Tinning

[Hibernicus]

Some more info to share:

The most important trick to hot dipping is cleanliness of the item to be tinned. Oils from your finger tips can affect how the tin adheres!

We don't use a flux for hot dipping.

You will also need to be able to reheat the item to wipe it to spread the tin since the tin can build up. Heat the item from the back and then wipe with a damp cotton cloth or damp brush. With some practice you can create a mirror finish!

We use flux for tinning with tin powder or tin/flux mixes others have mentioned.

My favorite is tin powder or a tin stick with tallow.
Tallow can be readily found at soap making suppliers
You can also use lard, but I've found that tallow works better.

Tallow or lard are used as fluxes.

Tallow: ever make a beef stew let it cool and there's a layer of fat on the surface? That's tallow. ...scrape off the fat, put it into a pot, reheat it over a low flame. This cooks off any water and causes the fat to become denser. If you filter it while its liquid you'll remove any solids.

You can kind of make your own OATEYS #95 by mixing tin powder with tallow.

Does not need to be refrigerated.

We tin over a metal tray with sides (cookie sheet or baking tray with low sides) because the tallow/tin mix will flow off of any item you are tinning. If you have a catch tray you can reuse the stuff that drips off.

A bunson burner style flame source is great for tinning belt plates and other small items. Not as hot as a propane torch... A small single burner camp stove works too...

A big problem with tinning is getting the item to be tinned too hot. The tin simply flows right off!

A surface that slightly abraded works better too. "Rough up" the surface with 4-ought (0000) steel wool.

Employ all fire safety tips!

[Matt Lukes]

Is there any evidence for dipping at all? Of the dozen or so artifacts I have with a tin/silver coating, it's ONLY on the face- never the whole object...

[Marcus Mummius]

Is there any evidence for dipping at all? Of the dozen or so artifacts I have with a tin/silver coating, it's ONLY on the face- never the whole object...

Indeed, the large amount of tinned artefacts I've handled over the last years were also always tinned on one side, never on both.

Wiping the tin on seems to be the way they did it.

Vale,

[Matt Lukes]

I wondered about possibly an analog of our solder paste- powdered tin/silver and some kind of flux

[Gaius Julius Caesar]

Someone mentioned using tallow as the base for a tin flux, perhaps they did too?

[Hibernicus]

I wondered about possibly an analog of our solder paste- powdered tin/silver and some kind of flux. Matt Lukes

Try what we've done... make your own "Oateys #95" .. tallow mixed with powdered tin. You can even make your own "powdered" tin by taking a rasp to a tin block. Use a finer rasp to make finer shavings. Add the fillings to tallow.

[Hibernicus]

If you want to avoid modern chems for polishing compounds try ground chalk or talc and oil with a wool pad or sea sponge. Works great on tinned kit!

Dip the pad in oil then the talc...

Now you'll be able to polish your kit at an event... in view of the public!

Nothing like a bunch of soldiers sitting about in the shade cleaning and polishing gear!

[sulla felix]

Try what we've done... make your own "Oateys #95" .. tallow mixed with powdered tin. You can even make your own "powdered" tin by taking a rasp to a tin block. Use a finer rasp to make finer shavings. Add the fillings to tallow.

As an old carpenter and joiner I recall tallow being basically animal fat (I still use it to "wax" the bottom of my planes!) . I know nothing of the chemical composition of flux, but I would have thought tallow is the last thing you would wnat to mix with the tin because it just would not bond (greasy fingerprints stop the tin "adhering" no?). Old plumbers use tallow to wipe soldered joints (applied to their rags) and not as some kind of flux substitute?

[Hibernicus]

I know exactly what you're talking about. Been there too!

Finger prints, human skin oil, can prevent tin adhesion with modern flux.

Try the tallow. Not as neat as modern flux, but its worked for me.

[/i]

[Tarbicus]

I did a Google on flux and tallow, and there must be a thousand pages saying you can use tallow for flux. Another option is rosin. Here's a discussion on historically re-tinning copper:
http://www.finishing.com/255/53.shtml

However THIS PAGE has a lot more options, which include various mixtures of different substances, including olive oil, sal ammoniac , to make fluxes. Borax also features a lot. The thing is, I think pretty much all of the substances mentioned would be available to the Romans.

Further reading for those with access to JSTOR, or if you can track it down, would be:
Antique Metal-Joining Formulas in the "Mappae Clavicula" by Diane Lee Carroll,
Proceedings of the American Philosophical Society, Vol. 125, No. 2 (Apr. 30, 1981), pp. 91-103

[sulla felix]

Interesting stuff thanks Jim!

[Matt Lukes]

Well modern acid flux cleans the metal surface of residual oxides as well as preventing oxidation before the solder has a chance to bond- tallow I'd think would only act in the latter fashion.

And I have tried it Sean, albeit with modern flux- it wasn't pretty but it worked, which is why I propose it as a possibility for the Romans to have done since dipping definitely isn't right.

I've also been told that simple wood ash makes a good polishing material- and there'd have been large amounts of that available at any given time to be sure...

I WISH I had access to JSTOR!

[Hibernicus]

We've had excellent success with hot dipping. Made some horrific glop ups too!

A quick wipe with that damp cloth helps to remove excess tin and spread it evenly .... also a reheat and a damp wipe to further refine the tinned finish as needed.

[Magnus]

It would appear that dipping is historically incorrect. Plus doing it the other way you'll use a bit less tin.

[Hibernicus]

I believe that Pliny mentions hot dipping.

Hibernicus