Author Topic: Self-Shielded Flux-Cored Welding: Choosing Your Gun?  (Read 528 times)

Offline PekkaNF

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Self-Shielded Flux-Cored Welding: Choosing Your Gun?
« on: June 27, 2020, 06:28:03 PM »
Got MIG/MAG welder, trying to use it for gasless flux-core welding.

The machine I got is Lincoln Speedtec 200C, 200A nominal amp Mig welder with torch Euro-connector.

I am using now 0,8 mm flux core wire with a standard SB-15 Parweld torch.

Main problem is visibility, the standard mig-torch nozzle is pretty restrictive, it comes very close to pudle. Free wire length should be about 12-15 mm and current bit over 100A. The standard mig gas nozzle goes way longer than conductor nozzle (as is customary). I have cut down the standard conical gas nozzle, but it does not quite solve the problem, merely chops of the cone and leaves the large diameter sleeve to block the view. Shortening it furher would lead to better visibility and surprice if you bump the conductor nozzle into metal while trigger is pressed... :zap:

There are nozzle covers that are designed to do just that, some sort of rubber condom looking thingys, but not for my torch or torches here.




Then there are real gasless flux core guns:


But they are pretty damn hefty and rare here....they all are more than 300A and I need about 150A max.
https://www.bernardwelds.com/self-shielded-flux-cored-welding-choosing-your-gun-p161916

So, I am torn between modding a normal gas gun or sucking up and use the standard gun? Or something else?

Pekka

Offline RussellT

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Re: Self-Shielded Flux-Cored Welding: Choosing Your Gun?
« Reply #1 on: June 28, 2020, 02:44:59 PM »
Hi Pekka

Can you explain a little more - the flux core torch you showed looks just the same as an ordinary torch with the shroud removed.  why wouldn't that work?

Russell
Common sense is unfortunately not as common as its name suggests.

Offline tom osselton

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Re: Self-Shielded Flux-Cored Welding: Choosing Your Gun?
« Reply #2 on: June 28, 2020, 03:26:51 PM »
I would think that would work.

Offline PekkaNF

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Re: Self-Shielded Flux-Cored Welding: Choosing Your Gun?
« Reply #3 on: June 28, 2020, 06:03:42 PM »
As you know innards of the MIG-gun are energized when trigger is pulled (cheap ones are always hot) and you don't want to poke the contact tip into part you are welding.

Therefore there is a gas nozzle in mig welding, it protrudes to cover the contact tip cpmpletely. There is no need to gas nozzle when doing gassless flux core welding (FCAW-S), but it would be really nice to see the small puddle or least the part you are welding (the gun is dragged and fairly perpendicular to work), therefore the flux core nozzle or thread protector would be a nice idea.

There is little info about 3:40 min mark on about this topic


about 12:00 you see the problem with T-joint: The standard gas nozzle would not cover pretty much all there is to see, but be pretty close to be gragged on the part (no problem other than access....thin flux core wire needs pretty short free wire length I.E. nozzle comes pretty close to part.


Offline PekkaNF

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Re: Self-Shielded Flux-Cored Welding: Choosing Your Gun?
« Reply #4 on: July 03, 2020, 02:12:29 PM »
One evening I got extra hour of garage time and parted of the cone from standard gas nozzle. Worked fine, but pretty much debris found it's way inside the nozzle cavity. I am thinking of using eventually gas shield and therefore that part must be protected. Bought cheap rubber gas hose one metre. 8mm ID sits perfectly and seals importat parts. I don't think that rubber will last that long, but experimental 15 mm piece has lasted few metres of flux core wire welding.

Works pretty well. I am surpriced.

I was trying to source a some silicone tubing that would fit over nozzle thread and use that only, but local shop had only 5 mm ID tube and threaded part is nearly 12 mm. That might give even better visibility, but at the cost of cooling.

Offline ddmckee54

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Re: Self-Shielded Flux-Cored Welding: Choosing Your Gun?
« Reply #5 on: July 03, 2020, 04:35:17 PM »
PekkaNF:

I made a custom flexible boot for the hot block on my 3D printer using some high-temp silicon RTV gasket goop in a 3D printed mold.  The kind of high-temp gasket goop that you can get at any auto parts store.  The boot has been in use for a couple of years now and has probably a couple hundred hours of use on it with no issues.  My printer's not as nasty of an environment as a welding gun, but something like that might work for you as a consumable.  (You can always make a replacement when it craps out.)

The mold parts only took a couple of hours to print and making the actual boot only takes a couple of minutes, of course you've got to wait overnight for the RTV to cure.

Don
Too many irons, not enough fire.

Offline PekkaNF

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Re: Self-Shielded Flux-Cored Welding: Choosing Your Gun?
« Reply #6 on: July 03, 2020, 05:10:42 PM »
Thank you. That is a very good idea indeed. There is a high temperature caulking for fire place use. Wonder how that could compare to RTV silicon.

Offline WeldingRod

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Re: Self-Shielded Flux-Cored Welding: Choosing Your Gun?
« Reply #7 on: July 03, 2020, 07:22:46 PM »
Really, all the silicones are good to high temp...  some are more oil resistant, though.  Fluorosilicone is more oil friendly, if I remember.

I suggest diluting silicone caulk with paint thinner and soaking it into fiberglass.  Then, smear more silicone on and wrap a few layers around the nozzle.

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