[Wildwelder96]

For the 7018 certification test 3g and 4g are we aloud to use whichever diameter electrode for the root? I've tried doing a 1/8 7018 root but It doesn't turn out that good. I've done a 3/32 7018 root and its much nicer and easier.

[Poland308]

I usually chose 3/32 for anything test day or critical. Easier to control means less chance of something bad happening. If something bad does happen then there less to grind out.

[snoeproe]

What test are you doing?
Pretty sure AWS D1.1 test only allows a 1/8" rod?
The CWB test only allows a 1/8" rod. I wouldn't want to go any smaller, especially on the root. A 3/32 rod on the root would force you to have more stops/starts that are unnecessary and can lead to potential problems. You can go to a larger rod than 1/8, but not smaller.
If you can't run a 1/8" 7018 rod cleanly and neatly in the 3G and 4g positions, then your not ready to take the test and be successful.

[Wildwelder96]

Yeah I am going to be doing the AWS D1.1 test. I've just haven't been able to get a good root with a 1/8 7018. I'm running at a 125 amps I'll start out good but then I'll get arc blow once I get closer to the top. I can do all the other passes fine it's just the root I have trouble with

[snoeproe]

125 amp is too hot for a vertical up root pass on a 3/8” plate with a 1/8” rod. You know your too hot when you loose it around 3/4 of the way up the plate.
125 amps is ok for flat or overhead but not for vertical up.

[Wildwelder96]

Ok thanks so what would be a good a amerpage setting ? For a 1/8 7018 for the root 3g?

[snoeproe]

Well, every machine can be different. Every buildings incoming power can be different. Single phase or 3 phase power etc....
You need to find out what amps works for you. I know what works for me. Myself, I’d set my machine somewhere around 105-110 amp range for a root pass on 3/8” plate with a 1/8” 7018. But, you need to determine yourself, what works for you and your set up.

[Poland308]

Well, every machine can be different. Every buildings incoming power can be different. Single phase or 3 phase power etc....
You need to find out what amps works for you. I know what works for me. Myself, I’d set my machine somewhere around 105-110 amp range for a root pass on 3/8” plate with a 1/8” 7018. But, you need to determine yourself, what works for you and your set up.

That seams reasonable. My experience is with pipe. We’re allowed 3/32. Didn’t mean to miss direct. 1/8 for me would be between 95 and 150. Depending on angle and base.

[snoeproe]

Well, every machine can be different. Every buildings incoming power can be different. Single phase or 3 phase power etc....
You need to find out what amps works for you. I know what works for me. Myself, I’d set my machine somewhere around 105-110 amp range for a root pass on 3/8” plate with a 1/8” 7018. But, you need to determine yourself, what works for you and your set up.

That seams reasonable. My experience is with pipe. We’re allowed 3/32. Didn’t mean to miss direct. 1/8 for me would be between 95 and 150. Depending on angle and base.

Yup. I gathered that. No problem.
I’m a structural guy. Smallest rod I’ve ever been allowed to use on a test was 1/8

[snoeproe]

I usually chose 3/32 for anything test day or critical. Easier to control means less chance of something bad happening. If something bad does happen then there less to grind out.

On structural tests, you can’t use grinders. You can have a wire wheel on a grinder for cleaning purposes but no grinding disc for grinding (metal removal).
This is CWB regulations. While I’ve never done the AWS D1.1, I’m certain it’s the same.
I know pressure tests allow grinders. Structural is different.

[bap_]

I've always been curious about that. I understand that we should all know how to weld d1.1 without powertools, however on the job site I imaging that grinders are widely used and a welder/helper would use one if they saw they trapped slag or had a shitty root pass or something.

I've taken d1.1 tests where grinders were allowed. I guess it depends on who is the administrator.

[Poland308]

They draw a line on pressure pipe certs there’s no grinding on the surface. But they do allow grinding up until you put on your cover. Pretty hard to guarantee an x ray weld if you have to fill in 3/4 inch of joint with no grinding. Not impossible just not practical.