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Need Help Forge Welding


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Hello, so I'm trying to forge weld some thinner pieces of steel that I have, I do know after spark testing that these pieces have a decent carbon content. I managed to get the metal up to a light orange color while fluxxed. I proceeded to hammer the pieces together at this temp but I could not get the pieces to stick. They were properly cleaned with a grinder before tack welded together. I will add some pictures of the pieces soon. But as for now does anyone have any suggestions or ideas as to why this is not working for me. Also should be noted that I am using a forced air wood forge. 

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Sounds like you might have been too cold.  I would describe the welding temp for high carbon steels as a butter yellow.

Thin pieces can be hard to weld because they cool down so quickly. (Unless you have a lot of them stacked up to create a big thermal mass)

Other than that, there isn't much to go on.  The pictures might help.

 

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I was using borax and I had four pieces stacked.

1 minute ago, Brian Dougherty said:

Sounds like you might have been too cold.  I would describe the welding temp for high carbon steels as a butter yellow.

Thin pieces can be hard to weld because they cool down so quickly. (Unless you have a lot of them stacked up to create a big thermal mass)

Other than that, there isn't much to go on.  The pictures might help.

 

 

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There are also some steels that simply won't weld.  5160 is well known for failing to weld to itself.  All flux does is keep O2 away from the surface to prevent scale, which will interfere with the welding project.  In and of itself, flux won't make the weld happen.

 

Geoff

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I'm just a beginner myself but i have noticed just what Brian said. Its much easier to weld bigger billets. I've had success in coal forge without using flux. I don't think its necessary using solid fuel.

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Another thing flux does is tell you when the steel is ready to weld. The flux should be visibly bubbling and boiling on the billet surface. If it isn't you are still too cold to weld.

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2 hours ago, Joshua States said:

Another thing flux does is tell you when the steel is ready to weld. The flux should be visibly bubbling and boiling on the billet surface. If it isn't you are still too cold to weld.

How accurate is this?  I've heard this a lot, but the Mule Team Borax I use start bubbling around 2000F in my forge which I always though was too cold to weld with a hammer an anvil.  

If I have my forge screaming at max gas flow, I can barely reach 2200F.  At this point the flux is boiling like mad, but it always feels like it is just marginal to get the weld to take for 1095 and 15N20.  I can't really get low carbon stuff to weld reliably at all, so I must be pretty close to the edge of the temperature range.

Edited by Brian Dougherty
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Considering the boiling point of borax (sodium tetraborate) is 2867F, I think it is safe to say none of us that have seen that phenomenon are actually seeing it boil, thus it is a different reaction that we see.  As such there is likely to be variables with the atmosphere in the forge (and possibly the surface of the metal) that will be changing the temperature at which it is bubbling.  My bet is that it has to do with the water content finally breaking free, so anhydrous borax probably doesn't do this at all.  

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usually i see something's happen in the fire or just above it, waiting any longer sparks will fly and the steel s burning. The atmosphere change above the fire is my queue for setting the welds. Of course this is whit coal, maybe anybody can relate this to a gasforge. 

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You are looking for the borax to start 'snowballing' - I was told by the blacksmith who taught me that it's like looking down on a kids snowball fight. Always worked for me and it does kind of look like that! So yeah, it's always at around a high yellow, should be so hot it makes you feel a little queasy looking into it (though you shouldn't be looking into it for too long!)

James

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Also, if you have a long very thin piece (around 0.5mm thick) of bar stock then you can poke the billet with this and at welding it should start to stick just by touching it.

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7 hours ago, Brian Dougherty said:

Sounds like you might too cold.  I would describe the welding temp for high carbon steels as a butter yellow.

Thin pieces can be hard to weld because they cool down so quickly. (Unless you have a lot of them stacked up to create a big thermal mass)

Other than that, there isn't much to go on.  The pictures might help.

 

Here's what ive got as a result. These are just some pieces I have cut out of the overall piece. 

1488239416669-645256457.jpg

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5 hours ago, Brian Dougherty said:

How accurate is this?  I've heard this a lot, but the Mule Team Borax I use start bubbling around 2000F in my forge which I always though was too cold to weld with a hammer an anvil.  

If I have my forge screaming at max gas flow, I can barely reach 2200F.  At this point the flux is boiling like mad, but it always feels like it is just marginal to get the weld to take for 1095 and 15N20.  I can't really get low carbon stuff to weld reliably at all, so I must be pretty close to the edge of the temperature range.

I still have a box of that 20 Mule Team and I have to say it never worked well for me at all. This is the product I use: https://www.knifeandgun.com/ProductDetails.asp?ProductCode=FWF and it never fails. (only I do) It is a very significant effect when the correct temp is reached. At lower temps it will move about and look right, but it's not ready yet. At proper temp it really froths and expands is the best way I can describe it. When I have done this in a forge with a thermocouple and digital readout, it's right around 2450* for Hi-C steel. Low-C steels typically require higher temps to weld.

 

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27 minutes ago, Brian Dougherty said:

I'm not sure what to make of the pictures yet.  Did you have to grind on the stack to get them apart, or did they just fall apart like that?

Those pieces were originally thicker. About one inch square and were pressed as tight as I could get them with my c clamps. I then proceeded to tack weld each corner once on the middle of each end and three more tacks on the longer edges. After I finished pounding it out I cut off the edges with an angle grinder I ground down the edges to see if the welds stuck but I saw lines on all of the edges. At that point I new none of the welds set. I then pulled the pieces apart and those pieces pictured are the inside edges of the pieces. Before clamping and tacking all pieces were ground clean and flat. 

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Between that info and the pictures, you're either using stainless or you were not running nearly hot enough.  You should not be able to look directly at the billet for more than a second.  Did I miss what steel you have and how thick?

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28 minutes ago, Alan Longmire said:

Between that info and the pictures, you're either using stainless or you were not running nearly hot enough.  You should not be able to look directly at the billet for more than a second.  Did I miss what steel you have and how thick?

I do know that it is not stainless steel. But heat may be an issue. I have been burning would but I am trying to get some coal instead as it will burn hotter. Trouble is finding a supplier in my area.

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3 hours ago, Joe kemp said:

I do know that it is not stainless steel. But heat may be an issue. I have been burning would but I am trying to get some coal instead as it will burn hotter. Trouble is finding a supplier in my area.

If I am taking from that that you're burning wood... You're not going to get anywhere near hot enough. Max you can get to is around 600C and you need to be about twice as hot as that. Coal or charcoal is essential. Coal I have always found much easier and you go through a lot less volume of fuel.

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Yes I am planning on picking up a bag of charcoal to burn in my forge for the time being as finding a supplier for coal in my area is rather difficult. The nearest supplier is a 30 minute drive from where I am so it's not easy to just make that drive for coal. But sometime soon hopefully I will be able to go there and pick up a big bag of that.

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Keep in mind all coal is not created equal.  You want blacksmith's coal, or technically metallurgical grade bituminous, low ash, low sulfur coking coal in stoker size.  I can get stove coal easily, but the batch the guy here has is high sulfur high ash and doesn't coke worth a darn.  I drive over an hour one way to get the good stuff for forging. It is getting harder to get as well, the last few hundred pounds have been about 5% rocks.

If stoker is all you can find it's usually okay, just avoid any with white or yellow spots (sulfur) and be aware some of it is oiled to keep the dust down.  This doesn't affect forging, but it makes a huge flame when you light it up and stinks terribly until the oil is gone.  Not that unoiled coal smells particularly good, of course. :lol:

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On 27 February 2017 at 10:42 PM, Jerrod Miller said:

Considering the boiling point of borax (sodium tetraborate) is 2867F, I think it is safe to say none of us that have seen that phenomenon are actually seeing it boil, thus it is a different reaction that we see.  As such there is likely to be variables with the atmosphere in the forge (and possibly the surface of the metal) that will be changing the temperature at which it is bubbling.  My bet is that it has to do with the water content finally breaking free, so anhydrous borax probably doesn't do this at all.  

I weld with anhydrous borax and it still displays this phenomenon, in my experience the bubbling is more vigerous in a rich environment than it is in an oxidising one. to the extent that I would change my gas mix if there was no bubbling. when I weld with borax I look for the "kids running around in a playground" vigourous bubbling that has been mentioned and that the borax is smoking. The colour of the steel is so subjective.....

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