seems to me your contact tip is in way to far,1/8th or flush should work better.having the tip that far in would create way to much stick out.in my experience keeping a tight arc with minimle stick out works best.another thing ,make sure your not into spray transfer,this would push way to much wire for the overhead position.anyway,hope this might help.
good luck
metalord

Hello Lawrence, something to consider here. As the other gentleman said, a contact tip recess of 1/8" to flush will generally serve you best when making most any type of FCAW dualshield weld with just about any diameter of wire. I am fairly familiar with the Excel Arc 71 that you are referring to, if you run it with the 75/25 shielding gas at a flow rate of approx. 30 to 35 CFH you should be able to get a great looking fillet weld with minimal spatter. I won't suggest specific voltages or wire speeds, instead I will suggest that you set the machine so that it will run a decent flat stringer bead and then bump the wire speed up slightly before you try running it overhead. One other suggestion has to do with the machine ground. Make sure that as much as possible your direction of travel is away from the ground, also use a visible stickout of about 1/2" to 5/8" on the nozzle. Gun angle can have a signicicant effect on the welds that you are describing, if you are pushing the welds, don't use much angle, keep the nozzle close to straight in, dragging can yield some of the same results when you are talking about gun angle, if you use too much drag angle you will get the balls coming off the weld that you have described. If you are running this combination overhead and you see balls forming on the end of the wire as you are making the weld this is generally an indicator that your wire speed isn"t set fast enough, on the reverse side, if the wire appears to be physically pushing into the puddle then you probably have the wire speed set too fast. One final item, check all of your machine connections and cables carefully to insure that they are all tight and that the cables are in good condition, make sure that you have a good ground to the work that you are welding on. Arc blow with dualshield in the overhead position is really common in the shop that I work in and your decription of the conditions that you are running into seem very similar to what I see quite often. You may need to do some more experimenting but I am sure that you will be able to remedy your problem. Regards and Good Luck, Allan

Hello lawrence, I agree with allen, you should be able to take care of your dilemna by following his suggestions, I used to have to make long overhead welds of about 15 to 20 feet long, I used both the 75/25 gas as well as c02, mostly the latter, the biggest thing I found that most people tend to do is to try and run their machine to cold, set it for a good flat weld and then bump it up a little bit, also increase your wire speed a tad too, just as allen described, you'll know it when you see it, very little spatter and little or know build up in the nozzle, Still one of my favorite welding positions, with exception to neck and shoulder suffering afterwards,lol, Good luck. Steve

Hi Lawrence, I always enjoy your post. we use the same type FCAW overhead at 180 amps and 25-26 volts, 75/25 with no splatter problems.Our electrical stickout is about 3/4", tip is about flush. Tilt the nozzle just enough to cause any falling material (there won't be much) to miss the nozzle.
Andy

Thanks to every one of you.


Excellent advice which worked perfectly.

I think the recess into the nozzel was the main culprit.

We are working with an SWPS so I *must* use 100% CO2. But with the parameters tweeked we are already running spatter free welds overhead.

This is a relief.. the smell of me cooking is not plesant.

Another thing with overhead is mill scale , paint and rust . Overhead is like flat except you have to set your wire speed just enough to overcome gravity ,no more no less . But some times mill scale and ect. doesn't melt out of the way . and you quickly over come surface tention and once your puddle starts to sag the under cut ahead of the wire makes it even more difficult to melt away the lack of a good electrical connection and efficiant thermal transfer . I always prefered the ion action you get with 75-25 over straight co2 with any wire feed partly because of this . I set my wire speed for vertical up by reducing my wire speed until it starts to melt back on overhead ,you know ,that little ball that forms on the wire . It doesn't melt back to the tip but needs help to hit the puddle . Like has been mentioned , out of position welding needs shorter stick outs . Other wise the current loss - added resistance - preheating of filler wire directly relates to a lack of heat being transfered to the base metal which in turn slowes up the travel speed but you can't have that because your rate of deposit demands you cover more ground . At one place I worked being low man on the totem pole ment you got stuck with the out of position welding . In school I was tought to weld stringers overhead but when you want to get done you need to weave like you do on vertical . You can pass a 1" over head plate test with out one stringer bead , both plates have to be level though . You can gradualy work up to some fast rates of deposit . .