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
Bee's wax will make a decent resist. Paint it on or dip the blade into it while it is fluid, them scratch the design into the wax. I don't remember which acid I used so many years ago, but it may have been nitric
Joseph Gwinn fired this volley in news: firstname.lastname@example.org:
Y'know, I've used ferric chloride to etch zinc, aluminum, and copper. But I never thought to use it on any iron-based alloy.
I'm a bit confused about this. Is the ferric chloride actually etching the iron, or just leaching other metals out of the alloy?
The reason I ask is, ferric chloride is chlorine and iron in its most stable dimer state of Fe2Cl6. It can dissociate/reassociate bidirectionally in aqueous solution to/from FeCl3, which is also stable.
So... my read is that it cannot actually etch iron. It can "stain" or "reveal" features in iron by leaching out other metals, thus leaving a distinct marking on the metal -- but not actually removing any significant mass of the "etched" area.
When I think "etched", I think of fairly deep removal of the surface metal -- i.e. "dissolved". My best bet is that your friend's blades felt essentially the same across the "etched" areas as in all other areas of the blade.
Ken - maybe search this group or google for electrical or electrolytic etching. I have not done it at home but recall reading about it (probably here!) - if I recall correctly you can use an auto battery charger and the etchant was quite a bit safer than ferric chloride or acid.
I used a system years ago for marking tools & prototypes that used some sort of waxed paper which was marked in a typewriter (remember those?). A mesh or something was used to clamp the paper to the workpiece. The paper was flooded with electrolyte and the mesh & workpiece hooked up to a power supply.
"Lloyd E. Sponenburgh" fired this volley in news:Xns999D6338FBD7Clloydspmindspringcom@220.127.116.11:
Hmmmm.... maybe I "oops'd" a little. Running the redox again, FeCl3 could dissolve some iron to yeild FeCl2, but it would be darned slow... maybe hours in the solution, unless heated nearly to boiling, and with lotsa agitation.
Was this the case? (I try to learn somethin' new ever day. Usually it's the "wrong" stuff that ends up surprising me.)
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
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
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.
Yep. I've etched stainless with FeCl3, it took half an hour to go 5 mils. Turned a sheet of shim stock into custom-size washers that way.
Marking, though, doesn't need much penetration. I've also (accidentally) got a little oxalic acid (used for bleaching wood) on a stainless knife, and it left quite a mark, frosting the surface (which started polished).
Which is best, I wonder: polish the blade, then etch to make a frosty mark, or etch, blue the blade, and polish to make a contrasty mark?
My nephew does not live near me and is here as a holiday until school starts . The etched design was an after thought or I could have done my homework ahead of time . So for this project it is going to have to be the stuff I can get my hands on the fastest . Thanks Ken Cutt
Hi Abrasha good to see your name attached to a post here again , seems like its been a while . At 11 he is still young enough to not mind a high level of supervision . No doubt that will change as he gets older . Being as his first attempt turned out so well the level of expectation is very high for the second attempt . So it is pushing me into new learning experiences , always good . I picked up the bees wax today and hopefully some acid tomorrow , should have the blank ready to etch by Sunday . Thanks Ken Cutt
I've never used Nitric Acid for etching, so I cannot offer a comparison.
I've etched carbon steel (1095) and high-carbon stainless steel (like
440C) with wax resist and a cotton swab soaked with concentrated ferric chloride solution at room temperature, sweeping over the area to be etched manually. I don't recall how deep it went, but it was not superficial. I recall it taking ten or twenty minutes total, but I was talking as I did it, so I wasn't keeping score.