Back to Ganoksin | FAQ | Contact

Diluting Nitric acid

Hi

I am hoping somone out there could give me some advice. I am a
relative novice when it comes to etching, we did some in a class I
took so I am aware of all the safety pointers but the acid was always
mixed for us do I dont know what rate it was diluted at.

I am trying to etch a design into an old silver plated nickel spoon
and I just cant get it to work. I have been diluting the acid 3 parts
water to one part acid - as recommended in one of my books but it
isnt even touching it.

I was wondering if it was because I didnt prepare the metal
correctly so I have stripped off all the stop out varnish, rubbed the
spoons down and I’m about to begin again.

Any ideas would be very gratefully recieved.

Best wishes
Jeanette

Hi Jeannette -

I’ve been doing a lot of etching lately with mixed success, until I
found that recipe for nitric acid - one part nitric to three parts
water - and the only thing I might be doing differently is mixing it
up and then letting it sit for about an hour before using it.

I emery the surface of my silver and I also put alcohol on it to
remove all traces of anything that might interfere with the resist.

Then I put it in a glass dish and let it sit for a at least an hour,
or until my resist peels away. All of the instructions that I’ve
seen indicate that you should brush the bubbles away, but I
personally like the effect of the bubbles on the surface of the
metal. I think it looks like tiny hammer marks.

Anyway. As you’ve undoubtedly learned by now, you are on the way to
success with your etching.

Linda

Jeanette,

You need to know the strength of the acid first. You are probably
using a diluted solution of nitric acid when the book is referencing
concentrated nitric acid. Concentrated nitric acid is 15.4 molar
which corresponds to 69.0% by weight. Please keep in mind that as
concentrated nitric acid ages, it can give off a red colored gas
upon opening. This is nitric oxide which very dangerous if you breath
it. So open any bottle of nitric acid in a chemical fume hood or
where there is a way to exhaust any gases away from yourself.

Also, ALWAYS add the acid to water! If you don’t, the whole mess may
boil back into your face. I not trying to scare you, but like any
strong chemical, you must know how to handle it.

Best regards,
Tom Warden
Stone, Metal & Paper Originals
Ft. Collins, Colorado

Hi Tom

You need to know the strength of the acid first. You are probably
using a diluted solution of nitric acid when the book is
referencing concentrated nitric acid.  Concentrated nitric acid is
15.4 molar which corresponds to 69.0% by weight. 

Thanks for the info.It says 59% on the bottle, so I guess thats
slightly less concentrated?

Would you recommend that I dilute the acid less than 3 parts water
to 1 part acid - i’m trying to etch silver plated nickel

Best Wishes
Jeanette

I just read your posting on trying to etch silver plate over nickel.
Your solution is probably too strong to be the most effective. You
need to get your solution down to 10%-30% strength. Use distilled
water, not tap water; acid into water.

Now then, to rain on your parade–no one who hasn’t had chemical
hazard
training and access to a fully equipped lab setting, with an
eye wash station and dump shower, should be using the highly caustic
acids. There is just too much potential for a serious accident,
particularly with your lung tissue. Please consider using a safer
alternative, such as ferric nitrate. It has a slower etch, yes, but
the nice advantage is that it will stop when it gets to the nickel.
Useful for multiple metal laminations, say when you want a contrast
situation, or to remove some material in mokume, so there is more
relief contrast.

I suggest you dilute 1 part acid to 2 parts water. That will give you
a three-fold dilution rather than the four-fold dilution recommended.

Best regards,
Tom Warden

Thanks for the advice. I did read about ferric nitrate last year but
wasnt able to find any to buy in england, I will have another try.

Best Wishes
Jeanette

Hi Jeanette,

I did read about ferric nitrate last year but wasnt able to find
any to buy in england, I will have another try. 

You might look for shops that sell items to electronics buffs. They
use it to etch printed circuit boards.

Dave

I did read about ferric nitrate last year but wasnt able to find
any to buy in england, I will have another try. 
 You might look for shops that sell items to electronics buffs.
They use it to etch printed circuit boards. 

That’s ferric chloride, which etches copper and brass, not ferric
nitrate for silver. (At least at Radio Shack!)

–Noel

You might look for shops that sell items to electronics buffs. They
use it to etch printed circuit boards.

No Ferric Chloride is used for PC board etching not Ferric Nitrate

Jim Binnion

James Binnion Metal Arts
Phone (360) 756-6550
Toll Free (877) 408 7287
Fax (360) 756-2160


@James_Binnion
Member of the Better Business Bureau

Hi Jeanette

I bought ferric nitrate from Rose Chemicals last year in the UK
http://www.rose-chemicals.co.uk

Joy

No Ferric Chloride is used for PC board etching not Ferric Nitrate 

Ferric nitrate makes a very nice brown patina on bronze…

Owen Walker