Just to add some anecdotal evidence regarding mill scale, I haven't ground mill scale or rust off the steel I use to make damascus in the last couple of years, and never had an issue.

Honestly it seems like the less complicated I make the whole process of damascus, the less issues I encounter.

One thing I did want to ask about however, in regards to "bare-back" welds, is whether you still feel the use of flux as a shielding agent for burn off and scale build-up in drawing heats is productive? JD I feel like I remember reading that you utilize this method, and it was brought to my attention earlier in the year by Jim Batson one day when I was making steel over at Bill's. At this point I was dry welding all my restacks with MIG'd edges, and was only using flux during the first weld. He gently reminded me that using a little borax on the billet between drawing heats would help reduce all the scale build-up I was seeing and reduce overall mass loss.

Anyway, I'm not a metallurgist, but it seemed to make sense to me, and observation has seemed to support that? Do you think/still think that this is an advantageous act?

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Bob,

Thanks for the response. I had a much better day on Sat and made a 15 layer billet of 1095, 5160 and L 6. I welded dry and had 2 minor edge issues in the billet that is 18 x 2.25". I was kind of proud of myself and enjoyed a couple of shooters of single malt scotch after. I'll post a pic when I get to the shop on Mon.

This has been a real learning experience for me and I certainly appreciate the helpful suggestions.

John

Pic of Sat fun. not a great pic though...

John

Brion,

Do you know what temperature your forge was running?

I'm going to try this on my next billet and record temp and soak time at welding heat.

This is fascinating!

Russell

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Just to add some anecdotal evidence regarding mill scale, I haven't ground mill scale or rust off the steel I use to make damascus in the last couple of years, and never had an issue.

Honestly it seems like the less complicated I make the whole process of damascus, the less issues I encounter.

One thing I did want to ask about however, in regards to "bare-back" welds, is whether you still feel the use of flux as a shielding agent for burn off and scale build-up in drawing heats is productive? JD I feel like I remember reading that you utilize this method, and it was brought to my attention earlier in the year by Jim Batson one day when I was making steel over at Bill's. At this point I was dry welding all my restacks with MIG'd edges, and was only using flux during the first weld. He gently reminded me that using a little borax on the billet between drawing heats would help reduce all the scale build-up I was seeing and reduce overall mass loss.

Anyway, I'm not a metallurgist, but it seemed to make sense to me, and observation has seemed to support that? Do you think/still think that this is an advantageous act?

To be brief Javan, NO. If you adjust your atmosphere properly, there will be hardly any scale at all... Those of you who've tried this already; very little if any scale right? Javan, please reread my "How It All Works " post a few up on this page. I explain that we're using the chemistry of combustion to deplete the scale of Oxygen, thereby reverting it back to pure metallic iron .

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Okay, I made up a billet , 9 layers, of 1084 and 15n20. Fired up the forge, mine is venturi, and adjusted the mix for a reducing atmosphere. The billet was brought up to heat and allowed to soak. Then to the power hammer and presto, light hits and a welded billet. No flux or kerosene was used, totally dry, mill scale left on. I did do two heats for welding. Then flipped the billet 90 degrees and hit on edge, no delaminations at all. The billet has been drawn out. Needless to say my method of making damascus has just changed. No splatter, or borax powder flying around. Thank you Bob and J.D.

Brion

AND... FAR more secure and stronger welds!! "Goin' Bareback" rules!

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JD's demo did in fact blow my mind a bit, until I got my head around what he was doing ( and JD thank you SO much for demoing at our hammer-in!)and realizing that the chemistry is similar to making steel from Ore in a direct reduction furnace (bloomery).

My thoughts after having a bit of time to think about and talking it over with my business partners, the bare-back method works and works well. How well it works for everyone will I think be contingent on a few things, the reducing atmosphere at high temps in the forge is a must and some forges will work better than other for it(In general I think it will work better with venturie burners rather than blown)and I don't think you could repeatablely do it in a coal or charcoal forge.

A few other types of welds I think will still require flux (welding the eye on tomahawks, welding the tip and edge on traditional Viking sword, etc) but how much this method speeds up and simplifies the whole process of making a billet is just incredible!

MP

Venturi or forced air; either works equally well. You're likely correct Matt. "Bare-back" may indeed NOT work with older style heat sources( coke, charcoal). But here's the thing, gas is a new styled heat source compared with traditional coke and charcoal. What happened was we all went mostly to gas and continued using the forge-welding techniques that worked in old style heat sources. What we've done is to update the technique along with the heat source, in other words, just go modern all the way.

Gotcha, thanks JD, makes sense.

Russell, my forge runs at approximately 2350-2400 at welding heat. One thought, does this process only work well for similar steels? In other words, similar carbon content and makeup. Such as 1084 and 15n20. Similar carbon content or close, .75 vs .84, and similar alloy except for the nickel in the 15n20.

Brion

The information in this thread is awesome! I want to thank JD for taking the time to do testing of welding without flux. This is work that I had planned to do, but had not got around to it. JD, you have saved me the shop expense of doing this work myself. Thank you!!

Not to be argumentative, but I think we should be cautious about suggesting that coal and charcoal forges are not suitable for dry forge welding. Over the millennia that man has been working with iron and steel, these were the only heat sources available. In my research, I have found many accounts of dry forge welding in coal and charcoal forges. As far as the heat source, what is critical is the control of the reducing atmosphere, no matter the fuel. I only throw this out, so as not to discourage those who only have coal and charcoal from attempting fluxless welding.

Related to this, is some information that I have heard regarding the making of damascus gun barrels in Belgium. The Belgian barrels smiths used side blast charcoal forges to weld damascus gun barrels. I have read that they mixed clay into the charcoal that was used in the forges. Exactly what the consistency of the clay was and what the percentage of the mix was, I do not know. I have also heard that they would gather forge scale from their work, mix it with clay and form it into balls. They would place the balls of clay into the forge. Perhaps the clay balls worked as a heat sink to help maintain the temperature of the fire. Exactly what this use of clay did for them, I am not certain. Just some anecdotal information that could have some relevance.

Brion's question about whether certain steels are better for dry welding is one that I also have. I've done a lot of research on mill scale. I have read that the alloys in the steel precipitate into the mill scale in approximately the same percentages as they exist in the steel. In more highly alloyed steels, there is that possibility that the alloys in the scale could affect the weldability, and/or require an adjustment to the welding process. This could be something to keep in mind, if problems with welding crop up.

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"Not to be argumentative, but I think we should be cautious about suggesting that coal and charcoal forges are not suitable for dry forge welding. Over the millennia that man has been working with iron and steel, these were the only heat sources available. In my research, I have found many accounts of dry forge welding in coal and charcoal forges. As far as the heat source, what is critical is the control of the reducing atmosphere, no matter the fuel. I only throw this out, so as not to discourage those who only have coal and charcoal from attempting fluxless welding."

Steve, I only suggested that it may not work. That is not anything I know for a fact by any means. All I meant was that I haven't tried it and do not know.

Since I do not use those heat sources and have no intention of doing so, I'm hoping some of those who DO use them, do some research in that direction and increase the knowledge base for this procedure( "Goin' Bare-back" ).

Gentlemen, fire up your forges and get crackin'!! Inquiring minds want to know!

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The information in this thread is awesome! I want to thank JD for taking the time to do testing of welding without flux. This is work that I had planned to do, but had not got around to it. JD, you have saved me the shop expense of doing this work myself. Thank you!!

Not to be argumentative, but I think we should be cautious about suggesting that coal and charcoal forges are not suitable for dry forge welding. Over the millennia that man has been working with iron and steel, these were the only heat sources available. In my research, I have found many accounts of dry forge welding in coal and charcoal forges. As far as the heat source, what is critical is the control of the reducing atmosphere, no matter the fuel. I only throw this out, so as not to discourage those who only have coal and charcoal from attempting fluxless welding.

Related to this, is some information that I have heard regarding the making of damascus gun barrels in Belgium. The Belgian barrels smiths used side blast charcoal forges to weld damascus gun barrels. I have read that they mixed clay into the charcoal that was used in the forges. Exactly what the consistency of the clay was and what the percentage of the mix was, I do not know. I have also heard that they would gather forge scale from their work, mix it with clay and form it into balls. They would place the balls of clay into the forge. Perhaps the clay balls worked as a heat sink to help maintain the temperature of the fire. Exactly what this use of clay did for them, I am not certain. Just some anecdotal information that could have some relevance.

Please don't misunderstand me, I don't want to discourage anyone from trying. I didn't say it couldn't be done just that I don't think it can be done consistently, what I meant by that is that in a solid fuel forge with this method the risk of particulates being trapped in the weld would be far higher with out a flux, also it would require very careful and consistent fire maintenance for long periods of heating, something I know I find difficult, and something I watch my students struggle with in blacksmithing classes. Others may in fact find it easier than I do, I don't get the chance to work on a coal or charcoal forge all that often anymore.

I very much may be wrong in this, but I think JD has a good point in modern tooling allowing for new methods. This is something Blacksmiths see in reverse with old ironwork, some of the forge welds and assembly methods in say colonial door hardware look impossible and almost are working in mild steel, do the same thing in wrought iron and it is simple method. The modern materials require a different methodology to achieve a similar result.

MP

JD,

I realized that you didn't mean to totally dismiss the possibility of dry welding in coal and charcoal forges. <img src=' http://www.americanbladesmith.com/ipboard/public/style_emoticons//biggrin.gi f' class='bbc_emoticon' alt=':D' /> I just wanted to offer that these types of forges should be capable of use for this work. Didn't want anyone to give up on trying it.

I actually have a lot of experience with both coal and propane forges; though none with charcoal. About 10 years ago, I evicted my coal forge from my nice clean shop and went exclusively to propane. Propane is great for welding big billets of damascus, but I honestly miss coal for blade forging.

Gathering from my experiences with both coal and propane, I have always felt that I had better control of a reducing atmosphere with the coal forge. What with my own concerns about my ability to maintain a proper atmosphere in a propane forge, your findings about the atmosphere not being so critical is a relief to me. Your sharing of this information is deeply appreciated by me!

Matthew,

You may have a point with the particulates from the coal. However the flip side of that, is that flux creates a sticky film on the steel that may attract particulates. The bottom line no matter what, is that the smith needs to always maintain a clean fire, position the work piece in a safe location in the forge and control the blast so as not to disturb the small pieces of coal more than necessary.

I definitely agree about modern tooling allowing for, and also requiring new methods! While we are replicating and duplicating items that have been produced in the past, we are often doing it with entirely different materials and tools. As you mentioned about wrought iron vs. mild steel; the modern steels that we have to work with have different working properties than materials from the past. But, we also understand much more about our materials than did the old blacksmiths. With our more complete knowledge, we are capable of making products that are superior to what has been possible in the past.

This thread got me thinking and wanting to give this a try so I did today. I started with a typical 20 layer billet of 1084 & 15N20 that I tack welded with my MIG. From there I placed it in my forge with the usual 6" flame coming from the opening in it. After a bit of a soak at welding temp I did my usual light squeeze in the press and back into the forge for another soak. The second time I did my usual heavy squeeze in the press. In order to really test the welds I did a "W" squeeze and drew it out. I cut it into six pieces and did a stack with only a spot weld to hold it together without doing any grinding. I wanted to see if leaving the scale on would make any difference. The only thing that I did different (other than leaving on the scale and no flux) was to let the billet soak for approximately 10 minutes at welding temp. Here's the billet:

Though it's a long way from a finished blade, I can't see any flaws so far. So far it sure looks like this process works.

Gary

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Russell, my forge runs at approximately 2350-2400 at welding heat. One thought, does this process only work well for similar steels? In other words, similar carbon content and makeup. Such as 1084 and 15n20. Similar carbon content or close, .75 vs .84, and similar alloy except for the nickel in the 15n20.

Brion

To me, this is a subjective question in that it depends as to where one insets their their thermocouple. I insert mine from between the bricks at the opening of the forge, and as such, work from there. If I place it on the floor of the forge, it reads higher. I think it's just a matter as to where your welding works best for your forge. I don't think there are any hard cold answers given the parameters.

That being said, 2330 in my forge seems to work best for me.

I mixed 1095/ L6/and 5160. It worked. I suppose someone will find something that doesn't work, and we'll all be that much better off, or enticed to try it. <img src=' http://www.americanbladesmith.com/ipboard/public/style_emoticons//smile.gi f' class='bbc_emoticon' alt=':)' />

John Emmerling

Well, seems like the results are coming in. Hey Guys, It's all physics and chemistry...It HAS to work...Set the right conditions ( and they're VERY liberal, we're finding )and you just let it happen...In fact, you can't stop it from being perfect...(except if you use flux)