Forge welding

[iron man]

First, sorry about using the same user name as a current member.

Forge welding this is new to me I would like to weld pieces of metal together. Whats the best flux to use, how hot should the metal should be? What's the best joining practice. Any help would be helpful. I've been using mig and tig welding to join to make it air tight.

[Ellen]

You're going to get a hundred different answers on this one, so I all I can tell you is what works for me.

1. I like to clean the scale or mill finish off the metal and prepare the surface, sometimes it needs to be scarfed or bumped up.
2. I like to wire together with soft wire, it melts at a higher temperature than steel with more carbon in it so it will hold the two separate pieces together, of course if folding a piece of sell over on itself this is not necessary and that is probably the best for a first weld anyway.
3. Bring to a red heat and flux.
4. Flux: lots of folks use plain old 20 mule team team borax available in 5# boxes in the laundry section of most supermarkets. Others swear by or at: Anti Borax #1 (from just about any welding supply house or online from PiehTooCo.com or Blacksmiths Depot.com)--this is basically solid boric acid crystals with iron filings, I like it it a lot; "Sureweld", and other trade name welding fluxes available from the online suppliers.
5. Bring to a welding heat (this is the tricky part, judging the heat); it can be anything from a "slippery orange" to a bright white just short of throwing sparks; tap lightly to start the weld, return to the fire as soon as welding heat is lost, reheat and repeat. As the metal welds together you can hit it harder.

Like I say, there's lot of different opinions on this....good luck!

[Tyler Murch]

Clean surfaces are key. Remember that borax (if you use borax) melts at 1300 something degrees F, and scale forms at 1500 something degrees F. So you have a window of about 200 F that you can apply the flux at without getting scale on the steel.

[Rich Hale]

Not sure if I got it right but if I did: I think you said you mig or tig welded to make it air tight, If that means you are going to forge weld two miecles together and did this as a method of holding everything in place,,think about how flux works,,You will get scale in a forge weld, I flux as soon as I think the flux will not fall off,,most of the time the metal does not show color yet when I flux. The flux does things that are best left to others to describe by the book but let me give you what I see happens, The flux tends to not only prevent scale from forming on the steel while you bring up the heat, it also helpt to remove any scale in the joint. To do that last part it needs to penetrate the joint. If welded all the way around and water tight it will also be "flux tight" (maybe). Ellen gave you a real key to a good weld, First hits should be taps. Even with light taps you will see a lot of stuff come out all sides (seeking flesh). A lot of that is flux but it brings with it scale that may prevent a good solid weld. At each heat I wire brush real fast and reflux before going back in the fire. Take a piece of half inch square mild steel and heat it and fold a couple of inches back onto its self. This when welded is called a faggot weld, and is the best place to learn welding in a forge. Do some destructive test on your welds,,try and chisel them apart. Get those welds right and move onto two pieces,,a tack on one end to begin is alright to hold in place. Then weld something everytime you fire the forge up. You will find the anvil sucks the heat right out of the steel. With a hammer in one had remove the welding heat piece from the fire and do not touch it to the anvil until you can tap it, Repeat everyday...good luck

[Dutchmancreek]

I agree with Rich in that you should practice a weld every time you light up your forge. I also try to warm up my anvil because it will remove just enough heat to make the weld very difficult. (I throw a large piece of iron in the forge and after it heats lay it on the face of the anvil while getting ready for my project.) For welding smaller pieces, I have a flat plate mounted right beside the forge to make the weld before heat is lost. Larger pieces will hold heat longer so they are usually all right for the 90 degree turn to the big anvil. I don't see a lot of difference between the commercial fluxes and plain old borax, other than the cost.

I also find that if I just go and make the weld without fretting over it I usually am more successful. I think it's an attitude thing.

Steve

[HWooldridge]

The right kind of fire and fuel is important also. For several years, I had a lot of trouble forge welding but other more experienced smiths would come to my shop and weld so I assumed the problem was me. In fact, I more or less gave up until I was working one day in a friend's shop on a different forge with coal from another source. I decided to play around and started hitting every forge weld I tried. Trying to analyze the difference, I concluded it was primarily blast control and the new coal - so I took some home and experimented. Turns out the other smiths knew what to look for but I didn't have enough experience to realize that dirty, marginal fuel and too much blast was hurting my forge welds. I began mixing my old coal with good stuff and using with the air gate to throttle the blast. I can stick welds with regularity now but realize that after 5 or 6 heats, I better clean the fire or the next one will fail.

If you have problems, don't get frustrated and waste time like I did. Instead, go to a workshop or get someone who is good at forge welding to come watch your process.

[stephangleissner]

for me forge welding is an ongoing challenge. i normally try to be as economical with my fuel as i can but unfortunately a good deep welding fire eats a lot of coal. i find it crucial to heat gradually and evenly so that the pieces are soaked all the way through when the sparks begin to fly. also important i find the positioning in the fire relativ to the blast. a weld i find diffikult is flat material, or worse, sheet material on top of each other. how they welded a spade the old way is beyond me. so i wouldn't mind to get some concrete tips about that. has anyone ever welded a spade for the craic?

[ThomasPowers]

I haven't welded a spade but I have done the socket on a chisel or arrowhead or two. my secret is to use real wrought iron and for quite small stuff press weld it with tongs while it's still in the fire and then clean it up on the bic.

Thomas

[HWooldridge]

how they welded a spade the old way is beyond me. so i wouldn't mind to get some concrete tips about that. has anyone ever welded a spade for the craic?

One thing that was commonly done in old shops was to use multiple fires when welding different sizes of material (to better control the heat). We sometimes forget that smithing was not a hobby and that large shops often existed that were the equivalent of modern job shops. It was rarely just a one-man show even in a small shop and the smith(s) usually had help. As today, businesses often specialized so there were those folks that only made shovels and related items. Those craftsmen would have had that process down pat - just like people who made anvils, firearms, etc.

[Mr Smith]

I've just recently learned to forge weld, and the way I learned was by making chain. A lot of chain.
With chain, you dont need to worry about getting two bits of metal in the right spot - they're already there. All that you need to worry about is the heat and flux.

Hope this helps!

[Hollon]

I have another question to add onto this. For someone who would be wanting to practice forge welding would getting a mild steel with a lower carbon content say 1006, make it easier to learn how to weld?

[ThomasPowers]

Yes and no. Mild steel resists burning more than a higher carbon steel does; but also requires a higher temperature to weld at.

What will help is to avoid alloys containing Ni or Cr as they are harder to weld without a more aggressive (and toxic) flux.

Thomas

[Hollon]

I figured that it would not burn as easy without as much carbon though? maybe not though, its not as if im an expert metallurgist