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Making my own flux


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I was working with a damascus billet today and had a delamination pop out. So I sprinkled a little borax on it and a pinch of 1084 fine mesh powder steel and it got it to weld back together. Well maybe I should say I might have gotten it to weld back together. I'm going to grind the blade tomorrow and we will see if it shows up. It might just be chance or maybe the powder steel helped? I'm going to drill a bunch of cast iron swarf and mix up a batch of ''special flux'' after I'm done with this blade.

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In grinding the blade and there isnt one delamination. Even the one spot I had to coax this back together with the 1084 powder and borax. I didnt use flux in making the initial billet because it is canister Damascus but it worked to pull it back together.

Now it's time to experiment with cast iron.

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  • 4 months later...

Here is my first attempt at making my own flux. This ended up a little heavier on the cast iron so I might mix a pinch more borax. I will try it out on a little hatchet that just wouldn't weld at the eye. The bit welded just fine and so did behind it by the eye until I went to do my final drifting and it popped open. We will see if I can get it to stick if not then it will go in the scrap pile and i will start a new one. 

Resized_20191008_122940.jpeg

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Technique has a lot to do with how the weld comes out.   It's the reason why many can weld at a lower temperature  than others or they can troubleshoot a weld that seems hopeless. 
 

Years back i added metal to the fluxes and noticed that the flux being up to melting temperature would eat the pans it was being made in. it also created a denser product so it took a 4/1 ratio or 4 parts of uncooked borax to make 1 cooked batch.   I also found that I could use less and it melted at a lower temperature and coated the steel better. 

Now I'm lazy so just us the Same borax that I was given to me in the mid 80's. 80lbs has lasted me all this time.  I think I still have maybe 10lbs left and I do a bunch of forge welding. LOL. 

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It seems like 30% cast iron is about the right amount!!! Anything more than that you get too much molten cast iron spray. It really does lower the welding temps though!!! I welded wrought iron at an orange to low yellow heat where it would normally have to be at a yellowish white. It works like a charm and I will be using it for all my wrought iron welding. I will use normal borax for any Damascus I might make as I'm not sure of it leaving any traces if it in my finished billet. Though a good soak would probably wash out any traces of it and the carbon would migrate into the rest of the billet.

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Clean, well matched, pressure and heat make for forge welds, get 3 of them right and you get a weld. Ask NASA what happens when you get accses panels to well matched, clean and under pressure from screws (hint, they will weld in vacume). 

Flux that melts below the scale/oxide forming temp and won’t boil off at higher tempetures is a good thing, not a cure all for bad technic but it helps us imperfect humans. Steve’s flux recipe adds sal-amoniac to the mix to address low tempeture chromium oxides forming as it melts before they form, wile the borax and boric acid stay around at welding temp.

As generaly higher carbon contents lead to lower welding tempetures I don’t take claims  that “x” flux allows you to weld tool steels at lower tempetures to seriusly anyway. 

As to welds not sticking, A36 can be an evil mistress, as it’s not a consistent material even in the same bar, you can find spots where you just can’t get it to weld wile other spots will stick to each other like magic. If you find your self in that spot when you consistently make good welds either move on to another piece of stock or use the old trick of inserting a piece of low alloy shim stock between the two pieces and try again. Back in the day shim stock was sold just for this use. Not being a metallurgist I suspect that this might be part of the reason for the continued use and antidotal success of iron and cast iron filings in flux mixes. 

A note on adding charcoal to your flux for O2 scavenging. Hardwood charcoal contain more silica than softwoods and thus make more ash. In this I am acualy referring to the quality of the wood not wether it’s desitus or not. Now the silica content may or may not help you in your work, just be aware of it. The Northern Europeans seemed to favor low density desidues woods for forging charcoal as they produced less ash. 

Now as to magic feathers...

 

  

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If you add charcoal a minuscule amount is plenty, you just want to raise the contacting surface's carbon content a point or two. That's one or two HUNDREDTHS of a PERCENT. Visualize adding 1/2 tsp to a pint/1lb. can of commercial flux.

Using charcoal of cast iron in your wrought iron flux will increase the carbon content at the joint surfaces probably making for visible weld lines. 

Fun stuff.

Frosty The Lucky.

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23 hours ago, Charles R. Stevens said:

it’s not a consistent material even in the same bar,

I have talked to a metallurgist about this statement and it is simply not true. Yes there may be variations from one batch to another but in the same batch the alloys are well "mixed". Alloys cannot change from one part of a bar to another. Same goes for rebar. It's not as inconsistent as people make it out to be. Sure it's not the best material but it is consistent!!! This is one of myths just like "annealing" in vermiculite.

As for the visible weld lines, a good soak will take care of it. Gary mulkey has demonstrated this in his Damascus.

 

Other discussion split off and moved to Heat treating section, called Amealing

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Every time an addition of scrap is made to the continuous caster, its alloy output content changes unless your using virgin material to charge it, or taking time to homogenize and re test, something that many budget castors wont do.   Explaining why the rest of us believe its not 100% the same end to end for the cheap fast produced items like rebar especially when alloy content is not critical for something only needing to meet a strength standard.

 

Even structural I beams for large building and bridges are having problems now, from when years ago we bought cheap steel from China. it has caught up with us

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When I lived close to the US/MX border I used to drive by a steel plant producing rebar and see the diversity in their scrapyard and wonder how tightly they could control things.  Remember the radioactive rebar "scandal"; would you say it represented tight controls?

I also remember when scrapyards commonly separated their scrap and even paid/sold it for different amounts; but my local scrapyard dumps it all together and sells it that way----steel and cast iron and various alloys.

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I understand what you mean now. 

The metallurgist that I talked to said that rebar has fairly tight tolerances and they keep records of all there pours for decades because when a bridge or building collapses the first thing they look at is the rebar and the composition and there strength testing records. 

The separation process for scrap steel is incredible and beyond my understanding but they have there ways of getting the desired end product.

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There is rebar and then there is rebar. The typical stuff from the building center is vastly different from the high spec material used in bridge and high rise building. You are correct as many times the structural engineers will specify steel formula. 

Typically tho A36 and rebar are engineering specs instead of steel formulas.  

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I've gotten A36 bars that were completely delaminated with inclusions nearly down both 20ft bars..  From the outside the inclusions were hard to see but as soon as you hit it while hot, it completely came apart.    the Metal yard would not warranty it out claiming A36 one gets what one gets. 

They then claimed that was a batch that came from India or china and there was a shortage of A36 in the USA so everyone scampered to get what they could from outside sources. 

 it was 3/8X 1.5 or around that size.. 

I find A36 to be hit or miss forge welding and it is one of the few steels that I pay attention to more so than any other when forge welding watching what is happening and adjusting accordingly.   The tomahawk video was shot using A36 and it fought me right out till the very end.  

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I did the same job I do now for a living, I am an Electrician, they produced many different items, the point I was making is people dont tend to throw away money testing for things they dont need to know all the time,

Did you test the Oxygen or Radon content of your  home today?  How about the exhaust of your car, what is your average unburnt fuel output today?  We will all admit these are important things but to test for them with out specific reasosn is not done

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Ok let's look at this in perspective. We all know trace elements do very different things in steel. They are tested for and regulated very strictly. In a continuous casting they melt the steel prior to pouring and there is several ladles already pre-charged with desired product and then poured into bars then drawn out. If it was a scrap pour with a constant unpredictable product it would run the risk of "break out" and major damage to the machinery. Maybe(?) In foreign countries they do crap runs but here in the states they produce quality product for the most part and testing for different alloys isnt that difficult and removing the impurities is simple. You guys make it sound like its impossible to create a quality product from scrap which just isnt the case.

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