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3/8 V-Grooved backed plate 3G test 7018
Posted: Fri May 28, 2021 11:09 pm
by delgriffith
Having trouble getting a decent root pass on this. Always seems to start well, then the bead gets stuck to one side, then it just goes to shit. Heat buildup is one obvious issue but that can't be all of it. Any pointers on what I should be doing and what might help practice root passes appreciated.
Re: 3/8 V-Grooved backed plate 3G test 7018
Posted: Sat May 29, 2021 8:17 am
by Poland308
Burning into one side over the other is most likely rod angle. Possible it might be bad rod but that is low on the list. Try adjust the height of your test plates. It probably has to do with range of motion of your body, I’m guessing it always goes wonky at about the same height.
Re: 3/8 V-Grooved backed plate 3G test 7018
Posted: Tue Jun 08, 2021 2:05 am
by delgriffith
I don't feel like angle is it. Or at least changing height doesn't seem to change things. I have 1/8" rods and there's very little room to either side in a 1/4" gap. I try to set the plate at 5/16" since that's allowed but it's still tight. I did a few more and seemed to maybe get away from sticking to one side, but I still have inconsistent bead height and a very convex bead that I'm not convinced is melting into the bevel plates very well. I get slag embedded on either edge of the bead that I can't get out and that can't be good. I've adjusted heat up and blow through the backing strip. Seems like the best results are around 110 amps. I had arc control cranked up to 10 but then dropped it down to 3, don't know if that made any difference. Grounding on the bottom of the plate, DCEP, Lincoln 350 MP. I try to keep the arc very tight so it's barely off the plate.
It's possible my fit up isn't tight enough. I seem to have a hard time getting the backing strip completely flat against the bevel plate. But it's not more than a hair or two away in some places and tight up in others.
I'm also using hardware store bought 7018 where they don't seem to feel the need to keep the moisture out of the rods. They weren't sealed and I didn't try to dry them out. I don't know if this might affect the way the bead won't set in nicely.
Re: 3/8 V-Grooved backed plate 3G test 7018
Posted: Tue Jun 08, 2021 9:07 pm
by Poland308
Fit up can make a big difference. Bead height, do they allow grinding between passes? If so fix the high spots before the next pass.
Re: 3/8 V-Grooved backed plate 3G test 7018
Posted: Mon Jun 14, 2021 11:35 am
by Superiorwelding
With you saying the bead is to one side I would say rod angle. You also mentioned fit up being a issue. I would get that backing plate as tight as possible to your test plates. Gaps won't be your friend. Pictures would really help us help you.
Jonathan Lewis
Re: 3/8 V-Grooved backed plate 3G test 7018
Posted: Mon Jun 21, 2021 11:40 pm
by delgriffith
Re: 3/8 V-Grooved backed plate 3G test 7018
Posted: Tue Jun 22, 2021 6:53 pm
by E T
Judging by the pictures.
On the root the transition from left to right bevel is to slow so You get exessive buildup in the middle.
Move faster across and hold a bit longer at the sides. The middle will then take care of itself.
On subsequent layers the steps going up are to big and You don't pause long enough on the sides which gives undercut.
You have to learn to read the puddle and to move when the crater you've made with the arc has been filled with weld metal.
Don't watch the arc, watch the puddle.
Re: 3/8 V-Grooved backed plate 3G test 7018
Posted: Tue Jun 22, 2021 6:54 pm
by Poland308
Your not hot enough and your long arcing.
Re: 3/8 V-Grooved backed plate 3G test 7018
Posted: Tue Jun 22, 2021 6:56 pm
by Poland308
Hardest part about 7018 vertical up is getting used to seeing the slag drip off and fall away but not reacting, but learning that the metal is still getting deposited.
Re: 3/8 V-Grooved backed plate 3G test 7018
Posted: Wed Jun 23, 2021 2:23 am
by delgriffith
Poland308 wrote:Hardest part about 7018 vertical up is getting used to seeing the slag drip off and fall away but not reacting, but learning that the metal is still getting deposited.
I learned about that a while ago and don't react. As far as long arcing, I usually have the rod shoved right up against the metal, any more and it would stick. Sometimes I slip and the arc extends a bit as I'm moving up or weaving to the other side, but I would think that I should at least have an inch here and there where it is flat and wet on both toes, not super convex with slag trapped on both sides that I can't get out. Turning up the heat seems to make it very easy to blow through the 1/4" x 1.25" backing plate or dig into it so far that I've got a mess that I can't fill in. I had it up to 125 on another plate and it was a mess, threw it out of the garage in disgust.
The problem I'm having is getting the bead to lay flat. It's so convex that I can't imagine the toes are penetrating the bevel plates. Looks like it's just sitting on top of the backing strip. Here's today's best attempt. 107 amps, 5 arc force. I stopped every couple inches and cooled the plate. At the top I tried to go too far and started digging into the backing plate, that is where it went really wonky. Subsequent passes are less convex since I have more back and forth room to hit the sides. I cut the weld and looks like I have porosity at the toes, although looks like it might have been on the second or third pass. Didn't have acid to etch properly and only made one cut but you can see a pit.
Root pass
Intermediate pass, still have trouble at the top since the underlying pass went bad in that area.
Two more passes and this
Cover pass
Section
Re: 3/8 V-Grooved backed plate 3G test 7018
Posted: Wed Jun 23, 2021 2:42 am
by delgriffith
Oh and just for fun I bought a can of lincoln excaliber, in case the hardware store unsealed 7018s were the problem. They seemed to run no different though. I'm using a 150amp electrode holder... can't imagine that matters though.
Forgot to mention it's 1/8" rod, which I've heard is tougher than 3/32, but that's what I'm suppose to test on if I can ever get this looking decent.
Re: 3/8 V-Grooved backed plate 3G test 7018
Posted: Thu Jun 24, 2021 9:08 pm
by Poland308
I am not trying to be disparaging. From the look of your pictures you need to grind down your first pass a lot more before trying to run over it with the next pass. If there is any sign of slag you need to grind it all out before you weld over it. V groove joints make it very important because the slag stays trapped. As noted by others you need to hold steady on the sides of your weave for longer. Running hotter will also help flatten out your bead profile. Make sure your weave pattern is from side to side not forward and back. I think if you could watch closely someone who can successfully do this weld you would be able to see these suggestions in practice.
Re: 3/8 V-Grooved backed plate 3G test 7018
Posted: Tue Jun 29, 2021 11:07 pm
by delgriffith
Disparage away, obviously something isn't right here so I need to change something. Grinding isn't allowed during the test, so I've been not doing it unless I had something go way out of whack and wanted to clean it up for the sake of practice on the next pass.
I tried one where I put like a 15-20 degree tilt on the plate and it made a huge difference in getting rid of the convex bead. I've heard that practicing with a tilt like that and slowly working to truly vertical is one way to improve. I might do that a bit more. I'll try bumping up the heat maybe just a few amps, 112 or something. I'm curious about 3/32 rod maybe being able to tie in to the bevel plate better and not look like just a bead sitting on the backing plate. Also not allowed on the test but maybe I can sneak in a couple rods in my waistband and pop them in when no one is looking
Kidding...
Re: 3/8 V-Grooved backed plate 3G test 7018
Posted: Wed Jun 30, 2021 10:07 pm
by Poland308
3/32 is much easier to control because your putting down metal at lower heat and a slower rate. If you see something in the puddle you don’t like you might have time to correct, but with 1/8 you don’t have much wiggle room. Especially on a grove joint that small. If I am unsure of a machines accuracy then I adjust my amps 2 or 3 at a time. Run a pass then change 3. Try again then change 3.