Questions and answers

No. Makers say batteries fit within their own platform: Makita says 18V LXT batteries go with LXT tools, and Milwaukee says M18 tools take M18 REDLITHIUM batteries. Even within one brand, RUPES uses different pack systems for its 18 V HLR75 and HLR15/HLR21 polishers. More in Cordless polishers and battery platforms

Not by the label. DEWALT's own footnote says 20V MAX is the maximum initial voltage without a load and the nominal voltage is 18 V. More in Cordless polishers and battery platforms

The battery and charger are not in the box. Makita sells the XOP02Z polisher tool only, and Milwaukee's '-20' polishers are sold the same way. More in Cordless polishers and battery platforms

Milwaukee's manual says to recharge only with the charger the manufacturer specifies, because a charger suitable for one battery type may create a fire risk with another. More in Cordless polishers and battery platforms

We found no maker that approves them. The makers we checked state compatibility only within their own platform, and CPSC recommends that cells, batteries, chargers and products be tested together as a system. More in Cordless polishers and battery platforms

Not by the label. DEWALT says its 20V MAX packs reach 20 volts maximum initial voltage without a load, and that their nominal voltage is 18. More in 20V MAX vs 18V batteries

Not across brands. Milwaukee and Makita each say their batteries work only within their own platforms, whatever the voltage on the label. More in 20V MAX vs 18V batteries

No. Makita says 18V LXT batteries go with LXT tools and 40V max XGT batteries with XGT tools. More in 20V MAX vs 18V batteries

No. Milwaukee says M12 tools take M12 REDLITHIUM packs and M18 tools take M18 REDLITHIUM packs. More in 20V MAX vs 18V batteries

It depends on the tool and pack. RUPES rates its HLR15 and HLR21 for up to 40 minutes at full power on an 18 V 5 Ah pack, and its HLR75 mini for about 35-45 minutes on its 2.5 Ah pack. These are maker figures. More in Corded vs cordless polisher

Some can. RUPES's iBrid HLR15 and HLR21 run cordless or corded, and the HLR75 runs continuously with RUPES's iBrid Power Adapter. More in Corded vs cordless polisher

No. Milwaukee's '-20' polishers are bare tools, and Makita sells the XOP02Z tool only. Battery and charger are separate. More in Corded vs cordless polisher

Yes, if both are on the same platform from the same maker. Makita says its batteries work only within each platform, and Milwaukee's polishers take M18 REDLITHIUM packs. More in Corded vs cordless polisher

In a damp location, yes: Milwaukee's general power-tool safety section says to use a GFCI-protected supply there. More in Corded vs cordless polisher

Yes, if it is a Makita 18V LXT battery. Makita says LXT batteries work with LXT tools, and the XOP02Z is an 18V LXT tool. More in Cordless polisher battery compatibility

No. Milwaukee says its batteries are interchangeable within a system but not across systems: M12 tools take M12 packs and M18 tools take M18 packs. More in Cordless polisher battery compatibility

No maker in our research approves one. Makita, for example, says its batteries are compatible only within each platform. Stay with the tool maker's own packs and charger. More in Cordless polisher battery compatibility

Do not assume so. RUPES lists an 18 V 2.5 Ah pack with a custom charger for the HLR75 and an 18 V 5 Ah pack for the HLR15 and HLR21. More in Cordless polisher battery compatibility

No. Makita says its 18V Rapid Optimum Charger cannot charge its 7.2V, 12V max or 36V lithium-ion batteries, which need different chargers. More in Cordless polisher battery compatibility

The tool makers say to avoid them. Makita warns that non-genuine batteries may burst and cause fires, injury or property damage, and DEWALT advises using only authentic DEWALT batteries. More in Genuine vs aftermarket tool batteries

Makita says using non-genuine batteries voids the Makita warranty for the tool and charger, and the tool's UL/CSA approval. More in Genuine vs aftermarket tool batteries

Makita says genuine batteries are black, with the Makita logo and lithium-ion identification on both sides and the Makita logo on the bottom. Counterfeits can copy that, so buy from a seller you can check and ask a Makita service center if in doubt. More in Genuine vs aftermarket tool batteries

Use the charger the tool maker specifies. Milwaukee warns that a charger suitable for one battery type may create a fire risk with another, and CPSC has warned about 'universal' chargers able to ignite incompatible lithium batteries. More in Genuine vs aftermarket tool batteries

No maker in our research approves one. Makita, for example, says its batteries are compatible only within each platform. More in Genuine vs aftermarket tool batteries

Health Canada advises charging lithium-ion devices where you can see them, away from soft surfaces, and not overcharging. Charging while you are present and awake follows that advice. More in Lithium-ion tool battery safety

Treat it as unsafe. Health Canada says not to use batteries that are swollen, dented or damaged, and Milwaukee warns a damaged pack may cause fire, explosion or injury. More in Lithium-ion tool battery safety

Milwaukee warns that exposure to fire or temperatures above 130°C (265°F) may cause explosion, and DEWALT advises storing and charging packs in a cool, dry place. More in Lithium-ion tool battery safety

Only as declared dangerous goods. Transport Canada says lithium batteries, including those packed with or inside power tools, are dangerous goods that must be declared to the carrier. Ask the carrier first. More in Lithium-ion tool battery safety

No. DEWALT advises against attempting battery repair or service, and Milwaukee warns that modified packs may behave unpredictably. More in Lithium-ion tool battery safety

Yes, if it is a Makita 18V LXT battery. Makita says LXT batteries work with LXT tools. More in Cordless polishers by battery platform

We found no FLEX statement that they do. FLEX lists the FX3321 as compatible with all FLEX 24V batteries, chargers and tools, so use FLEX 24V packs and a FLEX charger. More in Cordless polishers by battery platform

Milwaukee's where-to-buy panel listed retailers but not Amazon, and we have not found a listing for the 2684-20 or 2685-20 that meets our seller bar. Both take all M18 REDLITHIUM batteries. More in Cordless polishers by battery platform

Not necessarily. AliExpress's membership terms say it cannot and does not confirm each member's claimed identity. A link from the brand's own website to the store is better evidence than its name. More in Buying detailing tools safely

No. A Brand Store shows the brand enrolled in Amazon Brand Registry; it does not tell you who sells a given offer. Check 'Ships from' and 'Sold by' on the offer you buy. More in Buying detailing tools safely

Health Canada tells consumers to look for marks such as CSA, cUL or cETL on plug-in products; CE is not one of the marks it names. In the US, UL and ETL marks come from labs OSHA recognizes. More in Buying detailing tools safely

Milwaukee's where-to-buy panel for the 2684-20 lists US retailers but not Amazon or AliExpress. Makita USA links its Amazon Brand Store among other resellers. RUPES points to its dealer locator and its own online shop. More in Buying detailing tools safely

AliExpress's terms say it does not control, and is not responsible for, the quality or safety of products on its site. Look for safety evidence from the maker or a certifier, not the marketplace. More in Buying detailing tools safely

Read the 'Ships from' and 'Sold by' lines on the offer you are buying. Canada's Office of Consumer Affairs gives the same advice: check whether you are buying from the retailer or a third-party seller. More in Buying polishers and gauges on Amazon and AliExpress: what to check

Makita USA's Shop Online page links its Amazon Brand Store. That does not make every offer Makita's: a Brand Store shows brand enrollment, not who sells a given offer, so still check 'Sold by'. More in Buying polishers and gauges on Amazon and AliExpress: what to check

We could not confirm it. UNI-T's global where-to-buy page names a Singapore distributor and links no AliExpress or Amazon store, and AliExpress says it does not confirm each member's claimed identity. More in Buying polishers and gauges on Amazon and AliExpress: what to check

Only under the listing's terms. AliExpress's Free Return program covers participating products within 15 calendar days of receipt, subject to its conditions, so check for the Free Return label before ordering. More in Buying polishers and gauges on Amazon and AliExpress: what to check

Amazon.com says most items can be returned within 30 days of delivery, with exceptions, and third-party sellers may handle returns themselves. Check the offer's own return terms. More in Buying polishers and gauges on Amazon and AliExpress: what to check

Intertek, which runs ETL and is an OSHA-recognized NRTL, says ETL-marked products meet the same requirements as products bearing other NRTL marks. UL LLC is on the same OSHA program. More in UL, ETL, CSA and CE on power tools

OSHA's recognition of UL LLC lists UL 62841-1 for hand-held electric tools, with particular parts such as UL 62841-2-3 for disc-type polishers and sanders and UL 62841-2-4 for sanders and polishers other than disc type. That shows the standard a polisher would be certified to, not that any given product is. More in UL, ETL, CSA and CE on power tools

Health Canada says plug-in electrical products must be certified by an accredited certification body and tells consumers to look for marks such as CSA, cUL or cETL. CE is not one of the marks it names. More in UL, ETL, CSA and CE on power tools

On the product itself. Health Canada says certification marks must appear on the product, not just the packaging, so a logo in listing photos is not enough. More in UL, ETL, CSA and CE on power tools

Yes. UL Solutions tests power-tool batteries and chargers to standards including UL 2595, UL/IEC 62841-1, IEC/UL 60335-2-29 for chargers and UN 38.3 for shipping. More in UL, ETL, CSA and CE on power tools

It depends on the maker. RUPES pairs its 125 mm LHR15ES plate with foam pads of 130-150 mm, so the pad overhangs on purpose, while Milwaukee's manual says the plate diameter should match the pad diameter on its polishers. More in Polishing pads and backing plates: sizes and fit

Some makers allow it. Milwaukee lists 5-inch as the recommended pad diameter for its 15 mm 2684-20 and 6-inch as optional, and the reverse for its 21 mm 2685-20. Fit a plate that matches the pad when you change size. More in Polishing pads and backing plates: sizes and fit

Often not. Milwaukee's manual shows a backing plate as part of the 2684-20 and 2685-20 and states the polishing pad is not included. Check the box contents of your own tool. More in Polishing pads and backing plates: sizes and fit

Colors are not a standard across brands, and we found no maker source we could verify for pad cut levels. Use the pad maker's own description for its product line. More in Polishing pads and backing plates: sizes and fit

Do not assume so. Milwaukee's manual says to use only accessories specifically recommended for the 2684-20 and 2685-20, as others may be hazardous. More in Polishing pads and backing plates: sizes and fit

On some machines. Milwaukee lists 6-inch as optional for its 15 mm 2684-20, with 5-inch recommended, and says the plate should match the pad diameter. More in 5-inch vs 6-inch polisher pads

Pads are often named for the plate they fit. RUPES pairs its 125 mm plate with 130-150 mm foam pads, a deliberate overhang. Check your tool maker's rule before mixing brands. More in 5-inch vs 6-inch polisher pads

It covers more area per pass on a flat panel, but it reaches curves and recesses less easily. We found no independent measurement of correction speed by pad size. More in 5-inch vs 6-inch polisher pads

Milwaukee lists 6-inch as the recommended pad diameter for its 21 mm 2685-20, with 5-inch optional. More in 5-inch vs 6-inch polisher pads

It depends on the maker. Milwaukee says the plate diameter should match the pad diameter, while RUPES pairs its 125 mm plate with 130-150 mm foam pads on purpose. Follow your tool's manual. More in Pad and backing-plate compatibility

Only if the maker lists it for both. FLEX, for example, sells separate rotary plates (FT331, FT332) and orbital plates (FT333, FT334) for its 120 V machines. More in Pad and backing-plate compatibility

Milwaukee's manual shows a backing plate as part of the tool and says the polishing pad is not included. Its product pages do not say in text which plate size ships, so check the box. More in Pad and backing-plate compatibility

Milwaukee says to use only accessories specifically recommended for its polishers, because others may be hazardous. Treat a plate that does not name your tool as unverified. More in Pad and backing-plate compatibility

Makita gives no cut rating. It describes the T-02680 as semi firm and ideal for polishing, for 5-inch polishers with hook-and-loop backing pads, so we do not assign it a cut level. More in Pad and backing-plate compatibility

Not with magnetic or eddy-current probes alone. DeFelsko says paint over steel is measured with magnetic gauges, paint over aluminum with eddy-current gauges, and paint over plastic and fiberglass with ultrasonic gauges. More in Paint thickness gauges: what each type can measure

UNI-T explains that FE means magnetic substrates such as iron and steel, and NFE means non-magnetic metals such as aluminum and copper. A combination (Fe/NFe) gauge covers both. More in Paint thickness gauges: what each type can measure

No. Resolution is the display step, accuracy is the error band. UNI-T lists the UT343E's resolution as 0.1 µm below 100 µm but its accuracy as ±(2%H + 2 µm). More in Paint thickness gauges: what each type can measure

You need one that reads both steel and aluminum and that you check before use. Automotive meters such as DeFelsko's PosiTest DFT Combo and the Elcometer 311 FNF are made for this, and the makers publish their ranges and accuracy. More in Paint thickness gauges: what each type can measure

ASTM D7091 covers magnetic and eddy-current gauges for dry film thickness and describes calibration, verification and adjustment as three steps for accurate measurement. It is an industrial practice that supplements the gauge maker's instructions. More in Paint thickness gauges: what each type can measure

No. The page dates its prices to 20 May 2021, so it is a 2021 test of gauges sold in Germany at the time, even though the page is still online. More in AUTO BILD's 2021 paint-gauge test

It shows that one NexPTG Professional sample deviated by up to 118% from AUTO BILD's reference device in 2021. That is one unit of one model, not every NexPTG gauge or current models. More in AUTO BILD's 2021 paint-gauge test

AUTO BILD found implausible values from three specific budget models, including one reading above 2000 µm on a gauge rated to 1000 µm. That is a warning to verify any gauge, not a rule for all budget gauges. More in AUTO BILD's 2021 paint-gauge test

The Q-Nix 5500, because it was the most precise of the group on plastic control foils from 48 to 1006 µm. It was not an accredited laboratory master. More in AUTO BILD's 2021 paint-gauge test

It gives factory finishes as usually 80-150 µm and manual repaints as typically above 200 µm, but calls these only rough guidance and notes that factories sometimes repaint. It is not a threshold. More in AUTO BILD's 2021 paint-gauge test

No. The app shows what the probe measured, and accuracy stays what the maker states for the gauge, for example ±(2%H + 2 µm) for UNI-T's UT343E. More in Bluetooth and app paint gauges

Some apps color-code panels; NexDiag's NexPTG app labels them factory, repaired or repainted with its SAPL system. That is the maker's interpretation of a thickness number, not proof of a repair. More in Bluetooth and app paint gauges

No. NexDiag says PDF reports are not supported on its NexPTG Standard and Standard Plus gauges. More in Bluetooth and app paint gauges

UNI-T's product page lists only CE and UKCA certificates and no FCC or ISED marks. That does not prove there is none, so check the label on the unit itself. More in Bluetooth and app paint gauges

DeFelsko gives 35-50 µm (1.5-2.0 mils) as typical. That is a gauge maker's rough figure, not a carmaker specification, and we have no OEM figure in our sources. More in Can a paint gauge measure clear coat?

DeFelsko states that most auto manufacturers recommend removing at most about 8 µm (0.3 mil), but it names no carmaker document. Follow your own car maker's refinishing guidance if it publishes one. More in Can a paint gauge measure clear coat?

No. A magnetic or eddy-current gauge shows the total from probe to metal, including primer, color, clear, any repaint, filler and dirt, with no distinction between layers. More in Can a paint gauge measure clear coat?

Not precisely. UNI-T's stated accuracy for the UT343E is ±4 µm at 100 µm, half of DeFelsko's 8 µm removal figure, before you add the error from not hitting the exact same spot twice. More in Can a paint gauge measure clear coat?

DeFelsko notes that recent cars can have plastic bumpers, and magnetic or eddy-current gauges need metal under the paint. UNI-T says the measured object must be metal with a non-conductive coating. More in Can a paint gauge measure plastic bumpers?

An ultrasonic gauge. DeFelsko says paint over plastic and fiberglass is measured ultrasonically, for example with its PosiTector 200, which needs a couplant gel. More in Can a paint gauge measure plastic bumpers?

Not on the evidence we have. DeFelsko says its affordable ultrasonic models are intended only for non-metal substrates and are not a do-all instrument, so metal panels still need an Fe/NFe gauge. More in Can a paint gauge measure plastic bumpers?

It varies by vehicle. DeFelsko notes recent cars can have plastic bumpers and mirrors alongside steel and aluminum panels, so check each part before measuring. More in Can a paint gauge measure plastic bumpers?

No. DeFelsko defines zeroing on an uncoated sample as the simplest form of adjustment; calibration is a documented lab process against traceable standards. More in How to calibrate, verify and zero a paint gauge

DeFelsko puts no interval on its certificates and says users should set their own, with one year as a typical starting point. Check it yourself on shims before each use. More in How to calibrate, verify and zero a paint gauge

Not by itself. DeFelsko says a plastic shim is less accurate than a coating thickness standard, so its tolerance adds to the gauge's tolerance. More in How to calibrate, verify and zero a paint gauge

DeFelsko says that if readings disagree with the reference, all measurements since the last check are suspect. Re-zero, re-check and measure again; if it still disagrees, contact the maker. More in How to calibrate, verify and zero a paint gauge

DeFelsko says cheaper instruments drift and should be checked before use each day, with a zero check on bare metal and the included shims. More in How to calibrate, verify and zero a paint gauge

Not as the makers set them up. UNI-T and DeFelsko assign steel to the Fe (magnetic) mode and aluminum to the NFe (eddy-current) mode, so use Fe mode on steel panels. More in Magnetic vs eddy-current paint gauges

Usually. DeFelsko notes recent cars can have aluminum hoods and roofs alongside steel doors, and AUTO BILD notes tin-filled repairs on steel can only be found with a gauge that also has NFe capability. More in Magnetic vs eddy-current paint gauges

Hall effect is one way of sensing the magnetic field, so it is still a magnetic method for steel. Linshang, for example, uses Hall effect for its LS221's ferrous mode and eddy current for its non-ferrous mode. More in Magnetic vs eddy-current paint gauges

No. DeFelsko says paint over plastic and fiberglass needs an ultrasonic gauge. See plastic bumpers and fiberglass. More in Magnetic vs eddy-current paint gauges

Some do. Elcometer says its 311 FNF switches automatically between steel and aluminum, and UNI-T lists automatic or manual substrate identification on the UT343E. More in Magnetic vs eddy-current paint gauges

No. UNI-T lists the UT343E's resolution as 0.1 µm below 100 µm but its accuracy as ±(2%H + 2 µm), which is ±4 µm at 100 µm. More in Paint gauge accuracy vs resolution

H is the reading. The allowed error is 2% of the reading plus a fixed 2 µm, so at 100 µm it is 2 + 2 = 4 µm either way. More in Paint gauge accuracy vs resolution

Elcometer states ±5% or ±20 µm, whichever is greater, with 10 µm resolution, and says the figure needs at least 800 µm of steel or 300 µm of aluminum under the paint. It is an automotive paint meter, not a laboratory gauge. More in Paint gauge accuracy vs resolution

AUTO BILD compared ten gauges in 2021 on German-market models; one NexPTG Professional sample deviated by up to 118% from its reference device. It is one sample in one older test, so verify your own gauge on shims or standards. More in Paint gauge accuracy vs resolution

Multiply by 25.4. One mil is a thousandth of an inch, 25.4 µm, so 5 mils is 127 µm. More in Paint gauge accuracy vs resolution

An eddy-current gauge, or a combination gauge in NFe mode. DeFelsko says paint over aluminum and other non-ferrous metals is measured with eddy-current gauges. More in Paint gauge surface finder

So you know a blank reading there is expected. DeFelsko says plastic and fiberglass need an ultrasonic gauge, such as its PosiTector 200, used with a couplant gel. More in Paint gauge surface finder

Check the car's documentation or a body shop. DeFelsko notes that recent vehicles can combine steel doors and fenders, aluminum hoods and roofs, and plastic bumpers and mirrors, so do not assume one material for the whole car. More in Paint gauge surface finder

We show a value only when a maker, certifier or named independent source states it. When none does, the field says so instead of guessing. More in Paint gauge surface finder

Not on its own. Published ranges differ: DeFelsko calls 100-180 µm typical factory paint, PPG's Australia and New Zealand refinish guidance gives about 90-120 µm, and AUTO BILD calls its own figures rough guidance and warns that factories sometimes repaint. More in Used-car paint inspection with a gauge

Bumpers are often plastic, and magnetic or eddy-current gauges cannot read paint over plastic. DeFelsko says plastic and fiberglass need an ultrasonic gauge. More in Used-car paint inspection with a gauge

Compare like with like. DeFelsko looks for consistent thickness around the car and differences between adjacent panels, and AUTO BILD compares the same spot on both sides of the car. More in Used-car paint inspection with a gauge

It helps. AUTO BILD notes that tin-filled repairs on a steel body can only be found with a gauge that also has NFe (eddy-current) capability. More in Used-car paint inspection with a gauge

No. A gauge shows how thick the coating is, not why. Treat an unusual reading as a reason to ask questions or book a professional inspection. More in Used-car paint inspection with a gauge

As much thicker coating than the paint around it. In one DeFelsko case study a panel read 270 µm and then 930 µm against 105-115 µm elsewhere, and it turned out to be plastic filler over a rust repair. More in Can a paint gauge detect body filler?

DeFelsko says no reading may mean the thickness exceeds the gauge's limit, which could mean filler. Check the mode, the edge distance and that the part is metal first. More in Can a paint gauge detect body filler?

DeFelsko warns that some magnetic instruments can be fooled when steel particles are added to body filler, even on steel. More in Can a paint gauge detect body filler?

No, according to AUTO BILD: tin-filled repairs on a steel body can only be found with a gauge that also has NFe (eddy-current) capability. More in Can a paint gauge detect body filler?

Several points per panel on clean, flat areas, staying about one inch from edges and seams as DeFelsko advises, and the same spots on both sides of the car. More in How to check a used car's paint with a gauge

Not by itself. A gauge shows thickness, not the cause, and AUTO BILD notes factories sometimes repaint. Treat a difference as a reason to look closer and ask. More in How to check a used car's paint with a gauge

On a bumper or mirror the part may be plastic, which Fe/NFe gauges cannot read. On metal, DeFelsko says no reading may mean the coating is beyond the gauge's limit, which could mean filler. More in How to check a used car's paint with a gauge

It helps. AUTO BILD notes tin-filled repairs on a steel body can only be found with a gauge that also has NFe capability, and many cars mix steel and aluminum panels. More in How to check a used car's paint with a gauge

Yes. DeFelsko says cheaper instruments drift and should be checked before use each day: a zero check on bare metal, then the included shims. More in How to check a used car's paint with a gauge

With a paint gauge, look for a panel that reads clearly differently from its neighbors and from the mirrored spot on the other side. DeFelsko and AUTO BILD both use these comparisons; a difference is a strong lead, not proof. More in How to spot a repainted panel

No source we use gives a reliable number. AUTO BILD says manual repaints are typically above 200 µm but calls that rough guidance, and notes factories sometimes repaint. More in How to spot a repainted panel

Yes. DeFelsko reports about 430 µm on some SUV rocker panels and notes some vehicles are repainted at the factory. More in How to spot a repainted panel

Treat it as a flag. NexDiag's NexPTG app color-codes panels with its SAPL system, which is the maker's interpretation of thickness readings, not proof of a repair. More in How to spot a repainted panel

No source we use sets that threshold. AUTO BILD says manual repaints are typically above 200 µm but calls its figures only rough guidance, and DeFelsko reports about 430 µm of factory paint on some SUV rocker panels. More in Normal car paint thickness

Only that the coating on that spot is thicker than DeFelsko's typical factory range. PPG's 300 µm figure is advice to remove or sand back refinish films that thick, not a test for repaint. More in Normal car paint thickness

No source we use gives a meaning for a specific number. In one DeFelsko case study a panel read 930 µm and turned out to be plastic filler over a rust repair, but that was one vehicle. More in Normal car paint thickness

Yes. DeFelsko gives examples from about 75 µm on some roofs to about 430 µm on some SUV rocker panels, and notes some vehicles are repainted at the factory. More in Normal car paint thickness

Divide microns by 25.4. DeFelsko's typical 100-180 µm is about 3.9-7.1 mils. More in Normal car paint thickness

Readings near edges are less reliable. DeFelsko advises measuring near seams about one inch from the edges, and the same distance on every panel. More in Paint gauge readings that mislead

Small changes in position, probe angle, dirt and curvature all move the number. Clean the spot, hold the probe flat and steady, and take several readings; if they still wander, check the gauge on a shim. More in Paint gauge readings that mislead

DeFelsko lists ambient and surface temperature among the things that may require a gauge to be adjusted. Check zero and a shim when conditions change. More in Paint gauge readings that mislead

Treat it as a fault. AUTO BILD found one budget gauge reading above 2000 µm though rated only to 1000 µm in its 2021 test; re-check on shims and do not record the number. More in Paint gauge readings that mislead

Yes. Milwaukee's manual for its dual-action polishers warns that too much pressure, the wrong angle or improper motion may cause swirl marks or burning. A dual-action machine is more forgiving, not foolproof. More in Car polishers: dual-action, forced-rotation and rotary

On a free-spinning random orbital machine the plate is free to rotate. RUPES explains that if friction stops the rotation, the motion simply becomes orbital, which is how the design works rather than a fault. More in Car polishers: dual-action, forced-rotation and rotary

Not automatically. RUPES says its 15 mm LHR15ES runs at a higher rpm than its 21 mm machine, which it says gives equivalent cutting power. Milwaukee pairs its 15 mm machine with a 5-inch pad and its 21 mm machine with a 6-inch pad. More in Car polishers: dual-action, forced-rotation and rotary

Auto Care HQ says rotaries build heat and friction faster and are mostly used by experienced users, while dual-action machines are considered safer for beginners. Even so, any polisher can damage paint if misused. More in Car polishers: dual-action, forced-rotation and rotary

Milwaukee's polisher manual calls for eye protection marked to ANSI Z87.1 and warns that loose clothing, jewelry or long hair can be caught in the machine. More in Car polishers: dual-action, forced-rotation and rotary

Not necessarily. RUPES says its 15 mm LHR15ES runs at a higher rpm than its 21 mm machine, which it says gives equivalent cutting power. That is RUPES's claim; we found no independent test either way. More in 15 mm vs 21 mm polisher

Some makers allow it as an option. Milwaukee lists 5-inch as recommended and 6-inch as optional for its 15 mm 2684-20, and says the backing plate should match the pad diameter. More in 15 mm vs 21 mm polisher

A 15 mm machine with a 5-inch plate covers more of a car, including curves and tight spaces, according to RUPES retailer ESOTERIC Car Care. A 21 mm machine suits large flat panels. More in 15 mm vs 21 mm polisher

Milwaukee lists 2,400-4,500 rpm for the 21 mm 2685-20 and 2,650-5,100 rpm for the 15 mm 2684-20. Milwaukee does not explain the difference in the pages we read; a longer orbit already moves the pad farther on each orbit. More in 15 mm vs 21 mm polisher

It is one model name covering several machines. SPTA, for example, lists its CP501 in all four throws. Check which throw your variant is, and confirm the supply voltage, which SPTA's page does not state. More in 15 mm vs 21 mm polisher

Milwaukee's polisher manual calls for eye protection marked to ANSI Z87.1. Look for that marking on the frame or lens. More in Car polisher safety checklist

If you must use a power tool in a damp location, Milwaukee's general safety section says to use a GFCI-protected supply. A garage that is still wet from washing counts. More in Car polisher safety checklist

Use only accessories the maker recommends for the tool. Milwaukee's manual warns that other accessories may be hazardous. More in Car polisher safety checklist

Yes. Milwaukee's manual warns that too much pressure, the wrong angle or improper motion may cause swirl marks or burning. More in Car polisher safety checklist

No. Milwaukee says to recharge only with the charger the maker specifies, because a charger suitable for one battery type may create a fire risk with another. More in Car polisher safety checklist

No. RUPES describes a gear-driven polisher as having the plate both orbit and be forced to rotate. A rotary only spins on one axis, with no orbit. More in Forced rotation vs free-spinning DA polishers

On a free-spinning machine the plate is free to rotate, and RUPES explains that if friction stops it, the motion becomes orbital only. Less pressure, a flatter pad angle or a higher speed setting usually brings rotation back. More in Forced rotation vs free-spinning DA polishers

RUPES says so: it describes gear-driven motion as more aggressive than random orbital motion and says it generally vibrates more. We found no independent measurement of how much more. More in Forced rotation vs free-spinning DA polishers

Yes. Makita describes the XOP02Z as having selectable random orbit with forced rotation or free-spin rotation, with a 7/32-inch orbit. More in Forced rotation vs free-spinning DA polishers

No. Makita sells the XOP02Z as tool only, without a battery or charger, and says LXT batteries work only with LXT tools. More in Forced rotation vs free-spinning DA polishers

RUPES's HLR75 uses a 75 mm (3-inch) backing plate. FLEX's PXE 80 set includes 30 mm and 75 mm backing pads. More in Mini polishers for tight areas

RUPES says its 18 V 2.5 Ah pack runs the HLR75 for about 35-45 minutes, and that the dedicated charger fills it in about 35 minutes. The iBrid Power Adapter lets it run continuously. More in Mini polishers for tight areas

Do not assume so. Both are 18 V, but RUPES lists a 2.5 Ah pack for the HLR75 and a 5 Ah pack for the HLR15 and HLR21, and says the HLR75 charger is custom designed for its pack. More in Mini polishers for tight areas

FLEX's US kit 493503 includes a rotary adapter, random orbital adapters with 3 mm and 12 mm stroke, 30 mm and 75 mm backing pads, two 12 V 2.5 Ah batteries and a FLEX charger. More in Mini polishers for tight areas

The center of the pad travels in a circle 15 mm across as the plate orbits. RUPES's LHR15ES, for example, has a 15 mm orbit with a 125 mm (5-inch) plate. More in Polisher throw explained

About 5.6 mm. Makita uses 7/32 inch for the XOP02Z's orbit diameter, which makes it a short-throw machine. More in Polisher throw explained

No. A rotary spins the pad on a single axis with no orbit, so it has no throw figure. More in Polisher throw explained

No. RUPES says its 15 mm machine matches its 21 mm machine's cutting power by running faster, and describes its 5 mm gear-driven machines as more aggressive than random orbital motion. Both are maker statements. More in Polisher throw explained

Yes. Milwaukee's manual for its DA polishers warns that too much pressure, the wrong angle or improper motion may cause swirl marks or burning. A DA lowers the risk compared with a rotary; it does not remove it. More in Rotary vs dual-action polisher

Not better, different. Auto Care HQ describes a rotary as building heat and friction faster and as mostly used by experienced users, while DA machines are considered safer for beginners. More in Rotary vs dual-action polisher

On a free-spinning DA the plate is free to rotate, and RUPES explains that if friction stops the rotation the motion simply becomes orbital. That is by design, not a fault. See why a DA stops spinning. More in Rotary vs dual-action polisher

No. RUPES describes its gear-driven machines as having the plate both orbit and be forced to rotate through gearing. It still has an orbit, which a rotary does not. More in Rotary vs dual-action polisher

Most beginners start with a dual-action machine, often a long-throw free-spinning one. Start on a test spot, keep the pad flat and moving, and follow the maker's pressure and speed guidance. More in Rotary vs dual-action polisher

Usually not. RUPES explains that on a random orbital polisher, if friction stops rotation, the motion simply becomes orbital. If the plate also stops orbiting, or the motor labors or smells, stop and contact the maker. More in Why a DA polisher stops spinning

No. More pressure adds friction, which is what stops rotation, and Milwaukee's manual names too much pressure as a cause of swirl marks or burning. More in Why a DA polisher stops spinning

Its rotation is driven through gearing, so the pad keeps turning. RUPES says that makes it more aggressive and generally more vibrating than random orbital motion. More in Why a DA polisher stops spinning

A smaller pad sits flatter on a curve, so contact is more even. Milwaukee also says the backing plate should match the pad diameter and the pad should be centered for balance. More in Why a DA polisher stops spinning

The FLEX FC3321-Z: a corded 15 mm free-spinning machine. Free-spinning rotation backs off when friction rises, which RUPES describes as how random orbital motion works. More in Dual-action polishers by job

No. Both the Makita XOP02Z and the FLEX FX3321-Z variants we list are tool only. Buy the maker's own packs and charger. More in Dual-action polishers by job

None we checked met our bar for a maker-stated power source and a seller we could accept. The 15 mm vs 21 mm and mini polisher guides explain what to look for. More in Dual-action polishers by job

RUPES explains that a free-spinning random orbital plate orbits and is free to rotate, while its gear-driven polishers force the plate to rotate as well, which it says is more aggressive and generally vibrates more. More in Polisher type finder

Some can. Makita's XOP02Z has a selectable random orbit with forced rotation or free-spin rotation. More in Polisher type finder

Milwaukee pairs its 15 mm 2684-20 with a 5-inch pad and its 21 mm 2685-20 with a 6-inch pad. Other makers use other pairings, so check your tool's own specification. More in Polisher type finder

No. Milwaukee's manual for its dual-action polishers warns that too much pressure, the wrong angle or improper motion may cause swirl marks or burning. More in Polisher type finder

You need a gauge with an NFe (eddy-current) mode. DeFelsko says paint over steel is measured magnetically and paint over aluminum with eddy current; a combination Fe/NFe gauge does both. More in Metal body panels (steel and aluminum)

It measures everything between the probe and the metal. DeFelsko says that includes primer, base color, clear coat, any repaint, filler and dirt, with no distinction between layers. More in Metal body panels (steel and aluminum)

Some can. UNI-T specifies automatic or manual substrate identification on its UT343E, and Elcometer says its 311 FNF switches automatically between steel and aluminum. Check that the mode shown matches the panel. More in Metal body panels (steel and aluminum)

Most bumpers are plastic, and magnetic or eddy-current gauges need metal under the paint. UNI-T says the measured object must be metal with a non-conductive coating, and DeFelsko measures paint on plastic with ultrasonic gauges instead. More in Non-metal panels (plastic and fiberglass)

An ultrasonic gauge, used with a couplant gel. DeFelsko's example is its PosiTector 200; the B3 model can report total thickness and up to three individual layers. More in Non-metal panels (plastic and fiberglass)

It reads paint on steel panels, but AUTO BILD notes that tin-filled repairs on a steel body show up only on a gauge with NFe capability, and DeFelsko notes that many recent cars also have aluminum hoods and roofs. A combination Fe/NFe gauge covers both. More in Steel body panels

Sometimes. DeFelsko warns that some magnetic instruments can be fooled when steel particles are added to body filler. It also says a gauge giving no reading may be beyond its limit, which could mean filler. More in Steel body panels

DeFelsko suggests a zero check on an uncoated part, then a reading on the included plastic shims laid on the bare surface. It says separately sold coating thickness standards are more accurate than shims. More in Steel body panels

No. DeFelsko says paint over aluminum and other non-ferrous metals is measured with eddy-current gauges, and UNI-T's FE mode is for magnetic substrates such as iron and steel. You need NFe capability. More in Aluminum body panels

DeFelsko notes that recent vehicles can combine steel doors and fenders with aluminum hoods and roofs. Materials vary by car, so a combination gauge that identifies the substrate, or lets you switch to NFe, is the practical answer. More in Aluminum body panels

Magnetic and eddy-current gauges need metal under the coating. UNI-T says the measured object must be metal with a non-conductive coating, and a bumper is usually plastic. More in Plastic bumpers and mirrors

Not with a Fe/NFe gauge. DeFelsko measures paint over plastic with ultrasonic gauges; its PosiTector 200 B3 can report total thickness and up to three layers, and needs couplant gel. More in Plastic bumpers and mirrors

A Fe/NFe gauge cannot see through plastic to anything, so it cannot confirm or rule out a bumper repaint. DeFelsko notes that recent vehicles combine steel, aluminum and plastic parts, so plan which panels your gauge can actually read. More in Plastic bumpers and mirrors

Only an ultrasonic one. DeFelsko says paint over plastic and fiberglass is measured with ultrasonic gauges such as its PosiTector 200, using a couplant gel. More in Fiberglass panels

DeFelsko gives typical clear coat as 35-50 µm (1.5-2.0 mils). That is DeFelsko's rough figure, not an automaker specification, and it will vary by vehicle. More in Clear coat

DeFelsko states that most auto manufacturers recommend removing at most about 8 µm (0.3 mil), but it does not name an automaker document. No source we checked gives a model-specific limit. More in Clear coat

Not a magnetic or eddy-current one. DeFelsko says those gauges measure the full distance to the metal with no distinction between layers. Its PosiTector 200 B3 ultrasonic gauge reports layers, but only on non-metal substrates. More in Clear coat

There is no single number. DeFelsko gives 100-180 µm as typical factory paint, PPG Refinish (Australia/New Zealand) about 90-120 µm, and AUTO BILD's 2021 test 80-150 µm as rough guidance. More in Factory (OEM) paint

Not by itself. AUTO BILD calls its above-200 µm repaint figure rough guidance and warns that factories sometimes repaint, and DeFelsko says there is no absolute right thickness. Compare panels on the same car. More in Factory (OEM) paint

They come from different sources, markets and paint eras: a gauge maker's typical range, a regional refinish guide and a 2021 German magazine test. DeFelsko also shows wide variation within one vehicle. More in Factory (OEM) paint

Measure consistently around the car and compare adjacent panels and mirrored spots. DeFelsko says a significant difference between adjacent panels strongly indicates repainting; AUTO BILD gives the same mirrored-spot advice. More in Refinished (repainted) panels

No. A gauge shows thickness, not the cause. AUTO BILD and DeFelsko both note that some vehicles are repainted at the factory, and AUTO BILD calls its repaint figures rough guidance. More in Refinished (repainted) panels

No. NexDiag's NexPTG app color-codes panels with its SAPL system, which is the maker's interpretation of the readings, not independent proof. More in Refinished (repainted) panels

It can show unusually thick readings, as in DeFelsko's case study where a filled panel read 270 µm and then 930 µm against 105-115 µm elsewhere. The gauge shows thickness, not the cause, and steel particles in filler can fool some magnetic gauges. More in Body filler repairs

On a metal panel, DeFelsko says no reading may mean the thickness is beyond the gauge's limit, which could mean filler. On a plastic part it is expected, because Fe/NFe gauges need metal underneath. More in Body filler repairs

AUTO BILD says tin-filled repairs on a steel body can only be found with a gauge that also has NFe (eddy-current) capability. A steel-only Fe gauge will not find them. More in Tin-filled repairs

If you want to look for tin-filled repairs, yes, per AUTO BILD. A combination gauge also covers aluminum panels, which DeFelsko notes are common on hoods and roofs of recent cars. More in Tin-filled repairs

On a free-spinning machine the plate is free to rotate, and RUPES says that if friction stops the rotation the motion simply becomes orbital. Curves, pressure and pad contact all add friction. More in Free-spinning dual-action (random orbital) polishers

Yes. Milwaukee's polisher manual warns that too much pressure, the wrong angle or improper motion may cause swirl marks or burning. More in Free-spinning dual-action (random orbital) polishers

A free-spinning random orbital is one kind of dual-action polisher. A forced-rotation (gear-driven) dual-action machine also orbits but is geared to rotate, which RUPES describes as more aggressive. More in Free-spinning dual-action (random orbital) polishers

RUPES says a random orbital plate orbits and rotates freely, so rotation can stop under friction, while a gear-driven plate orbits and is forced to rotate. RUPES calls the gear-driven motion more aggressive. More in Forced-rotation (gear-driven) dual-action polishers

Auto Care HQ explains that on a forced-rotation polisher rotation and orbit are tied together, while a random orbital's rotation varies with pressure and angle and can stall. More in Forced-rotation (gear-driven) dual-action polishers

No. Makita lists a 7/32-inch orbit, about 5.6 mm, which is a short throw, not a 15 or 21 mm long throw. It switches between forced rotation and free spin. More in Forced-rotation (gear-driven) dual-action polishers

Auto Care HQ says rotaries are mostly used by experienced users, because single-axis rotation builds heat and friction faster, while dual-action machines are considered safer for beginners. More in Rotary polishers

No. It spins on a single axis, so there is no orbit. Throw figures apply to dual-action machines. More in Rotary polishers

There is no formal cutoff. On this site, short throw means the 5-12 mm orbits makers list, such as RUPES's 5 mm LK900E, Makita's 7/32-inch XOP02Z and SPTA's 9 and 12 mm CP501 versions. More in Short-throw dual-action polishers (5-12 mm)

SPTA's product page states no supply voltage, plug or safety mark, so we cannot confirm North American suitability from the maker. Check the specific listing and the tool's nameplate. More in Short-throw dual-action polishers (5-12 mm)

Neither is better for every job. ESOTERIC Car Care, a RUPES retailer, calls 15 mm machines more versatile on curves and in tight spaces and 21 mm machines suited to larger flat panels; RUPES claims equal cutting power at different speeds. More in 15 mm long-throw polishers (5-inch class)

On Milwaukee's 2684-20 the manual lists 5-inch as recommended and 6-inch as optional, with a matching backing plate. Other makers set their own rules, so check your tool's manual. More in 15 mm long-throw polishers (5-inch class)

No. Milwaukee says the 2684-20 works with M18 REDLITHIUM batteries and chargers, and that its batteries are interchangeable within a system, not across systems. More in 15 mm long-throw polishers (5-inch class)

ESOTERIC Car Care, a RUPES retailer, describes 21 mm machines as suited to larger flat panels and 15 mm machines as more versatile on curves. That is a retailer's opinion, not a test. More in 21 mm long-throw polishers (6-inch class)

Milwaukee lists 6-inch as recommended and 5-inch as optional for the 2685-20, and says the backing plate should match the pad diameter. Check your own tool's manual. More in 21 mm long-throw polishers (6-inch class)

Do not assume so. Both are 18 V, but RUPES lists the HLR15/HLR21 iBrid on an 18 V 5 Ah pack and describes the HLR75's 2.5 Ah pack and charger as its own system. More in Mini polishers (3-inch class)

RUPES quotes about 35-45 minutes for the HLR75 on its 18 V 2.5 Ah pack, and about 35 minutes to recharge. It can also run continuously from the iBrid Power Adapter. More in Mini polishers (3-inch class)

FLEX lists US kit 493503 with a rotary adapter, random orbital adapters with 3 mm and 12 mm stroke, 30 mm and 75 mm backing pads, two 12 V 2.5 Ah batteries and a FLEX charger. More in Multi-mode micro polishers

Milwaukee's general power-tool safety section says that if a power tool must be used in a damp location, a GFCI-protected supply should be used. More in Corded polishers

Health Canada says plug-in electrical products must be certified by an accredited body, names marks such as CSA, cUL and cETL, and says the mark must appear on the product itself. CE alone is not one of the marks it names. More in Corded polishers

OSHA's listing for UL includes UL 62841-2-4 for sanders and polishers other than disc type and UL 62841-2-3 for disc-type polishers. A product is certified only if its maker or the certifier says so. More in Corded polishers

No. Makita says its batteries fit only within each platform, Milwaukee says its batteries are interchangeable within a system but not across systems, and RUPES's two 18 V iBrid packs are different systems. More in Cordless polishers

Not by the label. DEWALT says 20V MAX is the maximum initial voltage measured without a workload and that nominal voltage is 18. More in Cordless polishers

No. Milwaukee's -20 suffix is the bare tool and Makita sells the XOP02Z tool only, so the battery and charger are separate purchases on the maker's platform. More in Cordless polishers

Makita USA warns that non-genuine Makita batteries may burst and cause fires, injury or property damage, and Milwaukee's manual says to use only specifically designated battery packs. More in Cordless polishers