Those old cast iron kitchen hand-cranked grinders, sausage stuffers, etc
are all silver. I have some that the coating is in pretty sorry shape &
they need a re-coat.
Am I correct in assuming it is tin?
How is it applied? Are they "tinned" as in dipping or coating in molten
tin or simply plated?
It is tin, pure tin. I am sure it is fluxed and dipped in molten tin.
Just like galvanizing, using zinc.
My father bought a dairy farm in 1957. The next year he had a bunch of
the milk containers re-tinned. A place in Portland, OR did it for him.
Can't tell you more than that.
My electronic assembly service uses a lot of lead-free solder for
circuit boards going in export products. The solder paste for the
surface-mount components is almost 100% tin, Just a few % other
metals. Most of the wire solder used to add components by hand is pure
tin. In all cases, very active flux is required to clean the area to
Molten tin reacts quickly with oxygen to produce a black tin oxide
powder that floats on the molten tin. Our CNC selective soldering
machine uses nitrogen gas to limit the oxygen getting to the molten
I have not heard of anyone tinning metal parts in a very long time.
Perhaps you can find a commercial food processor in your area and ask
their maintenance people about tinning their equipment.
The better ones are acid dipped then dipped in pure molten tin.
Others get plated and some even get metal sprayed.
When I had mine done I talked to a commercial kitchen supply place who
gave me a couple of local places that did tin work for them. It cost me
a bit less than a new grinder on the #10 and less than half on the #32.
The old stuff was hot-dipped, like hot-dip galvanizing.
It's not easy to replicate but you can probably do a good job with a torch
equipped for metal spraying. Good luck if you try to melt it on like solder.
Or just live with it. I have two grinders, one over 60 years old and with a
number of worn spots. I just wash and dry it good and give it a light wipe
with medicinal mineral oil.
assuming it's tin
For what it's worth, I picked up, some years back, some really nice heavy
copper pans at a garage sale, but the tin coating on the inside had worn
off - I put the pans on the stove, put in a dollop of acid flux, scrubbed
that around (with the heat on) until the pan was clean, and then poured in
some tin from a bottle of reasonably high purity tin I just happened to have
lying around - then when the tin melted, I scrubbed it around until it
covered the pan nicely - it's worked well for years - the same approach may
work for you, I don't know
I have seen mixing bowls re tinned with a torch,a bar of tin and a wet
rag. The bowl would be heated and the tin melted onto the bowl surface.
The wet rag would be used to spread the tin over the surface evenly.
In some old text I've got somewhere, it had how to do it for cast
iron. You've got to etch the stuff to get the graphite pockets
cleaned out, then use a pretty active flux to get the tin to stick.
Presumbably, the graphite surface pockets are still cleaned out on
used equipment, all that needs to be done is get the thing fluxed well
and re-tin. For repairing milk cans, it was more like tinning for
soldering, using a big soldering copper. Tinning cast iron was a
dipping process with flux floating on the molten tin bath. So for a
fairly large item, you've got to have a pretty big bath and a LOT of
tin. Not sure how well sandblasting would work for surface cleaning,
you want to have new media and not recycle it. I've done some sweat
soldering with small cast iron pieces, not easy even with acid flux.
Thanks for all the good replies!
I'll get the tin that Iggy found & clean it really well then try just
heating it up with the O/A torch. Between adding flux, tin & reflowing
what tin is there now it should turn out ok -I hope.
Doing a most likely inferior job for twice the time & money compared to
farming it out to the pros is what this group is all about, no?
I'll follow up after I am done.