Heat coloring damascus

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Les Voorhies

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I've got some questions about heat coloring damascus, I'm hoping someone has some answers.

I've got this really nice knife going with Delbert Ealy damacus on the blade and bolsters. When i got the bars they had been heat colored and they looked great, so i decided thats how i would finish the blade and bolsters. It didnt turn out like i planned. I tried the oven 1st but i was at 500 deg. and didnt want to go over that on the blad but at 500 you really dont get any color. So I tried a torch next hoping i wouldnt draw it back too far. the bolsters worked pretty well but the blade was a mess. I tried 3 times and got good color on one side with splotchy color on the other or good color in the tang but solid light blue on the bevel.

So now i'm wondering what i'm doing wrong. How do you all do it? how much does taking the blade to a blue color affect the temper? for now i have it etched with feric but it just isnt what i wanted. any ideas?

:confused:
 
Blue heat coloring requires a higher temp than you should use for a blade. It will shave points off the hardness. It would be fine on knife parts but not for the blade. Not what you wanted to hear, sorry.
 
Bruce is right you will lose hardness but, if you want to heat color you need to use blueing salts, then you will get the even coloring you are looking for. You can get the salts from brownells and if you call them and tell them you are a knife maker they will give you a discount on some items.

nitreblue, item no.082-090-020,(20lb bucket) $41.09(plus the hazardous material shipping charge)

www.brownells.com or 1.800.741.0015
 
I have toyed with the idea of heat-bluing a blade, but putting that part of it into the tempering process.
 
Yep, I'll chalk this one up to stupidity, I've been making knives for 10 years and I've reheat treated or tossed out a few blades that i've burned to blue during final grind. So if you ask me what made me think i could heat the blade to purple or blue with a torch and not screw up the hardness, I have to say it was a temperary loss of common sense. In my defense, I'm pretty sure I have seen knives with heat colored blades but i suspect they are wall hangers or maybe some of the stainless damascus that maybe you can get away with that heat. Has anyone else seen knives that claim to have heat colored blades or is my imagination?

Anyway, I'm tring to salvage the blade now, I dont have access to a rockwell tester since i got laid-off but a file told me for sure i had sofened it too much. if i can get it through anealing and heat treating without it warping, it shoud be ok (Turco is great stuff).
 
These points of view may be a little naieve and I'll be the first to admit I don't have a lot of damascus experience. I'm basing my opinion of a few premises that I hold to be true - and I'm open to being corrected.
  • Nomatter what etching or coloring process you use on damascus, it will wear off with use.
  • By it's nature (and design) damascus uses dissimilar steels and will not be of uniform hardness.
  • Unless scales and hardware are removeable, it's going to be somewhere between tough and impossible to re-blue / re-etch a worn or scratched blade.
  • If someone uses a damascus blade enough to dull even a soft blade, they have probably also affected the etch.
  • A damascus blade generally gets used to show off - maybe open an envelope or trim a loose thread. Opening packing crates and oil cans is reserved for the EDC.
So my question is why would you not consider heat bluing? The look is spectacular and the real world performance will be indistinguishable.

(playing devil's advocate a bit here.)

Rob!
 
Rob!:

I agree entirely with your position on the heat bluing, most steels we use are at optimum performance when tempered in the range that will give you a straw yellow to brown color if allowed to oxidize for an hour or more, heat applications that will get you to blue in less time is destroying the hardness levels you carefully preserved in the tempering. Nobody is mistaken that they have seen many knives hot blued, but folks will do whatever the market will allow; how many $1,000 knives will ever be pushed to the point that we will know what those pretty colors cost in performance? There are a lot of things that are justified by saying that you do what sells, but then more than one drug pusher has used the same argument ;)

now that I have agreed with you, I am going to put your openess to correction to the test, but just a little ;)

Very light etches will indeed wear off, but after about 8 to 10 minutes in the ferric chloride (if all goes right) you will have a topography that will darn near require regrinding the blade to get rid of. I personally like it this way because it makes for a very maintanence free damascus, even if it does rust just resand the high spots and things can be good as new.

Although it is common sense, dissimilar steels do not always yield differing hardness. This is heavily effected by number of layers, welding technique and, of course the, the steels used. Steel with many opportunities for inclusions will indeed be all over the map in rockwell, but I am still shocked myself at how consistant my O1/L6 mix can be. I have actually found that HRC readings on my damscus tend to be more uniform after tempering than O1 all by itself. just another one of those things that shouldn't make sense but does :confused: . Carbon content alone just will not get the variations that folks expect, and you need to mix some high contrasts in alloy content to get those kind of results, or as I previously mentioned trap a lot of crud inside the steel.

That is the extent of my differing, the rest I think you are right on the money.
 
I understand that an expensive knife will most likely not be used hard if used at all but "expensive" is relative. I sold a folder a while back, I think it went for $325, (I considered that expensive for my knives) he just sent it back to me to clean up the nicks in the edge. He said he was cutting cardboard and may have hit some staples. So you really never know, the knife may get some actual use. I dont really make anything yet thats a true wall hanger so untill i do i think i wont be heat coloring blades.
I agree with Kevin about a good etch, as for heat coloring, after buffing the color out of this blade a few times i think heat coloring might hold up half way decent.
 
Les Voorhies said:
Yep, I'll chalk this one up to stupidity, .
Click to expand...


I wouldn't go that far yet ...

if you want,, just keep the edge heat treated (differential tempering)
you can water tube the edge and then heat color the rest with the O/A torch long as you want :)
 
Dan Gray said:
I wouldn't go that far yet ...

if you want,, just keep the edge heat treated (differential tempering)
you can water tube the edge and then heat color the rest with the O/A torch long as you want :)
Click to expand...


The problem i would have then is only etching the edge, but there are some ways around that. I didnt think heat colored damascus and etched would look good together, thats why i didnt just heat the bolsters and etch the blade but maybe your way might help them blend.
 
That pretty blue color you get on your damascus bars is niter blue.The salts are melted at 500 to 700 degrees and ,depending on the temperature can produce vivid colors.You are about now saying,"500 to 700 DEGREES,my HT is shot!". The dip in and out of the hot salts is so fast it only heats up the surface (assuming you don't hold it in the pot for more than a second or two).You can melt it in a pan,but a low temp salt pot is far better.A thermostat is a real plus,a rheostat a minimum necessity.

I have an old burnout oven for casting.I am cutting a 4" hole in the top to insert a 4" melting pot. That way I can set the oven temp to what ever I want for the salts and it will heat the pot to that temp.I should be able to do a 10" blade.The oven goes to 2000F so ,theoretically, I can do almost any salt pot job.All I need to do to change salts is to insert the right pot( already loaded) and heat it up.Air tight caps for the salt pots will keep the salts dry and clean,and I will make a fire brick plug for the hole to use the oven as a small tempering oven,or casting.Heck, I could even use it as a small vertical forge by making a plug with a 2" hole.These ovens are fairly easy to come by,have an 8X8 or so chamber,and often have a good controller (some only have a rheostat).
 
I talked to him at the wolverine show in MI and i remember he got the color at low temps. Call him and ask. :cool:
 
Now that you have the responses on how to do this.Let me add something.

What ever finish you put on a knife can and will get scratched at some point in time,whether it is used or someone drops it or accidentally bumps it with another object or knife.Be ready to have to fix a finish on any knife you make.I personally have had blade finishes messed up a shows (gun) were someone picks the knife up and isnt careful and drops it on the table against the other knives :eek: rendering it unsellable untill I took it back home and fixed it.

Never-Never-Never send a knife out that is not capable of being the best and strongest knife you can possiably make..That goes for wall hangers,as some call them,remeber not all knives are bought to keep some are gifts for non knife people and they think it can be used to wack on anything.Or the collecter passes away in a few years and the knives get passed down to another family member then maybe to another,by then the costs dont matter and the knife gets used,guess what if it isnt usable your name get pulled through the mud really bad.Make the collectables so that in a hundred years when people are asking who this maker was or why did he make it like this,they also say it is a really awesome knife and holds a better edge than most anything they have ever owned,you know how it goes.This is our legacy for years to come and our name is only as good as our blade steel is.

So what ever finish you decide Please dont give up the edge holding ability of the knife..


Just my 2 cents and a bunch of rambling,
Bruce
 
yes what Bruce said keep the edge useable at the very least..
you can use low temp salts too
check this out
http://www.knivesby.com/blueingsalts.html



stacy is that unit ele or gas? if ele I'd worry about the eleaments in it from the salt fumes but other wise I think you have something there..
 
Thank for the link Dan, i assume Brownell would carry low temp salts. I'll have to try that at least see what it looks like. Bluing damascus isnt exactly the finish i was looking fo in this case but its something i've been wanting to play with.

Dan Gray said:
stacy is that unit ele or gas? if ele I'd worry about the eleaments in it from the salt fumes but other wise I think you have something there..
Click to expand...
The way it was described it sounds like the salts (or fumes) would never come in contact with the elements.

Kim Breed said:
I talked to him at the wolverine show in MI and i remember he got the color at low temps. Call him and ask.
Click to expand...
Are you refering to Delbert? I dont see how its possible to produce the colors with heat alone at lower temps.
 
Les Voorhies said:
Thank for the link Dan, i assume Brownell would carry low temp salts. I'll have to try that at least see what it looks like. Bluing damascus isnt exactly the finish i was looking fo in this case but its something i've been wanting to play with.
.
Click to expand...
the point with the link was
lye is the same stuff as what Brownell carries..
CAS Registry Number sodium hydroxide 1310-73-2

you can pick some up at your true value store if not at a hard wear store or have them order it..it may save you hazardous shipping charges :)
 
Electric.The salt fumes would be outside the heating chamber.The melting crucible (pot) will drop into the oven from the top,and project out above the oven.I have considered making a stainless steel "top" to protect the oven from drips and spatters.
Stacy
 
Dan Gray said:
the point with the link was
lye is the same stuff as what Brownell carries..
CAS Registry Number sodium hydroxide 1310-73-2

you can pick some up at your true value store if not at a hard wear store or have them order it..it may save you hazardous shipping charges :)
Click to expand...

Dan....so hardware store lye is the same stuff as Brownell's Nitre Blue? Just buy some of that and use it the same way?
 
I believe so Greg it's mixed with water and you'd have to monkey with the mix from time to time anyway because of evaporation...

Lye, years ago was on the shelves all the time for out-houses to reduce the waste rr you know POOP :D

look for the CAS Registry Number 1310-73-2 on it , it will tell you if it's the same stuff,, but lye is lye as far as I know.. :)
 
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