Hand forged stainless San Mai?

[JG Custom Metal Works]

Your challenges are multi faceted.
Truth is, if you had a good soak on the steel at welding heat and the pieces were quite smooth - like surface ground - you could probably get the first major weld done successfully in a vise with some jaw extensions to press the entire billet at once.
Then - bring it back up to heat with another good soak and do it again.
I'm not kidding you when I say this - if you have nearly perfect surfaces on your billet pieces and you weld that billet together while clamped tightly in a vise, you have a really good start.
Have your forge up to welding heat when you place the billet in.
Soak a good 15 minutes.
That alone may be giving you a weld.

I had thought about doing those a while back. I think I even made a thread about it here but was kind of scoffed at when bringing up smushing the weld together using a vise. Now I feel redeemed.

When using the vise method, would it be a good idea to heat the jaw extensions with a leaf burner or torch? To make it so it wasn’t heat sinking the heat right out of it ruining the weld?

Also, am I right in assuming you mean to use this method after dry welding the perimeter of the billet?

Lastly, when surface grinding the pieces of steel to use in the billet, what grit do you think would be optimal?

As always, thanks for sharing your knowledge Karl. You’re the man.

 

[Karl B. Andersen]

I surface grind with 60 grit. I see no need to heat the jaws. You would just be doing a squeeze and you're done. (But I would do that twice,)
I use a press - but the concept is the same.
The weld/press is secondary to the surface prep, weld temp and soak time. If you have those in order, the weld is a simple deal.
I soak at weld temp for 17:30. Don't ask me why.
This is a blade I forged yesterday while this thread was evolving. From corner to corner on that anvil is 10":

 

[JG Custom Metal Works]

I surface grind with 60 grit. I see no need to heat the jaws. You would just be doing a squeeze and you're done. (But I would do that twice,)
I use a press - but the concept is the same.
The weld/press is secondary to the surface prep, weld temp and soak time. If you have those in order, the weld is a simple deal.
I soak at weld temp for 17:30. Don't ask me why.
This is a blade I forged yesterday while this thread was evolving. From corner to corner on that anvil is 10":

Thanks a bunch for the information Karl, I really appreciate it. So, to get this right, you recommend heating to what, 2300f?

Hold it at 2300f for 17:30mins, press
Place back into oven/forge, bring back to 2300f
Hold for 17:30mins, then press a second time

Lastly, I don’t have the most adequate forge. But I do have a Evenheat oven that can reach 2400f and hold for exact times. Do you think it would be possible to use the oven? It would allow me to be more exact with the temperature.

Thanks again for the infor Karl. Sorry to pester at ya for more specifics. But as they say, the devil is in the details. For as much failing I’ve done with forge welding, I’m ready to get a working system down.

 

[Karl B. Andersen]

After your first weld you really just need to bring it back up to heat - not a long soak.
Use the same heat you would normally use for any forge weld.
I have no experience using an oven for welding. You're on your own with that one.
Here is how that one in the picture above came out:

 

[JG Custom Metal Works]

After your first weld you really just need to bring it back up to heat - not a long soak.
Use the same heat you would normally use for any forge weld.
I have no experience using an oven for welding. You're on your own with that one.
Here is how that one in the picture above came out:

Thanks for the reply Karl! Amazing looking blade too.

If you don’t mind me asking, what temp do you do your forge welding at? For say 410 and 1084 specifically. Sorry to keep pestering you for specifics on this, but I’ve just had a hell of a time with it.

I’m gonna modify a post vise later today for pressing a billet. No sure if how exactly I’m going to go about it, but I’ll figure it out. I’m a stubborn SOB and will keep banging my head against the wall until I get a break through or knock myself out. . That being said, if anyone else here has fabricated vise jaw extensions, I’d love to hear how ya did it. It’d be nice not to have to permanently weld them to the vise.

Also, if anyone else has any general tips for hand forging stainless San Mai, I’d love to hear them. What welding temps do you guys us?

Thanks again to all that have provided answers to my questions. I really appreciate it.

 

[gudspelr]

I’ve used some angle iron in the past for my vise jaws. The only thing is trying to keep them from slipping around. Depending on the size of the billet, you could have the jaws open just enough to fit the billet and the angle iron would still be in the jaws and not fall out. Of course, it could all be no issue with another persons helping hold stuff... Looking forward to seeing how it works out for you.

Jeremy

 

[kuraki]

Just tack weld them on. Knock them off when you're done.

 

[JG Custom Metal Works]

After your first weld you really just need to bring it back up to heat - not a long soak.

Your challenges are multi faceted.
Truth is, if you had a good soak on the steel at welding heat and the pieces were quite smooth - like surface ground - you could probably get the first major weld done successfully in a vise with some jaw extensions to press the entire billet at once.
Then - bring it back up to heat with another good soak and do it again.
I'm not kidding you when I say this - if you have nearly perfect surfaces on your billet pieces and you weld that billet together while clamped tightly in a vise, you have a really good start.
Have your forge up to welding heat when you place the billet in.
Soak a good 15 minutes.
That alone may be giving you a weld. When you start beating it with a hammer you may be actually fracturing the weld. What you want to do is increase the weld you have - not fracture it apart. Use that vise method.
I've been making stainless San-mai since before I got my JS in '08 - I know what I'm talking about. In a decade I've had two weld failures and, of course, I was the fault both times.
Then you're going to have to figure out how to keep the center - in the center.
I start with 3/8" core and 1/4" jacket sides and draw out to final dimension.
I forge down on the bias to squish down my ricasso and draw out my tang. My welds are 100%. I've often said that anyone who will not upset-forge their San-mai for fear of delamination should not be selling it. I only saw cut the tip becasue that's necessary for me to keep the core even on both sides.
I'm just illustrating a little experience here.
You can do it - I just wouldn't want to do it all by hand. Soak time is crucial.
This is one I just finished for Atlanta - the second one is archival.

Hey Karl, or anyone else for that matter. What is your opinion of using a 20 ton shop press with plates instead of the vise? I’m thinking it would be a lot easier to do.

I know those presses are inadequate for use as a forge press, and that’s not what I would want to use it for. I’m just wondering if you think it would be adequate for setting San Mai forge welds? One single weld. All in one press. I’d use plates that were very thick(inch thick probably) and were as long as the entire billet being pressed.

Again, I’ve read many times how it’s people’s opinion that these Harbor Freight Shop presses are very inadequate as a forge press. I don’t have any illusions. I wouldn’t be using it to make Damascus. Just set single welds, in one go. The physics of it seem like it would be just as efficient as using a vise. But of course I could very well be wrong. If this is the case please let me know before I go buy one. I’d also be using it for stamping a makers mark. This is the model I’d get probably.

https://www.harborfreight.com/20-ton-shop-press-32879.html

 

[DevinT]

The only way to get nearly 100% welds is to reduce the thickness by 50%.

If you grind to 60 grit, weld the edges of the billet, heat to the correct temp, and press in a slow hand pump press, at best you will get a partial weld.

To get a complete weld, you have to draw the piece out. And it’s best to draw to twice the length.

You’d be better off putting your money in a treadle hammer.

Hoss