Honest question about Turco vs. wrap

G

godogs57

Joined
Apr 16, 2004
Messages
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Not wanting to start a war of words, but I honestly want some enlightened opinions as to whether stainless steel foil wrap is better than Turco liquid for ht. From what I read on here, 99.99% of the folks use the foil. The Turco seems to be much easier to use, so I am wondering if there is anything advantageous to using it. I have ht'd both ways and currently use CPM154CM almost exclusively.

My reasons for asking are that most of my CPM blades come out nice and sharp...no problems. But every once in awhile I will get one that really does not want to hold an edge for long. I hardness test my blades and all come out around 60 after ht & triple temper, etc...so I am wondering if there might be something I need to consider those times I have used Turco, etc...


Your opinions are appreciated!
 
My reasons for asking are that most of my CPM blades come out nice and sharp...no problems.
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I wonder, do you HT them sharpened? If thats the case, yes it is very likely they wont hold that edge for long. Even if you cover the steel good with any medium you want it is possibly blade has a decarb layer even it is microscopic. But if you grind away at least some microns of outer layer and sharpen and then it doesn't hold an edge well, it is most probably your HT was gone wrong somewhere...
 
Noooo....don't sharpen them prior to ht. I ment that after everything is done, they are sharpened. Thanks for your input.
 
I've used both. I didn't have good luck with the turco. I like the foil because I grind my blades hard unless it is a large fixed blade.
 
I"ve used both as well. I found turco messy and more clean up was required on the blade after heat treat than foil and plate quenching.

Having said that, I do use turco for oil quench steel such as O1 - and they sure do come out cleaner than without.

I've talked to makers who favour both for one reason or another. Which method has led to the reduced edge holding for you? If that seems to be both, the may lead elsewhere... edge geometry... temperature variation in your oven... blade position in hardening or tempering operations... overheat when sharpening... sheath related edge abrasion... actual use compared to intended use...

Obviously I'm not suggesting any of these relate to your blades - just that you may want to consider more than the heat treat barrier.

Rob!
 
The reduced edge holding is with the Turco. I have read somewhere that Turco is not designed to go over 1800-1850 degrees, or thereabouts. I heat my CPM154CM to 1925 for 30 minutes and triple temper at 375 for two hours. I am wondering if I am ht'ing beyond the parameters of the Turco and getting a ton of decarborization, etc...
To me the Turco is easier to use. All my buddies that use the foil wrap...its just the biggest deal to take the wrap out of the oven and get it out of the foil and into the forced air quick enough to quench properly. Seems to me if I could get the Turco to work...things would be simpler. Just yank it out of the oven and into the blast of the fan to quench.

Thanks so much for your suggestions...they are appreciated.
 
godogs57 said:
..its just the biggest deal to take the wrap out of the oven and get it out of the foil and into the forced air quick enough to quench properly.
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You dont have to take it out of the foil if you plate quench. The hot blade should never see oxygen. Leave it in the foil - quench it between the plates - less than two minutes, you can hold it in your bare hand.

If you going to cryo, you should probably take out the foil before that because the liquid is going to seep in and when you remove it, it expands rapidly and can get a bit challenging.

If you aren't doing cryo, you can leave it in the envelope even for the tempers, though the envelope just isn't necessary for most tempering temps.

Rob!
 
I use Turco for carbon steel blades like O-1 and 8670. I use foil for stainless. It's not possible to get a blade out of foil in a manner timely enough to do it right, hence the Turco.

Turco works fine for a single blade. If I'm doing several, it appears that opening the furnace door long enough to remove a blade allows enough O2 that the Turco burns off the others and scale starts. I'll probably end up building a salt pot setup because I'm tired of scaled blades.

I've had no problems with foil. Yeah, I have to fast, but it works well for air hardening steels.

YMMV

Gene
 
OK....everyone who has used foil (that I have ever seen) has done the "mad rush" to get it out of the foil, etc to air quench. I have heard of plate quenching, but never paid any attention to it before now. Whats the deal on it? How big a plates do I need? Technique? I am interested in this...this may be a way to fix my problems...
Thanks!
 
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