Heat treating after inlay

Chujybear

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I understand that those of you working on guns will do all of your finishing work, including inlay, before shipping it out for various surface treatments.

I am assuming that this does Not include any hardening.

That's my question I guess..

I have had a few Damascus blades made, which I am sculpting and engraving, including excavating Chanel's to receive inlay.
An I correct in assuming that I do all my carving, harden, temper, and then carry on with my inlays?
Thank you.
 

rmgreen

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Chujbear,

As to firearms normally engraving and inlay work is completed prior to heat treatment and drawing. See thread Trigger guard -Phil Coggan. Normally the fine detail work of the inlays are done after hardening/drawing.

I have NO clue as to the order of work on knives. I would "think" because of the hardness that knives are typically hardened to that much the same process would be followed. All work is accomplished on the steel part while it is in the soft state. The inlay's hardness will not be affected by this process as to it's hardness.

Like all things there are exceptions.

RmG
 

jerrywh

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The inlays if they are gold ,silver or platinum should be done before any heat treatment. On fine gold or silver inlays any case hardening should be done at temperatures not to exceed 1550° max. I do my own case hardening and have done a lot of it. Believe me when I tell you that fine gold inlays on steel packed in charcoal will melt out or alloy with the steel at a temperature just above 1550°F. Some will argue that point but I do a lot of gold and a lot of case hardening and I have melted them out before. I have very accurate temp control. On regular hardening and tempering without a carbon pack I would tend to stick to the same rule because better safe than sorry. I know that gold melts at about 1880° but not when it is packed in charcoal. Try putting a small piece of gold in some melted lead or tin at 650°. Guess what? It will be consumed and alloy with the lead or tin. Gold has some strange properties. That is one reason why jewelers do not use lead solder.
I would be concerned about who was doing the heat treating.
 

Barry Lee Hands

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On a Damascus knife my method is to engrave, excavate gold cavity, harden, install gold. Etch Damascus,Polish gold with steel wool, detail gold.
If you put the gold in first at knife hardening temps it will alloy with the steel( turning whitish green ) and / or melt.
 

Beathard

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Barry is correct. Hardening of blades is at a much higher temp. But putting the gold in after hardening has a benefit, it easier to trim it flush without gouging the blade metal.
 

jerrywh

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Barry. Thanks for the good info. What do you do to prevent oxidization of the steel and if the inlays are flush ,how do you flush them off without scuffing the blade pattern? J.H. Ps. I should have made it clear that I was talking about color case hardening.
 
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Beathard

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Color case hardening on firearms doesn't get to the temperatures required to melt the gold. Blade hardening does.
 

jerrywh

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Color case hardening on firearms doesn't get to the temperatures required to melt the gold. Blade hardening does.

What temp are you hardening at??? Gold is strange and will alloy with some metals way below it's natural melting point when in contact with some metals. Is this the case with steel or Damascus???
 

Beathard

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I send it to Turnbull to be case hardened. It hasn't alloyed yet coming from him. Don't know the temperature.
 

sseib

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Chujybear,

I believe it is going to depend on the materials your damascus are made from. Most simple low alloy high carbon steels knifemakers use for damascus ( 1070, 1080, 1084, 1095, L6, 15N20 ) will harden below the 1550 deg F mark that jerrywh mentioned. When you get into the high alloy and stainless steels, the hardening temps go up to 1800 - 2300 deg F. It is also a good idea to have the damascus spheroidize annealed before machining or engraving for easier cutting.

Steve Seib
American Bladesmith Society Apprenticesmith
Engraver newbe
 

Barry Lee Hands

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Hi Jerry,
The way I do it on Damascus the usual
Methods are used to avoid scale, ceramic coating, stainless foil etc however, I blast whatever scale is there with aluminum oxide either before or after the gold is installed.
As to flush inlay, I don't do much of that, as it is for the most part out of fashion, however I use the usual methods described on this forum and others.
 
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Marrinan

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Barry Lee Hands, When I undercut the channels with a very small chisel or fine pointed knife engraver. The chisel usually leave a raised bump, which is normally flattened back as gold is set. If hardened before setting the gold do these act the same way. Thanks Fred
 

jerrywh

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Thanks Barry. I have thought of hardening the plates on flintlocks before overlaying the gold in the pan because the teeth will hold up better on soft iron or steel like 12l14 but never have mostly because I wanted to preserve the colors. In hardening wraped in foil I had a problem with slow cooling. the foil seemed to insulate the part. I never used ceramic coatings. I wonder how platinum investment would work? I have hardened with parts packed in granulated clay or kitty litter.
 

quickcut07

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Jerry nice lock what ever you are doing seems to be turning out beautifully. Wish I knew more about heat treat myself. Color case work is an art all alone not talking about the spray on stuff but the real deal old way method. Got a friend up here that did colour case hardening but unfortunately the years of gunsmithing, hardening , cleaning and the sort have taken a toll on him. Hopefully he will recuperate and be able to get back to work.

Eric
 

Chujybear

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W ceramic coating, does it explode off the blade in the fashion that investment does on castings, when quenched?
Might be what the above questioner is driving at too.
Gwaai
 
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