MIG vs. Flux Core Welding

[Transit]

Hummm, I must have been doing something wrong all these years. I get full penetration all the time, it may take some prep work, fit-up, V-notch, gap, multi pass. If done properly a weld will not break in a bend test. The man that taught me to weld was a WWII ship welder. He would cut my coupons across the weld and etch them to show the fusion.
Haven not done stick in years, mostly Mig and some Tig, more flux core than gas shielding. Some of the flux core wires will look like mig work. Some are just plan nasty looking.

 

[gauthier]

I said fillit weld,,we was talking fillit welds [or I thought so],go back and reread my post.,if you bevel your plate,its generally not considered a fillit weld any more.

Most structual welds are fillit welds,[bridge,buildings,car/truck/trailer frames],,if a plate or beam has to be joined to another[butt weld] it is a vee groove of some sort,but most are just tee joints,lap joints,no bevel,not intended to be full penatration.

 

[lostcause]

Hummm, I must have been doing something wrong all these years. I get full penetration all the time, it may take some prep work, fit-up, V-notch, gap, multi pass. If done properly a weld will not break in a bend test. The man that taught me to weld was a WWII ship welder. He would cut my coupons across the weld and etch them to show the fusion.
Haven not done stick in years, mostly Mig and some Tig, more flux core than gas shielding. Some of the flux core wires will look like mig work. Some are just plan nasty looking.

if you're getting full penetration, then that's fine. thing is, the rest of the world doesn't bother to. as gauthier said, for simple fabrication, it's a fillet weld world out there. there are certain special cases where full penetration welds are called for, but otherwise they aren't used because they are costly and wasteful. there's also some cases where i am pretty sure you aren't getting full penetration unless you are cutting an access hole on the backside - where you come to a tee or corner for instance. if you are using mig or flux core, you're likely going to either be using a backing bar or a backgouge to get full penetration.

 

[RPW]

Well I finally feel the need to enter this topic First I'm not a professional welder. I have taken some classes at the local community college recently but have been dabbling with welding for about the last 15 years. My first machine was an AC stick welder I picked up while being stationed in Germany. After that I've gotten a HF 110V flux core only and since then a Lincoln ProMig 140 a Miller econotig and a bobcat 225 gen/welder. I'm not pounding my chest but have found that the right tool for the job goes along way to getting the job done more effectively. What I've found about the little HF flux core is that the problem I was having with it was not with the machine but the HF wire was the worst there is. In using better wire (i.e. lincoln brand) I've found that I like using the little box. Besides lately most my welding has been outside and that has preclueded the use of the MIG. As far as full penetration as long as I'm withing the capabilities of the welder or take additional measures for proper fit etc. I do get full penetration. That's another reason for the wide range of machines. Amperage really hasn't been an issue as even when I'm welding 1/2 plate I'm really not using more than 100amps. If I do my stick rods start glowing excessively or I'm down to welding for about 1 min and then waiting.

 

[gauthier]

You get full penatration on your fillit welds?[tee,lap joint]

 

[Chilly807]

Amperage really hasn't been an issue as even when I'm welding 1/2 plate I'm really not using more than 100amps. If I do my stick rods start glowing excessively or I'm down to welding for about 1 min and then waiting.

I'm a long shot from being an expert on stick, but I think that's why you use a larger electrode for thicker metals? Not being sarcastic, just looking for feedback.

The 3/32 rods I use call for 75-100 amps, 90 is ideal according to the maker. The 1/8 rods ask for 110 amps, etc.

The pro I get advice from told me to keep to 3/32 rods for 90% of what I'll be welding, to vee out the joints and keep adding passes until it was done on thicker stuff.

Sean

 

[gauthier]

Yes and no,,you don't weld stuff in one pass unless you are working in a fab shop doing fillit welds,[or just putting on a small fillit].

You can weld 1 inch stuff with a 1/8 rod and get 100 percent fusion and penatration[talking a vee type groove].

Would you want to weld 1 inch thick stuff all the way with 1/8,no cause you want to get it done sometime,point being you are only welding a small area at a time with multi pass welds,if you know how to do it,you can do it.True with bigger rod you can run fewer passes,less starts and stop,higher heat,so there are quality reasons as well as time concerns for using a bigger filler on thicker stuff,but,you can make a quality weld with a smaller rod/wire as well,if you know how.

bigger the rod or wire the more amps it takes to burn it correctly,smaller rod or wire requires less amps to weld correctly with it..so when you change wire or rod size,you got to turn your machine up or down accordingly.

This one pass stuff was invented by welding machine salesmen for non welders to relate how many amps there machine would run,,and knowing that they didn't know how to make proper multipass welds.

 

[CharlieTR]

I don't want to hijack this thread but speaking of Lincoln. Anyone have any experience with the Lincoln 140 Mig. I see it is on sale for $499 CAD at Canadian Tire this week.

Luremaker,

That is a great machine and if the price is right I would get it.
I have almost the same machine and its nearly 10 year old.
I have built trailers for the farm, a crane, and welded 3/4 inch plates for hitchs, just need to make more passes. Never had a problem and use it all the time! Hope you get it, you won't regret it.:thumbsup:

 

[RPW]

Yep, larger rod for larger sized metal. But sometimes you have to use what you got. Pretty much my point is that for now..... I'm not welding anything thicker than 1/2 plate so pretty much all I have on hand are 5/32 or smaller.

 

[gauthier]

Now a days a 5/32 is a pretty big rod! You won't generally find them using any bigger on powerplant type work even on pipe that is about an inch thick.

Pipeline will often go up to 3/16,but thats about it,not because of thickness really,its generally all sch 40 on gas lines,just the way its welded,down,no stringer beads[cept the root is called a stringer],all one over the other