A History of the Idea of Glued Linen Armour

[Crispianus]

Pliny was wrong about lots of things and this is another one. Vinegar is a fabric SOFTENER - the complete opposite of a fabric stiffener. Mixing vinegar with salt produces hydrochloric acid and sodium acetate. Hydrochloric acid degrades the fibres in textiles, which weakens the material, so it would be pretty silly to apply it to cloth armour.

Yeah, that does seem like a silly idea.  It might help to get the fibers to stick together in some kind of felting, but there is no evidence for it, and I doubt it would work better than using pieces of woven fabric --so none of the vinegar / wine stuff makes sense.  I just hope some bits and pieces turn up --very frustrating, as reconstructions are expensive and it's basically flying in the dark.

Here it is:

" It was not yet high noon when missiles were discharged, the two
armies charged, and the infantry forces advanced and engaged in
pitched battle. When the sun was ablaze in the zenith and the signal for
battle was given, Conrad, with his purple-dyed emblem imprinted on his
and his troops' arms, was first to move. He fought then without a
shield, and in lieu of a coat of mail he wore a woven linen fabric that
had been steeped in a strong brine of wine and folded many times. So
hard and compact had it become from the salt and wine that it was
impervious to all missiles; the folds of the woven stuff numbered more
than eighteen. "

From: O City of Byzantium


I think as far as Pliny is concerned the reference is wrong, as it refers to a different method of dyeing fleece by the gauls and parthians with no details given, though the passage does go on to say something in regard to felted fleece treated with vinegar being resistant to iron and fire... which is clearly not valid, salt is not mentioned.
In any case we use vinegar normally in the wash as a stain remover...