Accessible Chemicals Guide

Every chemical used across builds — what it is, where to buy it, what it costs, and how not to hurt yourself with it.

This guide covers the chemicals and chemical-adjacent materials referenced in Junkyard Genius builds. Everything here is legally available to consumers in the US. "Accessible" means you can buy it at a hardware store, pharmacy, garden center, or online without special licenses.

Acetone

What it is: A powerful organic solvent. Dissolves adhesives, paints, resins, and toner. Also the main ingredient in nail polish remover (but buy pure acetone, not the diluted salon stuff).

Where to buy: Hardware store (Klean-Strip, Jasco — quart for ~$5-8). Also available at beauty supply stores, but hardware store acetone is purer and cheaper.

Approximate cost: $5-8/quart

Used in builds:

• PCB Etching Station — removing toner after etching

Safety notes: Extremely flammable. Vapors are heavier than air and travel to ignition sources. Use in well-ventilated areas, away from open flame. Prolonged skin contact causes drying and irritation. Wear nitrile gloves (note: acetone dissolves latex gloves — use nitrile).

Aluminum Powder

What it is: Finely ground aluminum metal, typically 200-325 mesh (particle size). The finer the powder, the more reactive. This is the fuel component of thermite and various pyrotechnic compositions.

Where to buy: Online pyrotechnic suppliers (Skylighter, Firefox Enterprises). Also available from some art supply stores (aluminum pigment powder). Not typically stocked in brick-and-mortar retail.

Approximate cost: $10-15/lb

Used in builds:

• Thermite Flower Pot — fuel for thermite reaction

Safety notes: Fine aluminum powder is flammable and can form explosive dust clouds when suspended in air. Store in sealed containers away from oxidizers (iron oxide, potassium permanganate, etc.) and moisture. Never use metal tools or containers when mixing with oxidizers — a single spark can ignite the mixture. Ground yourself to prevent static discharge when handling.

Bismuth

What it is: A dense, brittle metal with a low melting point (520°F / 271°C). Non-toxic — it's the active ingredient in Pepto-Bismol. When melted and slow-cooled, it forms stunning iridescent hopper crystals with rainbow oxide layers.

Where to buy: Online metal suppliers (Rotometals, Amazon). Sold as ingots, chunks, or pellets. Purity should be 99.99% for best crystal formation.

Approximate cost: $12-18/lb

Used in builds:

• Bismuth Crystal Garden — growing iridescent hopper crystals

Safety notes: The metal itself is non-toxic, but molten bismuth is over 500°F. Wear heat-resistant gloves and safety goggles. Never introduce moisture into the melt — steam explosions can splatter molten metal. Dedicate any cookware used for bismuth — never reuse for food. Work in a ventilated area; oxide fumes at temperature can irritate.

Borax (Sodium Tetraborate)

What it is: A naturally occurring mineral salt, widely used as a laundry booster, flux for soldering/welding, and a source of boron. Dissolves in water to form a mildly alkaline solution.

Where to buy: Grocery store laundry aisle (20 Mule Team Borax, ~$5 for a 4 lb box). Also available at hardware stores.

Approximate cost: $5/4 lbs

Used in builds:

• Colored Fire — boric acid (a borax derivative) produces green flames
• Various soldering/brazing builds — as a flux

Safety notes: Low toxicity, but do not ingest. Can irritate eyes and skin with prolonged contact. Keep away from children and pets. Wear gloves when handling concentrated solutions.

Calcium Carbide

What it is: A gray, rocky solid that reacts vigorously with water to produce acetylene gas (the same gas used in welding torches). The reaction also produces calcium hydroxide (lime) as a byproduct. Smells garlicky when reacting.

Where to buy: Welding supply stores, online (Amazon, eBay). Also sold as a mole/gopher repellent at some garden centers. Cave and mining supply stores carry it for carbide lamps.

Approximate cost: $10-15/lb

Used in builds:

• Calcium Carbide Cannon — acetylene gas production for ignition

Safety notes: Reacts with ANY moisture, including humidity. Store in airtight, completely dry containers. Acetylene gas is explosive in air at concentrations between 2.5% and 81%. NEVER use indoors. The calcium hydroxide byproduct is caustic — wear gloves. Keep away from open flame until you are ready to ignite intentionally.

Copper Sulfate

What it is: Blue crystalline salt (CuSO4·5H2O). Dissolves readily in water to form a vivid blue solution. Used industrially as a fungicide, algaecide, root killer, and in electroplating/electroforming.

Where to buy: Hardware store (sold as root killer — Rooto, Zep brands, ~$8-12/lb). Garden centers (sold as fungicide). Online chemistry suppliers for higher purity.

Approximate cost: $8-12/lb (root killer grade), $15-20/lb (lab grade)

Used in builds:

• Electroplating Station — copper plating electrolyte
• Electroforming Art — electroforming electrolyte
• Copper Crystal Tree — growing copper crystals
• Colored Fire — blue-green flame color
• Sodium Silicate Demos — blue tubes in chemical garden

Safety notes: Toxic if ingested. Irritates skin and eyes — wear gloves. Stains everything blue. Do NOT pour solutions down the drain — copper is toxic to aquatic life. Neutralize with baking soda and dispose through local hazardous waste facilities.

Dry Ice

What it is: Solid carbon dioxide (CO2) at -109°F (-78.5°C). Sublimates directly from solid to gas without melting into liquid. Produces dense, cold fog when placed in warm water.

Where to buy: Grocery stores with ice departments (Walmart, Kroger, Safeway — ask at the service counter). Some gas suppliers and ice companies. Usually sold in 1-10 lb blocks or pellets.

Approximate cost: $1-3/lb

Used in builds:

• Dry Ice Comet Balls — visual effects
• Dry Ice Bubble Cauldron — ground fog effects
• Ultrasonic Fog Machine — enhanced fog density
• Fog Chiller — cooling fog for ground-hugging effect
• Cloud Chamber — cooling the chamber

Safety notes: NEVER handle with bare hands — instant frostbite. Use insulated gloves or tongs. NEVER store in a sealed container — sublimation builds pressure and can cause an explosion. In enclosed spaces, displaces oxygen and can cause asphyxiation. Always use in well-ventilated areas. Never ingest.

Ferric Chloride

What it is: An iron salt solution (FeCl3) used as a chemical etchant. Dissolves exposed copper on PCBs, leaving only the masked circuit traces behind. Sold as a dark brown/amber liquid.

Where to buy: Electronics suppliers (MG Chemicals, on Amazon/eBay). Some Radio Shack replacement stores. Not typically at hardware stores.

Approximate cost: $10-15/quart

Used in builds:

• PCB Etching Station — etching copper from circuit boards

Safety notes: PERMANENTLY stains everything — skin, clothes, countertops, sinks. Wear gloves and old clothes. Work on disposable surfaces. Corrosive to metals. NEVER pour down the drain — it corrodes plumbing and is toxic to aquatic life. Neutralize with baking soda, then dispose through hazardous waste. Store in plastic containers only (it eats metal containers).

Fluorescein Dye

What it is: A fluorescent dye that glows vivid yellow-green under UV/blacklight and is visible at extremely low concentrations. Used by plumbers for leak detection and by the Coast Guard for sea rescues. Non-toxic at the concentrations used in demos.

Where to buy: Online (Amazon — "fluorescein sodium salt"), plumbing supply stores (leak detection dye), or science education suppliers. Also available as uranine dye.

Approximate cost: $8-12 for 100g (enough for hundreds of demonstrations)

Used in builds:

• Fluorescein Blacklight Fountain — glowing water fountain

Safety notes: Non-toxic at demo concentrations, but stains skin and clothing bright yellow-green for 24-48 hours. Wear gloves. The dye washes out of most fabrics eventually. In water features, use sparingly — a tiny amount goes a very long way. Check local regulations before adding to outdoor water features or drains.

Gallium

What it is: A silvery metal with an absurdly low melting point — 85.6°F (29.8°C). It melts slowly in your hand over 10-30 seconds of contact. Liquid gallium looks like mercury but is non-toxic. It aggressively attacks aluminum, creating dramatic structural failure demonstrations.

Where to buy: Online (Amazon, Gallium Source). Sold in small quantities (20-100g). Purity should be 99.99%.

Approximate cost: $15-25 for 50g

Used in builds:

• Gallium Melting Spoon — spoons that dissolve in hot drinks

Safety notes: Non-toxic to handle, but liquid gallium permanently destroys aluminum objects. Keep it away from aluminum cans, foil, tools, or anything aluminum you want to keep. It also attacks other metals over prolonged contact. Gallium stains skin with a gray residue (washes off). Use glass or stainless steel containers only.

Hydrogen Peroxide (3% and 12%+)

What it is: An oxidizer (H2O2). The 3% pharmacy grade is a mild disinfectant. Higher concentrations (12%, 30%, 35%) are powerful oxidizers used in chemistry demonstrations, rocket fuel, and industrial processes.

Where to buy:

• 3%: Pharmacy or grocery store (~$1-2/bottle)
• 12%: Beauty supply stores (hair developer, "40 volume" = 12%)
• 30-35%: Online chemistry suppliers, pool supply stores ("technical grade")

Approximate cost: $1-2 (3%), $5-8 (12%), $15-25/liter (30%+)

Used in builds:

• Elephant Toothpaste — the main reactant (higher concentration = bigger eruption)
• Luminol Crime Scene — luminol activator
• Chemiluminescent Fountain — oxidizer for chemiluminescence

Safety notes: 3% is relatively safe. 12%+ causes chemical burns on skin contact and bleaches clothing instantly. 30%+ is a serious oxidizer — causes severe burns, can ignite combustible materials on contact, and decomposes explosively if contaminated. Wear gloves and goggles at ALL concentrations above 3%. Store in original containers in a cool, dark place. Never mix with acetone, alcohol, or other organic solvents.

Iron Oxide (Rust)

What it is: Oxidized iron (Fe2O3), commonly known as rust. A fine red or black powder. It's the oxidizer component of thermite. Also used as a pigment and polishing compound.

Where to buy: Online (Amazon — "iron oxide powder," "red iron oxide pigment"). Art supply stores (pigment). Or make your own by soaking steel wool in vinegar and water for days, then drying and grinding the result.

Approximate cost: $8-12/lb (purchased), free (homemade from steel wool and vinegar)

Used in builds:

• Thermite Flower Pot — oxidizer for thermite
• Luminol Crime Scene — iron source for luminol reaction

Safety notes: Iron oxide powder itself is not particularly dangerous — it's just rust. However, fine powder can be an inhalation irritant. Wear a dust mask when handling. The danger comes from mixing it with aluminum powder (thermite). Once mixed, treat thermite with extreme caution — see the Thermite Flower Pot build for full safety protocols.

Isopropyl Alcohol (Rubbing Alcohol)

What it is: A fast-evaporating solvent and disinfectant. Available in 70% and 91-99% concentrations. The higher concentrations are more useful for builds (better solvent, burns cleaner).

Where to buy: Pharmacy or grocery store (70% and 91% readily available, ~$3-5). 99% available at electronics suppliers or online.

Approximate cost: $3-5/bottle (16 oz)

Used in builds:

• General cleaning and degreasing across many builds
• Fire-based demonstrations (clean-burning fuel for small flames)
• Electronics work (PCB cleaning, flux removal)

Safety notes: Flammable — keep away from open flame. Burns with a nearly invisible blue flame, which is especially dangerous in daylight. Vapors can accumulate in enclosed spaces. Prolonged skin contact causes drying. Use in ventilated areas.

Liquid Nitrogen

What it is: Nitrogen gas cooled to -321°F (-196°C). It's a cryogenic liquid that boils at room temperature, producing dense white fog. Used for flash-freezing, superconductivity demonstrations, and dramatic visual effects.

Where to buy: Welding supply stores (Airgas, Praxair). Some gas distributors and industrial suppliers. You typically need to bring your own dewar (vacuum-insulated container). NOT available at grocery stores.

Approximate cost: $1-3/liter, but the dewar costs $100-300

Used in builds:

• DIY Freeze Dryer — rapid freezing
• Supercooled Water — rapid cooling demonstrations

Safety notes: Extreme cold causes instant frostbite on skin contact. Boils rapidly at room temperature — 1 liter of liquid becomes ~700 liters of gas, which can displace oxygen in enclosed spaces and cause asphyxiation without warning. NEVER seal in a closed container (pressure explosion). NEVER pour on a person. Use only in well-ventilated areas. Wear cryogenic gloves (not regular gloves — most gloves absorb liquid nitrogen and make burns worse). Safety goggles mandatory.

Luminol

What it is: A chemical that produces a blue chemiluminescent glow when it reacts with an oxidizer (hydrogen peroxide) in the presence of a catalyst (iron). Used by forensic investigators to detect trace blood at crime scenes.

Where to buy: Online chemistry suppliers (Home Science Tools, Amazon). Sold as powder.

Approximate cost: $10-20 for 5-10g (enough for multiple demonstrations)

Used in builds:

• Luminol Crime Scene — creating glowing crime scene effects
• Chemiluminescent Fountain — glowing water effects

Safety notes: The luminol powder itself is a mild irritant. The mixed solution contains sodium hydroxide and hydrogen peroxide, which are the real hazards — wear gloves and goggles when mixing and spraying. The blue glow is not UV — it's chemiluminescence and is safe to look at. Use in ventilated areas due to the spray mist. Stains clothing and porous surfaces.

Magnesium Ribbon

What it is: Thin strips of magnesium metal. Burns at approximately 5,600°F (3,100°C) with an intensely bright white flame. Used as an igniter for thermite and other high-temperature pyrotechnic reactions that need extreme heat to start.

Where to buy: Online chemistry/education suppliers (Home Science Tools, Amazon). Also available from pyrotechnic suppliers (Skylighter).

Approximate cost: $5-10 for 25 feet

Used in builds:

• Thermite Flower Pot — ignition source for thermite
• Steel Wool Photography — bright flame source

Safety notes: Burns extremely hot and produces intense UV-rich light. NEVER look directly at burning magnesium without welding-grade eye protection (shade 5 minimum). Cannot be extinguished with water — water decomposes and fuels the fire. Use a Class D fire extinguisher or smother with dry sand. Store in a dry place; it reacts slowly with moisture. Once lit, a piece of magnesium ribbon burns to completion — it cannot be "put out" conventionally.

Muriatic Acid (Hydrochloric Acid / HCl)

What it is: A strong acid sold for cleaning concrete, brick, and masonry. The hardware store version is typically 31.45% HCl (approximately 10 molar). It's the same acid your stomach produces, but at a much higher concentration.

Where to buy: Hardware store (Klean-Strip, HDX brands — ~$8-12/gallon). Pool supply stores. Always in the masonry or pool chemicals aisle.

Approximate cost: $8-12/gallon

Used in builds:

• Anodizing Setup — surface preparation
• Hydrogen Generator — acid electrolyte

Safety notes: Produces toxic fumes (hydrogen chloride gas) immediately upon opening. ALWAYS use outdoors or in a fume hood. Causes severe chemical burns on skin and eye contact. Corrodes metals rapidly. Wear acid-resistant gloves, chemical splash goggles, and a respirator. Reacts violently with bases (sodium hydroxide) — causes splashing and heat. Store in original container. Never mix with bleach — produces toxic chlorine gas.

Neodymium Magnets

What it is: Not a chemical, but listed here because they appear in so many builds and demand similar respect. Neodymium (NdFeB) magnets are the strongest permanent magnets commercially available. Even small ones (1" diameter) can crush fingers between them.

Where to buy: Online (K&J Magnetics, Applied Magnets, Amazon). Hardware stores carry weak ones — for builds, buy from specialty suppliers.

Approximate cost: $1-5 per magnet depending on size (bulk is cheaper)

Used in builds:

• Electromagnetic Levitator — magnetic base
• Plasma Tornado Lamp — vortex generation
• Various motor and generator builds throughout the repo

Safety notes: Large neodymium magnets are genuinely dangerous. Two magnets snapping together can crush fingers, pinch skin, and shatter into sharp shrapnel. Keep away from pacemakers, credit cards, hard drives, and electronics. They are brittle — impacts cause them to shatter, and the fragments are sharp and still magnetic. Wear gloves when handling large magnets. Keep them away from children.

Nichrome Wire

What it is: A nickel-chromium alloy wire used as a heating element. When current flows through it, it glows red-hot. This is the wire inside toasters, hair dryers, and space heaters. Used in builds as igniters, hot-wire cutters, and heating elements.

Where to buy: Online (Amazon, eBay — search "nichrome wire"). Vape supply stores (sold as coil wire). Hardware stores sometimes carry replacement heating elements. Or salvage from any dead heating appliance.

Approximate cost: $5-10 for 25 feet (purchased), free (salvaged from appliances)

Used in builds:

• Fireworks Sequencer — fuse igniters
• Various heating-element builds

Safety notes: Nichrome glows at 1,000-2,000°F when energized. It can ignite fuses, paper, fabric, and skin instantly. Never handle energized nichrome. Use a physical kill switch in all igniter circuits. When used as igniters in pyrotechnic builds, never wire to fireworks until you are ready to fire.

Phosphoric Acid

What it is: A medium-strength acid (H3PO4). The main ingredient in rust converter/remover products and a major component of Coca-Cola. Converts iron rust into iron phosphate (a stable, paintable surface).

Where to buy: Hardware store (sold as "rust converter" or "naval jelly" — Loctite, Ospho brands). Also available in pure form from chemistry suppliers.

Approximate cost: $8-15/quart (as rust converter)

Used in builds:

• Metal preparation and rust removal across many builds
• Anodizing Setup — anodizing electrolyte

Safety notes: Less aggressive than muriatic or sulfuric acid, but still causes skin and eye irritation at higher concentrations. Wear gloves and goggles. The commercial rust converter products are relatively safe to handle. Pure phosphoric acid requires the same precautions as any strong acid.

Potassium Nitrate (KNO3 / Saltpeter)

What it is: A strong oxidizer. White crystalline salt. Historically used in gunpowder, meat curing, and fertilizer. In builds, it's used for smoke bomb compositions and pyrotechnic color effects.

Where to buy: Garden centers (stump remover — Spectracide brand is pure KNO3, ~$8 for 1 lb). Online chemistry suppliers. Some pharmacies carry it as saltpeter.

Approximate cost: $8-12/lb

Used in builds:

• Smoke Bomb Array — oxidizer for smoke composition
• Pharaoh's Serpent — oxidizer
• Colored Fire — oxidizer for sustained color

Safety notes: Strong oxidizer — do not store near fuels, organic materials, or reducing agents. Can cause fires if mixed with sugar, charcoal, or other fuels and exposed to heat or friction. Store in a cool, dry place in the original container. Wear gloves when handling. Legal to purchase, but large quantities may raise questions.

Potassium Permanganate (KMnO4)

What it is: A deep purple crystalline solid that is a powerful oxidizer. Dissolves in water to form a vivid purple solution. Reacts vigorously with glycerin, sugar, and other organic compounds — sometimes with spontaneous ignition.

Where to buy: Hardware store (water treatment/well supply — sold as "Pot Perm" or "Iron Out"), aquarium supply stores, online chemistry suppliers. Some survival stores carry it for water purification.

Approximate cost: $8-15/lb

Used in builds:

• Permanganate Auto-Ignition — spontaneous fire demonstration
• Chemiluminescent Fountain — oxidizer

Safety notes: Strong oxidizer that stains skin, clothing, and surfaces deep purple/brown (stains last days on skin). Reacts exothermically with glycerin, antifreeze, sugar, and many organic compounds — can cause spontaneous fire. Store away from organic materials and fuels. Concentrated solutions cause chemical burns. Wear gloves and goggles. Never mix with sulfuric acid (produces explosive Mn2O7).

Sodium Acetate

What it is: A salt formed from sodium hydroxide and acetic acid (vinegar). Known as "hot ice" because a supersaturated solution can be triggered to crystallize instantly, releasing heat. The crystallization looks like water freezing on command.

Where to buy: Online (Amazon, science education suppliers). Or make your own by reacting baking soda with vinegar and boiling down the solution.

Approximate cost: $10-15/lb (purchased), essentially free (homemade)

Used in builds:

• Instant Ice Sculpture — supersaturated solution that crystallizes on demand

Safety notes: Very safe. The crystallization releases heat (exothermic), but the temperature rise is modest — warm, not hot. Non-toxic. The main hazard is the hot plate/stove used to dissolve and supersaturate the solution. Be patient during the supersaturation step — boiling too vigorously spatters hot solution.

Sodium Hydroxide (Lye / NaOH)

What it is: A strong base (caustic alkali). Dissolves fats, proteins, and organic matter. Used industrially in soap making, drain cleaning, and food processing. Produces significant heat when dissolved in water.

Where to buy: Hardware store (sold as drain opener/cleaner — Red Devil Lye, Roebic). Soap supply stores (food-grade lye for soap making). Amazon.

Approximate cost: $5-10/lb

Used in builds:

• Luminol Crime Scene — making luminol solution alkaline
• Hydrogen Generator — electrolyte
• Various cleaning and degreasing steps

Safety notes: Causes severe chemical burns on skin and eyes — more insidious than acids because you may not feel the burn immediately. Generates intense heat when dissolved in water (always add lye TO water, never water to lye — it can boil and splash). Wear chemical splash goggles and nitrile gloves. If it contacts skin, flush with water for 15+ minutes. Reacts with aluminum to produce flammable hydrogen gas. Store in a tightly sealed container — it absorbs moisture and CO2 from air.

Sodium Silicate (Water Glass)

What it is: A liquid glass solution — sodium silicate dissolved in water. Used industrially as a sealant, adhesive, and fireproofing agent. Creates fascinating chemical garden formations when metal salts are dropped into it.

Where to buy: Hardware store (sold as concrete sealer/densifier — "sodium silicate" or "water glass"). Online from chemistry suppliers. Some art supply stores carry it for ceramics.

Approximate cost: $10-20/gallon

Used in builds:

• Sodium Silicate Demos — fireproof paper and chemical gardens

Safety notes: Strong base (pH ~12). Irritates skin and eyes. Wear gloves. Dries to a hard, glassy coating that is extremely difficult to remove from surfaces — protect your work area. The metal salt crystals used in chemical gardens (copper, cobalt, nickel compounds) are the real hazard — handle with gloves and dispose properly.

Strontium Aluminate

What it is: A phosphorescent (glow-in-the-dark) compound. The modern replacement for zinc sulfide in glow products. Charges under any light and glows for hours — much brighter and longer-lasting than older glow materials. Available as a fine powder in green, blue, and other colors.

Where to buy: Online (Amazon, art supply stores, specialty pigment suppliers — "strontium aluminate glow powder"). Not available in brick-and-mortar retail.

Approximate cost: $10-20 for 100g

Used in builds:

• Glow Resin River Table — glowing resin fill

Safety notes: The powder is an inhalation irritant — wear a dust mask when mixing into resin or paint. Once embedded in a cured matrix (resin, paint), it's completely safe. Non-toxic. Store in a sealed container to prevent clumping from moisture absorption.

Sulfur

What it is: A yellow elemental solid with a distinctive rotten-egg smell when burned. Used in pyrotechnic compositions, vulcanization of rubber, and as a fungicide.

Where to buy: Garden centers (sold as "sulfur dust" or "sulfur powder" for fungicide/pest control — Hi-Yield brand, ~$5-8/lb). Online chemistry suppliers for higher purity.

Approximate cost: $5-8/lb

Used in builds:

• Pharaoh's Serpent — component of the ash snake reaction
• Various pyrotechnic compositions

Safety notes: Flammable — burns with a blue flame that is nearly invisible in daylight. Burning sulfur produces sulfur dioxide gas (SO2), which is toxic and severely irritating to lungs. NEVER burn sulfur indoors. Combustible dust hazard when powdered — keep away from sparks and flame. Store in sealed containers.

Sulfuric Acid

What it is: A strong, dense acid (H2SO4). "Battery acid" in dilute form. The concentrated form (96-98%) is a powerful dehydrating agent that chars organic materials on contact. Generates extreme heat when mixed with water.

Where to buy: Auto parts stores (battery acid is dilute sulfuric acid — ~35%). Drain cleaning products (some contain concentrated sulfuric acid). Online chemistry suppliers for concentrated lab-grade.

Approximate cost: $5-10 (battery acid), $15-25/liter (concentrated)

Used in builds:

• Anodizing Setup — anodizing electrolyte

Safety notes: Concentrated sulfuric acid is extremely dangerous. Causes severe, deep chemical burns on skin contact. Generates extreme heat when mixed with water — ALWAYS add acid to water, never water to acid (the heat can cause the water to flash-boil and spray acid everywhere). Chars paper, cloth, and skin (dehydration reaction). Wear acid-resistant gloves, chemical splash goggles, and a face shield when handling concentrated acid. Keep baking soda (sodium bicarbonate) nearby to neutralize spills.

Thermochromic Pigment

What it is: Microencapsulated pigment that changes color at a specific temperature. Below the activation temperature, the pigment shows its color. Above it, it turns transparent (revealing whatever is beneath it). Available in various activation temperatures: 86°F (body heat), 100°F, 120°F.

Where to buy: Online specialty suppliers (Amazon, art supply stores — search "thermochromic pigment powder"). Not available in brick-and-mortar retail.

Approximate cost: $8-15 for 50g (enough for several projects)

Used in builds:

• Thermochromic Paint — heat-reactive wall paint
• Thermochromic Mug — color-changing drinkware

Safety notes: Non-toxic once mixed into paint or resin. The dry powder is a mild inhalation irritant — wear a dust mask when mixing. Degrades with prolonged UV exposure (direct sunlight). Use UV-protective clear coat for outdoor applications. Not food-safe unless specifically rated — do not apply to surfaces that contact food without a food-safe clear coat barrier.

Quick Reference Table