scutt wrote:
I am helping my 11 year old nephew make his second knife ( First attempt
won him 1st place at the Fair :-). I want to keep introducing new skills
so the plan is to try etch in a simple design on this knife . The steel
is an old leaf spring . Does anyone know what to use as a resist and
which acid would work for this application ?
Ken Cutt


Good for you to help your nephew.

Get him the book "Step-by-Step Knifemaking: You Can Do It!" by David
Boye. It was published in 1977, and is still available in paperback at
Amazon.com (http://tinyurl.com/32sdbl) for $14.93.

He dedicates an entire chapter to etching, with plentiful drawings to
explain the process. I don't know how good these are in the the
paperback version, I have the hard cover.

As a resist he uses a mixture of equal parts by weight of beeswax and
asphaltum. He explains how to mix them properly, and how to apply to
resist properly to the blades to be etched.

For acid he uses Aqua Regia (http://en.wikipedia.org/wiki/Aqua_regia).
This is an acid mixture that I as a goldsmith am very familiar with,
since it is the only acid that will dissolve gold.

I want to strongly caution you, that using Aqua Regia (as well as any
other acid used to etch steel) is risky and possibly very dangerous if
not used carefully and properly. Mixing acids is extremely dangerous if
not done properly. Especially when mixing with water to dilute the acid.

Do not let an 11 year old do this without supervision. I am not
suggesting that you would, just want to make sure.

--
Abrasha
http://www.abrasha.com