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Up Topic Welding Industry / General Welding Discussion / Flux core wire and slag removal??
- - By IowaBob (*) Date 03-26-2002 01:57
I have a lot of stick welding experience but am new to the MIG. I tried the MIG this weekend with my first real project (wood racks out of old steel fence posts) using the .035 flux core wire that came with the welder (no gas). Although the welds looked and held good, it took a lot more effort to clean the slag off than I'm use to with the stick. Thinking maybe it was the rusty posts, I tried the stick on a series of welds and the slag poped right off just as I'm use to. Is that the nature of the beast or might I be doing something wrong?

Thanks,
Bob
Parent - - By welder_guy2001 (***) Date 03-26-2002 02:57
flux core wire runs best when you're dragging the gun. and when welding vertical, move uphill. and make sure the machine's polarity is on Electrode Negative. sometimes rust can cause problems. it tends to hold in moisture. also, MIG and flux core welding kinda looks different from stick welding. some people either tend to move too fast or too slow with a MIG welder when they're first learning. move at a pace fast enough to allow the wire to touch the leading edge of the puddle, yet, slow enough to form that nice horseshoe-shaped crater.
Parent - By IowaBob (*) Date 03-26-2002 04:26
Thanks for the reply! Polarity is okay and I was dragging and moving up on the verticle but I do have difficulty keeping the wire in just the right place. You're right, it does look a lot different than a stick and I have trouble seeing the puddle clearly in order to keep the wire positioned correcly. I'm down to a shade #9 lens but the puddle still doesn't seem to be near as clear as with the stick (seems to be a lot more smoke). I think a lot of practice is in order for me to get that feel for the process.

Bob
Parent - - By Niekie3 (***) Date 03-26-2002 17:20
Self shielded FCAW often gives problems with slag removal. Also remember to keep to the current settings recommended by the wire manufacturer. Deviating from this can lead to the slag being more adherent. Also, as you already mentioned, there tends to be quite a lot of smoke with the self shielded FCAW. Thats why I prefer the gas assisted version.

There was a post on the board regarding FCAW a couple of weeks back. Check that string, and try to get one of the new FCAW-G wires from ESAB. You will be pleasantly surprised at how easy it is to weld with.

Regards
Niekie
Parent - - By IowaBob (*) Date 03-27-2002 02:55
Niekie,

Thanks! I found the other thread and you've now got my interest up on trying the FCAW-G wires. I went over to the ESAB site and looked at what they had available and found several (70 Ultra, 7000, 7100 Ultra) that looked like they would fit the bill for me. Most of my work with the MIG will be light duty repair and home project stuff on sometimes pretty rusty material (I'll use the stick for the big stuff as my MIG is only 125 A) so I'm wondering what your recommendation would be for that kind of application? I'm mostly concerned with getting easily cleaned welds and getting rid of all the smoke so I can see the weld better. One other question ... I spent some time trying to find an online retail source for the ESAB wires with no luck so far ... do you know of any?

I want to thank you, and others on this site, for helping out us amatures. It saves us a WHOLE LOT of effort and aggrivation trying to get our act together.

Thanks,
Bob
Parent - By welder_guy2001 (***) Date 03-27-2002 04:17
ok, i have a question now...when I tested on FCAW-G, it was .045 wire and it ran at not much less than 130 A. it ran the best in the 160-230 amp range. and I know that 1/4" steel was just about the thinnest stuff I could weld w/o it getting too hot. anyway, my question is, can you use .035 wire for FCAW-G on 1/8" steel? he only has a 125 A welder. most of the fence posts i've seen were 1/8" steel. Just asking, 'cause I haven't done much research on a FCAW-G application for low amperage projects.
and I agree...FCAW-G is great! even better than stick in some situations!
Parent - - By Niekie3 (***) Date 03-27-2002 17:35
I must say, that I did not realise you were looking at welding at low currents on thin material. Under these circumstances, FCAW of any description is not ideal. You may however try the following:

ESAB Dual Shield II 70 Ultra; 0.035"; 75%Ar 25%CO2; 90-180A; 16-23V.

As a general rule, FCAW gives a deeply penetrating arc. As such it is not ideal for thin materials. Under those circumstances, use GMAW(Dip transfer) or possibly SMAW(stick) instead.

In general, the low amperage GMAW machines are actually made for welding thin materials in the dip transfer mode. They are not really made for FCAW wires, which generally require currents of between 130 - 400A.

Hope this helps
Regards
Niekie
Parent - - By IowaBob (*) Date 03-28-2002 01:34
Hmmm? I've seen FCAW wires on the market rated done to 40 Amps that claim to weld down to 18 to 22 gauge. The ESAB Coreshield 11 & 15 are rated from 40 to 160 A in .030 dia. and 80 to 200A in .035 dia. I realize that GMAW is the prefered method for the very thin stuff but most of my work is on 1/16 to 1/4 inch material and often not too clean. I thought FCAW would be a better process for that type of work but I'm on a steep learning curve here and apparently didn't understand some of the material I read correctly. What is the weakness of FCAW compaired to GMAW for this type of application?

PS. I forgot to mention that all my welding is done outside and I was concerned about the wind with GMAW.

Thanks,
Bob
Parent - By welder_guy2001 (***) Date 03-28-2002 04:02
the weakness w/ FCAW on thin materials is, you can weld down to 1/8" thick steel...any thinner and it requires a bit of skill to read the puddle. FCAW on a small machine like your's is great for portability and fast welding. and it's good for when you're by yourself...you can hold the parts together and tack weld them easily w/ a FCAW (or a GMAW for that matter). i have a small machine like your's...a Hobart Handler 135...i've used it for FCAW and GMAW, and i think it performs better w/ FCAW in the 1/8" - 1/4" steel range than it does using GMAW. that's because FCAW penetrates more than GMAW and the bead spreads out like butter. if I had a machine w/ more amperage capability, I would use GMAW for a lot of things, but then again, a larger machine wouldn't be as portable.
and you're right...since you're outside, wind can be a factor. also, you don't have a gas cylinder to be messing with.
just find some nice clean 1/4" plates and run some beads...play around w/ the variables. wire feed machines are great once you get used to them!
Parent - By Niekie3 (***) Date 03-28-2002 17:40
You are right, that the Coreshield 11 and 15 can be used with these low amperages. They are of course self shielded wires and not gas assisted. I personally have never seen these wires in action, so I can not comment on their capabilities.

They are typically used for dirty material. According to the catalogue, coreshield 11 can be used up to 9.5mm thick deposits while the coreshield 15 is purely a single pass wire. This is important because if you try to weld too many passes with it, you will end up with a brittle weld deposit.

If wind is a big issue, then your self shielded wires would be your first choice. Obviously with too much wind, nothing will work properly.

Regards
Niekie
Parent - By dasimonds (**) Date 03-31-2002 04:58
Iowabob,
Undercut and irregular bead profiles will also contribute to making the slag adhere. As far as the rust issues go, have you thought about removing the rust before you weld?

Hope this helps.

Dale Simonds
Parent - - By IowaBob (*) Date 03-29-2002 00:54
Niekie/Welder_Guy,

Thanks for the help! With your help and some more reading I think I'm starting to get a clearer picture of the whole situation. I probably know enough now to get myself in real trouble. I simply can't believe how much the field of welding has advanced over the last 35 years, although I should'nt be surprised I guess. I welded for a farm equipment manufacturer for a couple years after high school and have pretty much had my head in the sand using the stick welder and torch for all these years and not keeping up with advances in the field. Boy, what a shock!

Thanks again,
Bob
Parent - By dee (***) Date 03-30-2002 02:30
Bob
This month's AWS Journal has a nice little article about flux-cored wire in general which might be of interest to you and others; it was to me. You might try to get hold of it I think it's also available online through a link on the AWS home page.

If you are impressed with how much welding had progressed over the past 35 years it might also be interesting to log on to an additional site as well (WELDREALITY.COM) where the host focuses on the irrationality of many solutions offered by local suppliers, and offers for sale his training materials. His focus is particularly on GMAW but specific SMAW issues are addressed when called upon. I had some problems with my salesmen and was ready to replace my (brand new) little miller 250x... info on his site led me to a gas mix the supply house didnt offer and ended my trouble. (I guess the other machine would have done as well at about a jillion times the cost) There is plenty of accurate information to be found there.

Regards,
D
Up Topic Welding Industry / General Welding Discussion / Flux core wire and slag removal??

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