Damascus/Forge Welding Woes

[mpc]

I’m a little bummed. I had a failed attempt at a “damascus” billet yesterday and I can’t figure out what went wrong. 

Here was the process. 
I cut several pieces of good steel (1084 and 15n20 from AKS) down to about 1 x 3. 

I cleaned them them with acetone, gave them a quick rough up on the belt grinder, cleaned them again with acetone, then stacked them and then welded the stack to keep everything in place.

I stuck the billet in some kerosene (overnight) and then went straight from the kerosene to my forge (the next day). According to my thermocouple probe, the forge was over 2200° when I put the steel in and I kept it there for 10 or so minutes (until everything was all the same color). 

I took it from the forge to the anvil, gave it several firm smacks with the hammer and then back into the forge. I repeated the process a few times and then started drawing it out.

It looked like it was welding but later, after I let it cool and did a little grinding, it became clear that the layers didn’t stick. Everything is still in place but there are clear lines between the layers and the top layer comes up when you grind it at an angle.

I can’t think of where I went wrong.

 

[ThomasPowers]

How oxidizing is the atmosphere in your forge?

[Steve Sells]

problems are more common when not using flux

[Bob Brandl]

I'm inclined to wonder the same thing with regard to the forge atmosphere. I've been using kerosene for a while when I make damascus, and have had no problems with it. Hmm...

[Momatt]

When I was learning to forge weld I learned mostly from discussions here and YouTube.  There were less YouTube videos 10 years ago and they were not as well shot generally. Best to learn in person if you can. Color from videos is wrong at least to me. I wasn’t getting things hot enough in my gas forge. It’s easy to make a sparkler in a coal forge, it’s never happened to me in a gasser.  Once I turned up the fuel so a 6 inch dragons breath came out the doors of my forge stuff started sticking. Makes for burned knuckles and for needing long tongs! Let it soak at a welding heat (to me looks white) a little longer than you are comfortable then add a minute.  I think you need to do more welding heats when using a hammer than when using a press or power hammer too. I have had steel at welding heats for a long time in and out of the forge many times and never had all the carbon leave the steel. Comes out of the quench way harder than my best file. 

[vern509]

I had a similar issue.

Tried 2 things, not sure which led to success:

#1 got a 25 gallon propane tank instead of the 5 gallon.  Huge difference is keeping proper gas flowing due to tank icing up.

#2 Warmed the anvil up.  I had a 8 inch by 3/4 square bar stock heating while I heated the billet.  I put it on the anvil yellow and let it cool to black 3 times before I attempted my first weld on the billet.

 

I use borax flux, never tried kerosene.  But other than that our processes are the same.

[billyO]

A couple of things stick out to me, based on my reading of your description of your process.

The first thing that came to mind is what others have mentioned, specifically what was the atmosphere in the forge?

Secondly:

On 4/5/2020 at 7:38 PM, mpc said:

gave them a quick rough up on the belt grinder

I'm not sure what you mean by this.  Did you get all the mill scale off each piece?  When I make a billet, I don't worry about cleaning with acetone, I just make sure that I've ground each mating surface down to bare steel before putting the pieces together (and avoid touching said surfaces with my bare fingers after grinding to keep oils off).

Finally:

On 4/5/2020 at 7:38 PM, mpc said:

gave it several firm smacks with the hammer and then back into the forge

This is hard to know what you did.  The first hits with a hammer have to be firm enough to 'set' the weld, but not too firm to cause any movement (shearing) between the layers which will prevent welding.  I usually do 2-3 heats where I'm only focused on setting the weld and not trying to do any forging to shape until I feel (and I'm referring to actually feeling through the hammer, as opposed to some other abstract 'feeling') the billet turn into one solid piece opposed to a number of layers of individual pieces.  Only then should one start forging to shape.

Apart from feeling the billet turn solid, you can also see if the whole piece cools down and changes color uniformly or if some parts seem to cool off faster than others, indicating separate pieces.

On 4/5/2020 at 7:38 PM, mpc said:

after I let it cool and did a little grinding . . . but there are clear lines between the layers

Also, not sure what you mean here.  How deep did you grind?  If all you did was grind off the scale, it's possible to still see the weld lines and still have a solid weld.  

Here's an example of a billet I was working on last year that shows what I'm talking about.  This was a solid billet after welding but before drawing out.

You can easily make out the layers of 1080 and 15N20 but the weld is solid.

[Frosty]

I'm with Billy on this. It's largely a prep problem. A quick roughing doesn't do it for me, I put a shine of joint surfaces. 

Acetone isn't going to remove things that are weld barriers like oxides. A little oil won't hurt a thing, many folks weld using light oil as flux. I've used 3 in 1 and can vouch for for it and no, I didn't do a perimeter weld just a quick tack of a simple lap weld in 3/8" square in a propane forge. Playing around I've given the joint an oily wipe and sprinkled on a dusting of flux. Oil kept the flux in place while I finished closing the joint. Worked a treat.

Shine up your join surfaces and just wipe the dust off with a mostly clean rag. Sprinkle a LIGHT dusting of flux between layers as you stack them and tack it up. 

Get it HOT enough, coating the outside of a billet with flux will prevent contact with ambient oxygen and limit scale production and decarb. Let it soak and set your welds.

Re-flux while it's hot enough to melt the flux, reheat, rebeat, repeat.

I get my best input for how a weld is taking through my holding hand, especially if I'm holding the stock itself, say welding a ring on a fire tool but a welded handle or tongs will speak to you about the condition of the project.

Frosty The Lucky.

[JPH]

Howdy:  I have a little experience in this ..so I hope you don't mind...

From what you have described I would say two things...dirty weld surfaces and not enough soak time at heat.. Both are easy to correct. I weld some exotic stuff so I use a very aggressive flux and I hold at temp for a good 30 to 45 seconds longer than I think it is ready..   The photo below is the first weld of a bar that is 1 1/4" square and 12 " in length..materials are 1095, L-6 and stainless heat treat foil for colour  50 layers 1095, 45 layers L-6  25 layers SS foil to start..(see below).

I tend to stay simple when I work..nothing fancy..I just know what works for me and the materials I use and I run with it.

 

JPH

[mpc]

Another attempt, another failure (mostly).

15n20 & 1084, I got the surfaces CLEAN, & I let it soak at temp for a LONG time.

I started with 10 layers but looking at it closely after I’ve beat it around a while, it looks like there were only 3 or 4 lines that don’t go away no matter how far I grind.

I assume that means that some of my welds stuck. I guess that’s an improvement.

The learning process is frustrating for a weekend warrior. It takes so long to fail and then you don’t get to try again for a week or two.

 

[MilwaukeeJon]

Sounds like you still might not be up to welding temp. I don’t use a thermocouple but have read here that 2350-2400F may be a better range:

What kind of forge do you use and what is the gas pressure set at? The billet should be a really bright yellow color, possibly leaning towards a whitish yellow and even smoking a bit, and soft under the hammer for the initial tack weld. You will feel it when it’s right...almost mushy feeling when the weld sets correctly. 

[basher]

if you are hand welding just using Karosene  and no borax that could be your problem. no problem with the technique at all but just that it does not really lend its self to welding with a hand hammer. If you are welding in a reducing forge or using Karosene then the problem you get is that as soon as the billet comes out of the fire it is being oxidised at the edges in the air. when you are welding with a power hammer or press its not really a problem because the whole billet can be shut before the oxidisation causes a problem. I would recommend using borax when hand welding as you are only really able to forge weld a couple of square inches of billet at a time. I would also repeat every pass at least twice .

In my work I mainly weld using a reducing atmosphere forge but also weld up by hand with borax and use quite a few other methods (seam welding before forge welding and even the good old hot cat and fold with borax from time to time.

[MilwaukeeJon]

3 hours ago, basher said:

 

.....seam welding before forge welding and even the good old hot cat and fold with borax from time to time.

So do you flux the cat or dip it in kerosene before folding?

[Frosty]

13 hours ago, MilwaukeeJon said:

What kind of forge do you use and what is the gas pressure set at?

PSI isn't a particularly valid indicator, there are too many variables from place to place: ambient temp, altitude, humidity, etc.  With practice you can get a much better idea of what temperature to expect from your burner by it's sound and once the temp has leveled out the color.

I"m sure Owen Fluxes hit hot cat, kerosene burns their skin making them scream, claw and run maybe even bouncing off the walls. Makes it WAY harder to set welds.

Frosty The Lucky.

[Steve Sells]

but if they run away before setting the welds its a real cat-tastrophe

[horse]

Here we go, poor guy makes one typo.  Very funny just wish I could add to the puns. Wish I had the gift. I just go cat-atonic when these things begin. 

[JPH]

Howdy:  

I gotta ask.....why no flux? I mean, I weld some high alloy stuff that most folks say can't be welded outside of a can but I do it in an open forge....Sure I use some nasty flux but it works.. Just use more than adequate ventilation.. It is rather rough on the forge lining...but that is what happens with these more aggressive chemicals.. but that is me... Now most folks would do quite well with a mix of anhydrous borax and boric acid..Especially when you are using the materials you are..these usually stick quite readily if the surfaces are clean and hot enough...  Anyway that's the way I see it anyways.. But then again..I am just one of many so...  

Back to work for the old man...

JPH

[mpc]

On 4/18/2020 at 10:09 PM, MilwaukeeJon said:

What kind of forge do you use and what is the gas pressure set at? 

Propane, 3 burner in an old tank (freon I think). I’m running between 10 & 15 PSI. 

I’m thinking I need to rip out the old lining and do it again. It wasn’t in great shape when I got the forge and it’s thin in some spots. 

[ThomasPowers]

That can make a huge difference; I once was putting off relining my forge and turning up the gas pressure to compensate for the heat loss. Well I finally relined it and forgot to run the pressure back down and so accidentally melted a piece of steel in the forge.   When folks tell me that propane forges don't get as hot as coal forges I tell them: "I've melted steel into a puddle in mine; how much hotter do you need it to be?"

[Frosty]

On 4/19/2020 at 3:29 PM, horse said:

Very funny just wish I could add to the puns. Wish I had the gift. I just go cat-atonic when these things begin. 

Off to purrgatory with you then!

Here's a suggestion from someone who's been building propane burners and forges for probably 35 years. Cover the pressure gauge with tape so you CAN'T SEE THE DANG THING!  It makes absolutely ZERO DIFFERENCE! 

Tune your burner to a SLIGHTLY CARBORIZING and just turn it up or down to suit the current need. You're depending on an instrument without any idea what the numbers mean. Your forge in YOUR shop is an individual piece of machinery specific psi is individual to YOUR location and shop. NOBODY ELSE'S. You can tell more from the sound and color than you can from a gauge. Once you've used it enough to know how it should sound and look the psig will make it a little easier to hit a particular temp RANGE before the forge gets hot enough to know for sure from the color. 

Frosty The Lucky.

[mpc]

On 4/19/2020 at 6:55 PM, JPH said:

I gotta ask.....why no flux?

I knew I left something out. This time I did use flux. Just regular Borax out of the box. 

I cleaned the steel & ground off any scale. Then I tack welded the layers together. Then I stuck it in Kerosene (to keep it from oxidizing while I got the forge ready).Then I got the forge up to temperature and putting out a good reducing flame. Then I put the stack in the forge for a while. Then I pulled the stack out and quickly applied borax to the edges. Then back in the forge until the stack was the same color as the rest of the forge. Then another few minutes longer just to be sure. 

Out of the forge and on to the anvil for some firm, straight blows (so it didn’t shift). Then - quick scoop of flux and back in the forge.

 

[ThomasPowers]

Tune "By Eye and By Ear";   one thing a lot of people don't realize is that cheap little pressure gauges that get knocked around a lot go out of calibration pretty fast and can actually be 50% off.  So when folks start harping on the psi I generally ask them: "When was the last time you calibrated the gauge?"  Haven't got any answer than "never" so far...

[mpc]

7 minutes ago, Frosty said:

You can tell more from the sound and color than you can from a gauge.

2 minutes ago, ThomasPowers said:

Tune "By Eye and By Ear"; 

In this way Blacksmithing is like my profession and it drives me crazy. You can’t really learn how to get it right by reading a book or watching YouTube, you’ve got to spend some time with people who know what they’re doing and watch them do it to get that “feel” for how it’s done. 

[ThomasPowers]

Yes, and we keep telling people that.  One reason blacksmithing conferences are so great; you can learn in person from other smiths. (Quad State usually has a handful of different demonstrations/demonstrators going on at the same time and you can sit front and center at one, say the Damascus Knifemaking one; or you can cruise between them as suits yourself.)

[MilwaukeeJon]

19 minutes ago, mpc said:

In this way Blacksmithing is like my profession and it drives me crazy. You can’t really learn how to get it right by reading a book or watching YouTube, you’ve got to spend some time with people who know what they’re doing and watch them do it to get that “feel” for how it’s done. 

I agree fully with Thomas that being able to watch folks at work is fantastic but you will continue to learn a lot from the ongoing trial-and-error aspect of initial forge welding. YouTube was my only source of visual info when first trying to forge weld  (and I'm definitely still learning!) and my early failures were very much based on not getting a high enough heat/long enough soak. Once I really got that piece smoking then I could feel the soft welding blows do their thing. And I did certainly overcook some pieces in the process and that was educational too. So do track down a live demo if you can but also keep at it in your shop. One of these days that weld is going to stick and that will be a wonderful epiphany....