The honest answer is that a small first order tested independently beats any amount of reading, and it costs less than most people expect.
The single most informative free test is asking for the certificate of the lot they intend to ship and then confirming, on arrival, that the code on the glass matches it. A supplier who can do that has a traceability system; one who cannot does not.
Set your accept threshold before you see the result. Deciding after the number arrives is how thresholds become negotiable, and everybody does it unless they wrote it down first.
Aggregate community ratings, including the one on this site, are opinion averages rather than measurements and should carry less weight than a single result on your own lot.
Testing narrows uncertainty. It does not turn research-grade material into something with release testing behind it.
Ask for the lot-specific certificate before ordering. It is free and it is decisive.
2Same experience here, different supplier. – orla_ferriter 2 months ago add a comment