forge welding a small billet

[Wolf's Den Armoury]

I was screwing around the other day and decided to give a try at forge welding a "folded onto itself" billet.

Folded it in half four times, and I *think* I got it to forge welding heat, brought it out of the fire (coal forge), put in on the anvil, and (as advised a few times in several places) tapped the billet lightly with the hammer.

Question is (and yes, this might be a *really* stupid question)....

How do I *know* this piece is actually welded? there seems to be an area between the folds where there is a "filled section", but its recessed about 1/16" from the edge, leaving the individual folds obviously visible.

So basically, I really don't know for certain if this is a successful forge weld or not. :confused:

Thanks for the help,

David

[rlarkin]

Can you pull it apart?

If you can, then it's not welded.

[pkrankow]

Well, you can draw it out some and then hit it on the edge and see if it separates. If not finish drawing it to a useful size and use it for something. You could also cut it up and then hit it cold and see if it delaminates, but then it may be hard to use for something. Destructive testing is a good learning tool.

I have only made a few successful welds, all fagot welds like you describe. You can also weld by pushing on the billet with the hammer (or a good wooden stick) and not even tapping.

Phil

[Wolf's Den Armoury]

Well, given the size I ended up with, I wouldn't be able to pull it apart by hand anyway.

Thanks for the advice Phil. I'll give those ideas a try tomorrow (pre-bird coma). I always thought the metal needed to be struck. Nice to know that a simple push might work.

Would that work witha jump weld (1-1/4" square tubing onto 4" x 8" plate for a portable hardy hole)?

[Frank Turley]

Without high tech testing methods, it would be a difficult to ascertain the quality of the weld. As a smith, one way might be to hacksaw the piece in two, and inspect the kerf for signs of shuts. Another way would be to continue forging the piece down to a haywire size. As you forge, any imperfections may appear.

In the 1930's, the British published a little book titled, "The Value of Science in the Smithy and Forge." The authors showed some photomicrographs of forge welds, and along the line of the welds, there appeared "slag inclusions" and grain growth. Slag inclusions indicate that fly ash and dirt are present, especially in a coal forge situation. Grain growth is a result of heating the metal to the incipient burning range. I would guess that a majority of coal forge welds are like this, and they are therefore not as strong as a gas or electric weld.

The pattern-welders have devised a couple of ways to keep oxygen and dirt from the weld area, thus obtaining cleaner, stronger welds.

In thinking about forge welding in 2009AD, if it's not so strong as gas and electric, why do it? We forge weld because a forge weld is forgable, whereas some modern welds will crack or break when heated and hammered. We also forge weld for aesthetic reasons, as when joining a branch to a stem. After welding, you gain a disappearing point at the base of the join, and it looks "organic" without further filing or touch-up.

Seldom will a forge weld be so weak as to affect the structural integrity of ornamental ironwork. In New Mexico, we have a cowboy saying, "I don't care how weak it is as long as it's strong enough."
http://www.turleyforge.com

[ksb]

One way to sorta tell - examp - several layers - heat up and watch colors fade. Looking at from the 'side' - layers visible - if a good weld colors will fade evenly across/down bar ( if that makes sense ) - bad weld will be brighter on one side of bad weld than the other or show up as a dark area.
ksb

Edited November 28, 2009 by ksb

[pkrankow]

I've never tried a jump weld, but it should work the same as drop-the-tongs if I understand it right. Pushing the parts together just out of the fire to get the initial stick seems to be a common idea, and many people have small blocks on the forge to do initial welds making sure they keep their heat.

I have failed at all attempts at drop-the-tongs but I haven't set up a block on my forge cart yet. I have a sledge hammer head needing a handle I am thinking about putting there for next time I try. I also have been having frozen bottle problems with my gas forge, a remedy has been ordered.

Phil