My little "shop" and a few toys from it

Mike Blue

Member
Sounds like a working problem solving process. The smell is excess gas and that is something you will want as forge welding works best in a reducing atmosphere (more gas than air). But I'd prefer to see some excess blue flame coming out the front of the forge than to smell much gas. LOL. Even so the air gas mix in the room is not likely to create any excitement.
 

Shawn

Member
Been busy as heck lately, but I've been able to do some work on the new forge. I got the kaowool in. 2 inches thick all the way around and a little extra to make the bottom flat. Got the kast-o-lite in and fired it today to do the final curing. Got it up to 2165F before shutting it down. Still have to put the metrikote lining in and can hopefully get it up to around the 2400 degree mark then.
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Shawn

Member
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Metrikote is in and painted. Paint probably won't last long, but it looks pretty for now haha. Might get some high temp grill paint down the road, but I'm happy with it for now.

Metrikote should be cured up enough by tomorrow so I can see just how high it will go for temp. Forge welding temp is my goal.
 

Bruno

Administrator
Staff member
Nice! That's looking really good. Even temperatures. I'm interested to know how fast it is going to get from cold to forge welding temperatures. for me that's the real test.
 

Shawn

Member
Funny thing, it doesn't seem to want to get to as high of a temperature now that the reflective coating is in. Might be from removing the burner to do so I didn't get it back in the right place? Going to fiddle with it a bit more and see what I can come up with.

I did have it lit up the other day and cleaned the teeth off of a couple old files. I laid three together sprinkled some 20 mule team borax on them and got them to weld, folded them and got another good weld, (even without properly cleaning them before folding.....) then twisted the billet and hammered it down flat. I got a couple cold shuts in the twisted part when I did that though.

I dunked it in some water to cool it off, (man that left some huge grain...) then stood it on the side and pounded it with an 8 pound sledgehammer until it actually started to break the edges. I cut it half way through then broke the rest and the only separation I had was on the outside where I got the cold shuts hammering the twists flat. I'm pretty sure I let it get too cold when I was doing that, so I'm confident of where that problem came from.

Anyway, I felt it was a good enough result that I placed an order for some anhydrous borax, 1084, 15n20, and some ferric chloride.

Also made a rescue today. Going to need a little TLC, but there is a new addition.

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RezDog

Member
Nice rescue.
I often learn a lot from things that don’t completely work.
I’m envious of your tinkering. I’ll be home soon enough.
 

Bruno

Administrator
Staff member
Twisting is usually safe as long as the temperature is high enough, and the cross section of your billet is closer to octagonal than square.
things can still go wrong but usually a high temperature makes it relatively safe.
Except for the ends which cool down quickly in the vise. they tend to split on me.
For me the highest rate of issues is when upsetting a billet. That is usually when any small flaw on the outside turns into an actual split layer.
 

Shawn

Member
I think once the good steel comes in, I'm going to try a birdseye or ladder instead of the twist. Provided the initial welds go well that is. :D
Seems like they are an easier pattern to do. I don't think any are going to be extremely easy doing it all by hand hammering, but I think those will be the lesser of the evils while still giving me a nice pattern.
 

Shawn

Member
So I got an email about my order. 1080 is not available with no expected date. 1095 is available though. So I got some if that coming instead. I'm hoping it isnt too difficult to make stick with the 15n20. Any advice to tricks for welding or heat treating a 1095 and 15n20 billet?
 

Mike Blue

Member
You'll have no problem building billets from 1095/15N20. I hope the price was right. That is my recipe for pattern welded steels. I try to get the steel supplier to provide the materials with the least amount of manganese if they can get it. It gives me the best control over the hardening line if I want to do that with the materials later. Manganese increases through hardening of the material during heat treatment. The hardening lines, if you see them, are muddy if you get one. There are some smiths who love 1084/15n20. See calculations below. It's not like the old days when manganese levels were less than 0.03 or less. With all the recycling the mills can't guarantee that low any longer.

Welding heat and borax is all I do. I try to get the forge to settle in just above 2350F and not keep increasing in temperature to avoid unwanted scale and carbon loss.

Carbon averaging: once your billet is above the austenitizing temperature carbon will migrate evenly through the billet. By the time you've had the billet up to welding heat four times all the carbon will be uniform throughout this steel mix (1095/15n20). Calculating the final carbon content of the billet is simple ratio math. I don't know what the thickness of your steels are, but I ordered materials that were 0.062 inch thick. As I build a billet I alternated the materials using 13 layers of 1095 and 12 layers of 15n20. This results in a billet about 1.5 inch thick. Multiply the carbon content of 0.95 by 13 and 0.75 by 12 (since the 15n20 is equivalent to 1075 with 2% nickel) add those together equals 21.35 then divide by the total number of layers equals 0.854. That carbon average is darn near the eutectic sweet spot, eh?

If you used 1084 instead of 1095 your carbon average will be 0.796. That's nicely at the 1080 range you originally wanted but you have to deal with all that stinking manganese. LMAO

((Carbon content A times number of layers) plus (Carbon content B times number of layers)) divided by total layers A+B equals average carbon content. You can optionally add additional carbon contents times layers if you mix more materials in. There is a math formula you can figure this out based on percentages or the thickness of the layers (volume) but the layer calculation is easiest if you know or can estimate the carbon content. It's best to use known materials for accuracy in advertising.

Only a pure nickel shim will stop the carbon from moving around but, if you do that, you will have pure nickel in the billet that will never harden.
 
Reactions: 32t

Shawn

Member
Thanks for the info Mike. Actually the 1095 was a little cheaper than the 1080. I have been ordering steel through Jantz supply. Knife maker supplies if you havent heard of them yet. Pretty decent prices and ine if the better ones I've seen for steel prices in a small shop quantity. Plus there is so much stuff available I can make one order instead of from 3 or 4 places.
Except my belts. Tru-Grit is still the best prices I've found for my 2x42 belts. Ceramics for under $5 are hard to beat haha.

As far as thickness my 15n20 is .049 and the 1095 is 1/8. Wanted thinner for the 1080/1095 layers, but that's what they had. Going to see how well I can make it work first, then get picky about layer counts and patterns later.
 

Bruno

Administrator
Staff member
Yeah it's really not rocket science and the most important thing is to reliably be able to stick things together
 

Mike Blue

Member
i know Jantz Supply. Nearer the PNW is a good fellow Kelly Cupples. He has access to good steels in about any flavor you want. I'll find his numbers.

To be picky, I would modify the math formula to account for the lesser thickness of the 15n20. It needs to change to a more proportional/volume calculation but it's not complicated.

All the best
 

Shawn

Member
So I got some time to play today. Took 5 layers of 15n20 and stacked 3 layers of 1095 between them. (8 layers total)
My stock is an inch and a half wide and I cut it at 2 inches long. This gave me a stack just about 5/8 of an inch. (.620) I cleaned them with de-greaser and knocked all the edges off, stuck the stack in the vise and welded the sides together, then threw it in the forge.

I took it to dull red, fluxed it then put it back in. I let it soak until it hit 2250F (about all I can get out of my forge it seems), fluxed it again and put it back in to soak a few minutes.
I pulled the stack out and started to tap and set the welds only keeping it out briefly so I wasn't getting it too cool. Did that 2 more times then started to try and move it.

I got it to between 1/4 and 7/16 thickness, varying from just over an inch and a quarter to 1 inch in width, and drawn out to three and a half inches in length.

I ground the edges just enough to clean them up and took them to 600 grit and here is what it looks like.

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I've got a piece of pvc pipe for my ferric chloride, but I don't have ends for it yet, so I did a quick vinegar etch.

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Not quite sure what I'm going to be able to squeeze out of such a small billet, but I was more interested in beating the crap out of it to see if everything held. So far it looks like it went well!!
 

Bruno

Administrator
Staff member
Looking great there!
When forging damascus, remember that layers generally don't mind getting beaten flatter, but are much more likely to split when upsetting them.
So if you know what you are going for, try to plan your forging so that do don't need to do a lot of upsetting in 1 go. That will improve your chances of success.
 

Mike Blue

Member
Okay, I'll give you points for luck or perhaps the forge gods are smiling on the innocent and will torment you later. As Bruno notes, upsetting the billet in any sideways direction will show you pretty quick if your welds are stuck. Those look stuck, but that's all I can tell from a photo. The fire will not lie to you.

That billet in all its thin glory looks pretty good. And you've learned that welding is not necessarily obligated to follow any rule books about temperature or other such mundane things we believe are true.

I am going to recommend you stack those thin laminates up to 25 layers or so and put the 1095 on the outside. Thermal mass (more is better) will hold the welding temperature in the billet for a few seconds longer and allow you to get more working time before it falls back. A stuck thin billet is mostly a miracle. LOL.

When the billet feels stuck, forge the vertical dimension, e.g. down into the layers, perpendicular to the flats, by at least 50% to spread that weld boundary out as far as that will allow, then turn the billet sideways and forge down/upset the layers sideways. A larger weld boundary is much stronger and less likely to delaminate. If the billet delaminates when it's hot, flux the edges and tap from the center of the billet out to the edges to close them up. Practice this a lot.

You will miss these heady days....
 

Shawn

Member
@Bruno and @Mike Blue Thanks for the tips guys. And while inexperienced, I do know that the sideways upsetting will make a bad weld split apart. That was actually why I did it. I wanted to abuse it and see if it was going to delaminate on me. This piece was more of a proof of concept, than any particular plan. I may see if I have enough to squeak a razor from though now that I have it.

I have the understanding that this isn't going to go right for me every time, but at least I know that it can be done with my setup now. Any future failures are on me, not the equipment.

Mike, is there a particular reason for putting the 1095 on the outsides? Is it just because in my situation the 15n20 is so thin I'm going to basically hammer it into nothing, or something else entirely?

The bigger thermal mass definitely makes sense as does the larger weld boundary. The only thing I'm not looking forward to is hand hammering it down from the thicker billet.
Although, it may go easier for me now that I am getting more heat in the steel. When I was starting out, I really dreaded thicker leaf spring sections as they took so much effort to move, but I wasn't getting as high of a temperature in my little forge as I am getting now.
 

Mike Blue

Member
Your arm will get stronger. Or you'll get a bigger hammer...so begins the tool acquisition disorder.

At higher temperatures the steel will move easier. Don't let it get too cold and keep it moving.

Either 1095 or 15N20 will make a fine edge by itself. The 1095 was cheaper for me to buy so I put some on the outside because decarburizing a cheaper steel made sense to my frugal nature. It makes no sense except for that reason. It's your choice on your steel.
 
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