Damascus: The type of sandpaper used...and the effects on etching??

EdCaffreyMS

EdCaffreyMS

"The Montana Bladesmith"
This might sound a bit picky, but those of you who know me, know that I'm really anal when it comes to fit and finish on my knives.

This morning I etched two Damascus blades....both were the same billet, same pattern, and hand sanded to 600 grit prior to etching. Not realizing it, I used Silicon Carbide paper on one, and aluminum oxide on the other. After etching and cleaning, I was looking them over carefully, and noticed that the blade I hand sanded with Silicon Carbide paper has a very slight "hazy" appearance in the pattern when compared to the blade sanded with Aluminum oxide paper. I would have never noticed it, had I not finished them out and laid them side by side on the bench.
I thought it might have just been something I did to one blade, and not the other....but I'm very mechanical in how I finish out Damascus blades....the only difference I can determine is the type of paper used to hand sand them.

I tried to take some pics, but you can't see any difference in the photos.

I wanted to ask if anyone else has experienced this? I likely would never have thought about it had I not used the two different paper types on nearly identical blades by accident. who knows, this might just send me off on a tangent to understand the whole experience! :)
 
If the difference is due to the sandpaper, is it the material or the brand that is causing the difference?
 
There's another variable that I hadn't considered! The Silicon Carbide paper is Norton Black Ice, and the Aluminum Oxide is RhynoWet from Super Grit.
When I get the time, I may have to delve further into this and see if I can figure it out....I'm not overly concerned about it, it's just one of those things than made me go "Hmmmmm???".
 
Could it be because the Aluminum Oxide is polishing a bit more and the silicon carbide is cutting more.
I always thought that aluminum oxide paper dulls faster and that could be why, Its polishing the steel instead of cutting.

Just my initial thought
 
That's completely reasonable Ernie. I've noticed that although the A/O paper breaks down and wears out much quicker than S/C, it does leave a noticeably finer finish grit for grit...that could very well be significant.
Looking at the blades with the naked eye, it's obvious that there is a difference in "sheen" that each exhibits. Heck, you folks may have figured it all out and saved me a lot of spinning my wheels! :)
 
Huh, I use Rhynowet paper too. I thought it cut more aggressively than any other paper I've used on steel, and left a slightly less "polished" surface at any given grit than comparable paper. That's why I use it, it saves me time and paper. I've not tried the Black Ice paper, however. Do you finish sand wet? I assume you finish by dragging new sharp paper down the blade, so it couldn't be that one blade has a "worn out paper" finish...

Just out of curiosity, what grit do you end at before etching, and do you normally use Rhynowet or Black Ice?
 
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