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I Forge Iron

Forge Weld Sparking


Ron Hicks

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Im not Forge Welding Billets
Im Forge Welding Mild Steel
Im not Forge Welding Tool Steel
Im Forge Welding Mild Steel

Forge Welding MILD Steel
When you bring it out of the fire it will be sparking or it will not weld right?
Cause I havent gotten a weld with out sparks
I havent gotten a weld with just a few sparks
But I have welded with a good amount of sparks

It seems every one has told me no sparks
Im not making a knife and not welding billets
MILD STEEL
Coal is the fule BIG Fire Crank Blower
Now Im not making a knife or sword but I just watched a Japanise guy forge welding a sword and it was sparking.

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I forgeweld mild steel for ornamental purposes and do not get a lot of sparks. I see a few bursting sparks above the fire right before the work is removed - maybe one or two per second or thereabouts then I see a few when the work comes out of the fire. The flux is very liquid and can be slung off easily. The weld goes SPAT! when I hit it - if I don't hear that noise then it very likely won't stick. I use SureWeld for 90% of my work - although I also use EZ Weld when I can hammer all sides of the weld. I don't use straight borax because I have had trouble with it leaching out of crevices later.

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Ok before I started asking ? I was getting a few Forge Welds
I also was watching the fire for sparks like you say and getting welds.
So I have an idea how slow to heat
say I take a 1/2 in rd. bar & bend back on itself to come up to heat how long should it take?

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I try to not look into the fire very much, it seems hard on the eyes. I watch for a few dandelion seed looking sparks coming up, turn the piece over if I can while slowing down the blast, watch for a few sparks again, and go to the anvil. Some things to watch for, can you get from the fire to tapping the piece in 1-2 seconds? Is the hammer already in your hand when you leave the fire? Is the anvil chilly? I keep a chunk of 2" round on the forge, I heat it to spit-bubbling hot, and use it to get the first weld set. It's only 8 inches from the fire, and saves time. After the pieces are stuck, I move to the anvil. If you're using flux, the dandelion sparks may be subdued, and hard to see until it's too hot. Everyone has their own method of knowing when it's hot enough, I started to get a feel for it after many tries and a big pile of scrap.

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ron if all suggestions fail you can try bringing your fire to welding heat, put the peice in and get it almost to welding heat, then let the fire die down to an orange. This should get the heat to really soak into the billet. Then leave the peice in and bring it to welding heat again and see if it'll stick.

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So you're welding mild then? ;)

in the case of the 1/2" round bar, I would:
Get forge to temp
bend bar back on itself and make sure it's properly aligned (I would probably cut halfway through at the bend first, your mileage may vary)
Get it hot again
enough flux to get between the pieces and scrape off any of the fluffies on the outside of where the weld would be. I use good ol borax.
More heat
flux a little more
back in the heat.
Get something to drink. Go to the bathroom. Talk to the wife... whatever is going to take 5 minutes or so for the heat to soak into the core of the metal.
I'm looking for the flux to start rolling around on the piece. Just like tossing a little water in a hot skillet to make sure it's hot enough for pancakes :)
I don't get sparks from my propane forge. From solid fuel I would expect a little sparking- but be aware that yellow outside doesn't mean yellow inside. bring the whole piece up to temp.
take it out, firm but light taps- don't kill it.
wire brush the heavy scale away.
back in the fire
flux
wait
hit it again....
rinse. repeat.

the best tip I've been given is: less air. That promotes scale formation and will burn the steel (as mentioned above)

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Ron it depends on your forge.

Thanks Thomas

Not sure I brought it up but working in a coal fire and only way to see the flux is to dig it out and lose heat.
Only way I have had any luck is get a good fire going with lots of coke.
Pull all burning coke from pot clean out fines & clinkers. Fill pot back with burning coke and pile green coal on sides and back. put work back and get on the blower till it a good orange and slow down blower but keep cranking till sparks come from fire.

If I go to slow my coke all burns out under my work

Just some stuff to look at-
Check this guy out it looks like hes really pouring the air to the coal
YouTube - The Marsi Chandelier Part 2 - Hot Forging & Forge Welding

good stuff I found looking for forge welding
YouTube - Forge Welding - 1904
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You should be able to see into the fire without moving the work. The work ought to be laying more or less level with 3-4 inches of fuel under the piece and about the same on top. There are usually small crevices in the coke that allow you to watch the temp.

I do not flux in the fire - some people do but I think it makes clinker worse and the flux usually sticks to the spoon to a some degree. I get the work to a dull red, pull out and apply flux, then go back in for the welding heat. Everyone's eyes are different but a welding heat is hard to look at - it's incandescent and bright yellow - almost white. "Orange" as you describe it is not hot enough. If you are sticking the part down into the fire, the piece is burning on the surface but is not really hot enough to weld properly. That's why you get a few to stick but the welds probably could be broken if you twisted them.

This is cheating to the purists but I do a production forge welding job - 20 or more pieces at a time - and I worked on the process to get maximum output. I upset and scarf as normal, tack the two pieces with a MIG on one side, flux everything with Sure Weld, then clean the fire and go to welding. The Sure Weld cools down but forms a glass that protects the scarfs. I can get 4 welds and then the fire needs cleaning - the 5th one rarely sticks because of clinker blocking the air. This is very repeatable for me using my forge and fuel, your results may vary.

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Ron I agree with HWooldridge, I take my steel to near white if it is sparking your burning your steel and can make your weld look ugly. I find if you are using coal that the impurities can cause problems with your weld, I make sure I only have coke in the fire and keep the coal on the outside to make more coke. A lot of times I will make bar shoes and not even use flux, placement in the fire is important you do not want it to deep it will just oxidize the steel and frustrate you when your weld fails. I keep about 4" of coke under the steel and at least that much on top usually more though.

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My suggestion for beginners welding is:

Get the forge *hot* and then Turn Off The Air and stick the piece in to preheat with NO air---go get a coke or use the bathroom, etc.

Then *quickly* pull the peice out, wire brush any scale off and flux---over a metal pan to catch what fluffs off---it's anhydrous then and works better the next time. And back into the fire.

Turn the air back on and bring the fire up again nice and slow---no oxidizing wanted! rotate the piece if possible to make sure it heats evenly.

When you see the *first* spark take it out and weld making the first blow firm rather than sharp and as my first forge welding instructor used to say "don't look at it *HIT* *IT*!

Most folks get too much air in the fire
too little fire depth
piece too close to the tuyere
and have trouble hitting it *fast* but not sharply

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I want to Thank Everyone who has replied -you all have gave me some good info. and it is helping.
I also want to Thank the Blacksmith that called me last night to help me with Forge Welding. Not sure If I should mention his name but you helped me think about what I was doing wrong Thank You Very Much !

I think Im having some luck finally its all about the fire.
Ill tell what I have learned so far

1 - You have got to learn what your Coal will do in your Forge.
I was digging out the fire pot every time for a nickel size cliker. All I was doing was breaking up my coke into fine bits and choking off the air with fines.

Today I built my fire like every one has told me and left it alone. I just pulled coke in on top when needed & banked wet coal on the sides of the coke.
I kept a even flow of air in the fire also- I wasnt cranking it up and letting it die down just nice and even.

I have had this fire pot for years and until today I did not have a clue what it would do. I bet I was wasting a good 1/3 of my coal by over cleaning the fire, I had to remove the fines to get air .
I ran it for a good 3 hrs. and made 7 forge welds with out cleaning the fire, my 1st & 7th wasnt to great but 2-6 was fine.
Getting back to the fire pot , by not over working the fire the pot could do its job . I bet I only hand a hand full of ash come out of the dump and the clinker was one chunk the size of a small pancake.

#2 A few mention watch for a spark in the fire- I was doing this & it works but If its not hot inside it wont weld.
After talking to the Blacksmith last night and doing the steps like he suggested-
Bring it to red to orange wire brush flux put back in fire-yellow wire brush flux back in fire- watch for first spak pull and tap together flux back in fire- next spark pull light hammer when cool a bit & hammer out.

Wire Brush helps Flux helps but another thing was happening at the same time- it was giving me something to do. Pulling it out to Wire Brush & Flux it was letting the outside cool some and helping the heat to even out.

I need a lot more pratice
Thanks everyone
and thanks for the call last night
Ron:D

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Ron - that's great news, I think I speak for everyone by saying it's always satisfying to see someone succeed.

BTW, you have some really high quality coal if that's all the clinker you get after a few hours. I get one as big as your hand after 3-4 hours but it's some old nasty stuff from Oklahoma.

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  • 3 months later...

I did my first forge weld this week, trying to weld on the reins of a pair of tongs using 1/2" sq bar. I used my new forge, made a very deep fir about 7". and used borax as a flux.
It went great, I managed to get half the section to stick, a good solid joint but the other half is a big gap. And I have allready forged the pre-upset section down to the required size. what do I do now, or should I just arcweld the gap closed and try again on the other half of the pair?
What could have caused this and how can I improve?

Wim

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Is your weld area bigger than your hammer area? Where the gap is, was it allowed to cool by placing on the anvil while you got the other part to stick?

Since this is practice how about cutting it off and try again. If you don't have enough reins left, well I guess arc weld and make 5 more as penance. ;)

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Another thing to watch is make sure the heels of the scarfs are at welding heat. (see attached drawing) If the piece is not far enough in the fire the tips will be at heat, but the heel will not be. The hot tip will then not stick to the colder heel of the other piece.

An easy way to save your piece, would be to forge braze it. Wrap a couple wraps of thin copper wire around the joint, flux with borax, and heat until the copper melts. Then pull it out of the fire, and as soon as the copper solidifies, dunk it in the slack tub for a second or two to pop the flux off and wire brush and let cool.

2964.attach

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Hi Wim. Once the scarf is forged down to below the thickness of the parent stock, the game is over, unless you are willing to arc cheat ;). I wouldn't consider this a really bad cheat. There are other kinds of cheating which are much more objectionable. Many cheaters I have known are immoral or morally relativistic, self-centered, and hedonistic people. Arc cheaters, I have found, can be very decent people. In fact, if you arc cheat this pair of tongs, it will allow you to move on to improve your welding skills later. I have calculated the cost of throwing tongs in the scrap heap which could have been fixed with just a tiny little arc cheat, and the carbon footprint is much lighter if you just cheat a little. Once I was at an estate auction and I saw a pair of tongs with a horrible rein weld on them. The rein and the jaw looked like an X. The two bars were just laid on top of each other, and welded at the overlap. It was so bad that it looked like you could lose a finger in the notch if the power hammer flung them. The tongs looked 100 years old and I quietly gave them a little tug. No harm done, I figured, the smiths weren't going to buy them. The weld turned out to be pretty strong. Certainly stronger than a set of one piece forged tongs that I bought that cracked off a jaw.

Mills and BT have very good suggestions. I learned a lot from them. Now I understand better why the scarf should be kept short. Thanks!

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Guys, thanks so much. I'll be honest, Im gonna archweld this one and give it another bash on the other rein. Mills, yes, I think I allowed it to cool down on the anvil, cause that is the side that didn't take.
BT, I never checked the heel of the scarf temp, I will keep in mind when I try again.
Evfreek, thanks for your elaborate explanation about arch cheating. Now I don't feel so bad.
Wim

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