having trouble forge welding

[Sanderson Iron]

 

Not sure how much I'm gonna add here, but I think there are a few things that haven't been said.  

Whenever I teach someone to forge weld, I always start them by taking a single piece of iron and folding it back onto itself.  Take a piece of 3/8" or 1/2" round hot rolled about a foot long or so, and fold it over onto itself a couple inches or so on the end.  This way, it's held together, and it's the same alloy with the same melting and welding point. 

Heat your folded bar evenly in a neutral fire.  A neutral fire is harder to make if you're using the popular clinker maker firepot, but do your best.  Somewhere between red and orange, bring it out of the fire and sprinkle it with borax.  Put it back in the fire when you've got a good coating.  

Now it gets more critical.  Heat it fairly quickly in a hot, neutral fire, without an excess of oxygen.  Probably the most important thing is to be sure it is heated EVENLY--both sides of the fold, which you're about to stick together, need to be the same temperature or you're gonna have troubles.  As the temperature rises, you'll start to notice a green flame coming out of the fire.  That's the borax burning.  This means you're really close.  Bake it some more so it's all nice and even, turning it over occasionally to add to your confidence.  Welding is more about fire control and temperature control than it is hitting it together.  Remember that, and you'll figure it out.  If you see sparks, it means you have an excess of oxygen in the fire.  Go more by the flames' color than anything.  With time, you'll know how hot your iron is by reading your fire, but for welding, the green flame is a pretty obvious clue. 

Bring it to the anvil quickly and hammer it together.  I'm not going to tell you to hit it lightly or hard, because that means different things to different people.  You've gotta work them together, and you have to be sure to keep them the same temperature (again, it's about fire and temperature) by not sucking the heat out of the bottom by pressing it against the anvil.  

 

[bird]

A few people have mentioned fire maintenance and oxidation, but not enough. Limiting the available oxygen to your part is as key as heat and cleanliness. Limiting the oxygen will allow your steel to get hotter than it normally would without burning. (Nothing burns without oxygen.) And that heat is one good way to facilitate welding.

Start at the beginning. You said you might break down and build a coal forge...what are you using now? Specifically, what's the depth of your firepot and where is your metal with respect to your air and fuel?

It seems technius Joe differs (with some interesting reasoning) but most people will say oxidation is the enemy when you're forge welding. In the presence of excess oxygen, your steel will actually burn at lower temperatures.

The fire will have oxidizing, neutral, and reducing (oxygen starved) areas, in that order, from where your blower enters the firepot. You need to heat for welding in a neutral to slightly reducing environment. In practice this means (varying slightly with firepot shape and blower power) you need to heat for welding about 3 1/2" -4 1/2" above your air inlet and have your work surrounded by fuel (that's consuming oxygen). Generally at least 2" of clean fuel over and around your work. If you are using a flat bottom bbq or rivet style forge, get a couple of fire bricks and build up the sides of your "pot" around the air inlet. 

Charcoal will have lots of orange sparks. Your steel will spark differently. Look for bright yellow "sparkley" sparks like from a 4th of July sparkler. Just a few. You shouldn't be able to see your part well. If you can there's not enough fuel around it consuming oxygen. A small taper that heats quickly can be a good tester: touch it to your part in the fire and see if it sticks a bit. If it does, you're ready. 

Finally, are you outdoors or indoors? Daylight will make your fire and part appear cooler than you read by color and make sparks harder to see. Work in shade if you can. 

Hope this helps. Good luck. 

[Gijotoole]

You should look-up Tom McInnis. He runs a shop in Ozark, right next door to you, called Ozark Knife Makers. I took a tomahawk class from him some years back and we forge-welded our own Hawks from rasps to finished product. I carry mine any time I go out to the bush. He uses propane but is a master blade smith.

You can probably give hm a call and come by to watch him work or ask him questions. Taking a class would be best because it's only four or five students and you get plenty of attention and answers to all of your questions. Plus, his wife cooks lunch for you on the second day of class and it's amazing.

[Creature]

Good day all.  So I was trying to weld up a billet to Forge into an axe. I have quite a bit of new leaf spring which I assume is 5260 I attempted to weld. 

I could not get it to stick. 

I have read it is difficult but for some reason thought I could it. 

So it also difficult to weld 5160 to other steels or just to itself. 

[ThomasPowers]

Depends on the other alloys; some yes, some no.  In general you will want to avoid other alloys containing chrome or nickel .

[EricJergensen]

I have successfully welded a leaf spring of unknown provenance to itself. My conclusion (just a guess really) from that success is that the spring wasn't 5160.

It is probably easier to weld 5160 to mild steel than to itself. You could try that just to see what happens. Also, why 5160 to 5160? Wouldn't you use 15n20 or similar for contrast?

I'm not a fan of unknown ("junkyard") steels. They cost too much.

[Creature]

Thanks guys. I am trying to use steels that I either have on hand or can get locally. Shipping steel gets pretty pricey.  Though I now have a source of 01 drill rod and flat. 

As for welding up a billet I wasn't going for a pattern.  Just the size needed for an axe

[SReynolds]

 

I work very little with high carbon as it can be tricky to weld. Easier to weld low carbon to high carbon. But also, I will add, if you follow T Joe's method (looking for the steel to just begin to spark (burn) you can weld all sorts of low carbon. I mean, you can literally try to NOT weld it and it will. Do it with a can of Mt Dew soda in one hand. It just WANTS to weld. I mean two separate pieces. Not that folding stuff where you have got one piece. But two. Real real easy. But you gotta have that extra oxygen thing going. Now...if you leave it in there after it begins to spark a bit it WILL burn apart, obviously.

I just grab up scrap steel I have (1018) and fuse it together. No trick at all. 

 

[rockstar.esq]

It's worth pointing out that if you're only heating the end of a large metal piece, you'll lose heat rapidly when you pull it from the fire.  Small stock loses heat quickly, making it harder to work with.  A lot of beginners struggle because they're using stock that's too small.

The different perspectives of color can play havoc with comprehension.  I was taught to wait until the metal is the same color as the fire.  That, and to let off the blower for a second before pulling the steel.  If the color darkens immediately, the metal hasn't soaked long enough to heat the center through.

Joes' comments square with a lot of articles I've read in terms of preparing the surfaces to squeeze out the flux. 

I didn't see anyone mention it thus far, but there's no particular reason to think you always get a perfect weld in a single heat.  I can't recall the fella's name on youtube but he's got a couple videos on forge welding where he makes test samples of welds he forge welded the same joint once, twice, and three times.  He wrenched on the test samples until the weld or the material failed.  The samples where he welded once or twice both failed at the weld.  The twice welded was notably stronger.  The thrice welded joint didn't fail - the material did. 

Another point nobody's mentioned thus far is that you can use the flux to reduce the scaling on the entire piece.  We get so focused on keeping the welding surfaces clean that we forget that we're losing stock to scaling.  Thin stock getting forge welded three times will lose quite a bit to scale otherwise.

[SReynolds]

Yes  10-4 Roger that three weld thing.

Done mentioned that.

 

[Francis Trez Cole]

forge welding is not rocket science. First do not over think it. cleaning is important with a gas forge it dose not get as hot as a coal forge. 

these are the steps I follow 1. heat metal. 2 flux, 3 bring up to welding temperature. 4 go to anvil and hit once. re-flux back in the fire. 5 once hot enough hit once. 6 re-flux heat and repeat. 

You can break your weld until you get it to blend together.  the most important thing is a saturating heat.

[ThomasPowers]

Say what?  I've melted steel in my gas forge---is a puddle hot enough?  I know other smiths who have turned a billet into a puddle in their propane forges; (Remember that time at Ohio Village Patrick?)   Perhaps you are interpreting it as "not being as hot" but forge welding is a *SOLID* *PHASE* *WELD* and so a molten puddle is way too hot!