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Up Topic Welding Industry / General Welding Discussion / 3G VERTICAL UP WITHOUT BACKING STRIP
- - By cmhines Date 11-04-2002 18:05
Hello, great informative site. my question is this...what does "3g vertical up without backing strip" mean? im avid in mig/tig and am looking into applying for a job that has this requirement. the job is in the aircraft ground support equiptment area. also is there a printable table of welding blueprint codes avaiable? my experience has been in the overhead conveyor tooling area which doesnt involve much more knowledge than common sense and basic fabrication skills. thanks in advance.
Parent - - By pipewelder_1999 (****) Date 11-05-2002 00:25
Here is a page showing the plate test positions. The plates shown are without a backing strip.

http://www.weldinginspectionsvcs.com/groove_weld_positions_for_plate.htm

Allow about 30 seconds for the page to load on a 28.8.

Hope this helps

Gerald Austin
Parent - - By cmhines Date 11-05-2002 01:54
THANKS FOR THE REPLY. I WAS JUST WONDERING IF BY "3G VERTICAL UP" THEY MEAN I WILL WELD THE PLATES TOGETHER STARTING FROM THE BOTTOM?? I WAS TAUGHT THAT VERTICALS SHOULD BE STARTED FROM THE TOP. ANY MORE HELP ON THIS MATTER IS THANKED IN ADVANCE. ONE MORE THING...WHAT IS A BACKING STRIP?
Parent - - By pipewelder_1999 (****) Date 11-05-2002 03:07
Thats correct. Your travel will be from bottom to top. The travel direction is a qualification variable for most tests for vertical.

A backing strip is a piece placed behind the root of the weld to support the root and assist with fusion. Without the backing, welding of the root requires greater control of both the welding parameters such as amperage, travel speed etc and also requires a bit more skill on the part of the welder.

The sketch show at http://www.weldinginspectionsvcs.com/VeeGrooveWithBacking.htm shows what is meant by backing strip.

Have a good day

G Austin
Parent - - By cmhines Date 11-05-2002 03:33
I HAVE REALLY NEVER TRIED DOING A VERTICAL FROM BOTTOM TO TOP. IM JUST GUESSING FROM WHAT IVE CAME ACROSS AND READ THAT IT CAN BE DONE AND IM GUESSING THAT THEY WILL WANT IT TO LOOK THE SAME AS GOING FROM TOP TO BOTTOM TOO HUH?!?? ANY ADVICE OTHER THAN PRACTICE? SUGGESTIONS ? WE HAD A GUY AT A TRAILER SHOP WHO USED TO DO VERTICALS FROM BOTTOM TO TOP AND THEY WERE ABOUT THE NASTIEST MESS I EVER DID SEE. AND I GUESS THATS WHY OL JOSE "QUIT" AFTER 1 DAY. I WOULD BE GREATFUL TO GET A FEW COMMENTS ON GETTING THE BEST WELD FOR MY SITUATION. THANKS AGAIN IN ADVANCE.
Parent - - By pipewelder_1999 (****) Date 11-05-2002 03:45
You probably can't get them to look the same. The tecnique you use will depend upon what electrode you use.

If you are gonna do a test on 3/8"-1/2" Vee groove with backing I suggest practicing macking vertical uphill fillet welds in 1/4" or thicker material. When you get those looking smooth its just a matter of bead placement to make the final product look good.

You can also practice running stringer beads side by side to make a smooth cap. See the picture at http://www.weldinginspectionsvcs.com/WeldCapProfile.htm

Good night

Gerald Austin
Parent - - By cmhines Date 11-05-2002 16:17
this test will be using mig
Parent - By pipewelder_1999 (****) Date 11-05-2002 23:47
Mig uphill works pretty nice provided you have enough base metal thickness to absorb the heat and have your machine set correctly.

G Austin
Parent - - By CHGuilford (****) Date 11-05-2002 14:08
There is no reason to believe that vertical up welds have to look bad. With practice, you will be able to do it; "Jose" just hadn't practiced enough with the process and materials.
CHGuilford
Parent - - By cmhines Date 11-05-2002 16:17
this test will be using mig
Parent - By Kix474 (*) Date 11-07-2002 20:32
on 3/8 plate try 17 volts use your judgement on wire feed speed just get it sounding pretty good like crackling bacon. 3/32 ROOT FACE 3/32 root opening. Unscrew your tip a bit or push your cup back so your tip is sticking out of the cup about 3/32 to an 1/8 inch run your gun angle about 90 degrees to the plate and chock that gun in the bevel. This is assuming u are using .035 wire. Not to close but close enough to where you can see the pudle real good. Run it straight up the seem no side to side motion or any movement at all just a straight machine run all the way up the seem. Voltage and wire speed seeting will vary on different machines so use the amper and voltage meeters if you have them. Try this a few times and adjust where u think u need to. Ray C.
Parent - By oldkid (*) Date 11-17-2002 01:45
Where I work we are required to weld both uphill and downhill vertical with and without a backing strip. You will find you will need to turn your voltage and wire speed way down when running uphill. For instance on 1/4" running vertical downhill I run at 26 volts 550 inches per minute. For the same weld going uphill I will run 23 volts 175-200 inches per minute. The recently required us to run uphill on material as thin as .143
Most of the guys thought it couldnt be done, however, if you set your machine correctly, the weld will pentrate completely and look very nice.
Dont forget to try different methods of movig your puddle such as an inverted horshoe pattern ,looks kinda like "U". One of the new methods they are teaching at the local college is a triangle pattern. I have tried them all including going just sraight up and I prefer the horshoe. Its up to you,try different settings and methods until you find one that works for you. Good Luck
Up Topic Welding Industry / General Welding Discussion / 3G VERTICAL UP WITHOUT BACKING STRIP

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