How were Cannon finished?

[Fidlock]

My wife posed me with question I have never considered. How were canon finished. We’re they painted, oiled or tarred . i have no idea despite quite a bit of reading about the more nerdy aspects of naval practices. Does anyone know?

[mtaylor]

Depends on the cannon material.  Brass/bronze were usually left on finished.  Iron (and this is one of those "depends" answers) painted or left bare (wrought iron ones not cast).

[mtaylor]

1 minute ago, mtaylor said:

Depends on the cannon material.  Brass/bronze were usually left unfinished.  Iron (and this is one of those "depends" answers) painted or left bare (wrought iron ones not cast).

 

[Mark P]

Evening Fidlock;

 

Iron cannon were painted black.

 

As were anchors,  deadeye straps,  and all other exposed ironwork.  These last items were normally listed in painters' contracts.  Cannon were the property of the Ordnance Board,  who were independent from the Navy,  and organised the painting themselves.

 

All the best,

 

Mark P

[Jaager]

One question = what was the effect of the heat generated from firing a cannon on a paint layer?

Most colors before the late 19th c. would have been mineral, so able to withstand some heat,

but black was likely carbon based and enough heat would allow it to combine with oxygen.

The binders were also possibly an organic resin, and open to conversion to CO2.

[mtaylor]

They were probably cleaned and repainted after use, Jaager.  I vaguely remember reading somewhere that painting the guns was part of maintenance activities.

[wefalck]

There are actually various official instructions, at least for the 19th century. As pointed out by mtaylor, the surface treatment indeed depended on the material used. Off the top of my memory, the following procedures were applied in general:

 

- bronze guns were either left untreated and attained a greenish patina or where treated e.g. with sulfur-containing compounds to obtain a brownish or greenish-blackish patina; there are various recipes for this.

 

- high-graphite cast-iron, does rust in patches, rather than uniformly, therefore, cast-iron guns were painted (usually) black; paints were made up from lineseed oil with lamp-black (soot) as pigment; guns would not allowed to become so hot that the carbon in the lamp-black would oxidise/ignite - at such a temperature the barrel would distort.

 

- cast-steel muzzle-loading guns were carefully degreased and then rubbed with vinegar; this rubbing with vinegar was repeated until a uniform brown iron-oxihydroxide and -acetate layer was formed that attached well to the barrel; the barrel was then rubbed in lineseed oil, effectively generating in situ a redish-brown paint; care was taken to not touch the bore with the vinegar; the procedure was repeated periodically as needed.

 

- cast-/wrought-steel breech-loading guns could not be treated that way or otherways the delicate lock mechanisms might become corroded, as it would be difficult/tedious to remove the vinegar from these parts; such guns were painted again in oil paints - often in dark brown to resemble the treatment of earlier steel guns, in black, in yellow, or later in grey, as appropriate to the colour scheme of the navy.

[Bill Wells]

Sometimes iron guns were painted to appear bronze.
This is an article from a small blog I do. 

http://simplyforgotus.blogspot.com/2014/01/guns-of-another-color.html?view=flipcard