Forge Welding Question

[gudspelr]

I built my gas forge (2 burner, horizontal) with the hope that someday I'd be able to forge weld with it.  I'm thinking I'll need to line it with ITC 100 (just has some kiln cement over Kaowool from a local pottery supply place now), but to be sure I could get the right temps, I have a plan...

The same pottery place sells these "cones" that melt at specific temps.  What I'm hoping someone will tell me is what temp do I want to shoot for with my forge?  I understand different steels have different characteristics, but is there an overall "good enough" temperature?  The "cones" come in packs of 25 and I didn't really want to have a whole load-just want to aim for the right temp.  Thanks for the help


Jeremy

[Scott Roush]

I usually am welding wrought to high carbon.. I'm shooting for almost a white atmosphere inside my forge. I suggest firing up your forge, sticking some scrap high carbon steel in there and TRY to burn it...get it to spark. And watch the colors inside your forge (sparingly.... not good for your eyes... wear protection).  Once you know what conditions can actually spark your steel, you have a great idea of what your welding temp is.  But not all forges can burn steel like mine does.  In short... Experience will tell you what works with YOUR forge...

Also remember that long soaks solve a lot of welding problems.

[Lin Rhea]

Jeremy, just so you understand, sparking is too hot. Welding is just under that. That said, the atmosphere of the forge will have to be hot enough to spark, but you will have to gauge the heat in the particular work piece with the amount of time it's in there. A thicker piece will take longer to heat up as would a billet. Testing the heat with a small demension scrap might be misleading since it would spark much sooner than your intended billet sized piece. Time is the element that you control along with the intensity of the forge.

Karl says it good when he says something to the effect of "heat X Time". But, if the heat is not intense enough, it wont reach welding heat no matter how long it's in there. After the atmosphere gets hot enough, then all that's left is time.

[gudspelr]

Karl says it good when he says something to the effect of "heat X Time". But, if the heat is not intense enough, it wont reach welding heat no matter how long it's in there. After the atmosphere gets hot enough, then all that's left is time.

The mentions about time are very helpful-pretty sure I'd have made more work for myself there.  The heat being intense enough is what I'd like to make sure of so I can rely solely on my (lack of) skills to cause my failures   .  I've heard of guys welding at 2050 to 2300.  Am I good if I can get in the neighborhood of 2000 with a long soak or would higher be needed?  Thanks

Jeremy

[Scott Roush]

Sorry I didn't clarify!  I just meant to try to spark a piece of scrap to get an idea of the upper limits.  Once you see what it looks like to be TOO hot, then it becomes easier to avoid as well as get an idea of what the actual welding atmosphere looks like.

Yes.. don't burn your steel!

[Lin Rhea]

Scott, I knew where you were going with it. I was afraid Jeremy might get the wrong idea and used the opportunity to mention the "time" thing.

Jeremy, it really needs to be 2350 or so. Conditions have to be perfect, which are rare, to weld any lower. It will take your full attention to not burn it up, but your success rate will be higher.

[gudspelr]

Thanks guys-I sure appreciate it.

Jeremy

[Bobby Urban]

What happens when it sparks?  Not sure I have ever had any steel get that hot but if I did/do is it ruined?  Is carbon burning off?

Thanks - Bob

[kbaknife]

Originally posted by Bobby Urban:
What happens when it sparks?  

Thanks - Bob

Get another piece of steel.

[gudspelr]

Bob-

From what I understand, the sparking is the carbon burning away.  If that's incorrect, hopefully one of these smart knife makers will help out   .


Jeremy

[Lin Rhea]

That's right. If you get it too hot, just cut the bar back enough to get rid of the burnt part. The rest of the bar is still good. I dont mean to call anyone stupid or anything. I'm just clarifying that.

[kbaknife]

Originally posted by Lin Rhea:
........just cut the bar back enough to get rid of the burnt part. The rest of the bar is still good.  

Ya mean there's still some good stuff left?
Just think of all the steel I could have saved.    

[Lin Rhea]

You're killin me Karl!
 

[JohnHV]

Thanks Jeremy for posting this question and thanks to those who responded.  I might give forge welding another try.