Liquid metal thermal paste is made from a gallium-based alloy, typically combining gallium, indium, and tin. This combination, sometimes called Galinstan, stays liquid at room temperature and conducts heat far more effectively than traditional silicone-based thermal pastes. Pure gallium has a thermal conductivity around 33.7 W/mK, roughly 10 to 15 times higher than even premium conventional pastes.
The Core Ingredients
The base of virtually every liquid metal thermal compound is gallium. On its own, gallium melts at about 29.8°C (85.6°F), which is just below body temperature. That’s useful but not ideal, since you’d risk it solidifying in a cool room. By alloying gallium with indium and tin, manufacturers push the melting point well below 0°C, ensuring the compound stays liquid across all normal operating temperatures.
The exact ratios vary by product, but the most common formulation follows the Galinstan recipe: roughly 68% gallium, 22% indium, and 10% tin by weight. Some products tweak these proportions or add trace amounts of other elements, but gallium always dominates. Unlike older liquid thermal compounds, modern liquid metal pastes contain no mercury, making them considerably safer to work with.
Why It Conducts Heat So Well
Traditional thermal paste uses a silicone or oil base mixed with thermally conductive particles like zinc oxide, aluminum oxide, or silver. The base itself is a poor conductor, so even the best conventional pastes top out around 5 to 12 W/mK. Liquid metal skips the silicone entirely. The alloy itself is the conductor, and metallic bonds transfer heat far more efficiently than particles suspended in grease.
A standard gallium-indium-tin alloy achieves thermal conductivity in the range of 25 to 35 W/mK right out of the syringe. Researchers have pushed this even higher by mixing in metal nanoparticles. Adding just 4% copper nanoparticles by volume to a Galinstan base boosted conductivity to roughly 65 W/mK in lab testing. Tungsten microparticles have also been used, reaching about 57 W/mK at higher filler concentrations. These experimental composites aren’t widely available in consumer products yet, but they show where the technology is heading.
One quirk: gallium-based alloys form a thin oxide layer when exposed to air. This oxidized surface drops thermal conductivity to around 13 W/mK. That’s still better than conventional paste, but it’s one reason proper application matters. Once the liquid metal is sandwiched between a processor and heatsink with no air exposure, the oxide layer is minimal and performance stays high.
Physical Properties That Set It Apart
Liquid metal behaves nothing like traditional paste. The bulk material is a true liquid with extremely low viscosity, closer to water than to toothpaste. What makes it tricky to handle is that thin oxide skin, which gives the surface an elastic quality. The oxide layer creates a slight resistance when you try to spread it, almost like a skin on pudding, but once you break through, the material flows freely.
Surface tension is also dramatically higher than conventional paste. Gallium-indium alloys measure around 444 millinewtons per meter, which means the liquid beads up aggressively on surfaces rather than spreading flat. This is why you can’t just put a dot in the center and press down like you would with regular paste. You need to physically spread liquid metal across the entire surface using a small applicator or cotton swab, working it into the microscopic grooves of the metal.
What It’s Compatible With
Liquid metal’s biggest limitation is its reactivity with aluminum. Gallium attacks aluminum aggressively, breaking down its structure in a process called liquid metal embrittlement. A single drop of gallium on an aluminum heatsink or heat spreader will permanently damage it, visibly eating into the surface. This rules out any aluminum cooler, and you should also confirm that all-in-one liquid coolers don’t use aluminum cold plates before applying liquid metal.
Nickel-plated copper is the safest surface. Most modern CPU heat spreaders (the metal lid on top of the processor) are nickel-plated copper, and liquid metal works well with them. You’ll see some cosmetic staining over time, but testing by hardware outlet GamersNexus confirmed it’s largely removable and doesn’t affect thermal performance. Bare copper also works, though the staining is much more severe. Gallium ions migrate into the copper surface, effectively plating it permanently. The good news is this doesn’t degrade performance either, it just looks rough if you ever take things apart.
Electrical Conductivity and Risk
Because liquid metal is an actual metal alloy, it conducts electricity. This is the single biggest risk when using it. If any amount spills or migrates onto exposed circuit traces, capacitors, or resistors on your motherboard, it can create a short circuit and permanently damage components.
The practical risk depends on where you apply it. Between a CPU’s heat spreader and a cooler, there’s a relatively contained space and spillover is unlikely if you use the right amount. Applying it directly to a bare processor die (under the heat spreader, or on a laptop chip) is riskier because the die is surrounded by tiny surface-mount components. Many people mitigate this by applying a thin border of non-conductive nail polish or liquid electrical tape around the die before applying liquid metal.
How Long Liquid Metal Lasts
One of liquid metal’s biggest advantages over conventional paste is longevity. Standard silicone-based pastes dry out over time as their carrier oils evaporate, typically needing replacement every three to five years. Liquid metal doesn’t have a carrier that can evaporate. It’s a stable alloy at operating temperatures, so it can last seven to ten years before needing attention. This makes it popular in gaming consoles and laptops where disassembly is inconvenient. Sony uses liquid metal from the factory in the PlayStation 5 for exactly this reason.
Handling Safety
Liquid metal paste is safe to handle in the small quantities used for PC building, but gallium is classified as a corrosive material. Direct skin contact can cause irritation, and prolonged or repeated exposure is worth avoiding. Wearing nitrile gloves during application is a sensible precaution and also keeps skin oils from contaminating the surface you’re working on. If you get some on your skin, washing with soap and water is sufficient. The amounts in a single syringe (typically 1 to 3 grams) are far below any level that would pose a systemic health risk, but gloves make the whole process cleaner anyway.