Tires: Sidewall Repair, liquid cement, steel belts

Question
I bought four new car tires about a month ago.  The local dealer where I got them has a good reputation but does not offer tire protection.  A small tear caused a flat tire recently (less than 500 miles on the tire).  The dealer offered to fix it for $25 using a special liquid cement (it's blue but I won't give name brands) and a patch and showed what he would do on the inside of the tire.  He was very confident that the patch would not fail.  He also said that he has been doing this personally for years, but he will not allow anyone else in his shop to perform sidewall repairs.

Can a small sidewall repair be safe under these conditions?  Usually, I've heard that sidewalls should not be repaired but the owner/mechanic seemed honest and experienced with such repairs.

Thank you for your time.

Answer
Jay,

Sidewall repairs are problematic.  The movement that the tire experiences in the sidewall is complex, so any repair has to be able to stand up to that.  And unlike the tread area where there is reinforcement in the form of 2 steel belts that don't allow much movement, the sidewall sometimes only has 1 ply - hardly a reassuring amount.

But the big thing is the failure rate.  This guy may be very experienced and very knowledgeable, but for him a 1% failure rate is just "Super".  But to the one in 1,000 who has an accident as a result, this is totally unacceptable.

I don't think sidewall repairs are reliable enough to trust.