(This is an extract from Bad tin, but I thought it worth surfacing as its own page.)
When you’re considering whether to send your copper for retinning to a particular retinner, ask:
Is copper restoration and retinning a substantial part of the business? You want a company that routinely and frequently tins pots and pans, not one where this work is an occasional sideline. You want a place that advertises copper work as a passion and to which lots of people send their stuff.
Does the company do the work in-house? It’s not a dealbreaker if a shop outsources its retinning, but you need to know who is actually doing the work so that you can assess what their practices are. But if a shop outsources, they may not want to tell you where they send it because they don’t want you going around them. I can understand this from a business perspective, but as a consumer, you should insist as it is in your best interest to know. Also, if you intend to retin lots of copper, it may also be in your best financial interest to work directly with the tinner and save yourself some money.
Does the company use specialty tin ingots or pellets that are 99% pure or better? The only correct answer here is “Yes, and we’d be happy to tell you where we get it and show you the assays to prove its purity.” You cannot accept anything less than high-purity tin of documented quality backed by a responsible and accountable supplier. (Bad tin is the story of a retinner who used “tinning compound” rather than pure tin.)
Can you see some examples of the work they’ve done? You should expect to see lots of photos of really beautiful copper that looks like it’s been to the beauty parlor. Look for bright tin of consistent color and texture with a minimal amount of visible wipe marks and no black splotches or fingerprints. Look for closeups that tell you that the shop is proud of its work.
If you get “yes!” answers to all of these questions from the website, word of mouth, or from asking the shop directly, you’ll likely have a positive experience.