Nice forge welding video...

[KYBOY]

YouTube - Blacksmithing Forge-welding a branch

[Rob Browne]

Now that looks too easy to be true. Just shows how important preparation of the joint and the cleanliness of the surface is. I think I will be watching it a few more times yet :)

[KYBOY]

Yea, he does make it look waaayyyy to easy dont he ;)

[Mark Aspery]

If there is a secret to forge welding, I think that it is how the two scarfs (SP?) fit together.

I know that the hammer blows need to be light initially so that I don't blow the weld. If there is a gap between the scarfs then the light blows won't close the gap or unite the pieces.

The scarf on the video is a beginners scarf in that the step is not very deep and that the end has a lot of mass to carry the heat from the forge to the anvil.

With practice, the step can be a little deeper - making the weld finish quicker.

The two pictures attached show the scarfs going into the weld and the initial weld. The weld has taken without the two ends being deformed overly - I hope that this shows the importance of the scarf fit.

[HWooldridge]

I have more trouble with forge welding than any other BS process so I have always tried to focus on fixing my mistakes. One thing I do for myself is thin the scarf to a point - not a feather edge across the whole joint but an actual point on the scarf tip. I find this blends better than other methods but like most things, practice is the best teacher - especially after you've seen it done successfully by someone else.

[Mark Aspery]

One thing I do for myself is thin the scarf to a point - not a feather edge across the whole joint but an actual point on the scarf tip. I find this blends better than other methods.

I agree with Holister. The toe of the scarf should be narrower than the bar to which it will be welded.

This is to counter the 'Anvil effect' of the two pieces.

If you had a 4 x 4 solid bar 12 inches long, all hot, as hot as you like. Hold the bar on end and upset it to form a cube with your hand hammer. How much effect do you think you would have on the bottom of the bar?

Nil!

At some point a bar, even though it is all hot, can act as its own anvil.

The light blows used when uniting two pieces during a forge weld will not fully penetrate to the lower bar. The top bar (toe of the scarf) will spread on top of the lower bar. If the toe of the scarf is the same size or bigger than the bar to which it will be welded - well you get those little wings creeping out at the side of the weld, and they are a bit pesky to get to weld.

[HWooldridge]

Agreed, Mark. The other problem with a full width scarf is that it can leave a small void, which creates a notch and can start a point of failure. I have hot twisted forge welded areas and seen them break from these small origins.

[Mark Aspery]

If you look at the photographs attached you will see some bars assembled ready for a proposed weld.

The arrows indicate the direction of the hammer blow. It (I hope) can be seen that some hammer blows are not coming from the right direction.

I am going to draw a conclusion to this, that the force applied (your hammer blow) should come at about 90 degrees to the welding surfaces. If the welding surface and the hammer blow are in the same plane they will not weld.

That being the case, if the ends of a scarf are not tapered, then they are still in line with the hammer blow and not in a welding plane.

This will cause what appears to be a crack at the end of the weld as seen in the drawing.

Forgeweld copy.psd

[KYBOY]

I still have problems with a solid thru forge weld at times...Like when Im doing a faggot weld for more material one one end..Like for forging a ferrul, etc...Ill get what seems like a good strong weld..Cant chisel it apart but when I get it almost flattened part of the seam will seperate :mad: I wish I could stop that..The grinding my teeth do because of it isnt good :D

[HWooldridge]

Kyboy,

Don't work it below a dark yellow/light orange. I have most failures when I'm trying to forge it much below these temps - higher is better. I think it is because steel has a tendency to slide from the forging so welds often split instead of moving.

A forge weld is something of a glue job until the pieces are driven together enough to make a completely homogenous bond (which does eventually happen - Damascus pattern welding is a good example). Once a weld takes completely, heavy forging at high temps only makes it better. All the more reason for large upsets before welding.