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Recently I went to using 1084 in my pattern welding (changing from using 80CrV2), and I have been having issues with etching. On another post I showed the crosses I made for Christmas presents. They were made of 1084 and 15N20. What I didn't say is that they took over 4 hours to etch and that is after I boosted my FeCl2 with 34% HCl. For clarity, the crosses had been fully heat treated as I know there can be issues with etching non-heat treated steel. This brings me to my latest etching issue on the knife that I have been working on every now and then. I started etching it this morning and got some weird patterning in the etch. There are spots that just are not etching. I took it back down to 1000 grit and tried a second time and the problem is even worse than before. My guess is that I have an issue with my heat treat as the blemish is basically the same on both sides of the blade. Most of the blade has etched beautifully deep  and dark, but the blemish spots are almost smooth.

 

Any ideas / suggestions? Thanks for any comments.

Etching issues_IMG_0375.jpg

 

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Really nice twist. Might just need a really hard degrease.

Just a guess. But I've had something similar  happen. The cloth I laid my blade on after cleaning had some oil on it and it transferred to blade.

Old eyes here but I seem to see 2 finger prints. One on top of ricasso and another about a half inch in front .  

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1 hour ago, vlegski said:

Really nice twist. Might just need a really hard degrease.

Just a guess. But I've had something similar  happen. The cloth I laid my blade on after cleaning had some oil on it and it transferred to blade.

Old eyes here but I seem to see 2 finger prints. One on top of ricasso and another about a half inch in front .  

Thanks for the compliment. Not quite what I was shooting for but close. Still has too many layers in this one.

 

Thanks for the reply but I'm going to have to say probably not on the de-grease suggestion. The non-etch pattern is basically the same size, shape, and position  on both sides of the blade. As for de-greasing, my standard protocol is: wash down with a 50/50 mix of isopropanol / water with a little dish soap, followed by 90% straight isopropanol, followed by 100% ethanol, followed by 100% acetone... all while wearing nitrile gloves.

 

There may be fingerprints there now. I was handling it without gloves after the etching to take pictures but there shouldn't have been any grease / fingerprints before hand.

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Well, you definitely have a serious degrease regimen that is way more than I ever do. I also don't sand my PW past 400, but I know a lot of people do.

So let's talk about your etching regimen.

1. What is your etch tank? (please do not say it's a clear glass bottle)

2. Do you agitate the etch in any way? (Stirring, fish tank bubbler, etc. )

3. How often do you cycle the blade in and out of the etch?

 

Next up, what condition is the blade in when you go to quench and temper? Is it fully sanded down to clean metal, or are there spots with scale still on them?

Is the blade pretty close to finished thickness when you quench, or is there still a lot of grinder work to be done?

This is peculiar to say the least, and the fact that the affected region goes through the blade in the same location, definitely makes me think there is something  happening other than a resist. Do you have any kind of hardness testing gear? Even a set of Matt P's chisels would be a good test to see if there is a hardness/HT differential happening.

 

 

Edited by Joshua States
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11 hours ago, Joshua States said:

Well, you definitely have a serious degrease regimen that is way more than I ever do.

Part of my anal-retentive scientist nature.

11 hours ago, Joshua States said:

1. What is your etch tank? (please do not say it's a clear glass bottle)

2. Do you agitate the etch in any way? (Stirring, fish tank bubbler, etc. )

3. How often do you cycle the blade in and out of the etch?

1. 36 inch tall, 4 inch diameter PVC tube filled to three inches below the lip with FeCl2.

2. Fish tank bubbler with a 36 inch long tube (goes to bottom of the tank) and bubble stone (thank you for the suggestion - works wonders!)

3. usually 10 minutes in, then wipe down with cotton pads. Repeat until deep / dark enough for my liking. Final sanding with 1500-2000 grit wet/dry wetted with 100% ethanol and a hard backer. The 100 % ethanol SEEMS to set the oxides just about as well as boiling in water for 10 minutes.

 

11 hours ago, Joshua States said:

Next up, what condition is the blade in when you go to quench and temper? Is it fully sanded down to clean metal, or are there spots with scale still on them?

Is the blade pretty close to finished thickness when you quench, or is there still a lot of grinder work to be done?

This is peculiar to say the least, and the fact that the affected region goes through the blade in the same location, definitely makes me think there is something  happening other than a resist. Do you have any kind of hardness testing gear? Even a set of Matt P's chisels would be a good test to see if there is a hardness/HT differential happening.

Blade is completely belt finished to 240 grit before HT. Edge is about half the thickness of a dime at HT. HT treat for this blade was probably incorrect as I used my process for my 15N20 / 80CrV2 without thinking there may be a difference. Briefly, cycle 1600 F/ 1500 F/  1400 F; 45-60 second "soak" time for each temp; cool to dark in still air in between temps. Heat to 1550 F, quench vertical, point first, in 100 F high flash-point, vacuum pump mineral oil ( got 5 gallons of it from work). Temps are monitored with a thermocouple in the forge - highly reducing atmosphere; small amount of dragons breath coming out the forge as well as several large pieces of anthracite coal in the forge. Blade usually comes out coated in a fine layer of carbon during the thermocycling (which gets wiped off between temps). HT forge is a small (10 inch diameter, 30 inch long) modified Don Fogg barrel forge.

 

Very minimal warping at the tip after quench; easily straightened in the temper. Knock on wood I keep this up, but I have never had scale after quenching; at most flakes of solidified oil. Blade was "brillo cleaned" after quench and lightly sanded to clean steel before temper. Temper was two, 2 hour cycles at 375 F.

 

Finish work after HT is pretty much just cleaning it up and taking the edge down to a sharpen-able edge -no major material removal.

 

Unfortunately no hardness testing gear. Up to this point, "never needed it". I've been meaning to get something, but it has been low on the priority list (and after my splurging on Christmas presents it will still be waiting for a bit). This was my initial thought too that I got some weird hardness differentials going on, but the patch work nature of it has me scratching my head.

 

Thanks for the links to the chisels. Will have to look them up after I pay off Christmas.

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10 hours ago, Gilbert McCann said:

I think it looks like a random hamon. I wonder if your quenchant was fast enough. Just a guess. Looks like soft spots. 

Don't know if hamon would be the correct terminology, but I am wondering about my quench oil too. I have use this oil on:

 

80CrV2

CruForge V

15N20

5160

8670

4140

15N20 / 80CrV2 pattern weld

 

(all "slow quench" steels) and it works great. Just saying that my "problems" only started when I started using 1084 in my PW.

 

Additional note, all my steel recently has been coming from NJSB so no weird, questionable steel sources.

Edited by Bill Schmalhofer
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1 hour ago, Bill Schmalhofer said:

in 100 F high flash-point, vacuum pump mineral oil

This is the only thing I can identify that is outside of what I would normally consider a "good" process.

11 hours ago, Gilbert McCann said:

I think it looks like a random hamon. I wonder if your quenchant was fast enough. Just a guess. Looks like soft spots. 

This is what I am leaning towrds. Who is the 1084 supplier? Can you find an assay for the stock you are using?

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I'd also vote for those being spots that didn't harden.  When I switched to 1084 in my pattern weld mix from the 1095 I had been using, I had a couple stumbles where I didn't have the blade quite hot enough to get the hardness I was expecting.  I ended up bumping my oven up 50 degrees F and my problems went away.  I'm not very familiar with 80CrV2, but you may be in a similar edge case.

 

WRT the crosses:  You and I are in the same climate.  I don't know if your shop is heated, but I've noticed that my etches take far longer when my shop gets cold.  My 10 minutes cycles in the summer months can easily become 30 minute cycles in the winter.

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1 hour ago, Joshua States said:

This is what I am leaning towrds. Who is the 1084 supplier? Can you find an assay for the stock you are using?

NJSB for both the 15N20 and 1084. Both 0.07 inch steel.

1084: C:0.825  Si: 0.200 Mn: 0.726 P: 0.0059 S: 0.0020

15N20: C: 0.730 Si: 0.320 Mn: 0.389 P: 0.0045 S 0.0010 Cr 0.137 Ni 1.980 Mo 0.038

 

1 hour ago, Brian Dougherty said:

I'd also vote for those being spots that didn't harden.  When I switched to 1084 in my pattern weld mix from the 1095 I had been using, I had a couple stumbles where I didn't have the blade quite hot enough to get the hardness I was expecting.  I ended up bumping my oven up 50 degrees F and my problems went away.  I'm not very familiar with 80CrV2, but you may be in a similar edge case.

 

WRT the crosses:  You and I are in the same climate.  I don't know if your shop is heated, but I've noticed that my etches take far longer when my shop gets cold.  My 10 minutes cycles in the summer months can easily become 30 minute cycles in the winter.

I'm beginning to get the feeling the consensus is not hardened spots.

 

My shop is "split". Hot work is done in my back yard as my HOA won't let me put up out buildings. All my finish work is done in my basement (usually). When I was having issues with the crosses, I took my etching outside when I was "boosting" my FeCl2 with the 34% HCl (WOW, potent stuff!). But it was before Christmas when IN was having that "heat wave" of 60 degree days so it wasn't too cold. I'm beginning to think the crosses had the same issue as this blade. They were 1/4 inch thick, so the likelihood of my sub-standard quench oil not getting them cold fast enough was probably amplified. 

 

Hate to do this as the knife was basically finished (just had to glue the handle on :angry:), but I think I'm going to get a gallon of Parks AAA and re-heat treat this blade. If that works, nothing lost but time (probably end up having to make a new handle) and valuable information gained. If it doesn't work, still no loss as I couldn't sell this knife this way anyway (but the question of WTF happened will still remain :unsure:).

Edited by Bill Schmalhofer
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34 minutes ago, Bill Schmalhofer said:

(probably end up having to make a new handle) 

Why is that?

 

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Before you go too wild, try heating the oil more.  100F is too cold for straight mineral oil and 1084.  130-150F works for me.  Heated by quenching big chunks of iron until it's hot enough I don't like to leave my finger in it more than one second.  Heating the quench is counterintuitive, but it really works to speed up the quench.

If you do get the AAA oil, you will note the directions say the working range is 130F-170F.  Parks 50 recommended working range is 60F-90F, but heated to 130F it will do positive sori on water-hardening steels with a wedge cross section.  If used at the recommended temperature, you get zero sori or even negative sori (nosedive) if the blade is a wide full flat grind. 

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4 minutes ago, Joshua States said:

Why is that?

 

Probably...

Depends on how much I have to take off the ricasso to clean it up after quench. Hope I won't, but I'm never that lucky :lol:. Minimally a new guard.

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2 minutes ago, Bill Schmalhofer said:

Probably...

Depends on how much I have to take off the ricasso to clean it up after quench. Hope I won't, but I'm never that lucky :lol:. Minimally a new guard.

Ever try using anti-scale coatings?

 

Edited by Joshua States
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3 minutes ago, Alan Longmire said:

Before you go too wild, try heating the oil more.  100F is too cold for straight mineral oil and 1084.  130-150F works for me.  Heated by quenching big chunks of iron until it's hot enough I don't like to leave my finger in it more than one second.  Heating the quench is counterintuitive, but it really works to speed up the quench.

If you do get the AAA oil, you will note the directions say the working range is 130F-170F.  Parks 50 recommended working range is 60F-90F, but heated to 130F it will do positive sori on water-hardening steels with a wedge cross section.  If used at the recommended temperature, you get zero sori or even negative sori (nosedive) if the blade is a wide full flat grind. 

I was just looking up past posts on mineral oil (as I remember you said that's what you used - which is why I got the mineral oil from work when I could) and saw I was too cold. Things are starting to make more sense. When I was doing the crosses, I started at 100F but by the time I was done the quench tank was positively hot (basically quenching the equivalent of 7 3/4 x 3/4 x 6 inch bars of steel in relatively rapid succession). The crosses I had issues etching were the first ones I quenched. The last 3 actually etched fine. 

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18 minutes ago, Alan Longmire said:

If you do get the AAA oil, you will note the directions say the working range is 130F-170F.  Parks 50 recommended working range is 60F-90F, 

 The stats I have are a little different.

 

Oil stats.JPG

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6 minutes ago, Joshua States said:

Ever try using anti-scale coatings?

 

I'm going to jinx myself here but I've actually never really had an issue with scale. I think the coating of carbon I get on the blades during the HT process helps. I do kind of wonder what that carbon is doing to my oil though...)

 

My main issue is going to be the guard fit up. I'm going to take the blade back down to smooth again before HT ( the etching that did happen is really deep - can almost use it as a washer board in a banjo band :P). Don't think it is a good idea to HT with that much topology. Let me know if I'm wrong on that count though.

 

 

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I think the topography would just lengthen the nucleate boiling phase of the quench, acting to slow the process.  So yeah, it might work, but it'd be safer to take it back smooth, in my wild guess opinion.  

 

39 minutes ago, Joshua States said:

 The stats I have are a little different.

My mistake, I must've been looking at the row just below AAA.  

 

My mineral oil data came from Ed Caffrey, as he used vet grade mineral oil for both his JS and MS blades, and for years afterwards.  

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18 minutes ago, Alan Longmire said:

I think the topography would just lengthen the nucleate boiling phase of the quench, acting to slow the process.  So yeah, it might work, but it'd be safer to take it back smooth, in my wild guess opinion.  

 

My mineral oil data came from Ed Caffrey, as he used vet grade mineral oil for both his JS and MS blades, and for years afterwards.  

Thanks! Will take it smooth and give the mineral oil another go before the expense of Parks.

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  • 3 weeks later...

Update on this etching issue.

 

Took the blade back to smooth. Did a 1500F and 1400F normalization, then a quench from 1550 into very warm mineral oil. Quenched fast enough to get a slight amount of sori (?) bending the tip down. Tempered twice at 375F. Cleaned it up only to 1000 grit belt finish and etched only two 10 minute rounds with a bubbler.

 

Aaaannnnnd the results. Worse than ever...

IMG_0397.jpg

Not super apparent in the picture as I didn't do a *full* etch, but it is there.

 

Still no hardness testers but I tested the "old fashion way"

 

Shave...

IMG_0393.jpg

 

Chop a 2x4 in half (you can see the non-etching spot better here)...

IMG_0395.jpg

 

Shave...

IMG_0396.jpg

 

It hardened, and takes a NICE edge.

As much as I hate to do this with as much time as I have invested in this thing, I'm going to try snapping it in a couple of places and see what the grain looks like.

 

Don't expect any comments on this failure (unless you think you have some idea what's going on), but wanted to let the people who tried to help know what happened - or didn't happen as the case is.

 

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Update #2: The hardest thing a knife maker EVER has to do...

 

Don't think it was my heat treat. Someone correct me if I'm wrong...

 

Tip

tip_iMG_0401.jpg

 

Middle

middle_IMG_0405.jpg

 

Ricasso

Ricasso_IMG_0407.jpg

 

Got the HT on the tang good too.

 

After tip break

tang 1_IMG_0402.jpg

 

Had to go to a 3 foot long piece of PVC to break the middle and ricasso.

 

Then just to see if I could break the tang...

Tang 2_IMG_0409.jpg

Nope.

So painful. Will recycle this knife in a hearth furnace run. Waste not want not...

 

10 minutes ago, Alan Longmire said:

Before you get too hasty, maybe try a coffee etch and see if that evens out the colors?  That's all I have left, sorry... :(

Sorry Treebeard. Got too hasty. Nice to know my HT is still good though.

 

Edited by Bill Schmalhofer
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5 minutes ago, Alan Longmire said:

Before you get too hasty, maybe try a coffee etch and see if that evens out the colors?  That's all I have left, sorry... :(

Just a (very conceited) thought. Could my grain be too fine?

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I have no idea if that would affect etching that much.  I mean, that is good fine grain, and it certainly hardened all the way through, so I don't think it's failure to harden from to much normalizing...

 

But I've been wrong before and will continue to be in the future. :lol:

 

 

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