Silicone Rubber Fish Sculpture




Introduction: Silicone Rubber Fish Sculpture

About: I'm a refugee from Los Angeles, living in backwoods Puerto Rico for about 35 years now and loving it. I built my own home from discarded nylon fishnet and cement.

This silicone rubber fish sculpture uses an unusual construction technique.  Most of it was done by extruding lines of aluminum-colored silicone in air!  It's like 3-D drawing.   The material is light-weight and basically unbreakable.  

I love the see-through potential of this technique, allowing suggestions of internal anatomy.   Now I can make my own fossils!

A fish swimming in the air is like a fish swimming in water.  Hanging, as a means of display also eliminates the need for bases and dedicated floor space.  

This piece has a temporary string support now.  It is also set up with a socket through the center of the body so it can be mounted on a base with a vertical rebar as a stand.   That way, it can also be displayed in more conventional show settings someday.  

This could have lots of applications in education; such as biological models, architectural models, or really far-out art projects.  

Step 1: Armatures

Sculpture armatures are like skeletons upon which other materials are built up.  In this case, there is a wire running through the spine of the fish, and some smaller ones in the fins to help keep them in position.  Since the silicone is soft and flexible, gravity can make things sag.  If you don't want it to sag, it needs to be thick enough to resist sagging, or have reinforcement.  

Since I was developing the technique as I went along, I didn't really know what I was doing and had to do a lot of adapting -- which was fun.  This armature, a simple line through the spine,  was not ideally shaped for positioning in space.  Ideally, an armature should have three attachment points, not in the same line.  Three points define a plane.  By adjusting the positions of the three points with adjustable lengths of string from overhead, you can position the plane, and your work, in any position.  

A universal armature might be something like three wires radiating out from a central point, each wire with an eye at the end for attaching strings.   When the sculpture is completed, you can cut off any extruding armature wires and patch the spots with more silicone.  

If you want to keep everything flexible and rubbery in the finished piece, you can use string in an armature, instead of wire, attaching the string ends to a temporary, rigid external armature that is cut off later.  

Step 2: Drawing in the Air

Silicone is really fun to work with.  When freshly extruded, it is a soft, sticky, almost-solid, liquid material.  It has strength limitations, which improve as it hardens up.  Because of those limitations, if you try to draw too long a line, it will sag and break under its own weight.  

For very long lines, coat some string with silicone first, by rubbing it on with your fingers, using rubber gloves.  You can then drape that long line, attach the ends with silicone, and then build up the line thickness later with added extrusions.  

For shorter lines, just press the tip of the silicone cartridge to your work to attach one end of the line, extrude the line, and press to attach the other end.  

Once you get a network of basic lines in place, it is fairly easy to fill in the gaps with more lines, and eventually skin over areas for a more solid appearance.  

For more detailed extrusions, you can use plastic-tipped syringes, available at pet stores.  Fill them directly from the big cartridge.  As with the big cartridges, the conical tip can be cut at different locations to make bigger or smaller extrusion diameters.  To clean them out, remove the plunger and wipe it.  Let the silicone inside the syringe dry and then you can push and scrape with wire tools to get it clean.  Pumping the plunger in and out rubs the inside of the syringe to get the walls clean.  I use something like a giant cotton swab to get the little loose particles out.  

Step 3: Hanging or Base-mounted

I started out with the idea of hanging the sculpture when completed, but then decided I wanted the option of mounting it from a base with a vertical rod into the body of the fish.  

Here you can see the rod added, running through a piece of plastic tubing.  The tubing was locked in place with silicone in the body of the fish, creating a socket for the removable rod.  After the silicone hardened up, I removed the rod and trimmed the tubing flush with the bottom of the fish.  A string can go through the tubing for hanging the fish, or the rod can go through the tubing for base mounting it.  (A stop on the rod would keep it from coming out the top of the tubing and completely penetrating the body of the fish, or the top of the tubing could be capped.)

Step 4: Adding Fins

Instead of building the fins in place, I just drew them out on a non-stick polyethylene cutting board and attached them when they hardened up.   I used some stainless steel welding rod, where needed, for rigidity in the fins.  Stainless steel is best for armature wire because it will never rust.  The silicone rubber and stainless steel combination has got to have excellent longevity.  

Step 5: Don't Throw Away the Empties!

I try to recycle everything, including the empty silicone rubber cartridges.  

To get the plunger cup out of the cartridge, cut the tip of the cartridge so the hole is big enough to push a rod (1/4" rebar) tool through it.  Push the plunger cup out the back of the cartridge.  When the silicone hardens up, it peels right off the cup.  You can get it out of the cartridge using tools made of rebar, or other materials, that can reach in and scrape, or rub.  

As music toys, the empty cartridges make good maracas.  Use two plunger cups to close up the openings trapping seeds, or other shaker things inside.  

I also like to paint and buy my acrylics in pint jars.  It's cheaper in bulk.  Since one can lose a lot of paint to drying from opening and closing the jars all the time, I like to transfer the paint to empty silicone cartridges with caps.  Then, I extrude what I need and never lose paint to drying.   See:



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    23 Discussions

    I bet I could turn this into a dinosaur sculpture! It looks awesome. Does that silicone rubber stuff come in any other colors? It'd be really neat to do it in like tan or dirty cream color. Like a fossil.

    2 replies

    The standard colors for silicone are clear, white, black, gray (silver) and brown (bronze). For other colors you have to mix powdered pigments with clear silicone.

    The advantage to store bought colors is that you can extrude them directly from the cartridge. If you mix your own colors you have to mix them on a palette and then pack them back into a cartridge, or smaller syringe barrel.

    I have used the empty silicone cartridges as storage containers and dispensers for acrylic paints. Never tried repacking them with silicone.

    You can mix small batches of colorized silicone and paint it onto your base silicone for painterly effects, and to economize on pigments. Normal paints don't stick to silicone. You can paint with pigmented clear silicone, though. Silicone sticks to silicone.

    I was seeing dinosaur skeletons when I did this fish, but never got around to it. Hope you get to do the project. Share the results if you do.

    Thanks, Thinkenstein! I'll probably be doing this project before long, and hanging the finished fish or dino from my ceiling.


    You mentioned a socket and that got me to thinking, could this socket be replaced by an electrical socket and the sculpture used as a lamp?

    6 replies

    Silicone does burn, but I don't think it is electrically conductive. I doubt your light bulb would ever get hot enough to start a fire. I could imagine some really nice lamps being made out of silicone this way, maybe using clear silicone. If you saturate cloth with clear silicone, you can get some nice back-lit color effects, too.

    I agree with the comment that the silicone could take the heat. But also make sure the bulb gets enough convection to not overhead. Too much silicone coating it or blocking airflow could cause the bulb to overheat and burn out before its time.

    It would largely depend on the type of bulb used. Although, an ordinary incandescent bulb probably won't actually burn the silicone, it might weaken it enough to become a concern (particularly a higher-wattage bulb).

    However, if you're using low-energy Compact Flourescent Lights (CFL's), I really don't see a problem, given that they put out so comparatively-less  heat.

    On the other hand, just to be really sure - and potentially offer more flexibility (pardon the pun) - you could look into using LED's or, even, embedding them along the armature...

    LED's are a nice idea. A hidden battery pack would be good, except for the need to replace batteries. The only problem with light shows is that you have to do it in the dark, and everybody has to agree to go without light for other things they want to do.

    To keep it simple, maybe a string of Christmas lights, with blinking patterns and all, could be incorporated into a sculpture design. If something went wrong with the string of lights, though, you couldn't replace the string easily, or at all.

    Silicone is typically good into very high temps well above the 250F or so the surface of an incandescent may reach if in the 60w to 75w range. High temp usage is a hallmark of silicone products. I don't think an incandescent would be a problem. Check the temp range on the product used and if in doubt, use a smaller wattage bulb. A 25w bulb stays below 120F typically for example. CF bulbs run much cooler but also have quite bit of mercury in them and if you wan an interesting read, check out how the procedure recommended by the EPA for cleaning up a broken CF bulb.

    A battery pack would "simply" have to be incorporated into the original design - or, at least, a space for it would, in a similar way to your mixing pot formed over a tuna tin. More of an issue might be its colour (if you don't have an almost-clear one - and if you do, then I don't know of any clear batteries), if the sculpture is to be anywhere near clear - again, a design consideration.

    The wiring would present similar issues, though I know it's possible to get clear stuff (around 'silver'-coloured strands, in particular).

    If your wires (and LED's) are covered in silicone - to the extent of actually being part of the sculpture - then once it sets, they'll be held much more firmly in a working position, so should last much longer. And any weak spots should be more obvious, as the silicone would have to fail first.

    that's cool that you keep and recycle everything. i want to see what your house looks like if it's made up of net and cement.

    1 reply has photos. Also, do a search on instructables for "nylon-cement" and you will probably come up with lots of projects I have posted.

    Hjjusa, What about using Electro-lum.(EL) wire in the frame of the sculpture & clear silicone. The whole thing would glow !!!

    1 reply

    You may have better access to materials like Electro-lum than I do. It might make a good instructable for you to tackle. It sounds beautiful.

    Well,Thinkenstein, outside the box again !! Great idea !!! I often use silicone at work to make parts & shapes I need, but nothing on this scale. Cheers!

    I love trying new materials with no idea how to do it and just see how it goes, this looks like a LOT of fun

    1 reply