Knife making problems looking to solve.

M

Mr Wyman

Joined
May 6, 2014
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2
Aight, I am a absolute noob at knife making, but I got into about 6 months ago and have made a few knifes im decently proud of. Now I have the Honors of making a cake cutting knife for a viking style Norwegian wedding for 2 of my really good friends and my backyard skills are going to be on the line to make a knife worthy of this. So a couple questions:

1. How much do you sand after you shape your knife before you heat treat it?

2. I dont have a way to measure the heat, but I have been using a blowfan set up and wood coals in my bbq to heat my knife to where it loses magnetism, I know this is primitive, but is it somewhat correct??? (1080 HR steel)

3. I have also picked up somewhere to use Olive oil as a cheap alternative to the right oil...is this right at all??

4. After heat treating my knives have formed these little "bubbles" or like wart like spots on certain areas, there a gosh darn pain to remove....Why does this happen???

5. I have been tempering in my oven, I know I am a noob, but i am poor and use what I got, can I get some info on if im using my oven, what temp, for how long??

6. I final finish after temper right???

I appreciate any help that isn't sarcasm or telling me I need better equipment so far I have made a knife that I butchered 2 deer with without sharpening, so I could only imagine I have to be doing something right, but I know there is a lot to learn here and I am one to listen!

Thanks ya' all!
 
1. Sand down to about the thickness of a dime and finish to no less than 120.

2. BBQ will do but its not ideal and you may not be able to exploit the full potential of 1080.

3. Olive oil will cost you more in the long run than a quality oil like Parks 50 or AAA

4. You're looking at a mix of decarb and scale. You should see them disappear when sanding down to final thickness.

5. Check out Kevin Cashen's Website for some of the best heat treating information out there.

6. Yes.

Also, you should fill out your profile. You never know if an established maker is near you and may extend an invitation to his shop.
 
Thank you, I will, I just rushed the registration process with grit on my hands still to see if I can save myself some time with hand sanding!
 
Canola oil is cheaper than olive oil and will more than likely work better. I'm in the same boat you are as far as funds go, some of us can't shell out the money for Parks or AAA, even if it is cheaper in the long run.

It has been said many times on here that a little more than half the thickness of a dime is ideal for pre-HT thickness.

Take the pre-HT finish to around 400 and save yourself a lot of time hand sanding hardened steel. After HT, degrease, soak it in vinegar to soften the scale, then drop to 220 and work your way back up to your desired final finish.
 
I think if you do a seax, which is style appropriate for the wedding, you could make something beautiful and memorable without having to do much hand sanding.
 
I second a simple 8" blade seax shaped cake knife. Nothing fancy, with a plain handle. All the Celtic knotwork and double/triple fullers is mostly TV and movie fantasy. If you have the ability to do a single fuller, that would be nice, but it is not at all necessary ( especially on a cake knife)

Sand to 400 grit before HT. At 400 you will easily find any deeper scratches or other problems. Any large scratches or rough areas will be very hard to remove after HT.

Take the edge to about .030" thick at HT. This is about 2/3 the thickness of a dime.

Your BBQ and magnet system works sort of OK for a small knife, but a knife as large as this one isn't likely to HT well in that setup. It would be much wiser to send it to someone else for hardening or find a local friend and go over to his shop and do it. For a knife that size you need at least 2 gallons of quenchant. If you decide to do it in your wood coal forge, heat it as evenly as possible and when it becomes non-magnetic, heat one shade of red hotter. You want it about 1475-1500°F at quench. Quench point first in a tall metal container of canola oil warmed to 130°F. Realize that the blade may warp some in quench. After about six seconds in the oil you can pull it out, wipe it off with a rag, and straighten it with gloved hands for the next ten to 15 seconds. When it starts to feel stiff, STOP STRAIGHTENING, or it will break. This is because the blade is very soft and bendable until it drops to 400°F and becomes brittle martensite.

Tempering in the kitchen oven is OK. A cheap digital oven thermometer is a good idea to know the real temp of the blade ( and oven). I set my blade on the probe to get the most accurate reading. Let the oven warm up for 15 minutes, and put the blade on the middle shelf. Temper for one hour at 400F and then take out and cool off in running water in the sink. Dry off once cool, and put back in the oven for a second hour long temper. Cool again in water. The blade is now hardened, tempered, and ready to finish sand.


The "bubbles" sound like scale. After HT and tempering, soak the blade in vinegar overnight to remove most of the scale. Rinse it off well and then scrub hard with coarse steel wool. It should be much easier to sand then.

Sand after HT and tempering starting with a grit one grit lower than your last grit pre-HT ( 220 for a blade taken to 400 pre-HT) and go up the grits to your desired finish. 400 is the minimum.
 
There's a great hand sanding video in the stickies by Nick Wheeler. He gives some excellent advice on paper, tools, and techniques. You don't have to take a blade to mirror polish, a 600grit finish that is even and consistent looks great.
Canola Oil works fine for 1080 when warmed up around 130F and you can get it by the gallon at big name superstores.
 
For question number 2...IF it were me....

I would get a large piece of square tubing and use that inside the forge to bring the blade up to critical temp. Just keep it moving. Should help you keep from overheating some.
 
The biggest tip I can give on hand sanding is to do it wet. The quality of the sanding job and the length of time the paper lasts is amazing. I use a bowl of water with a squirt of dish soap in it. Dip the paper, sand, dip, sand, wipe off the blade, dip, sand,.........
I have observed that sanding wet also reduces J-hooks a lot, as well as leaves a more satin look ( less scratchy looking).

I also cut up the sheet of sandpaper into quarters in both directions...giving me 16 sanding sheets per 8.5X11 sheet of paper. I cut up a bunch of sheets and keep all those individual pieces in a labeled zip-lock bag.
 
What would you use to wet the paper for a quick rusting carbon steel like 01 Stacey? I have used WD40, but wonder if there is something better now I hear of soapy water. 01 would pit out before you finished the 2nd side.
 
Andy, I use regular Windex when hand sanding. All of my knives thus far have been made of 52100. While sanding, I will periodically clean with Dawn and warm water. I sand to 600-1200 grit, depending on the knife. Haven't had any pitting issues thus far using this method. I've been meaning to try WD-40, just haven't gotten around to it yet.
 
Just use water and soap. It won't rust in any way that will cause problems. The red stuff that forms on the blade sometimes is mostly the super-fine steel dust in the swarf. When done sanding for the session, rinse off well, dry, and oil. On blades that I don't want any surface rust risk, like a katana, I put a little baking soda in the soapy water.

There are folks who use Windex (surfactants, isopropanol, ethylene glycol, ammonia, various organic compounds, and water), WD-40 ( yuk!), water soluble cutting oil ( OK I guess, but smells funny), motor oil ( works, buy is messy and terrible on your hands), and a host of other things.
 
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Baking soda in the water will slow the rust process? Thats a new one for me. I don't hand sand many blades, one a year or so-ish. But I'm getting antsey about the next level, and what I need to do to get there. I want to show something markedly better than last year to the Guild at this year's show. I'm also considering getting more into carving handles. Maybe knots or something CRex-ish, but for some reason my mind is stuck on ovals. I keep picturing eyes, and eggs, and other oval things carved into a handle. I've dreamt about carving a fried egg into the side of the handle repeatedly this year. Now who the heck wants an egg carved in their handle? I'm definitely having craftsman/artist issues here at FF, and improvement in the last year IMO was mostly business efficiency related. So all that bunch of spill means is that hand sanding the blade might be the first direction and I appreciate the tips. (Then, eggs, for sure, or maybe a knot?)
 
Raising the Ph a bit will retard oxidation. It also reduces the surface tension and helps lift the swarf. A little washing soda is often added in the oke (water tub) when doing togi.
 
When I've hand rubbed O1 with water it does rust quick. I use windex now and it still does but not as bad. When I flip sides I make sure to dry and oil the side I just worked on. For me WD-40 just makes a mess.
 
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