Welding Tips and Tricks

i had my second day practicing for a 3g open root xray test in mig today, made heaps of progress over the first day lol. almost had a plate worth sending off for the xray but dropped the ball with a very stupid mistake

did 75% of the root run well with v good penetration and fusion, then after a long bead muggins here ignored the root gap which was closing up a bit

was a small area of with a lack of fusion around where i restarted (about 1/2 an inch or less) so i was instructed to grind out the root at that point only, with a 2.5mm cutting wheel (root gap was 2.5mm) then "patch up" the root run before continuing

so what do i do, get impatient and put the grinding wheel on to get most of the metal out of the way before breaking through with the cutting wheel, only ground too far so i had something like a 6mm root gap

tried my hardest to weave like a madman and salvage but it was looking like a mess and may as well re-do another plate next time.

used that plate to practice my fill and cap passes, i'd improved 1000% since the 1st practice day and got some really nice flat fill/cap passes in. previously i was running too slow, holding the edges too long and stepping up too high each weave leading to a convex sagging globby looking piece of crap

this time i was moving quicker and watching the puddle size, keeping it relatively small and just letting it walk across the gap and catch up to the arc before weaving again in as close to 3mm vertical increments as i could (doing a Z weave)

i noticed as the plate got hotter i was weaving quicker and pausing shorter as the puddle was growing larger and faster

i wish i could have taken a photo but my phone batteries died, anyway felt like having a brag its a good feeling when things go right

I"m having trouble imagining this happening, shouldnt you make a plate holder thing to keep the plates from closing up? I thought all welding schools had them? Then again as i think back, mine didnt have them either. Anyway, cut two small u shaped plates, welding one sides to each plate, top and bottom. the u shape is to avoid the backing strip. This should keep them apart. Weld only one side of each plate, that way when your done, you can just break them off.

I know this is hard to imagine.


Here is what they sorta look like, top down.

###############
#.......&& ...... #
/////////////////


The /// is the plates, the && is the backing strip, and the ### is the plate i refered to.


hope this helps. it works wonders. Good luck!!

-Rick

hi rick,

i had 2 backing plates as you described on them, but the gap still closed up a bit. maybe i spaced them too far apart or something

the gap only closed slightly but it was enough to cause a small problem over that 5-10mm strip, next time i should just open it up with a 2.5mm cutting wheel before welding

went back in today, and finished a full plate

root run went perfectly, did 2 runs stopping once in the middle

ground it down completely flat and removed any tiny little notch or crevice and did 2 fill passes, grinding down to completely flat and smooth metal after each then did the cap.

i was very dissapointed in my cap, was a hot day (was about 34 deg C outside and probably 10 deg higher in the windowless welding bay lol) and i'd been grinding a sh**load to get back to completely smooth metal each pass

by the time i got to the cap i was pretty fatigued, but the instructor said it is probably good enough to pass visual inspection anyway and get sent off for the x-ray. since i spent so much time grinding out any divets, edges or crevices after every time i layed down a weld i am very confident that the xray will be fine

i could have done the cap much better and it was looking perfect on all of my practice plates. unfortunately made 1 or 2 small errors that required more and very precise grinding (as you are not allowed to have any grind marks on the finished cap) leading me to do more restarts than i would have liked, so there were a few lumps on the cap and the cap was done in about 4 separate sections instead of 1 or 2 big ones like i had planned lol, so there is some inconsistency along its length

if it doesn't pass visual i will just grind the cap down completely and re-do the cap from start to finish another day, which is probably what i should have done anyway rather than keep fixing little problems. was no undercut and at least the cap fused with the plates properly at the right distance from the groove anyway lol

will try and get some pics up; sorry for terrible focus


root penetration (was consistant like this the whole plate, though only 1/4 of the plate is shown)


fill:




and the ugly cap:



so hopefully the xray doesnt show anything and they can forgive me for that cap pass (they've seen me do plenty of perfect caps on practice pieces which is in my favour)

cheers for reading and criticism is welcome!

not bad at all. seems as though the Zs were a bit tight and weld a bit cold. but should pass. I like weaving using like a u patern. to help the consistancy you could also draw a line down each side of the filler before you cap, sort of guidlines for the width of the cap. makes good practice. Dont think you should have a problem on the visual though. Good luck.

Anthony

thanks anthony,

it passed the visual and im just waiting to find out the results of the x-ray now.

i think the biggest problem i had on the cap was going too slowly, was kinda not all there by that stage of the day and on the practice runs ive done before+after that piece i got a much better looking cap using the same weave+settings and just moving faster without letting the puddle build too much

good tip on drawing some lines down the sides, i will remember to do that next time i have to do a test piece

cheers again
Dan