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Can Lincoln Electric 3/32 7018 electrode be also used DCEN?

Posted: Tue Nov 14, 2017 7:29 pm
by gr8gary1
Trying to build a desk for my wife. Getting a lot of porosity and don’t know why. On my ranger 10000, the amps are set to 90 and the dial all the way to just above five. These are new off the shelf electrodes. I am holding a tight arc and good to me travel speed. I also have a bad wrack to it. All the cuts are dead nuts on. I put the gussets on the bottom frame prior to welding the legs to the top frame and I think it’s putting strain on it not allowing it to level out. Can I get some help. I can upload more pics if necessary when I get home in a few.

Re: Can Lincoln Electric 3/32 7018 electrode be also used DC

Posted: Tue Nov 14, 2017 7:50 pm
by gr8gary1
These are Lincoln Electric 7018 AC-RSP electrodes by the way. Refers to the pic for more clarity.

Re: Can Lincoln Electric 3/32 7018 electrode be also used DC

Posted: Tue Nov 14, 2017 8:23 pm
by MinnesotaDave
Normally on DC those are run DCEP

Around 90-100 amps is where I usually run 3/32" 7018.
Sometimes as low as 85 amps.

edit: I looked up your machine. You're set on the 40-90 amp range so you're only at about 65 amps or so. Pretty low for 3/32" 7018.

Re: Can Lincoln Electric 3/32 7018 electrode be also used DC

Posted: Tue Nov 14, 2017 8:38 pm
by gr8gary1
Thanks for the prompt reply Dave. I appreciate the information and will make the changes. I move the amperage down due to the fact that I kept blowing through this material is less than 1/8 inch thick so I was trying to keep from blowing through. I will adjust my technique and try it with the higher amperage. I am getting good penetration however, But with a lot of porosity.

Re: Can Lincoln Electric 3/32 7018 electrode be also used DC

Posted: Tue Nov 14, 2017 8:45 pm
by Farmwelding
Have any pictures of the porosity and the electrodes? Have they been exposed to a lot of moisture?

Re: Can Lincoln Electric 3/32 7018 electrode be also used DC

Posted: Tue Nov 14, 2017 8:55 pm
by gr8gary1
Farm welding, I will get some pictures when I get home. As I said in my original post, these are brand new electrodea so I have no idea what their exposure has been. I bought them at Lowe’s so anything is possible.

Re: Can Lincoln Electric 3/32 7018 electrode be also used DC

Posted: Tue Nov 14, 2017 9:43 pm
by gr8gary1
Ok here is a pic of a little porosity and yes, under cut. Also a pic of the thickness. I believe it it just over 1/16”

Re: Can Lincoln Electric 3/32 7018 electrode be also used DC

Posted: Tue Nov 14, 2017 10:06 pm
by Poland308
Are you getting porosity only on the last weld that is sealing up the tube? Oil contamination will also cause holes like that.

Re: Can Lincoln Electric 3/32 7018 electrode be also used DC

Posted: Tue Nov 14, 2017 10:20 pm
by gr8gary1
Poland308 wrote:Are you getting porosity only on the last weld that is sealing up the tube? Oil contamination will also cause holes like that.
.

I didn’t use acetone to clean it but I tried to make sure it was bright shiny metal. Just clarify though, this was scrap metal from my neighbor. Maybe there was something on it although there didn’t appear to be.

Re: Can Lincoln Electric 3/32 7018 electrode be also used DC

Posted: Wed Nov 15, 2017 12:35 am
by Poland308
On real thin 1/8 or less I’d personally run a little colder than Dave. Just personally. I’d be at about 70-80. If there is any oily residue on the inside of the tube then it will get pulled through the molten pool as you weld. This can definitely cause porosity. Some kinds of Left over paint or any kind of zinc/galvanizing, same thing. If you weld the pipe or tube totally closed and don’t allow for hot air to escape then this can cause porosity as well, but usually only as your making the last stretch of weld. Rod condition is less likely. I have some 7018 that got rained on, the iron powder in the flux actually has started to rust. I use it for lots of non essential stuff with no porosity. However if the flux is soaked in oil, water, glycol, or cracking and flaking off in chunks either before or during a weld then it’s worthless and will also cause holes.

Re: Can Lincoln Electric 3/32 7018 electrode be also used DC

Posted: Fri Nov 17, 2017 2:57 pm
by gr8gary1
Ok so, I changed to AC and bumped the amps to 65 or so. There is still a little porosity but not as bad as it was before. Still sticking a lot whic I think is indicative of low amps but I don’t eat to burn through. I appreciate all your help. I will post a pic of the final product.

Re: Can Lincoln Electric 3/32 7018 electrode be also used DC

Posted: Fri Nov 17, 2017 4:05 pm
by gr8gary1
Apologies for the numerous grammatical errors. Using my thumbs on my phone and didn’t see them for correcting.