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Post by Sir Thorfinn on Mar 16, 2020 0:48:34 GMT
I'm thinking of using cold bluing on a Kitchen knife I bought a while back.
I LOVE LOVE LOVE the knife, but being carbon steel, it can rust, and boy oh boy does it. Even with a light coat of oil, in a few days it starts getting spots.
So the thought is to do some sort of surface treatment to help slow the rust. And for the record...it's the knife, not environment, as in it's sister slots in the block are blue and white steel carbon steel knives, which slowly patina-ed with use.
So...My thoughts are vinegar which will be grayish, or blue which is dark to black.
Thoughts?
PS: Out of disgust, I took it to my power buffer to get it back to near normal. I have significant hours behind a buffer/sander with sharps...
Thank gawd I was wearing these:
Pakel Y-01-08 High Performance En388 CE Level 5 Cut Resistant Knit Wrist Gloves (amazon)
Plus leather apron and glasses...
It caught the wheel, skipped, tapped a finger and I backed away, turned everything off and looked on in HORROR at the dime size divot in the wheel and my unharmed hand. Glove is unmarked.
Holy s-t, wear safety stuff!
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Post by Timo Nieminen on Mar 16, 2020 1:19:10 GMT
I haven't done a forced patina myself, but it's common enough for carbon steel kitchen knives. Vinegar, coffee, potatoes, mustard, fruit and fruit juice are all common methods (and all are food-safe).
You can get more details if you search for "coffee patina knife" etc.
What oil do you use? I use Ballistol (non-spray, so food-safe), and even my rust-happy knives don't rust.
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Post by Sir Thorfinn on Mar 16, 2020 1:32:23 GMT
Oil... I tried olive (semi success), wd 40 (lol...no), corn oil, coconut oil, flax oil...all about the same. I had totally forgotten coffee or a tannin patina..... Far better alternative and food safe. Thanks for the tip!
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Post by Timo Nieminen on Mar 16, 2020 10:30:12 GMT
The problem could be the water content of the oils. About 0.05% to 0.2% is fairly common, with olive and coconut oil often at the higher end of that range. It is possible to get rid of most of that moisture by heating it, making e.g. "boiled olive oil". Here are some traditional instruction for drying olive oil by pouring molten lead into it: hemamisfits.com/2017/03/03/how-to-care-for-your-sword-like-a-napoleonic-soldier/I wouldn't use that method for kitchen knives! Plantains might give you a very durable patina. I managed to patinate one of my stainless knives cutting plantain (don't know the cladding alloy, but might be 304). The stain was visible for a couple of years despite daily use and cleaning. (It's the oxalates.)
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Post by treeslicer on Mar 17, 2020 1:50:10 GMT
I'm thinking of using cold bluing on a Kitchen knife I bought a while back. I LOVE LOVE LOVE the knife, but being carbon steel, it can rust, and boy oh boy does it. Even with a light coat of oil, in a few days it starts getting spots. So the thought is to do some sort of surface treatment to help slow the rust. And for the record...it's the knife, not environment, as in it's sister slots in the block are blue and white steel carbon steel knives, which slowly patina-ed with use. So...My thoughts are vinegar which will be grayish, or blue which is dark to black. Thoughts? PS: Out of disgust, I took it to my power buffer to get it back to near normal. I have significant hours behind a buffer/sander with sharps... Thank gawd I was wearing these: Pakel Y-01-08 High Performance En388 CE Level 5 Cut Resistant Knit Wrist Gloves (amazon) Plus leather apron and glasses... It caught the wheel, skipped, tapped a finger and I backed away, turned everything off and looked on in HORROR at the dime size divot in the wheel and my unharmed hand. Glove is unmarked. Holy s-t, wear safety stuff! Congrats on not being injured. Don't use gun blue on food utensils. It deposits selenium, which is a toxic metalloid.
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Post by Sir Thorfinn on Mar 17, 2020 11:25:03 GMT
Thanks for the tip Treeslicer! This is why I ask these things...nobody knows everything, but between our hive mind, we know most of it. Plus we forget... So now I'm saving coffee grounds, so I can do it like I did a helm once. IMO, the real trick is gonna be finding something that's close to the knifes size to soak it in. I mean, I've got some totes...but don't want to mix up gallons of the stuff if I can avoid it.
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Post by paulmuaddib on Mar 17, 2020 14:26:35 GMT
Thanks for the tip Treeslicer! This is why I ask these things...nobody knows everything, but between our hive mind, we know most of it. Plus we forget... So now I'm saving coffee grounds, so I can do it like I did a helm once. IMO, the real trick is gonna be finding something that's close to the knifes size to soak it in. I mean, I've got some totes...but don't want to mix up gallons of the stuff if I can avoid it. Buy a piece of pvc and an end cap for it. What ever the widest measurement is on knife blade is buy just a little bigger. Don’t know where your located but Home Depot and Lowe’s both sell 2 foot pieces in several diameters. Cut it to the length you want to stand knife in. Of course measure inside diameter of pipe. That’s how they’re measured, 1 1/2” is inside diameter, etc. you’ll just have to figure a way to keep it upright. If pieces are tight enough you won’t have to buy cleaner and glue but if you do it will still be about $10 or so dollars for everything. If you’ve never worked with it pm me and I can walk you through it.
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Post by paulmuaddib on Mar 17, 2020 14:32:13 GMT
Oh yeah, good on you for wearing safety gear. I’m a handyman and sometimes I’m a little lax on safety glasses unless I’m grinding metal. Also don’t forget ear protection when using power tools. They may not sound that loud but can still do damage. I’m 63 and been doing construction most of adult life. Have almost religiously worn ear protection and still have very good hearing.
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Scott
Member
Posts: 1,675
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Post by Scott on Mar 18, 2020 0:17:07 GMT
I've used vinegar before without problems. As for a container I just use a plastic bottle cut down to an appropriate size, if I'm not going to re-use it it can go straight into the recycling. I even managed to fit a billhook into a 2 litre bottle at one point.
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Post by Sir Thorfinn on Mar 18, 2020 1:06:30 GMT
Huh, Was the Vinegar patina gray or brown for yours?
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Scott
Member
Posts: 1,675
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Post by Scott on Mar 18, 2020 1:11:40 GMT
Grey. I use a roughly 50/50 mix of vinegar and water, it's always given a grey patina.
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Post by tensho on Mar 18, 2020 1:25:59 GMT
Boiling vinegar/water will give you great results. Especially if you brush the blade and repeat a couple times. I have not done this with kitchen knives. I would expect some "drag" when cutting unless you buff the blade.
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Post by Sir Thorfinn on Mar 30, 2020 20:30:22 GMT
So some pics... I took a few lbs of coffee grounds, and boiled them a bit for richness... Cooled to room temp. Stuck super clean polished blade into solution. Checked a few times, left in a total of 24 ish hours. Not a perfect job, but enough. Worst case I polish it out. So from right to left: Grounds and polished knife Polished knife Soaking in coffee/salsa jar Last 2 are views of the brown, my camera does not do it justice. Thoughts?
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Post by MOK on Mar 31, 2020 4:34:22 GMT
Thought: That'll work. If you want a deeper and more even color, just do it two or three more times.
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Post by Sir Thorfinn on Mar 31, 2020 12:21:58 GMT
Thats what I'm thinking. I need to use it a bit, and while I do that...I'll save more coffee. Overall, I'm pretty satisfied. There are a few blotchy areas, and I need to do some hand polishing to bring the tang back to bright.
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ohira
Member
https://www.instagram.com/nutmeg_uchigumori/
Posts: 7
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Post by ohira on Apr 21, 2020 17:43:09 GMT
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Post by Timo Nieminen on May 2, 2020 3:43:25 GMT
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