Welding Tips and Tricks

I need some help interpreting/understanding what I am doing wrong. I am trying to learn to wire feed weld (Flux Core) with a cheap Lincoln HD100 machine. I've read/watched a bunch of information, but either I am misreading or misunderstanding what I am reading...

I am using mild steel (square and angle) from Home Depot, it is apx 3/16" thick. The chart on the machine suggests D-1.2-2 settings for this metal project. My steel is plasma cut (just learning this too), then ground on a grinder to get a good fit, and held with the magnetic welding braces...

If I use the lower speed 1.5 setting the wire seems too slow, it comes out, arcs, melts quickly and then stops until more wire is out. If I speed up to 2-2.25 I blow through the wall of the steel. I move the tip across the metal a tad bit faster and I have no penetration... The difference between blowing through and no penetration seems almost imperceptable...

I have used Oxy/Ace for years, mostly for brazing, but also for welding too. I know what to look for in a weld to know good/bad etc... I am so frustrated with the flux core that I am about to throw the machine in the trash and go back to oxy/ace so that I can eventually get started on my project....

My best guess is the machine's polarity is backward for the type of wire. Some wires require the gun to be positive, others negative.

Have a look at the manual, see if you can swap it, and try again. (You'll know right off if you've made an improvement.)

Steve S

On the wire specification you can read what polarity you will put the gun.
I have seen lots of Pipe welding with Flux Core wire that you need to invert the polarity.
The same wire feed on Solid wire and Flux Core is not the same deposition of metal.
Flux Core needs less temperature to melt. So, you need to change the settings of your welding machine.
The gun on DC- will have a different behavior. Less temperature on the wire but a better penetration on the base metal.
Try this way as fast as you can, or with a controlled motion in short circuit deposition.

Try first in some scrap metal of the same material with a shiny bright preparation with at least half an inch from the joint.

I personally try this way. What do you think?


PS: Sorry about my English.

It may very well be polarity. All of the flux core I have used (up to .035) is DCEN or DC Electrode Negative.

I am not familiar with your machine, but it may also be that you have the voltage up way high, and the wire speed too slow.

If your setting are close to correct, the arc will sound like the proverbial "Bacon Frying". Jody has several videos that cover this particular problem.

Hope this helps.
PSC

Im not sure its the polarity... I followed the directions in assembling it. The wire im using is what come with it as well. I did go over the assembly a second time last night, and everything is by the manual.

Ill have some free time this weekend to experiment some more. Would anyone have some suggestions for things to try, maybe some basic welds or something like that? I have some 1/16th tube, also 3/16th angle and flat stock. I think I also have some 1/8 square tube...

Ive got some 3/16 angle cut to size to build a rack/cart for my ace/oxy tanks. Ive also got several jigs and stands to build for my project, so I have plenty of things to practice on...

I double checked the manual ... And found a good pic you can use to verify your polarity. That's a good first step .. Then I always like to make sure there are no feed restrictions & check the drive roll tension. Assuming you find everything correct, try a lower setting - perhaps C - and play with the wire speed.

Here's how I like to set a small MiG: the main voltage tap should be set first. The wire speed will change according to that setting. You may have run a higher wire feed setting at a lower voltage setting on that machine. But, it may give you more range of adjustment ... So you don't go from no penetration to "excessive" penetration

Note: industrial MIG units have independent voltage & wire speed settings. But, smaller units scale the wire speed to the voltage setting. As you increase the voltage setting, the wire speed range is also increased - which brings up the amperage (heat) at any given wire setting. This matches the wire speed range to each voltage setting so you're always in or near a good welding condition.

Technique is also something to experiment with. You can try a slight push angle or conversely, a slight drag angle - all relative to the direction of travel. You should also try to maintain a consistent stick out (tip to work distance).

If you continue to struggle, post some pics .. Good luck!

I figured this one out... i had tightened the wingnut on the wire spool too tight. The rest was/is just newbe error.

Ive been so frustrated by this that Ive almost tossed this little welder in the trash, but Im not one to give up. So here is how my thought process worked. Yesterday i was watching one of the videos on here for building a downdraft table. In the video he used TIG welding. The first time I watched it I thought he was using oxy because of the welding rod. The second time I watched it, a lightbulb come on. "TIG is like oxy, but used electricity as the heat source."

Now that i was thinking of oxy, I remembered how my uncle taught me to weld with oxy. He had me cut a bunch of rebar into 6 inch lengths (of course with a haxsaw). Then he welded the first two together, and then told me to keep welding the together until my weld looked like his.

So, that got me back to my frustrations with flux core, so today on my way home from the office I bought 40 foot of rebar. I first used the plasma cutter (something else im learning) to cut a 10 foot section into 6 inch sections, then i proceeded to start welding with the flux core... On the second weld I noticed the wire wasnt coming out smooth, it was jerky. This got me looking and I found the spool problem.

Once i fixed the spool, I went back to welding the rebar, and for the first time ever i was finally able to see the weld pool y'all keep talking about. After that it was all down hill to finally getting good welds....

When I have some more time I'll get some time in with rebar to angle, and then Ill start working down to lighter and lighter materials... Then Ill start all over again with Mig...

I'm also in need of recommendations for a good TIG setup. I'm working towards building a small plane which is all 4130. Im learning flux core now because I had the welder, bought it 4 yrs ago for a project that never got started.

My tig needs are up to .125 4130, a little breathing room would be nice. I would also like for it to be dual voltage. I only have one 220v socket in my garage, and it gets shared with a lot of stuff as is. And budget is a big concern, Ive spent a lot of money on tools and equipment. I'm estimating $1000 as about the top end of the budget.

Also, right now I have Oxy setup using 80cf bottles, cheap amazon plasma cutter, and lincoln 100hd with conversion to use mig. Also keep in mind that Im a weekend warrior, so I dont need anything industrial sized that lasts a lifetime in a fulltime shop....

I just reread this, and it was the wire spool wing nut being too tight.

3/8 rebar, is had amps set to mad (D), and I started with wire speed set at 2, but I couldn't keep a steady arc, I kept increasing the wire speed until i could hold a steady arc... I ended up with 4.5 to 5 for wire speed. This gave me a steady arc, and as I did a few welds I finally started to see the metal pool at the arc. Then all i did from there was to move the tip at a pace to keep the pool with the arc.

I havent sliced the welds to see what penetration was like, but i hit them pretty good a few times with a 3lb sledge and they didnt break.

Just a note for other newbies, in doing this, I finally started to get the feel of the torch tip. I was able to feel the wire pushing the tip, especially when i drifted back off the weld, I was finally also able to get a steady arc that sounded like bacon too. My welds with this are not up to par yet, but I finally feel like Im gonna get this figured out...

The 40 feet of rebar cost me $15 at lowes, and its the best $15 that ive spent out of the $10k plus ive spent on tooling up for this project.

BDoubleU wrote:I double checked the manual ... And found a good pic you can use to verify your polarity. That's a good first step .. Then I always like to make sure there are no feed restrictions & check the drive roll tension. Assuming you find everything correct, try a lower setting - perhaps C - and play with the wire speed.

Here's how I like to set a small MiG: the main voltage tap should be set first. The wire speed will change according to that setting. You may have run a higher wire feed setting at a lower voltage setting on that machine. But, it may give you more range of adjustment ... So you don't go from no penetration to "excessive" penetration

Note: industrial MIG units have independent voltage & wire speed settings. But, smaller units scale the wire speed to the voltage setting. As you increase the voltage setting, the wire speed range is also increased - which brings up the amperage (heat) at any given wire setting. This matches the wire speed range to each voltage setting so you're always in or near a good welding condition.

Technique is also something to experiment with. You can try a slight push angle or conversely, a slight drag angle - all relative to the direction of travel. You should also try to maintain a consistent stick out (tip to work distance).

If you continue to struggle, post some pics .. Good luck!

michialt ,

If you're planning a homebuilt aircraft project, I have two big recommendations right from the start.

First, subscribe to EAA Experimenter magazine, if you haven't already.

Second, 4130 filler is NOT the best TIG rod for 4130 airframes, unless you have the ability to fully normalize. Go with E-80-S2.

And practice, practice, practice.

I have an armload of other advice, and a stack of books that would hobble a mule, if you pursue this.

Another member, WerkSpace, will be able to contribute a great deal of information, as well as confirm or refute any advice I may give.

Steve S

Ive been a member of EAA for more than 10 yrs now. This is actually my 2nd build, and third that I will finish. This is the first welded fuselage that ive done.

I have a few projects to build before I start the plane, I need to organize my garage so that I have enough work area for safety, was going to build wood cabinets, but Ill build then from square tubing now, as well I need a 16' solid, flat and level work bench as well, again instead of wood i'll use tube steel. And a few jigs that ill do in steel.

By the time Im finished with these projects, and have all the spruce wing ribs built up I should be pretty decent at welding. My phylosophy is that you dont have to be good at welding to build an airplane... You just have to be good at determining the quality of a given weld and know when to reject a weld and do it over.

michialt wrote:Ive been a member of EAA for more than 10 yrs now. ..
...My phylosophy is that you dont have to be good at welding to build an airplane... You just have to be good at determining the quality of a given weld and know when to reject a weld and do it over.

"Do-overs" are not healthy on 4130.

Get your practice in for whatever funcky position and do it right. You'll have so many tag-ends to play with from the cuts and copes! If you reject a weld, you reject everything it's welded to. Reworking it weakens everything it's attached to. I know you can't completely avoid rework, but, It's an airframe, so less is more.

Steve S

Sounds like a cool project! What part of the world are you in? Have you ever been to Oshkosh for the fly-in? I spent many days in the demo booth welding coped tubing with Mig and Tig. EAA has some good articles in the archives about 4130 and recommended practices - and as Otto mentioned, filler metal is key ... Using mild steel like 70 or 80S will provide good strength while maintaining ductility.

4130 is an interesting metal - very hard, strong and extremely sensitive to heat. Accurate copes will make easy work - as you'll find when you do your practices pieces. Any gaps will create problems like holes that keep growing But, once you get hang of it ... It's fun! Keep your heat input to a minimum and your welds as narrow as possible (within reason).

You may also hear info about preheat, post weld heating or other techniques. While some may have merit, the real key is to control your heat input and allow welds to cool slowly.

From an Tig equipment perspective - you only need DC for chromoly. But, most people working on a home build go with an AC/DC unit so they can weld the aluminum components of the aircraft. However, a MIG with C25 gas and the correct filler will work on chromoly too ...

You'll have to start a thread and keep us in the loop with posts and pics of your progress. Let me know if you make a test flight up to Oshkosh ... it's just down the road! Hit us up with questions - it will make for a good discussion too!

Good Luck!