etching - confused newbie
 

Dear All !

I've read megazillions of pages on etching, and now I'm really confused:

Background: I want to etch a blade, about 17 inches long, potentially mechanical damascus. The blade is from a museum (still had a catalogue number "dotted" on it), where it was cleaned very well - the surface is non-shiny gray.

Things that I can't seem to find out:

a. Should I dunk it into the acid, or should I use swab and put the acid on it ?
First things seems complex - I don't have plastic bottles 17 inches high.

b. Should I let it sit for an hour, or should I let it sit for a minute, wash with soda or Windex, grind with paper, and repeat the whole process until reaching the desirable result ? Should I use sharpening stones (I would like to sharpen it a bit) after or during the etching ?

c. Some recipes categorically recommend FeCl, some go for vinegar, in between we have mixtures of cider, juices and coca-cola. Should I start with vinegar ?

d. Can I use my sink or pro-chemistry lab (have one available) do better ?

e. Should I preheat the blade couple degrees (don't want to go to high T), or it really won't make such a difference ?

Please help a dumb newbie !

Sincerely yours,

K.Rivkin

Others here have done this much more than I, and will have better advice. However, my personal advice is to go slow. Start with weaker acids (FeCl is strong stuff). Try wiping on warm citrus fruit juices to see if you get the effect you're looking for. Keep a bottle of base nearby (baking powder dissolved in water works well) to neutralize the acid when the desired etch is obtained.

Soaking for long periods of time can be problematic. (Don't ask. :o )


Incidently, Rivkin, what kind of blade is it?

If you do any sharpening it's best to do it before the etch for a more even surface appearance and a possibly microserrated edge, or after the etch for a smooth, polished edge that will hold and will cut smoothly. I prefer an acid bath for a naked blade, if you can suspend it in there, preferably vertically, without the flats resting against anything that might leave a mark (what was that..."don't ask"....?). If you go with a wiped on etch, the trick is to keep the whole surface constantly and consistently wetted, and to not create a false grain affect with your wiping motion. Acid is tricky, and old alloys vary tremendously. Watch that stuff closely 'til you know it well, then you'll know to watch it closely ;D

Thanx a lot, the blade is this one:
http://www.vikingsword.com/vb/showthread.php?t=152

I think I'll try 1:4 vinegar or lemon juice first.

Have a look here http://www.vikingsword.com/vb/showthread.php?t=157
it seems as if Spunjer has tried alum, and that it works slowly.
I know that some build a bath of plexiglass for the etching, so the blade can hang freely, and you should at the same time be able to keep an eye on how the etching is going.
I fully agree with Andrew and Tom, don't rush it, if you don't suceed the first time, clean the blade and start all over again.
Good luck
Jens

Etching long blades is really a problem, specially if you cant unmount the hilt.

(For "newbies": Do NOT touch a hilt from organic material with acid!)

For knifes i use a big jar were i can bleach all the blade and feel safe about the hilt. This way a solution 1/3 of vinegar for few hours gave me exelent results. Maybe a different solution or time could do something better. I dont know.

I prefer vinegar for 2 main reasons:
1. It is cheap and easy to find
2. In my country we produce a lot and it is "traditional" to use vinegar for thousand of actions, among them to clean things (my wife use it for cleaning the carpets :D )

A friend sugest that for a long blade we have to make a "bath" from adhesive tape like this: [_] where [ and ] are the sides of the tape and _ is the blade. I have not tried it yet but it looks ok and I will do it.

In another post, this is what I said about alum:

"Actually I have used alum on a kard and it does being out the little subtlties. It is still in progress. What I do is have a dish with a little water and a lot more alum until it becomes a watery paste, heat the mixture, and apply with a brush or rag (use distilled water). It will take lots of time, but the results are interesting. Water and alum make a weak acid. Hope this helps. I would only use this with wootz from India or Persia."

Even when I heat both blade and solution, it still is a slower but very controllable process and brings out the wootz pattern. I use other etchant like Radio Shack (diluted) for PI and other stuff.

Yannis, do you have plastic waste plumbing tube material available in your country ?
Lengths of this material with a cap glued on one end makes a marvelous and inexpensive re-useable bathing chamber for etching .
Cut to needed length ! :)

So simple! :D Thanks Rick!

ok, the blade is now yellow with ultra-ugly rusty spots...

jens, sorry, but i haven't tried alum.

incidentally, how do you strip the ren wax off the blade. battara recommended nevr-dull before. anything else?

rivkin asked:
good question. any comments on this phenomenon?

Well, here is what I've got:

a. Dunking works way better than rubbing.
Rubbing produces yellowish-red cast, dunking is more blackish.

b. Vinegar produced arch-horrible yellow color, which looked like 5 year old rust.

c. FeCL was way more controllable - the color dependent on the time spent in the mixture - less than 2 minutes - simply acsents the pattern, 2-4 minutes - yellowish rust, 4-10 minutes - black+yellow.

In the end I had two "good" times - at the end of 15th 1 minute dunking the pattern appeared with no major changes in blade's color from grey. However the pattern was not really well defined.

After that I've started to increase the time in the bath until the blade got blackish - with the full pattern displayed. May be in time I'll reetch the blade to more grayish color.

Nev'r Dull is a petroleum based polish .
I remove Ren Wax with acetone and 0000 steel wool , then I scrub the blade in a smooth full length pattern with a paste made from Bar Keeper's Friend or Bon Ami and water applied and rubbed in vigorously with a rag .
After that I wash the blade with a liquid dish soap and rinse with hot water.

Any kind of oil on the blade will ruin an etch .