Which Windshield Repair Kit Brand Wins?
In our test 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.
ClearShield
Price shown in test: $319
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Permatex
Price shown in test: $13
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Permatex
Price shown in test: $13
Affiliate link. We may earn a commission at no extra cost to you.
The quick take
The short version of why each pick lands where it does, built straight from the measured results.
“the Clear Shield kit is by far the best with an average finish at first place”
Best in 1 of 2 measurements, including Average Finish.
The measured results
Every number below is read straight from the test. Products are listed in the order they finished.
Glass Strength Test
- 1ClearShield12.5 lb
outlasted the glass before it broke
- 2Permatex20.6 lb
outlasted the glass
- 3Rain-X21.4 lb
outlasted the glass
- 4JB Weld23.6 lb
more than enough strength to outlast the glass (strongest of all 7)
- 5Antswish18 lb
outlasted the glass
- 6Unioon8.6 lb
resin let go (failed), less than half the strength of most other brands
- 7Athlon Tools4.6 lb
resin failed (weakest of all 7, even weaker than Unioon)
Scratch Resistance
- 1ClearShield
held up fine to a Mohs number 2 pick, damaged by a number 3 pick (tied for hardest resin of all 7)
- 2Permatex
outlasted a Mohs number 2 pick, damaged by a number 3 pick (tied for hardest resin of all 7)
- 3Rain-X
held up fine to a Mohs number 2 pick, damaged by a number 3 pick (tied for hardest resin of all 7)
- 4JB Weld
a little harder than Antswish, but still experienced damage from a Mohs number 2 pick
- 5Antswish
easily scratched by a Mohs number 2 pick (among the weaker resins)
- 6Unioon
very soft, quite a bit of damage from a Mohs number 2 pick
- 7Athlon Tools
extremely soft, a lot of damage from a Mohs number 2 pick (weakest of all 7)
Injection Mechanism Quality
- 1ClearShield
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 test
- 3Rain-X
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 test
- 6Unioon
resin 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 attempts
- 7Athlon Tools
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 legs
- 2Permatexnot tested
- 4JB Weldnot tested
- 5Antswishnot tested
All measurements (6 more)+
Repair Time
- 4JB Weld35 minutes
following the instructions exactly
- 6Unioon
about twice as long as Rain-X
- 1ClearShieldnot tested
- 2Permatexnot tested
- 3Rain-Xnot tested
- 5Antswishnot tested
- 7Athlon Toolsnot tested
Average Finish
- 1ClearShield1st place
/ best overall per the narrator's stated average finish
- 2Permatexnot tested
- 3Rain-Xnot tested
- 4JB Weldnot tested
- 5Antswishnot tested
- 6Unioonnot tested
- 7Athlon Toolsnot tested
Kit Quality
- 2Permatex
adhesive disc held together noticeably better when removed than the JB Weld kit's; kit contents and instructions nearly identical to JB Weld's
- 1ClearShieldnot tested
- 3Rain-Xnot tested
- 4JB Weldnot tested
- 5Antswishnot tested
- 6Unioonnot tested
- 7Athlon Toolsnot tested
Repairs Per Kit
- 3Rain-Xapproximately10
repairs possible from a single kit
- 1ClearShieldnot tested
- 2Permatexnot tested
- 4JB Weldnot tested
- 5Antswishnot tested
- 6Unioonnot tested
- 7Athlon Toolsnot tested
Repair Quality
- 4JB Weld
performed 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'
- 1ClearShieldnot tested
- 2Permatexnot tested
- 3Rain-Xnot tested
- 5Antswishnot tested
- 6Unioonnot tested
- 7Athlon Toolsnot tested
Usability
- 7Athlon Tools
UV 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
- 1ClearShieldnot tested
- 2Permatexnot tested
- 3Rain-Xnot tested
- 4JB Weldnot tested
- 5Antswishnot tested
- 6Unioonnot tested
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”
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.
