Printable View
Well, OK maybe it's a bit early for a Christmas pun, but...
This is the first time I have ever had a weld that wound up with holes in it and I am wondering what caused it. The rod was 1/8 7018 at about 120A on the buzzbox. I did notice that the worst spot is where I experimented and got really perpendicular, but even where I kept a lower angle it still is a bit porous. :(
Attachment 3373Attachment 3374Attachment 3375
That's really interesting how it blew out like that.
1> Have you tried running these same rods in the same exact way on a different piece of like flat stock?
2> How old are your 7018's and are they dry? - I've seen blow out like that when a guy had moisture in his rods.
3> You might try 7018AC's to see if it improves any. - Since you are using an AC power source.
i like to call those worms, but really its porosity. you need to CLEAN your metal before you weld it. especially with 7018. 6010 you might have gotten away with it. with that flat weld, you should have about a 45-60 rod angle.
What I see is fairly good. The holes are in the slag. Too long of an arc/too cool is part of the problem if the slag holds fast like that. Go watch our powerarc video online and you'll see an example of how slag should pop right off.
That is actually one of the few welds I've made that I'm not embarrassed to show in public. :D It is also the first one I've done that required enough fill that I actually got to play in the puddle.
Believe it or not, I did run the grinder down the trench after I tacked it, but maybe the little bit at the bottom I couldn't reach was enough to hose me.
Good to know about arc length and slag adhesion, I had noticed that sometimes it pops easily and other times not but never figured out why.
Just for grins, I ran the last half of the rod on the nastiest piece of steel I could find, and came up with one of the most consistent beads I have ever laid down. Go figure. :confused:
Attachment 3381
What brand of rod are you running? Hobart 7018s seem to be cantankerous at times, especially trying to run them on AC.
I think they were Lincolns, but it's been a long time since I got them and I didn't save the box label. Whatever they are, they were the reason I fell in love with 7018, easiest rod I ever used.
I see what you mean about the Hobarts, just cracked a new box of 418 and couldn't even hold an arc :(, granted, it wasn't a very nice piece to be running a bead on, but I'm used to being able to throw a good arc on just about anything with the batch I'm working on now. Guess I'll have to get that TIG now just so I can burn the new box of rod. :)
I would play with your temp settings, when the temps are right the slag tends to chip away pretty easy. That may help with you purosity as well.
It looks like porosity at the tie-ins, to me. if you don't get a new rod going before the slag puddle cools, you have to chip/grind it out, or you get porosity like this. it's less of a worry with 6010/6011, they leave thinner slag and burn out more crap than 7018.
+1 on the slag indicator of heat, too. if you watch a couple of Jody's vids (at weldingtipsandtricks.com), there's at least one that he chips the slag off with the butt end of another rod. that's how easy it should come off. this vid @ about 8:15 http://www.weldingtipsandtricks.com/stick-welding.html
[edit:] I just noticed that Jody's 'backstepping' technique is tieing into cold slag. he doesn't seem to be getting porosity, but I've had issues with it before.
you can tie in without cleaning the slag off, but you have to be careful as ya, you can get porosity, slag inclusions and other crap in your weld. usually if im running a few beads or whatever and my base metal is still hot, i usually wont worry about it. i dont allow anything to really cool, just pull out the burnt rod, slap a new one in and keep going. i also run fairly hot with 7018 all the time so it helps to burn that crud out.Quote:
Originally Posted by ogorir
redbeard,
You should pull out a grinder and clean up the material before welding. If you are on clean metal you will have much better luck keeping a consistent ark. Also, cleaning off slag will help with the weld. You are not performing welds that will be radio-graphed but if you do not clean off the slag on a radio-graphed weld it will fail and is not the best practice if you ever make critical welds (e.g. fix a trailer).
DVA
Good catch that it is mostly at the tie-ins, there are a few odd ones out in the middle, but I hadn't really thought about the cold slag aspect. Most of the beads I've run are usually shorter than a full stick, so I haven't had to deal with that.Quote:
Originally Posted by ogorir