Antminer S21+ Hydro Thermal Grease Stencil – Stainless Steel with Positioning Frame

Antminer S21+ (Plus) Hydro Thermal Grease Stencil – Stainless Steel Hashboard Application Tool with Black Positioning Frame

This is a custom-designed thermal grease stencil for the Antminer S21+ (Plus) Hydro miner. Made from high-hardness stainless steel and equipped with a high-strength black positioning frame, the stencil aligns precisely on the S21+ Hydro hashboard so every ASIC chip receives an even, controlled bead of thermal grease in a single pass. It solves the chronic pain points of repair-bench grease application — uneven coverage, smearing onto neighbouring components, and chip-by-chip thickness variance — and is built for high-volume mining farm refurbishment, hashboard chip replacement and water-cooling system maintenance.

Why a Dedicated S21+ Hydro Stencil Beats Manual Application

Manual grease application onto a hydro hashboard is the single biggest cause of post-repair temperature spikes: too thick on one chip, too thin on the next, smears that bridge to neighbouring components. The S21+ Hydro stencil enforces a uniform thermal interface across the entire chip array in a single squeegee pull, producing a flat, repeatable joint between the ASIC tops and the water-cooling plate. The result: better heat transfer to the cooling loop, lower chip junction temperatures and a hash rate that holds at spec instead of throttling under thermal stress.

Stainless Steel + Black Positioning Frame

The stencil itself is made from high-hardness stainless steel — corrosion-resistant against coolant residue and isopropyl-alcohol cleanups, and not easily deformed by repeated handling or wash cycles. Aperture geometry stays sharp run after run, so the bead profile on chip number 200 looks exactly like the bead on chip number 1. The high-strength black positioning frame is the real time-saver on a busy bench: it indexes the stencil onto the hashboard in seconds, locks it against shifting during the squeegee pull, and is forgiving enough that a junior technician can be productive on day one without ruining a board.

When to Use This Stencil

Three situations call for it on an S21+ Hydro: (1) ASIC chip replacement on the hashboard after a failed unit is swapped out, (2) water-cooling system maintenance when the cooling plate is removed for inspection, gasket service or coolant-line repair, and (3) heat-dissipation optimisation when a unit is running hot from pump-out, dry-out or migration of the original grease layer. In all three, a fresh, uniform grease layer is what restores the original temperature delta and lets the miner hold its target hash rate.

Application Workflow

Power off the miner and depressurise the cooling loop before disassembly. Strip the existing thermal compound from the hashboard chip tops and the water-cooling plate contact surface using isopropanol and a lint-free wipe. Lower the stencil's positioning frame onto the hashboard so the apertures register cleanly with the chip array, dispense your thermal grease across the surface, and pull in one steady motion with a flat scraper or squeegee. Lift the stencil straight up — do not slide — to leave even gel deposits on every chip. Lower the water-cooling plate straight down onto the chips and clamp at the recommended torque. Re-pressurise the loop, check for leaks, and only then re-energise.

Important Notes — Compatibility, Storage & TIM Choice

This stencil is compatible only with the Antminer S21+ (Plus) Hydro — the chip-pattern and water-plate footprint differ from the air-cooled S21+, the S21 Hydro and the S21 XP Hydro, so do not attempt to use it on those models. For best results, pair the stencil with a high-conductivity thermal grease (≥6 W/m·K is the standard recommendation for dense ASIC hashboards); an 8 W/mK silicone gel is the recommended class for this hashboard density. The stencil is a precision tool: handle without bending, store flat in a dry, dust-free environment, and clean residual gel off after every session to keep aperture geometry sharp.

Antminer S21+ Hydro Thermal Grease Stencil Specifications

Related Antminer S21+ Hydro Parts & Thermal Tools

• BM1370BC ASIC Chip – S21 Pro / S21 XP / S21+ / S21 Hydro
• Antminer S21 Hydro Water Cooling Heatsink Plate
• DOWSIL TC-3080 8W/mK Blue Thermal Gel 1kg – Recommended TIM
• Antminer S21 Hydro Thermal Grease Fixture – Sister Tool

Refurbishing a fleet of S21+ Hydro miners? Contact us at contact@lys-sz.com for stencil sets, positioning-frame spares and bulk thermal-grease pricing. Worldwide shipping from our Shenzhen warehouse.