt your design over each sketch. You will need two molds to create one fin, unless of course you want on half of your fin to be flat and without texture or detail.
Build a wall of clay around your sculpt, spray Dawn/water mixture as a release agent, pour your plaster or resin with fiberglass matting. Let harden. Clean mold.

Fluke

This is usually the most distinctive and individual part of your tail! Be unique, be creative, have fun!

Use a large piece of tracing paper (tape paper together if you need to), and trace your monofin lightly onto the paper.
Fold the paper in half over the center vertical line of your monofin and sketch one half of your fluke design around your monofin.
Flip the paper over and trace your sketch. You want your design to be as close to vertically symmetrical as possible. This mold will be used for the front AND back of your fluke. It will not fit correctly if it is not symmetrical.
Sculpt your design over your sketch.
Build a wall of clay around your sculpt, spray Dawn/water mixture as a release agent, pour your plaster or resin with fiberglass matting. Let harden. Clean mold. Fiberglass is recommended for the fluke. Plaster is heavy and fragile. Make sure to pour your plaster or resin thick enough so that your mold, and all your hard work does crack and go to waste.

Oil-based, sulfur-free clay is the best kind of clay to sculpt with. Plastalina or Monster Maker are the recommended brands. Use other kinds of clay at your own risk. Silicone can be finicky. If residue from the clay is left in your molds, the wrong kind of clay can inhibit your silicone from curing (that is, remain sticky/tacky). Air-dry clay can be difficult to remove from molds.

NEVER let latex near your molds or your silicone! Silicone HATES latex and other kinds of rubber.

Step 4: Measuring for Your Tail Body

Materials:

tape measure
pen and notepad
tracing paper
power mesh (swimsuit lining)
scissors
a partner or helping hand

Measuring Tape Method

You want your tail to fit like a second skin. Some mermaids recommend a tighter tail while other recommend a looser fitting tail. For your first attempt, make it as close to your own measurements as possible.

For the best fit, use a partner to take your measurements and stand straight with feet together. Have your partner measure all the way around your waist (starting at your belly button). Record the measurement.
Move two inches down and measure all the way around and record the measurement.
Continue taking your measurement every two inches all the way to the floor.
Mark which measurement is your hips, knees and ankles.
Measure your waist to floor vertical measurement.
Take a sheet of tracing paper as tall as your vertical measurement. Fold it in half vertically. Make tics every two inches all the way down the sheet.
Divide your previous measurements by four. Use the tracing paper and the measurements to create your pattern.
Cut out your pattern in paper. Use the paper to cut out two pieces from your power mesh.
Sew or glue your power mesh at the seams.
Test the fit.

If you are not weary of pins, you can use two halves of power mesh and pin it around your legs for your size. Remove it, sew or glue it, and remove the pins. It will be like a skin tight skirt. Make sure it does not stretch too much while on. The silicone will reduce the stretch later.

Some draw a pattern around the legs from the belly button past the toes. This is not an accurate way to make your tail skin.

Duct Tape and Body Double Method

You will need Duct/Packing Tape and Plastic/Cling wrap for this method. You definitely need a helper for this one.

Stand with your feet together and have your partner wrap your legs with plastic wrap. Do not wrap too tightly, this will cut off blood flow. Do not leave to loosely or it may fall off.
Cut off strips of tape and cover the plastic wrap with it. Overlay the layers of tape so that it doesn't tear later.
Once your entire lower half is wrapped in tape and you can't move, make a single cut down the legs to remove the form.
Repair the cut with more tape.
Use foam, cotton or some other packing material to fill your dummy.
Cut the power mesh to fit your body double. You can now use your body double to assemble the rest of your tail on.

Step 5: Pouring Your Silicone and Tail Assembly

Materials:

Platinum Cure Silicone: Two Gallons is a good start. (Smooth-On's Dragonskin 10 Medium)
Monofin
Mixing Cups
Plastic spoons or sticks for Mixing
Sewing/fabric pins
Krylon Lacquer
Small plastic/vinyl tubing
Power Mesh (swimsuit lining)
Isopropyl Alcohol
Original Dawn Dish Soap
Spray Bottle
Silicone Pigments (optional)
Sil-Poxy (optional)

This is where things get tricky. Silicone can be a testy beast! Certain materials will inhibit its cure entirely. If it doesn't cure, there is little you can do to fix it, other than scrapping it and starting over.

Pouring the Silicone

Latex-free, vinyl gloves.
Prep your molds. If using fiberglass molds, be sure they are cleaned well. Wipe with alcohol to remove contaminants. Mist with dish soap and water. Let dry.
Smooth-On's Dragonskin is mixed in a 1:1 ratio. Measure parts A and B into separate cups. The silicone will not cure if it is not mixed in the correct ratio. Keep in mind you can have a little extra of part A and the silicone will still cure. If you have extra of part B, it will not cure. You can add some silicone pigment to part B before mixing, but this is optional. (Pigment was added to the silicone before pouring of the blue and pink fluke pictured.)
Mix the silicone thoroughly. If not mixed well, it will not cure. Pour your silicone into your molds.
Check your silicone's curing time and other specifications. Silicone will not cure if the temperature is too cold, if it is a little cold, it will cure slowly. If the humidity is too high, it will not cure. Getting the picture? Silicone is finicky. Wait your silicone's curing time, maybe a little longer if the room's temperature is below the recommended temperature.
Make sure it is no longer tacky before attempting to pull it from the mold. If you waited its cure time it should be ready. If still slightly tacky, wait an hour. If still tacky, it is likely something inhibited its cure. You can try covering the mold with a towel and blow drying the towel, but it probably can't be fixed.
If all worked well, you should have pieces of your future mermaid tail! If not, go through your materials, troubleshoot. If you're lucky, it was something simple like not mixing the silicone enough and you can try again.

Assembling the Fluke

This is the hardest part of the whole tail. Even professional tail-makers tend to have different processes. Basically, you take the two silicone fluke halves and sandwich the monofin between them.

Silicone only sticks to silicone, which means a pocket can form in the fluke where the silicone doesn't stick to the monofin. Air and water can be trapped there. There are multiple ways to fix this. Some professional tail-makers have discovered a way to make the fluke solid so that there is no pocket. Some drill holes in the monofin so that the silicone goes through the holes and adheres to the other half, though this method is not usually recommended. It weakens the monofin. Some make a power mesh pocket for the monofin and glue the power mesh to it. The silicone then adheres to the power mesh. Regardless, a power mesh layer strengthens the silicone and protects the monofin from tearing through the silicone fluke.

A tail needs to be able to drain. The water will enter your tail through the waist, no matter how tight it is. The water then needs a way to escape. Place the plastic/vinyl tubing between your fluke halves to create drainage channels. Once the silicone cures, the tubing can be removed.

Almost ALL monofins have some sort of rubber construction. Rubber inhibits the cure of silicone. Use the Krylon Lacquer to create a barrier between the rubber and silicone. Spray the rubber monofin with the Lacquer and give it time to dry and the smell to dissipate. The Lacquer will eventually chip and come off.(Tip brought to you by Mermaid Jessica.)

Place one half of your fluke textured side down.
Prep your monofin and place it on top of your fluke half.
Lay the plastic/vinyl tubing across the monofin. Make sure you leave enough at the end of your fin so you can pull them out afterward.
Glue the other half of your monofin onto the top. You can use the Sil-Poxy for this or just more silicone.
Use clips and weights to press the pieces together as it cures.
Remove the tubing. Test drainage and adhesion in your shower or tub. As a last resort, you can use scissors or an X-Acto Knife to cut extra drainage.

Assembling the Rest of the Tail

You will need a sheet of plastic or your body double inside your power mesh so that the inside of your tail does not melt together.

Attach the power mesh to your fluke. You can use silicone or Sil-Poxy for this.
Decide what scale pattern you want. Begin gluing your scales (using silicone or Sil-Poxy) to your tail. It is usually best to start at the fluke and work your way up. Make sure you thoroughly coat the power mesh with your "glue". The silicone or Sil-Poxy should go through the little holes of the Power Mesh to adhere to it.
If you used the scale sheet method, you will need to be creative on seaming up your tail.
Use pins to hold it together while it cures/dries.
You can attach your extra fins now, but it will make painting more difficult. I suggest painting your fins before attaching them with pigmented silicone or Sil-Poxy. Use the two fins sandwiched together around a piece of Power Mesh. The Power Mesh will make your fins stronger and protect them from tearing.
Assembling your tail can be messy. Keep some Isopropyl Alcohol on hand to wipe up drips.

Once your tail is assembled, you may want to test the fit and make sure every scale is well-attached. Make sure you've pulled out all the pins!

Step 6: "Painting" Your Tail

Materials:

Platinum Cure Silicone (Dragonskin 10 medium)
Silicone Solvent (NOVOCS)
Silicone Pigments (Silc-Pig or Jacquard's Pearl Ex Pigments recommended)
Airbrush or disposable paintbrushes
Mixing Cups and Mixers
Original Dawn dish soap
Isopropyl alcohol

This is probably the most fun part of tail-making. You get to see all your hard work come together. You aren't actually "painting" the silicone. You are brushing your silicone with more pigmented silicone. Actual paint will not stick to silicone. Only silicone sticks to silicone.

Prepping

You want to make sure your tail is ready to accept your "paint". If it is not ready, or something is inhibiting the cure of your silicone, the silicone will not adhere and your "paint" will peel off (shown in the last photo above).

Wash your tail in the tub. Use the Dawn soap to clean it of contaminants.
Rinse thoroughly!
Rinse and wipe off again with Isopropyl alcohol. Any soap that is left on the tail will act as a release agent and the silicone may not adhere fully.
Allow to dry completely before painting.

"Painting"

Light colors take more layers than dark. Silicone is transparent. If you do not pigment your silicone beforehand, or don't add enough layers of "paint", the monofin, power mesh, or even legs may show through.
Pigment and solvent is added to part B of the silicone before being mixed with part A. Make sure your color is slightly more saturated than the color you want before mixing with part A.
Hand-painting your tail will result in a different effect than airbrushing. Hand-painting generally requires more layers and will reduce some of the texture of your sculpts.
If using an airbrush, be sure it is set aside for silicone alone. Be sure to thin the silicone well for the gun, and clean it thoroughly afterward. There are many forums and tutorials out there for airbrushing, use them to your advantage.
If after your cure time, the silicone is still slightly tacky, cover it with a towel and use a blow-dryer on the highest setting to heat it and help it along. This tip brought to you by Mermaid Julz.

Step 7: Putting on Your Tail and Tail Care

Tail and Tutorial: Rogue Siren

Tail Model: Lopti

So you've invested a ton of money and time into your tail. Take care of your tail and you can enjoy many years of swimming. Like anything, if you neglect it, it will break down. Silicone is strong, but it is not indestructible.

Depending on your tail's thickness and extra fins, it may take different processes to put it on. Never pull your tail at the seams. It can weaken them over time. Pull gently on the top and bottom of your tail to pull it up.
Some tails can be folded inside-out so you can slide your feet in. Once your feet are securely and comfortably in your monofin, you can unroll your tail and pull it up.
Always use a water-based lubricant to help put on your tail. Other lubricants can break down the silicone in your tail. Water-based lube can be found in most pharmacies, but adult stores carry a much larger and often more inexpensive range. Water-based lubricant and a spray bottle to mist your legs in water can help getting on a tight tail. Spot test the lubricant on your skin before use to be sure you are not sensitive to it.
Use a towel or foam yoga mat underneath your tail. Never try to put on your tail on hard concrete or tile. It can damage your tail.
Don't try to put on your tail with long fingernails. Trim your nails. If you try to put on a tail with long nails you may puncture your silicone and put a hole in your tail.
Do NOT stand in your tail! It outs unnecessary stress on the heel. The heels and knees are the most delicate part of the tail and can break down the fastest.
Always rinse your tail in cool, fresh water inside and out after use. Some swear by a mixture of white vinegar and water to clean the tail of chlorine, contaminants and discourage mold. Isopropyl alcohol is also safe to use to discourage mold. Rinse your tail again with fresh water after these methods. Do not use hot water.
Others swear by giving your tail a bath of baking soda to rid it of chlorine.
Make sure to dry your tail thoroughly after use. This is the best method to discourage the growth of molds, other fungus and bacteria. First rid your tail of extra water with a towel. Some people build tail-racks. A pool noodle down the length of the tail to hold it open and a fan placed at the waist is a great and easy way to dry your tail.

Putting on your tail takes time and practice. It is not pretty. It is awkward. Experiment and figure out which way is best for you. Mernetwork is a valuable resource for this.

Step 8: Swimming and Support

Tail and Tutorial: Rogue Siren

Tail Model: Lopti

So your tail fits and you want to take it for your first swim. You're excited, but don't jump into things too quickly. Even if you are an experienced swimmer, even if you are familiar in swimming with a monofin or fabric tail, take your time.

Bring a buddy! NEVER swim alone, with or without a tail.
Put your tail on near the edge of the water. You want access to the water to be easy, and again NEVER stand in your tail.
Stay near the wall to start. Hold onto the wall and kick your legs. Test your fin. Get used to the movement, figure out how it moves, how heavy it is, etc.
When you are ready, let go of the wall.
Keep your fluke away from the walls and floor. They have a tendency to suction to them, making it difficult to swim and potentially damaging your tail.
NEVER swim anywhere you wouldn't swim without a tail. Swim only in water shallow or deep enough for your ability.
Swimming has its own inherent risks. Always take precautions with or without a tail!
Be safe but HAVE FUN.

If you have questions regarding anything mermaid, Mernetwork is a wonderful resource.

If there is enough interest in this tutorial I will consider making a tutorial to make silicone scale tops, like the one in the photos. Thank you!