Guides

Practical answers to buying and setup questions, with links to the relevant choices.

• 15 mm vs 21 mm polisher: throw, pad size and the jobHelps you choose a 15 mm or 21 mm long-throw polisher from plate size, panel shapes and the makers' own specifications.
• 20V MAX vs 18V: what the battery labels meanStops you choosing a cordless polisher or battery on the voltage label, and points you to the platform name instead.
• 5-inch vs 6-inch polisher pads: plate size and throwHelps you choose 5-inch or 6-inch plates and pads to match your polisher's throw and the panels you polish.
• What AUTO BILD's 2021 paint-gauge test shows, and its limitsHelps you use the one well-known independent gauge comparison without over-reading it.
• Bluetooth and app paint gauges: what the app addsHelps you decide whether a Bluetooth gauge is worth it and how far to trust its app's verdicts.
• Buying polishers and gauges on Amazon and AliExpressWalks through the checks to make on a marketplace listing before paying, so you get the genuine model, the right variant and a seller you can trace.
• Can a paint gauge detect body filler?Helps you recognize a likely filled area on a used car and know what the gauge can and cannot prove.
• Can a paint gauge measure clear coat?Stops you using a total-thickness reading as a clear-coat reading before you polish.
• Can a paint gauge measure plastic bumpers or fiberglass?Explains why your gauge shows nothing on a bumper and whether an ultrasonic gauge is worth adding.
• Car polisher safety checklist: eyes, hair, cords and platesGives you a pre-start checklist for any car polisher, built from what the tool makers' manuals require.
• Corded vs cordless polisher: runtime, platforms and powerHelps you decide between a corded and a cordless polisher based on runtime, the battery platform you own and where you polish.
• Cordless polisher battery compatibility by platformTells you which batteries and chargers a cordless polisher can use, so you buy into the right platform or reuse the packs you have.
• Forced-rotation vs free-spinning dual-action polishersHelps you decide whether you want a free-spinning or a forced-rotation dual-action polisher, or a machine that does both.
• Genuine vs aftermarket tool batteries and chargersHelps you avoid counterfeit or third-party batteries and chargers for a cordless polisher, and buy genuine packs from a seller you can check.
• How to calibrate, verify and zero a paint gaugeShows you how to check a paint gauge before trusting its readings, and when a lab calibration is worth paying for.
• How to check a used car's paint with a gaugeGives you a repeatable routine for a pre-purchase paint check and a sober way to read the results.
• How to spot a repainted panel with a paint gaugeShows you how to find panels worth questioning on a used car without over-reading a single number.
• Lithium-ion tool battery safety: charging, damage and shippingGives you the charging, storage, damage and shipping rules for cordless polisher packs from regulators and tool makers.
• Magnetic vs eddy-current paint gauges (Fe vs NFe)Helps you choose between a steel-only gauge and a combination Fe/NFe gauge before you buy.
• Mini polishers for tight areas: 3-inch and smaller systemsHelps you decide whether you need a mini polisher, and which kind, by comparing what the makers actually specify.
• Normal car paint thickness: why there is no single numberStops you judging a car against a single 'normal' paint number that no source supports.
• Pad and backing-plate compatibility: what the makers allowHelps you buy plates and pads that fit your polisher by following the tool maker's own rule instead of a universal one.
• Paint gauge accuracy vs resolution: reading the spec sheetStops you choosing a paint gauge by its display resolution instead of its stated accuracy and conditions.
• Polisher throw explained: 5 mm to 21 mmLets you read a polisher's orbit spec and know which kind of machine and pad size it points to.
• Rotary vs dual-action polisher: how each moves, what goes wrongHelps you choose between a rotary and a dual-action machine based on how each moves and the paint risks the makers describe.
• UL, ETL, CSA and CE on power tools: what each mark meansShows which marks on a polisher, charger or gauge are evidence of North American safety certification, and how to tell a real mark from listing artwork.
• Why a dual-action polisher stops spinning on curvesHelps you tell a normal free-spinning stall from a fault and fix it without pressing harder on the paint.
• Paint gauge readings that mislead: edges, curves, filler and driftHelps you tell a real difference between panels from a measuring error before you act on it.
• Cordless polishers by battery platform: Makita LXT and FLEX 24VMatches a cordless polisher to the battery platform you already own and explains what else you need to buy.
• Dual-action polishers by job: long throw, short throw, cordlessNarrows the choice to three dual-action polishers with a stated power source and explains which job and battery platform each one suits.