The when and why of flux core

I suppose the better quality flux cores aren't so splattery? Or atleast the flux comes off better? I didn't like it before cause it never looked good on that 110 machine. But probably cheap Canadian tire wire. However I was surprised how well it would weld with gas. I changed the power cord to a 12 awg and used it on a 15a circuit that was direct. Using it on a 20amp circuit doesn't give you any more amps than a 15a just means it won't trip out at 15. But being a direct circuit and a beefier cord will give the welder more headroom to pull the amps it wants. A 15 amp circuit will happily give you 20amps for short periods of time as long as it's not a spike.
We used to instal construction heaters in new builds during construction. 30a heater in the stove and/or dryer circuit on a 20a breaker all day long. We did that because once the heater got caked in drywall dust it would trip the breaker before burning out the heater.

This airco machine I'm using now is 220v and much more powerful. It'll do 160 amps 22v for mig and 200amps 28v for stick. I have 25/75 gas and is far I like it. But, I don't weld much heavy duty very often. I did some 1/4" last week and it did fine. Moving a bit slower with .030 wire but god penatration. More often than not it'll be 1/8"
 
under what circumstances would you want to use flux core, or dual shield flux core?

Like was mentioned here, flux core is great for windy/outdoor conditions and being able to go remote without shielding gas. Flux core can also give underpowered machines a bit more poop. Flux core generally is run with a bit more stickout, this is to preheat the wire some, and should run in a "spray" type transfer. If you are short arcing flux core, she ain't gonna run right.

Dual shielded wires are wonderful when high deposition and high penatration are desired and the slag is usually easy to remove.

Metal core wire is another high deposition option for larger machines. No slag, high dep, spray transfer and beautiful appearance. I use Hobart Fabcor 86r and love it.

There are adapters available to adapt the small 2# spools to your machine that uses the 10" or 12" spools

https://www.amazon.com/Universal-Welding-Spool-Adapter-Spools/dp/B00DU03UEA
 
I fabracobled a new mounting plate to accept a smaller roll.
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Gave it a test run. Ran HORRIBLY... Remembered flux core us run reverse polarity. This airco welder doesn't have any option for that. I'd have to actually go inside the machine and change some leads around, which would result in modifying the machine.

Is it my understanding that in order to run the reverse polarity that you simply swap the ground and hot leads?
How do other machines achieve this with only switching one wire under the hood?

I had been thinking about rigging up such an option. Under the feed section of the unit, installing and rewiring an option to easily swap the polarity without having to dig into the machine itself.
Which is no small task. The leads are all bolted to that blade switch.
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I did try to just switch the ground and hot lead to try but the eyelets and bolts are two different sizes. Likely designed as such.

I havr been trying to dig up more info about this machine, but there really isn't much. Trying to join Miller's forum but it's a slow process. Most of the information about this machine is actually there.
I found the owners manual and there's no mention of flux core. So obviously, never designed to run it.

The whole reason for this flux core is our small construction company is in the process of buying a dump trailer that will need a couple repairs. Those repairs will be done outside. So, as stated several times, flux core is desirable in those conditions.
If it's not reasonable to make this work, then I have a roll of Hobart flux core to take up space on my shelf and I'll just stick weld everything. Lol
 
I fabracobled a new mounting plate to accept a smaller roll.
View attachment 236796
View attachment 236797

Gave it a test run. Ran HORRIBLY... Remembered flux core us run reverse polarity. This airco welder doesn't have any option for that. I'd have to actually go inside the machine and change some leads around, which would result in modifying the machine.

Is it my understanding that in order to run the reverse polarity that you simply swap the ground and hot leads?
How do other machines achieve this with only switching one wire under the hood?

I had been thinking about rigging up such an option. Under the feed section of the unit, installing and rewiring an option to easily swap the polarity without having to dig into the machine itself.
Which is no small task. The leads are all bolted to that blade switch.
View attachment 236798

I did try to just switch the ground and hot lead to try but the eyelets and bolts are two different sizes. Likely designed as such.

I havr been trying to dig up more info about this machine, but there really isn't much. Trying to join Miller's forum but it's a slow process. Most of the information about this machine is actually there.
I found the owners manual and there's no mention of flux core. So obviously, never designed to run it.

The whole reason for this flux core is our small construction company is in the process of buying a dump trailer that will need a couple repairs. Those repairs will be done outside. So, as stated several times, flux core is desirable in those conditions.
If it's not reasonable to make this work, then I have a roll of Hobart flux core to take up space on my shelf and I'll just stick weld everything. Lol

I forgot to mention the polarity thing. Generally FCAW is ran in straight polarity and solid wire, FCAW-G (dual shield) and metal core are ran in reverse polarity. Straight polarity is DCEN....have you considered (if there's room) using Tweco connectors? You could extend the output lead from your machine to the feeder and extend the work lead as well. You could then cut the leads in a convenient spot and install the Tweco connectors. This would allow you to swap leads easily. Like these.

http://m.cyberweld.com/cabcon.html?...DHN3dXgZjEgRT1CSKwJuDfpr3JQ989FRoCClcQAvD_BwE

None of my Millers are a one lead swap to change polarity. No machines that Im aware of work that way. Gotta swap both work and power.

If you can tent, tarp or the breeze is calm, I would just run gas on your dump repair and save some hassle and cost.

Gasless fluxcore has its purpose but, Is usually last on my list.

Your small spool adapter looks slick. I like it.
 
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Essentially what I was thinking, but mounting it inside the feed side cause there's so much room. And if I mount it, say, on some delrin for insulating, then I don't have the big connectors just flapping around on the inside. And, it'll give me an excuse to machine something. I machined that small reel mount. It's all shoulders for getting nice tension.
This is more so turning into determination thing, that's just what happens with me when I get something in my mind. Lol.
 
Essentially what I was thinking, but mounting it inside the feed side cause there's so much room. And if I mount it, say, on some delrin for insulating, then I don't have the big connectors just flapping around on the inside. And, it'll give me an excuse to machine something. I machined that small reel mount. It's all shoulders for getting nice tension.
This is more so turning into determination thing, that's just what happens with me when I get something in my mind. Lol.

I get the determination thing....for me, it's not so much that I need something, it's me wanting to see if I can do it. If you want a project, go for broke and make some insulated pass thru parts with terminals. Pics...lots of pics.
 
a lot of the 110v machines will run better on a 20 amp circuit.
i have a HF 90 amp (110v operation) flux core unit, it is set to max amps, i vary the wire speed & i use .030 innershield NR232
i also have a Lincoln SP125 (110v operation) mig that i use for thin stainless welding .030 309L wire & Tri mix (argon/helium/CO2 mix)
both welders are incomparable to my PowCon 200s (220V 3 phase) FCAW .035" NR232 innershield, the penetration and range of thickness of materials i can weld is much greater than any 110v unit
110 units you are limited to 3/16"ish material
220 units can weld thick sections without a problem

If you haven't already, you may want to try the DCEN conversion on the HF 90-amp welder. It reduces the spatter a bit and seems to help with penetration as well. There are quite a few youtube vids on the conversion process. About $35-45 in materials.
 
I get the determination thing....for me, it's not so much that I need something, it's me wanting to see if I can do it. If you want a project, go for broke and make some insulated pass thru parts with terminals. Pics...lots of pics.

That's the plan!
This week I'll go to the metal supply and get some delrin flat stock. I have some bar, but I don't think that'll work.
And I'll rewire it.
 
If you haven't already, you may want to try the DCEN conversion on the HF 90-amp welder. It reduces the spatter a bit and seems to help with penetration as well. There are quite a few youtube vids on the conversion process. About $35-45 in materials.

I'm only going to add terminals to switch the polarity of the mig gun. I can control the stick section of the welder via the selection knob.
 
So I made some threaded bushings out of delrin. I decided I didn't need delrin plate, and that I could just make bushings. I'll drill a hole in the feed housing in the wall between the feed and electrical section and thread the bushing through.
I need longer bolts tho so I can use two nuts. One to hold the stud to the housing, the second to hold the cable and to give some extra distance between the male bushing and the housing. Don't need to be making any contact with the housing and blowing everything to smitherines...

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What's delrins heat rating? Just in case I wind up with an issue with heat?
 
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