7018 Stick welding tips anyone?

[james gonzalez]

I am doing some structural work for the money this week. We are welding up some deck frames with a "Burco Mosa" little "chopped DC" gas engine welder. I think the thing is about 150 amps. we are using the Excalibur 1/8" 7018s to do flat and vertical downs. Should these rods be heated up a little before use? It's a new canister and they're not wet, but my helper was having a xxxx of a time up there. I was on the ground cutting parts with the gas rig listening to him curse. Any suggestions for using this particular rod?
thanks

[Dragons lair]

I would drop your rod size to 3/32. Make sure its DC rod. I had a little 140 Airco wasp AC gas welder only used 3/32 rod.
Ken

[BIGGUNDOCTOR]

Run it DC reverse.

For vertical welds you go UP with 7018, not down.

I love 7018 due to how smooth it runs. When doing a vert weld stay on the sides, and fast through the middle, and keep the arc length short. In other words, strike the arc and hold it on one side till you see the metal flow out, then move to the other side and repeat. Each side to side you move up a little. The flux is nonconductive, so let the flux touch the sides of the vee, and keep the arc length short. The main thing is don't rush it, don't move till you see the metal flow to the side that you are holding on. When you are done the slag should practically fall off on its own. You'll know if the rod is burning right by looking at the tip when you finish a bead. The tip should form a cup that is flush with the rod end.

[jimmy seale]

Also u the rod to pre heat the metal....and yes if you drag the rod it will have a dome to the welds, but you push it it will be flat, (my limited exp,) hope this helps, jimmy

[Glenn]

Hobart 718 electrodes have been designed to provide weld metal with high toughness at very low temperatures (-50

[cami]

Thoughts on 7018.....

These rods are very hygroscopic:

For any critical applications I never take more than I can use in a couple hours; leave the rest in the oven. Follow re-bake procedures for rods left out and toss any that actually get wet. If it's good steel that you're welding then it's not too big of a deal....but let the engineers worry about that. The stuff I do in my backyard is a different matter.....

I've heard of companies that were allowed to put rods into sealed canisters to take to the job site but once a rep. from the Canadian Welding Bureau was doing a compliance check where I was working and told us he wanted rod ovens installed on all of our trucks. Sheesh!

As for preheat, don't bother unless the procedures call for it or the steel is wet. Just a quick pass with a torch to drive off condensation is fine.

Regarding the direction of travel for vertical welds:

It's structural, right? Follow the procedure you're qualified for and that the engineer specified. Are you doing job tests on site?

Any procedure tests I've done were up-hand weldng. There is a prequalified welding procedure for pipe on the books in British Columbia that's 6010/11 downhand but I've never seen anything formal regarding downhand welding with 7018.

I weld a lot of stuff downhand; in fact, whenever I can. It's fast so there's less heat input (if that's an issue) but that speed doesn't give you the time you have when welding uphill to ensure perfect fusion and prevent slag inclusions. What I mean to say is that the quicker pace is less forgiving to mistakes/daydreaming.

Really keep an eye out for a lack of fusion if you're going downhill; this is the downside of the speed/low heat input. 6010/6011 penetrate a lot better and are less of a problem in this regard. Some codes up here are more forgiving than others for lack of fusion faults. Would you believe that water pipes are more critical than natural gas pipes? A non-compressable medium is harder on the pipes....

As for current:

What feels right? For 1/8" 7018 with short, fat cables I prefer it at ~120A for most stuff. Welder in the basement with cables strung to the roof? Boss bought smaller(cheaper) cables than he should have? Maybe a fair bit more.

Run it electrode positive. By the way: sometimes you run low hydrogen with straight polarity. For low hydrogen open root welds the root pass is usually done with straight polarity. I've done pipe with 9018 this way. It took a while to get the hang of it, haven't done it since, and may never do it again(especially if I have my way).

Anyway...

Why was your helper cussing, exactly? Some machines are better for starting welds than others; smaller machines can be trouble. If your machine runs well but takes a few seconds to get there, then use a run-on plate. Basically, you clamp a scrap next to where you need to start, strike the arc on the scrap and wait until the arc is stable before moving it over where you need it. Or you could rent a bigger machine for the job.

If you're close to the rated output of a smaller unit, it would be prudent to check the duty cycle. Since it's stick, you'll be stopping to chip slag and change electrodes so it doesn't necessarily need to be 100%. Each machine and situation is different...if yours won't cut it then rent one that will.

Structural, eh? A quick tip for when you're on the roof and the welder is in the basement:

A good rule of thumb is that for a current setting that works for your 7018, the next larger size of 6010/11 will run nicely too. So, if you're running 1/8" 7018 put a few 5/32" 6010 in your bag and it might just save your tail in a pinch.

Actually, if I'm in the situation of having my welder on a different level or outside, and I'm doing work with no weld specification given then I'll take a few sizes of 6010 with me rather than make a 5 minute trip every time I want to adjust my current. Want it hotter? Switch to a smaller rod.

The ability of 6010 to penetrate so well and burn through its own (relatively light) slag under most situations means a rod of a given size can be usable over a wider current range than 7018...in my experience...it makes this trick easier than you might think.

A funny snippet about welding in Canada:

In Canada, our welding standards are set by the Canadian Standards Association(CSA) and the codes for our electrodes are basically the same as the AWS system except our tensile strength is given in Megapascals...but most of us use KPSI like Americans. SI hasn't taken over the trades up here yet!

Anyway...the position code for 7018, according to the AWS is good for all positions including vertical-downhand but the CSA up here says it's good for all positions except vertical-downhand.

Sometimes you get an electrode with a CSA and an AWS code printed on it that both have the same position code...but two meanings... Does that mean that I can't weld downhill in Canada?

One last thought: When in doubt, farm it out.

Holy smokes! What started as a few quick thoughts kinda' grew.

[james gonzalez]

Thanks for all the input, folks.
I am going to hand my helper a can of 3/32" and if he keeps cussing I will climb up and do it myself. The little generator will only run low voltage rod which is why I do not resort to 6011. The structure is cold fastened with 2x 3/4" bolts at all joints so the welds are not as critical as they could be.
Well, off to make breakfast.

[cami]

What's a low voltgage rod?

[arftist]

150 amp machine is plenty big enogh for 1/8 excaliber. 110-120 amps for flat or vertical up is enough. For structural, only weld uphill, never down. Preheat is required. Weld 7018 with DC electrode positive only. In Boston a light iron work license is required.