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Aaron Rheams

The incredible disappearing steel

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I have HAND-worked a damascus billet to 89 layers so far over a few weeks.  No cold shuts, and it's looking great.  The odd number is due to continuously adding extra steel because it keeps shrinking.  I started with 4 - 12"x1.5"x1/8" strips of 1095 and 3 of the same (slightly thinner) of 15N20.  Does anyone know why little fiery gnomes show up and take all my expensive steel?  The billet is now the volume of maybe 2 strips if I estimate generously.  The best I can figure is that this is a combination of scale and compression, but I am shocked at how impactful this is.  I probably have $60 in this knife now, just in steel.  Does anyone have any general insights as to whether this is normal, if most of this is actually compression, if I'm getting more strength because of it, etc.?  Maybe hand working is causing too much forge time which is burning it off as scale.  I'm wondering if I should abandon damascus without a press or power hammer.

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When you are at forging temps out in the atmosphere hammering scale off by hand, you are losing steel. :(

Get yourself some striker friends, or a press, make a power hammer if your feeling froggy!

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Yep, that's loss to scale, which tells me your forge atmosphere is way too oxidizing.  You'll always get some scale, especially when welding (and using a lot of flux will make steel go away fast as well), but some forges cause less than others.  What is your setup?  

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Also to be clear, 0% of your volume loss is compaction.  When we are talking about volume of starting steel and ending steel.  You may compacting a billet in terms of removing air gaps, but the density of the steel remains constant.  

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Oh lort... my setup.  :(  It's a little embarrassing.  The forge probably has about a 3 liter volume of working space.  I've put two modified Reil burners in through the side of a restaurant tea urn (with the middle cut out).  Koawool, Kast-O-Lite, and Matrikote on the inside.  This was working fairly well, but it wasn't hot enough to weld, so I decided to use the tea port as a forced air intake.  So I got an air mattress inflator and have been using it as a blower, but not through the burners.  It enters through the tea port and mixes inside the working area.  It gets nearly white hot, but I know I'm oxidizing everything to death this way.  I just didn't expect such an incredible loss.  Assuming for a moment that modifying it would be cost and time prohibitive, could I protect the steel with copious amounts of flux?  Maybe sand?

Hmm... no compaction.  That sucks.  As to striker friends, my kids and their friends, lol.  I was forced to do a fold after one of them mangled the billet.

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Somewhere on the forum there was a discussion on material loss in projects like this.  I seem to recall that the consensus was at least 30% if everything is ideal.  Any step away from that just makes things worse.  If you can, a picture of your set-up would help.  Modifications for a huge improvement may be quick and easy.  

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I'd like a photo of your set up forge just because it sounds absolutely ingenious! A restaurant tea urn? Holy cow man, that is some creative thinking. 

Yeah, the atmosphere is the killer. get that tuned up better and try another suggestion to avoid the massive shrinkage and loss. Weld your initial 4 strips good and solid. Set the billet aside. Weld another 4 strips good and solid. Set those aside. Repeat until you have 4 billets of 4 layers each. Cut each billet into roughly 3 4-inch pieces and weld those three together.  You should now have 4 12-layer billets. Weld those together for a 48 layer billet. Fold once for a 96 layer bar, or leave it at 48 and see what you have. Sometimes a low layer billet looks really cool.

Edit: I realized later that you are starting with 7 layers, so rework the math a bit.

Edited by Joshua States
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My average steel loss in doing up a steel billet over 300 layers is 40 per cent or even more, and that's using a press and a good gas forge setup. Scale happens. As for compression- that's not happening. You're not going to "compress" anything unless you're starting with really raw bloomery steel.

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With that air injection you are indeed a scale-making machine.  Flux will make it worse, since what it does is combine with surface oxides.  In that oxygen-rich atmosphere it will basically eat the steel.

Oddly enough, I know two other people who used a tea urn for a forge body.  They work great!  I have one myself, just never lined it because I never decided if it would be better horizontal or vertical...

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Tea urns do appear to make a great oval forge if you're willing to punch out the middle with an angle grinder.  I have had some luck with a random discovery that appears to have reduced SOME of my losses to oxidation.  Burnt sugar, borax, and sand combined make a goo that seems fairly resistant to heat.  The floor of my forge doesn't like it, obviously, but I've had less loss of material in these latter stages by keeping the billet coated with this. 

I will try to get some pictures of my setup soon.  I knew that forced air should be integrated into the burners, but I tend to fly by the seat of my pants when I do things. 

Anyway, here's the billet in a state of working toward a finish.  You can see at the edge where the patterns aren't present because the final stack contains the original billet cut longways and stacked around 2 unfolded 15N20 strips with a center 1095 strip.  I knew this would not be ideal, but I was without recourse after losing so much material.  I now see how important it is to overestimate the material.  At 89 layers, I'm also a bit disappointed that I'm only getting 5-6 good lines in the pattern.  I speculate that the rest of it is too fine grained to stand out and that this is all a result of inconsistency due to adding steel at different stages.  By God, though, I made damascus.  And I did it by hand.  I'm thinking my next attempt will turn out much better.  I plan on grinding a very careful continuous bevel to maximize what I do have here.

BTW, it does appear that I have a few small cold shuts, but I'm hoping they will grind out by the time I get it to the proper shape.

20190113_212246(0).jpg

Edited by Aaron Rheams
Left out something.

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My setup...

Blower goes into tea dispensing port.

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Reil burners sealed in the back due to precombustion.  Holes drilled in the sides.

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Holes...

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Top view

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Rear view.  The back is stuffed with kaowool.

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Top view dragon breath

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Burners pulled out... I left them detachable to make all of this more portable.

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Cooling down... flux everywhere, carbon, damage, junk, etc.  It will be time to reline eventually.

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Railroad track anvil, modified claw hammer, big hammer, poker, and brush...

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A live sander zip tied to a dead sander.

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Front view... I use the kaowool in the front to direct the forced air to the rear of the forge.  I could make some more permanent modifications with Kast-O-Lite, but I've been too preoccupied trying to make damascus.

20190117_202429.jpg

Edited by Aaron Rheams
Picture annotations

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In following the advice from everyone, I ordered some more steel and I am going to build four billets, 6" x 1.5".  I did decide to deviate from the even number on each billet, though, as I want both sides of the knife to be the same steel.  Resultantly, I will stack four billets of three 1095 and two 15N20.  The thing I hate about working these individual billets down is that I end up having to sand all of them to get a clean surface, and I cannot seem to forge anything perfectly flat, so I lose a good bit of material.  I certainly cannot stack them all, though, so I suppose it's going to have to be done this way. 

I thought about attempting a manual press from a hydraulic jack, as I have seen this idea thrown around with mixed stories on the internet.  I am very reluctant, though, as I can see being highly disappointed at the outcome.  In the meantime, I guess my arm has some punishment coming soon.

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