Forge weld with big daddy whisperer

[horse]

I have a three burner NC big daddy whisperer. It is about 15 years old and still in good condition. I cannot forge weld in it. I believe it does not get hot enough. It will bring steel to white heat but have never had it burn up a piece. I called the company to see if there is some kind of modification for my elevation. He tells me that there is not. Very nice and helpful but said some can weld in these and others can't. He did not have any info about high altitude performance. I am at 5200 ft. North of Denver. I have cleaned jets and aligned burners still not as hot as I think it should be. I run about 12lbs on the regulator. Higher than that and I get tremendous dragon breath and feel like I can smell I burned gas. Any ideas about how to beat this thing up. I have just found a somewhat unlimited source for big band saw blades and would like to start fooling with some layers. 

[Ridgewayforge]

Is it a non-possibility to build a solid-fueled forge for this purpose? 

[Buzzkill]

You may want to look into decreasing the volume of the forge using fiber board or something similar.  What we don't know is if your burners are unable to produce forge welding heat or if you are losing heat so fast that the interior of your forge can't get hot enough.  If it's the first then the only way to deal with it is to tune, modify, or replace the burners to get the heat you need.  If it's the second option then decreasing forge chamber size and/or closing off any place heat can escape (except what's required for burner function) will help out.

One more thing.  If you are close to temp, then a fresh coat of ITC-100 or comparable product may get you over the hump.

 

[Frosty]

Judging temp by color is too subjective to really tell us how hot your fire is, steel melts at bright yellow, aprox. 2,700f. If the forge is hitting even med high yellow, say 2,200f you can weld in it, some of the old school fluxes will let you weld at high orange, say, 1,800f. but haz mat regs have pretty much shut those out.

What are you using for flux? How clean and well matched are the joint surfaces? If you're prepping properly and it still isn't working for you or you just "need" a hotter forge try closing off some of the volume. A little Kaowool propped up just outside the outside burners to concentrate all three flames in a smaller volume will make a hotter forge.

About prepping to weld, this is how I do it YMMV. I match the surfaces as closely as practical. The closer the two surfaces are to meeting without gaps and such the easier they are to weld. I'll take a single cut file to the faces if it's a lap weld or other large surface area join. I want the faces shiny if possible and have taken my belt grander to them with a worn 340 belt and a spritze of 3 in 1 oil to prevent oxidization. The 3 in 1 also makes a perfect surface to sprinkle flux on it makes it stick where I want it. 

With the faces matched and clean I flux cold and close the joint as much as possible BEFORE putting it in the fire. Why? Flux isn't glue, it's there to first and foremost keep the steel from oxidizing in the joint or even reduce iron oxide back to iron. A lot of old school books say it's there to carry debris out of the joint when struck. . . Well, okay. I try to avoid conditions where the joint is so dirty I need it pressure washed by molten borax. It happens though. Anyway, I like to flux cold when possible, the colder the slower chemical reactions happen like oxidization. Borax melts at a temp of about 1,370f. and forms a layer on the steel that keeps the air off it. Being a strong base it dissolves any iron oxides that have formed before it could shield the joint.

My home shop recipe is 1pt. boric acid to 2-3 pts borax, laundry booster. Yeah, it foams as the water boils out if that moves your join around on you it might not have made it to the anvil anyway, wire it or tack weld it next time. Boric acid has a lower melting temp and sure it's an acid, combines with the borax to make a salt but that's no THING, commercial welding fluxes almost universally contain anhydrous borax and boric acid just like the old school fluxes or modern "forge welding" fluxes like Swan and Black Magic(?).

I've stopped using my home brew when I discovered a 1lb. can of welding flux at "Aire Liquid" the welding supplier down the road from me carries a number of fluxes for gas welding, brazing, etc. I read the label and did a MSDS search online. Well guess what it's anhydrous borax, boric acid and something proprietary to turn it blue or maybe it makes a better flux. I'm using Pattersons #2 blue. and it works a treat. Their #1 (I think #1, in a yellow can) contains powdered iron oxide but I'm applying flux to prevent and or remove iron oxide so why do folk put it i n their fluxes? All the "better" forge welding fluxes have iron oxide in them. I'm sure there's a good reason I'm not chemist enough to understand but . . . Nevermind.

Oh yeah, a 1lb.  / pint can of Patterson #2 costs $27.xx off the shelf in Wasilla Alaska, shipping included. Price a can of Swan, Cherry Heat, etc. and include about $15. S&H. I drive past the welding supply all the time it's no thing to stop in, I'm right there.

Anyway, that's my thoughts. #1 improve your prep and technique. If that fails reduce the volume of your forge to increase the temp.

Frosty The Lucky.

 

[Steve Sells]

I will ask, why would anyone want oxides in the joint? since the big reason for using flux is to exclude oxidation?

[Buzzkill]

Since the iron oxide is powdered (i.e. lots of surface area so reactions are completed quickly) and the flux helps reduce the iron oxide to iron, that would result in a lot of small particles of elemental iron that can help fuse the other 2 pieces together.  That's my best SWAG, but it wouldn't be put in commercial flux if it hindered rather than helped the process.

[ThomasPowers]

Unfortunately the flux does NOT reduce iron oxide to iron but insteads dissolves/liquefies it for physical removal during welding.

[Michael Cochran]

I have a little two burner from NC tool that looks to be almost as old as I am (32) and it'll reach welding heat. I have to turn the gas way up and close the door flap but it'll do it without much effort. I don't even have good insulation in it anymore due to being gouged moving steel in and out as well as burned spots from flux dripping. If my old beat up one can do it yours should provided that the air isn't too thin up there, I'm only at about 1000 feet here.

[Buzzkill]

 

25 minutes ago, ThomasPowers said:

Unfortunately the flux does NOT reduce iron oxide to iron but insteads dissolves/liquefies it for physical removal during welding.

Some fluxes are indeed reducing in nature.  Without knowing the other components of the flux in question we can't say for sure one way or the other. 

FWIW, here are a couple snippets from a discussion on a pottery site which may have some pertinence here:

" Red iron oxide is a refractory, but becomes a flux when it turns into
black iron oxide, which happens in a reduction atmosphere, or in an
oxidation atmosphere when it reaches a certain temperature. "

" Certainly more of a flux in reduction - Hamer says a strong flux because it
melts quite low (800C) when reduced so that makes it comparable to the
alkaline fluxes."

Their definition or use of a flux may be slightly different than ours, but again the oxide would not be in the flux unless it had a positive effect.

 

[Frosty]

Red iron oxide has to absorb another oxy atom to become black iron oxide, black iron oxide is maxed out on oxy so can't absorb more in a weld joint.

One of our guys "Teenylittlemetalguy" on Iforge makes a flux he calls "Alaska Flux" that contains powdered charcoal which not only scavanges any available oxy molecules say from black and red iron oxide it raises the carbon content of the surfaces being welded and so lowering their melting temps.

Now, if a person were to  add unoxidized iron filings to flux it might help but probably not as much as high carbon filings. The higher the carbon content the lower melting temp. There that carbon and liquidus thing is again.

Frosty The Lucky.

[beammeupscotty]

Get better burners.  Either convert to a forced air burner or get yourself a couple T-Rex burners and I suspect you will get to the temps you wish to reach.  The NC tool forges were designed with farriers in mind.  Farriers typically do not need to weld.

[Judson Yaggy]

I had a NC Low Daddy for about a decade and welded with it all the time at 10psi, even with beat up insulation.  I'm only at 800 ft. elevation thou. The one thing I found that made it run better was to every now and then bend a wire bottle brush so you could stuff it up into the burner nozzles inside the forge and clean out the crud.  BMUS is correct that the burner design has been surpassed by others in recent years but they are still functional.  

[Buzzkill]

15 minutes ago, Frosty said:

Red iron oxide has to absorb another oxy atom to become black iron oxide, black iron oxide is maxed out on oxy so can't absorb more in a weld joint.

It's been a while since I've had any chemistry classes, but I think you have that backwards.  Red iron oxide is Fe2O3 and black iron oxide is Fe3O4. In a reducing atmosphere with hydrocarbon fuel this would be the reaction we'd expect:

3 Fe₂O₃ + H₂ → 2 Fe₃O₄ + H₂O . 

Regardless, during the conversion from red iron oxide to black iron oxide there is one more oxygen atom than is needed to make the change, so oxygen is given off as a result of the conversion, not absorbed.

[ThomasPowers]

Red is more oxidized.  As far as putting stuff in that doesn't have a positive effect, marketing is rather full of contra examples---also are you familiar with the placebo effect?   I just wish I could get Dumbo's magic feather to mix into my fluxes!

And I was in error; the fluxes I use, which are plain borax or borax mixed with boric acid, do not have any reducing properties at heat.

Neither does rice straw ash, dirt dauber's nests, powdered glass, clean quartz sand,... Other fluxes may be reducing I would have to analyze them and how they work on an individual basis.

[Frosty]

Uh huh, either way I'll stick with powdered charcoal, carbon has a greater affinity for oxy than iron AND raising the C content in the steel lowers the melting temp. Win win.

Tristan is still experimenting with the % of charcoal to add but his is effective flux.

Frosty The Lucky.

[JHCC]

I made up a batch of Alaska flux with some home-cooked anhydrous borax and managed to forge weld garage door spring to itself. 

[horse]

Thanks for the replies. I have access to a solid fuel forge but needs work and would simply prefer to work in the gasser if I can. I failed to mention that this forge is open on both ends to handle long stock. I did close one end once and it seemed to warp that end of the forge. That troubled me a bit.  I am aware it is a Ferrier forge bought it a long time ago when I was young enough to nail shoes onto my Belgian horses. I am now too old and smart enough to leave that to the  Youngsters. I think I will try blocking the port again. I do not recall the flux I have used but some high dollar stuff from a local ferried supply house.  I have stuck some welds in solid fuel. I certainly confess I am not a seasoned welded in a solid fuel either

[horse]

One more thing. frosty are you saying u use 3 - 1 oil when steel is stone cold?  Could sure be the case I am fluxing too hot. 

[timgunn1962]

Can you get smaller gas jets for the forge?

You mention that you get "tremendous dragons breath" above 12 PSI. This suggests that your Air:Fuel ratio is too fuel-rich.

A Neutral flame gives the hottest flame temperature and a very rich flame is quite a bit cooler.

Since there does not seem to be any way to adjust the air intake and they seem to be Naturally-Aspirated burners, using a smaller gas jet should lean off the mixture and raise the flame temperature. Although the flame will be hotter, there will be less of it at any given gas pressure due to the smaller gas jet, so the forge may not get any hotter overall. 

However, if you then increase the gas pressure, you should be able to get the gas flow back up to where it was with the bigger jet and see higher forge temperatures.

I'd initially try for a 10% reduction in jet diameter and see how it goes. Going too small will give an Oxidizing forge atmosphere and you'll just produce a mass of scale. You still want some DB, which is a good indicator of a reducing forge atmosphere, Just not too much.

With a gas jet 90% of the diameter, you'd have 81% of the area and would need one and a half times the gas pressure to get the same flow as before: 

(100%/81%)squared = 1.524.

I don't imagine you'll have a gauge that'll read to that degree of precision, so 1.5 is good enough. 

 

[Judson Yaggy]

55 minutes ago, timgunn1962 said:

Can you get smaller gas jets for the forge?

He should be able to, IIRC they were just the standard brass gas nipples threaded into a square tube manifold.  And you are correct that there was no adjustment on the air intake, I often meant to add a way to choke the intake but in the end just sold the thing and built a couple of custom gas forges that better suited my needs.  

Typing that jogged my memory.  Horse, have you removed or loosened the manifold from the burners?  I remember doing that once to mine when relining the forge and realigning the injectors with the intakes was a bear, it ran like crap unless all 3 were in the perfect spot.  

[horse]

It has been a while but after a call to the folks that manufacture the forge I did the alignment and felt like all was good.  I am going to use Frosty's advice and use some oil and make sure I am as clean as I can be..  I will then find a way to reduce the chamber size and see what happens  Very conceivable that I simiply cant weld in the xxxx thing.  I am guessing others can.  I will keep trying    thanks all

[Farmall]

Have you looked at available high alumina kiln shelf sizes that should fit?    I have the two burner NC Tool Forge and was looking at them in varying thickness to decrease the volume when I wanted to get a higher heat.  I just got the forge, so haven't fired it yet,  The kiln shelves I have seen were in thicknesses 1/2", 5/8", 3/4", and 1".  They can be cut with a tile or masonry saw.  Still researching this, but I believe it would work.   

[gote]

To add carbon to flux makes a lot of sense. To add iron oxide does not. However, a chemical analysis is traditionally made on an oxidised sample and the result may be given as oxide. Maybe it really is iron powder of sorts. I recall seeing flux recipies containing iron filings.