Remove Scraches from High carbon steel
- This topic has 4 replies, 3 voices, and was last updated 03/03/2018 at 1:56 am by
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Barry, welcome to the Wicked Edge Forum. Can you share with us what steps you have taken up to this point to remove the scratches? What kind of finish are you attempting; highly polished and scratch free?
Marc
(MarcH's Rack-Its)1 user thanked author for this post.
Barry just like sharpening a knife is a progression from coarser grits to finer grits the scratches need to be treated similarly. You’ll get out of it exactly what work you put in. To remove the scratches I’d start with a coarse sand paper and work stepwise down till you reached a very fine grit, sanding the surface in a uniform direction in line with the steel’s grain. I find emery cloth works well for rough sanding metal because it’s durability and flexibility. Emery cloth seems to me to be more coarse comparing grits for grits with sand paper, though. After the initial rough sanding is done with an emery cloth progression, I use sand paper. I like 3M Trizact sandpaper designed for metal auto body finishing. This is available from 80 grit through 5000 grit, I believe. So you’ll be able to take it as smooth as possible.
Some steels have a grain to them similar to wood grain. So even if you remove the scratches you may steel see some grain. I wouldn’t polish it till after I’ve sanded to remove all the scratches. Then I’d polish it or buff it on a cloth wheel again in a progression with finer rouges. With high carbon steel I think the steel will probably want to tarnish or rust quickly when freshly sanded and polished. You may find having to settle for a natural patina, although scratch free.
Marc
(MarcH's Rack-Its)I happen to have recently done much the same thing on a couple of knives with deep scratches. Generally, the factories are happy to let their knives go out with a scratch pattern of about 220 grit, as long as they’re parallel and vertical. Judging from Barry’s photo, I’m guessing the deepest scratches are from a grit coarser than 220, which would mean that there’s a lot of hand sanding in his future. When hand-sanding large areas, it’s really difficult to remove much steel, even with coarse grits. Imagine trying to remove the scratches on a 4-inch wide bevel with your WEPS.
I have buffing wheels down to 240 grit, but in this case, I’d be inclined to use a 120 grit belt on my 1X30 belt sander, using the platen as a back-up to the belt. Then 180, 220 and 320 before going to the buffing wheels at 400, 600 and on to the true polishing compounds. When doing the lower grits on the buffing wheels, I’ll use the 45L, 90, 45R, 90, 45L pattern to be sure I’d removed all traces of the previous grit. Finish up at 90-degrees to the spine.
When polishing a large area by hand, it’s really easy to create some waviness which will reflect light when fully polished, hence the recommendation to use a platen-backed sanding belt. I might even stay with the belt up to 600 or 800 grit to reduce the chance of creating an uneven surface. If you don’t have a a belt sander, then you should use a sanding block to keep the surface flat.
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