Damascus Knives & Re-Etchng

[GorillaGrunt]

Ah, I missed that you weren't just polishing a smooth face but smoothing a hammered face. I've done re-etches on things like a Shun Classic - this is a different set of operations.

Note that anything after this point I don't have much of an idea what I'm talking about, but if I were doing it I might use my coarsest inexpensive stone to grind off the hammer marks and then use sandpaper wet to polish out the stone scratches. It sounds like there's a fair amount of metal to be removed, which means coarse abrasives and in this case I might go dry if I were using paper, though this puts more dust into the air (use a mask), and definitely with a backing pad or block.

If you want to know the thickness of the core steel, and enough is exposed near the edge to be at or close to the full thickness, you could measure there with a micrometer or calipers. Alternatively, you could paint some etchant on the spine - I noticed that even stainless-clad stainless takes etch differently and the core steel is revealed - and measure there. Keep in mind, again, that this is just stuff I've done while messing around and someone here probably actually knows the right way.

 

[cardey1988]

Hello again,
Thanks for the tips, I've gotten most of the hammer marks out now, otherwise I'd probably give it a go on one of my stones, the coarsest I have is 300 unfortunately is wasn't a overly cheap stone though. I think I'm going to use a courser sandpaper dry to try and smooth out these holes, the way I'm seeing it is if they do go through the cladding they're going to leave dark spots on the etch regardless so I may as well try and smooth them out a bit. I'll prob use the courser sand paper to thin out the remaining hammer marks aswell (i've been out and got some 120) It came with some 80 and 40 as well but I'm thinking they'll be a bit too course. I'll see how I get on with the courser grit, and if I get worried I'm getting too close to the core, I may try putting a bit of etchant on the spine as you've mentioned.
Thanks for suggesting the use of a mask, the thought hadn't crossed my mind, I've been and got one.
I just have one more question for now, I've read a in a few places you're better not polishing it up too much before the re-etch, so the acid has something to bite on to. I just wanted to ask what grit am I best using to get it ready for the re-etch? Would 600 do it?

 

[GorillaGrunt]

600 sounds good. What kind of paper are you using? Note that ANSI (American) and FEPA (Euro) grit sizes are quite different. 600 grit FEPA is 25 micron, about 380 grit American, and 600 grit ANSI is 14 micron, about 1300 grit Euro. I live in the US but use FEPA graded papers so I tend to think in FEPA grit.

 

[Nemo]

600 sounds good. What kind of paper are you using? Note that ANSI (American) and FEPA (Euro) grit sizes are quite different. 600 grit FEPA is 25 micron, about 380 grit American, and 600 grit ANSI is 14 micron, about 1300 grit Euro. I live in the US but use FEPA graded papers so I tend to think in FEPA grit.

And to add to the confusion, the micron grades vary between FEPA-P (Sandpaper) and FEPA-F (bonded adbrasives), especially in the higher grits.

Fortunately, FEPA-P and JIS are much more similar throughout much of the grit range.

Most EDM stones are rated according to FEPA-F, so be aware of the differnces if using EDM type stones (Boride, Gesshwin and Congress are examples of companies making EDM stones).

It's confusing enough that I usually look up a micron eqivalency chart if switching from one type of abrasive to another.

 

[cardey1988]

Hey guys, Thanks for the advice I wasn't aware of the differences in grit size, I'm using european FEPA-P I think, I found a good chart online as you've suggested, showing the differences i grit size. I think 1200 grit is the closest to matching 600 ANSI, it jumps to 1600 after 1200 in the pack I've bought, so I'll finish it with the 1200.

 

[Gjackson98]

Good read! I am going to give it a try here too bad I can't find any Radio Shack anymore

 

[stringer]

I have been using this one. I have etched 3 knives and used maybe 3 ounces so far mixed half and half with distilled vinegar so you could probably go a smaller bottle. But it works great.

https://www.amazon.com/MG-Chemicals...eywords=ferric+chloride&qid=1569939693&sr=8-3

https://www.kitchenknifeforums.com/threads/advice-sought-on-rehabbing-damascus.40357/

 

[Gjackson98]

I have been using this one. I have etched 3 knives and used maybe 3 ounces so far mixed half and half with distilled vinegar so you could probably go a smaller bottle. But it works great.

https://www.amazon.com/MG-Chemicals...eywords=ferric+chloride&qid=1569939693&sr=8-3

https://www.kitchenknifeforums.com/threads/advice-sought-on-rehabbing-damascus.40357/

Thank you thank you!!