2023 test7 productsCar Care & Detailing

Which Windshield Repair Kit Brand Wins?

We compared 7 windshield repair kit options head to head. ClearShield came out on top. See the measured results, the runner-up, the budget pick, and a link to the full test video.

The verdict
Winner

ClearShield

Price shown in test: $319

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Runner-up

Permatex

Price shown in test: $13

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Budget pick

Permatex

Price shown in test: $13

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The measured results

Every number below is read straight from the test. Scroll sideways to see all measurements. Products are listed in the order they finished.

ProductGlass Strength TestScratch ResistanceInjection Mechanism QualityAverage FinishKit QualityRepairs Per KitRepair TimeRepair QualityUsability
1ClearShield$31912.5 lb, outlasted the glass before it brokeheld up fine to a Mohs number 2 pick, damaged by a number 3 pick (tied for hardest resin of all 7)two O-rings form a tight piston-ring seal; built up significant pressure and enough suction to hold onto a finger; easily lifted the curing-strip suction test1st place / best overall per the narrator's stated average finishnot testednot testednot testednot testednot tested
2Permatex$1320.6 lb, outlasted the glassoutlasted a Mohs number 2 pick, damaged by a number 3 pick (tied for hardest resin of all 7)not testednot testedadhesive disc held together noticeably better when removed than the JB Weld kit's; kit contents and instructions nearly identical to JB Weld'snot testednot testednot testednot tested
3Rain-X$1221.4 lb, outlasted the glassheld up fine to a Mohs number 2 pick, damaged by a number 3 pick (tied for hardest resin of all 7)resin chamber threads in without protruding, legs of larger diameter and stronger than Union/Ethlon; built up some pressure while threading but not enough suction to lift the curing-strip testnot testednot testedapproximately 10 repairs possible from a single kitnot testednot testednot tested
4JB Weld$1323.6 lb, more than enough strength to outlast the glass (strongest of all 7)a little harder than Antswish, but still experienced damage from a Mohs number 2 picknot testednot testednot testednot tested35 minutes following the instructions exactlyperformed well but a small amount of visible damage remained; the professional technician's stated critique was that the resin 'did not stay within the repair'not tested
5Antswish$918 lb, outlasted the glasseasily scratched by a Mohs number 2 pick (among the weaker resins)not testednot testednot testednot testednot testednot testednot tested
6Unioon$158.6 lb, resin let go (failed), less than half the strength of most other brandsvery soft, quite a bit of damage from a Mohs number 2 pickresin chamber has insufficient threading and protrudes out the bottom; barely any pressure built when threading; could not lift the curing-strip suction test; the assembly acted like a funnel rather than forcing resin into the crack, requiring several extra attemptsnot testednot testednot testedabout twice as long as Rain-Xnot testednot tested
7Athlon Tools$194.6 lb, resin failed (weakest of all 7, even weaker than Unioon)extremely soft, a lot of damage from a Mohs number 2 pick (weakest of all 7)resin chamber design nearly identical to Unioon's; barely any pressure built; also acted like a funnel rather than forcing resin into the crack's legsnot testednot testednot testednot testednot testedUV curing light requires 2 AAA batteries not included in the kit, and the light shuts off about once a minute, requiring roughly 10 restarts during a single 10-minute cure

How it was tested

  • resin/repair strength test on glass coasters and test tubes until the glass breaks (lb of force)
  • Mohs hardness pick scratch-resistance test on cured resin
  • injection-tool pressure and suction quality (screw-cylinder design brands: Rain-X, Unioon, Athlon Tools, ClearShield)
  • actual windshield chip/crack repair performed by the narrator across 11 damaged areas
  • a professional windshield repair technician's independent repair and subjective quality grading of each brand's result
  • repairs obtainable per kit (value)

the Clear Shield kit is by far the best with an average finish at first place

From the test video verdict.
Data notes and caveats

The hired professional technician's live subjective letter-grade ranking (A through E) of the finished repairs is captured in the transcript almost entirely as deictic references ('that one', 'this one') pointing at physical glass samples off-camera, rather than by naming brands; only two data points survive cleanly (Rain-X explicitly given a 'C', and JB Weld explicitly critiqued for resin 'not staying within the repair'). The other grade-to-brand pairings could not be reconstructed from the transcript alone; this video should be logged to data/onscreen-only.txt for a possible video-frame recovery pass on that specific segment. The clean, well-supported final verdict (ClearShield best overall but expensive; Permatex best DIY kit; Rain-X good resin/poor injector and best value at ~10 repairs per kit) is unaffected by that gap.

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