Fun with Acid

Robert Dark

Robert Dark

Joined
Aug 27, 2004
Messages
2,522
Here is a new one that has a deep acid etch using a resist on the edge.

O-1 Flat Ground
Stabilized Maple Burl
Mosaic and Stainless Pins
OAL 8 3/4"
Blade 4 1/4" Tip to Handle

Thanks for looking.........Robert

o1-4cab.jpg
 
Where can find the "recpie" for this etching procedure you performed ? What kind of "resist" (acid protection) did you use on the blade ?
 
faramir said:
Where can find the "recpie" for this etching procedure you performed ? What kind of "resist" (acid protection) did you use on the blade ?
Click to expand...

Ferric Chloride mixed around 3:1. I etch the entire blade for about 15-20 minutes. (I usually do this twice and sand with 600 between etches)

Then I made my resist by using a #2 pencil and sketching out the "scallops" on the lower part of the blade. You could sketch out pretty much any design you want.

Using the pencil line as a guide, I carefully paint the lower part of the blade with regular old fingernail polish, being sure to cover the entire lower portion on both sides of the blade.

Then its back into the FC for another 20 minutes or so. The acid keeps eating away at the upper part of the blade, but won't touch the part thats under the nail polish.

After etching and rinsing the FC off, I just use lacquer thinner to remove the nail polish, do whatever final sanding you think is needed, and.............Wa-Lah.

Its not reallly the prettiest thing I have ever seen, but it is definately different. I have had some good comments on the looks, but the main comments I get is "HOW DID YOU DO THAT?"

Thanks for asking.

Robert
 
Thanks for the instructions. I have no idea as to where to purchase this thing but i can probably make my own from Fe2(S)4)3 and HCl. Can you please elaborate on "3:1 mixture" ? 3 parts in weight of FeCl3 and 11 part of water ? Or where those volume ratios ?

How does this process affect the strength (brittleness) of the blade ? I imagine the blade is weakened but how brittle does it become (does it chip more often than it normally would) ?

Oh and one thing i haven't mentioned before: really great placement of rivets through the handle slabs, i like the geometry of those, you can really visualize the curve going through the handle when held in hand (some people put the rivets off-center or in odd arrangement and they never look good that way).
 
faramir said:
Thanks for the instructions. I have no idea as to where to purchase this thing but i can probably make my own from Fe2(S)4)3 and HCl. Can you please elaborate on "3:1 mixture" ? 3 parts in weight of FeCl3 and 11 part of water ? Or where those volume ratios ?

How does this process affect the strength (brittleness) of the blade ? I imagine the blade is weakened but how brittle does it become (does it chip more often than it normally would) ?
Click to expand...
Faramir:
The FeCl3 I get comes from Radio Shack. They sell it as an etchant for circuit board projects. The mixture I use is 1 part FeCl3 to 3 parts water.

I have not noticed any significant changes to the integrity of the blade after etching.

Hope this helps.

Robert
 
Well, we don't have Radio Shack over here across the big pond :) Chemicals can be purchased in specialied stores or made by oneself. I think it's going to be the latter in my case. Judging by your response it was volume proortions you were talking about - 3 parts (in volume) of FCper 1 part (in colume) of water, and not weight proportions. This brings up another question: what do they sell n your Radio Shack stores - water solution (if that's the case what concentration is it ?) or pure FC (salt, undissolved in water) ? This is important for getting the ratios right (which directly affects concentration of acid formed once FC is tossed into water).

Thebrittleness part, it's only logical that blade with pores in it (etched by the acid, resembling the pores left by bad castng process) would make the blade more brittle. Could it be that your balde is wide enough (has enough metall unaffected by the acid underneath) not to display any additional brittleness ? I'm not knife expert, this is mere chemistry and experience with casting of metals other than iron (the area i'm more familiar with).
 
faramir said:
Judging by your response it was volume proortions you were talking about - 3 parts (in volume) of FCper 1 part (in colume) of water, and not weight proportions. This brings up another question: what do they sell n your Radio Shack stores - water solution (if that's the case what concentration is it ?) or pure FC (salt, undissolved in water) ? This is important for getting the ratios right (which directly affects concentration of acid formed once FC is tossed into water).

Thebrittleness part, it's only logical that blade with pores in it (etched by the acid, resembling the pores left by bad castng process) would make the blade more brittle. Could it be that your balde is wide enough (has enough metall unaffected by the acid underneath) not to display any additional brittleness ? I'm not knife expert, this is mere chemistry and experience with casting of metals other than iron (the area i'm more familiar with).
Click to expand...
No..........No............No !!!!! Its 1 part FC and 3 parts water.

I have no idea what the original strengh of the "Radio Shack" FC is. Radio Shack is a chain of stores designed, in part, to sell "do-it-yourself" people all types of electronic gadgets, parts, and materials.

All I know is that it works!!!!! I suppose that theoretically, the strength of the blade may be diminished by etching, however, I feel that it is a "mute" point. The etching is generally for cosmetic purposes (in addition to retarding the rusting charactistics of O-1)

Maybe we should test two identical pieces---one etched, and one not etched,.............I doubt that the "breakage-point" or "edge-holding" abilities would be significant.

Your best bet, if you want to discover the advantages, or non-advantages of etching, is to experiment.

Also, seacrh these forums for a world of information on etching and other knifemaking stuff.

Robert
 
Yes, i meant the other way around, sorry, got it wrong again :D

Regarding the forum searching - i woudl if i could: it seems that search is broken for anything but single-word search patterns. I tried to search for 'acid etch' and 'acid etching' but it doesn't work (one of the side-effects of the reent crash ?). Anyway, i noticed others are having problems with search function too so it can't be just me. I've also been looking for L6 heat treatment temperatures which were no doubt posted somewhere but 'L6' is too short a search pattern and multi-word pattern won't work.
 
Faramir:
I just happened to have a bottle of Radio Shack Ferric Chloride on me....No really. The top's a little crusty, couple of years old but appears still good. Iuse it just as it is out of the bottle

As stated on the bottle:
"For removing excess copper from printed circuit boards".
"The strength of the etching solution is formulated to give best results when used WITHOUT dilution."
Contains 39.00%FeCl3 and 61.00% H2O. Specific Gravity 1.415.
 
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