3G test coming soon - have an issue I need advice on
Posted: Fri Mar 23, 2018 4:13 am
Quick background. All of my arc welding experience has been in a classroom, 3x/week since January 24. SMAW, GMAW and for the past 2 weeks, FCAW (Dual Shield) Flat and Fillet I've got figured out with all 3 types and SMAW vertical uphill is decent.
Currently working on 3G pieces in preparation for a cert test in about this time next week. 6" x 2" x 1/2" plate, 1" x 8" X 3/8" backer, 1/4" gap, 30 degree angle on the work pieces. (60 degree opening) Wire is 0.45"
First 4 to 4 1/2" inches of the root pass are ok, but the last bit goes haywire. Arc seems to sputter and the resulting bead (if you can call this portion a "bead") turns very ropy and piles up. Literally everyone in the class is seeing this and it's almost become a running joke after 5 sessions of vert uphill. The machine I'm working on seems work best for me at 22.7 volts and not quite 300 IPM wire speed. Gas (CO2) is running about 30CFH. Other students are running similar settings.
We've all started watching each other run to see if an extra pair of eyes can see what might be going on, but there's nothing glaringly obvious going on with technique (Not surprising since we're all newbies still) and with 10 of us having similar issues on 5 different machines, it's getting very frustrating.
On the rare occasion one of us gets a decent root pass in, the following stringers seem to flow ok, but the top of the bead tends to get more buildup than the lower 4 - 4 1/2" inches and by the time we've got 5 to 6 passes in the groove and are ready for cover passes, that area is already right at the excess reinforcement limit.
Towards the end of class tonight, I was able to complete all my passes, but I had to grind down the last 3 stringers in the "bummer zone" low enough so I could get my cover passes done without them being too tall. Cover passes went down fine after that.
Anyone have any idea what's causing all the grief in that last inch and a half or what to look for in the puddle? Again, we're all pretty decent with the first 2/3 of the passes but that last bit just doesn't seem to want to play nice.
Thx!
Currently working on 3G pieces in preparation for a cert test in about this time next week. 6" x 2" x 1/2" plate, 1" x 8" X 3/8" backer, 1/4" gap, 30 degree angle on the work pieces. (60 degree opening) Wire is 0.45"
First 4 to 4 1/2" inches of the root pass are ok, but the last bit goes haywire. Arc seems to sputter and the resulting bead (if you can call this portion a "bead") turns very ropy and piles up. Literally everyone in the class is seeing this and it's almost become a running joke after 5 sessions of vert uphill. The machine I'm working on seems work best for me at 22.7 volts and not quite 300 IPM wire speed. Gas (CO2) is running about 30CFH. Other students are running similar settings.
We've all started watching each other run to see if an extra pair of eyes can see what might be going on, but there's nothing glaringly obvious going on with technique (Not surprising since we're all newbies still) and with 10 of us having similar issues on 5 different machines, it's getting very frustrating.
On the rare occasion one of us gets a decent root pass in, the following stringers seem to flow ok, but the top of the bead tends to get more buildup than the lower 4 - 4 1/2" inches and by the time we've got 5 to 6 passes in the groove and are ready for cover passes, that area is already right at the excess reinforcement limit.
Towards the end of class tonight, I was able to complete all my passes, but I had to grind down the last 3 stringers in the "bummer zone" low enough so I could get my cover passes done without them being too tall. Cover passes went down fine after that.
Anyone have any idea what's causing all the grief in that last inch and a half or what to look for in the puddle? Again, we're all pretty decent with the first 2/3 of the passes but that last bit just doesn't seem to want to play nice.
Thx!