Etch before final sanding?

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Jul 1, 2017
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Good afternoon!
I tried a peroxide/muratic acid etch on a 1/8th 1080 “bird and trout” style knife, I didn’t like the results, so I finished it off the tang and top with brownells gun kote and hand sanded the blade. It seemed after the “etch,”. Was the fastest easiest hand sanding up to 400grit I’ve ever done. Anybody else have experience like this or am I huffing to many shop fumes....
 
Intrigued W WA209 . I have 4 near identical blades in 3/32 52100 sitting at hand sanded 220 so when I got home I etched one in vinegar for about 20". I have pretty uniform technique so all should have been close to the same scratch depth at the hand sanded 220, ie uniform pressure etc. I also make several light passes at each grit after they are finished, thinking it may knock down the tallest ridges a bit (seen that trick somewhere here I think).

The un-etched side took 18" on a 4 inch blade and four 1/16 sheets of 400 grit. It did have a handful of scratches that were stubborn though. The etched one took 12 minutes and two 1/16th sheets, possibly due to fewer stubborn areas but still.... (this is for one side each on two blades). Maybe you're onto something cause I've never seen or heard this before. If it pans out with more tests I say we name the technique after you... erect statues, maybe even a monument! Hopefully the real metal guys will chime in here and let us know if you're onto something with the technical explanations, but for right now I'm going back out for a repeat test on the other sides.

Cheers.

ETA: So the second(left) sides went faster in both, about 12" and two 1/16th sheets for the non etch and 9" and less than two 1/16th sheets for the etched. They were clean. So maybe my right side (that I pull to the left) is less finished coming off the grinder at 220, making me work harder at initial 220 grit hand sand on that side, thus making the 400 grit take longer. Two blades tested doesn't make it so and I still think the etch may help in the coarser transitions. Two more to go.

ETA2: #3 unetched took 13" per side and two 1/16th sheets. Won't get to #4 tonight tho.
 
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I was at a seminar and one of the vendors selling equipment for polishing metallurgy samples recommended that 220 grit is the fastest way to remove deep scratches. They said it is basically the fastest for stock removal and that lower grits worked faster because it allows the grit to bite deeper and then you have to remove those scratches. Next they recommended using the etchent and rubbing the sample to acid polish before going to the abrasives. I have tried it on a couple of blades and feel like it helps. It makes sense that the acid will hit the thin high points a bit harder. After all its kinda the same concept as acid sharpening a file.
 
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