pre-heating for welding?

[Lumpy Grits]

That's why they look so clean
I just use .035 fluxcore wire and no gas.
LG

[daniel_buck]

I've used a bit of .35 fluxcore wire (no gas), I need to use it more though, I'm just not familiar with it to get consistent results. I built my welding cart using mostly the flux wire to get some practice using the flux core, some welds turned out good and some were very porous, with seemingly no difference in what I was doing, I'll get back to the flux core later.

[RAT]

Daniel,
Do yo have any .030 wire? That may help you with the penetration a bit. The bigger wire actually burns a little hotter so that might help. And I understand the practice welding; just don't practice on your projects!

[daniel_buck]

I've got .035, don't think I have any .03

[RAT]

Try the .035. It may weld a little better for you. If you look at your welds, the upper and lower edges have a serrated look to them. That is caused by too fast weld speed, too low current or insufficient electrode size for the base metal being welded. The faster more metal you can melt in to the kerf the better. That eliminates undercut.

[RAT]

this is the serration I mentioned. But... That weld will more than hold for what you are building. I wouldn't worry about those welds. Just keep practicing, and when you find what works for your machine, remember the settings/wire sizes, etc.

[inVERt'D]

3/16" Flat bar, now that doesn't sound so crazy, either for a little distortion with 110 MIG or for a battery box. The distortion isn't apparent to me in the pics. I guess you might be checking it with a straight edge?

I think the consensus is you could use more heat/ current, which is to be expected. Your welds look nice, but they're on the cold side. For one thing, it doesn't appear that you're getting any penetration at the root. Besides the suggestions that have already been made, you can use a two-pass procedure to help with that. The first pass keep the the electrode pointed at the root--don't weave much if at all--and go fast enough to avoid piling it up. If you need to grind out excess then do so. Then go back over and fill in the joint with a weave. You'll probably get more distortion with that, but you'll have better joints. Really the best solution is more heat/ current.

If you're more concerned about distortion, you can use shorter welds, like RAT mentioned. A common method when welding things you don't want to distort is to use stitch welds: usually 1" or longer welds, spaced 1" or further apart. For that project, with what you're working with, I'd preheat the steel until it starts getting the bluish heat signature, weld the crap out of it, and say distortion be damned.

[brokenujoint]

The first photo here, this is the one that bent the most. The bottom flat bar is 3/8", which is the piece that bowed a bit. And the angle iron is 1/8". Probably over kill, but I welded it all around (get any practice in that I can!)




The other two photos, show a bent piece of 3/8" flat bar, welded up to another piece of 1/8" angle iron. Here, I bent the flat bar and tack welded the angle iron to match the angle of the frame, and still keep the top side of the angle iron level. But after I did all the final welds, the angle was off! Something bent.

Granted, yes, the battery sits just fine in there, it's not that big of a deal. But since I'm doing more and more of this metal work, I'd like to try and get better at it, learn when somethings going to bend, and how much

(edit) Oh and it may not look like I cleaned the metal in these photos, but I put a wire wheel on my bench grinder to all the edges and sides of the metal pieces that got welded, to remove the mill scale. I think I need a heavier wire wheel though, I don't think I got all the way down to bare steel in some of the pieces.

Your movement with the stick looks good but as mentioned, to much weld material and it doesnt look like it penetrated very well. Turn down the feed, turn up the burn and do a second pass with a 110. Just because you have a cosmetically good looking weld doesn't mean its strong. Not at all. Also pull your C's a little more to each corner. Did you fillet your mating piece of metal? Helps with penetration a bit and also be sure to thoroughly clean before welding esp with a baby welder.. MEK, or even acetone helps.
Also the main reason that it bent is because you didnt take your time. Throw down a few spot welds to set it up. Then do welds of about 1" then let it cool. Metal that gets hot to fast (as in welding) will cause the metal to expand. Then as it cools the metal doesnt go back to its original state. The carbon molecules want to stay away from ea other. They're hot dang it! Take baby steps and it wont warp.. As much... Pretty good for a 110 though. Ive seen slightly better and much worse

[Lumpy Grits]

OP stated he was on the max heat setting.
LG

[daniel_buck]

yes, it was at max heat. I do have a cable to plug it into 220, but I don't have 220, haha!

[inVERt'D]

I know flux core has already come up, but you were unhappy with the porosity you were getting. The best results I've gotten with FC have been by turning the wire speed up quite high. With my little 220 Lincoln I can get a nice spray transfer buzz going like that. With a 100 amp 110, the wire starts stubbing into the joint when the feed is too fast, but I've still gotten some nice beads by running the wire much faster than the recommended settings.

Regarding FC and porosity, if you can't get satisfactory results on clean steel, you can try "dual-shield" : flux core wire with gas.

[daniel_buck]

I'll ive that a try next time I run FC wire, turning up the speed, as well as trying with gas. A MIG type mix of argon and CO2?

When my FC welds looked good, I was actually quite happy with them. They didn't look super pretty, but they didn't build up on top of thick metal like the solid wire does, they sank in pretty good. I guess that's because FC hits hotter than solid wire? I already know I'm lacking power for solid wire on thicker metals.

[inVERt'D]

Flux core is usually an electrode positive (DCEP/ reverse polarity) process, although I've heard there are wires designed for DCEN. DCEP produces a hotter arc with more force (arc force, as it's commonly referred to).

To run dual shield you'll need a special wire designed for it. For instance, Lincoln Outershield as opposed to Lincoln Innershield. Generally speaking you can run 75/25, or straight CO2. Straight CO2 is of course, much cheaper than mixed, but then you'd want a separate tank for MIG. Of course, you can MIG carbon steel with 100% CO2, but let's not go there.

Dual shield is used for structural steel applications, and I've seen some beautiful beads made with it. I've never actually used dual shield, so that's about as much as I can help you with that.

[daniel_buck]

If it's just a matter of picking up a different FC wire type, I'll give that a try

And yes, I do swap the polarity when welding FC


But regardless, I probably just need more practice, haha! I probably weld maybe once or twice a month, and usually only a few beads and some tacks unless I'm in the middle of a project. I got pretty good at doing 1/16" square tubing for furniture using the .024 wire, but I've got enough power to adequately penetrate 1/16", so I think that makes it alot easier.

[inVERt'D]

If you do try it, post up your results. Even if it doesn't work great with 110, you can save it for when you have 220.

More practice would help any of us, but in the end you still need heat to melt metal. 220 would sure make things easier for you in that regard.

If this guy can do it, you can do it

http://www.youtube.com/watch?v=4FDtKpae-p8