Thread: questions

Originally Posted by onimaru55

IIRC it was acid. I think the Dovo video shows the process.

Yep, a resist was placed on the polished blade, then acid was used to etch the exposed parts. Remove the resist, and you have a pattern of shiny areas. Zak (Voidmonster) has done some experimenting in this regard.

Yeah, the historic method was acid.

I've used hot vinegar, naval jelly and ferric chloride (circuit board etching solution). They all work, but ferric chloride is fastest and gets the best result. I'm sure that the recipe for the acid has varied a lot from time to time and place to place.

On most earlier razors you'll see etched designs where the resist (which is any thing that'll stick to the metal and resist the acid -- wax, being the most common in the early days, I gather) was a negative image, so basically a brush or quill was used to apply the design and then the acid ate away all the parts that weren't it -- so the text or illustration is shiny on a dark background.

The advent of photographic processes in the 1820's eventually led to photo-resists, which let them make the lettering or design dark on a polished background. Electrical etching has been done for a surprisingly long time too. I think it goes back to the 1840's.

Yes, people etched before laser. Or electricity. Funny thing, really, quite the coincidence this thread coming up now. Just yesterday I handed in my MA thesis on an early 16th century Middle English commonplace-book (i.e. collection of various useful texts) and in it were two recipes for etching, or engraving.

The first:

To wrytt appon
a Sord

Take powder of ablon glas and
Salt gomme and Temp yt vpp
wth old vryn and wrytt ther wth

Edited translation:

To write upon
a sword

Take powder of glass (no idea what ‘ablon’ refers to, poss. even 'a blown glass')
Salt gum (prob. sodium alginate) and temper it
with old urine and write with it


The second:

To graue
Take a quanty of 4 benes of
gryne Coppar and half ʃo moch
of verdegrecc and bay ʃalt
The quantyty of 2 benes bray
all theʃʃe to gether and then put
Them in a yerthen pott wth
4 ʃpoonfull of ʃharpp vynagar
and Stopp the pott Cloʃʃe &
wth in 2 dayes ffollowyng you may graue ther wth.

Edited translation:

To engrave

Take a quantity of 4 cups (bin, a food receptacle) of
Green copper (i.e. copper corbonate) and haf as much
Of verdigris (prob. copper acetate) and bay-salt (prob. sea-salt crystals)
The quantity of two cups; crush them together into a powder and then
put them in clay pot with
4 spoonfuls of sharp vinegar
and close the pot tightly and in two days you can engrave with it.

So yes, a form of acid, mixed with salt in some shape or form. Not quite sure why anyone would have a stash of old urine, though. But I guess it's just one of those things that you never know when you need it.

Originally Posted by Pithor

Not quite sure why anyone would have a stash of old urine, though. But I guess it's just one of those things that you never know when you need it.

From the urine people extracted ammonia, and it was commonly gathered by tanners, dyers, bakers, and metal-smiths going as far back as ancient times.

Originally Posted by rkuchenbecker

From the urine people extracted ammonia, and it was commonly gathered by tanners, dyers, bakers, and metal-smiths going as far back as ancient times.

It was also an important part of wood finishing. Especially for musical instrument as the finish effects the quality of the sound.

Originally Posted by Pithor

Yes, people etched before laser. Or electricity. Funny thing, really, quite the coincidence this thread coming up now. Just yesterday I handed in my MA thesis on an early 16th century Middle English commonplace-book (i.e. collection of various useful texts) and in it were two recipes for etching, or engraving.

The first:

To wrytt appon
a Sord

Take powder of ablon glas and
Salt gomme and Temp yt vpp
wth old vryn and wrytt ther wth

Edited translation:

To write upon
a sword

Take powder of glass (no idea what ‘ablon’ refers to, poss. even 'a blown glass')
Salt gum (prob. sodium alginate) and temper it
with old urine and write with it


The second:

To graue
Take a quanty of 4 benes of
gryne Coppar and half ʃo moch
of verdegrecc and bay ʃalt
The quantyty of 2 benes bray
all theʃʃe to gether and then put
Them in a yerthen pott wth
4 ʃpoonfull of ʃharpp vynagar
and Stopp the pott Cloʃʃe &
wth in 2 dayes ffollowyng you may graue ther wth.

Edited translation:

To engrave

Take a quantity of 4 cups (bin, a food receptacle) of
Green copper (i.e. copper corbonate) and haf as much
Of verdigris (prob. copper acetate) and bay-salt (prob. sea-salt crystals)
The quantity of two cups; crush them together into a powder and then
put them in clay pot with
4 spoonfuls of sharp vinegar
and close the pot tightly and in two days you can engrave with it.

So yes, a form of acid, mixed with salt in some shape or form. Not quite sure why anyone would have a stash of old urine, though. But I guess it's just one of those things that you never know when you need it.

I watched a doc. on the discovery channel and they kept urine and let it ferment into a type of ammonia. they used it I think for dry cleaning. of course I could be wrong.