I have some new centerfire nozzels on 300 amp GMAW guns. We run 0.035 ER70S-6 wire on clean hot rolled bar/ plate materials. Operate C-25 gas @ app.35 -40 CFH, 17-22V @ 240-380 IPM depending on joint type and material thicknesses. I have been getting a lot of porosity. I take off the nozzel, bang it on the work bench, and get a very very small pile of small spatter that had built up on the holes that are down in the nozzel on the ring inside the nozzel---not much at all and the porosity goes away until next time. This has happened on many of the ten welding machines. we operate I had noticed on some of the nozzels that these same holes in the ring have burned away thereby elongating the holes. I have changed out these nozzels.
The question is has any body else having the same problems with these type nozzels? What are they doing about it? Is it a design problem with the nozzels?
The old style nozzels never exhibited this problem.
shot circuiting will always cause splatter. running higher volts will (spray) help with splatter.
By Lawrence 
Date 03-25-2008 20:57
Edited 03-25-2008 21:02
Your wire feed speed (anything over 300 ipm) is very high for short circuiting transfer,,, This is going to cause problems no matter what kind of nozzel you use.
If your working @ 380 ipm with 0.035 wire maybe you should consider changing gasses and and process to spray transfer GMAW. This would provide spatter free welds on material from thicknesses of 1/8 inch to unlimited.
C25 gas cannot produce spray transfer GMAW with 0.035 wire, the best you can do is globular transfer and this is a very spattery type of weld with fusion problems very common.
Short circuiting transfer is best for materials less than 3/16 and sheet. Thicker sections can be welded with short circuiting transfer, but it takes higher skilled operators and the work will still be more subject to sidewall lack of fusion issues
Plate and bar are more economically welded, and with higher quality when the spray transfer mode mode is used.
Again, it's not an equipment problem... it's a process control problem. GMAW on plate and bar should be nearly spatter free with the proper short circuiting parameters and completely spatter free with proper spray transfer parameters.
Change to Argon 80% - C20 up to 90% Argon - C10 (this range of Argon have the ability to switch between short circuit & spray) gas and just bring the voltage up and you will be in the spray transfer mode. Use about 1" wire stick out and a recessed contact tube. If you are welding alot of spray transfer I would recommend 0.045 or 0.052 diameter wire.
By Goose-em 
Date 03-26-2008 17:40
Edited 03-26-2008 17:42
We purchased new welding machines last year and they came with the Barnard centerfire nozzles. Within a day we were having porosity problems so we started to try to figure out what was going on.
The porosity problem continued for about a week and we had a theory regarding those little holes. We took an old nozzle and put it on a gun that was having major porosity issues. Without changing the parameters or anything else the porosity went away. Hmmmmm, I thought let's try a little experiement.
I took one of the nozzles to the mill and enlarged the holes. Porosity was still present but was intermittent and we saw much less of it.
I called the Bernard rep and he brought the Tri-Mark rep and the Miller rep. The bernard rep tried blaming it on the wire but that was a bunch of hooey. I put Tweco guns on and showed him no porosity. I retrofitted all the centerfire guns to accept the old Binzel nozzles and still no porosity.
Over time as the guns wore out (I think some of the welders made them wear out) we switched back to Tweco guns and haven't had a moments problem since.
In my opinion the centerfire nozzle is a gimmick that doesn't work. Maybe it works for some but it didn't work for us.
Oh I should add.
Miller dimension 450 NT
Miller 74DX feeder
Tri-Mark Mettaloy Vantage .052
90/10 shielding gas
Spray transfer
The simplest solution for you, if you plan to stick to the bernard guns, is to switch the nozzle over to the Binzel nozzle and your problems will go away. If you have many of these guns get the rep in and show them the problem, our rep switched us to the binzel nozzles at his expense.
The other option is to stock up on carbon rods and grinding wheels!
been using centerfire in short curcuit for about two months now and have noticed that the nozzle acts alot like a gas lense. Been using them for about 2 years with 45 and 52 spray arc. I put a flow gage on the end of my nozzle and found that i was actually 7 to 10 cfh higher at the nozzle with centerfires vs. the old ones. The higher flow has given me fits more so in short with 30 and 35 vs running spray with 45 and 52. Nature of the beast.
Just a thaught but I use the same nozzles and find that 35 - 45 cfm is a bit high for gas flow and produce better results with 25 - 30cfm max.
I appreciate the replys regarding the spray vs short circuit and the gas types of spray and short circuit. I am well aware of these issues.
The total amount of spatter in this case is VERY, VERY minimal and would not even be considered in any other nozzel. The spatter in question is at the inside ring and it is very small and very little in quantity. The outer rim of the nozzel has little spatter also but eliminating this dosen't make a difference. It seems to be the inside minor spatter that is the cause.
The responses regarding the centerfire nozzels seem to be the exact experiences I am having and I also question the design of the product. I talked with another company about this problem and he stated they threw away their guns and replaced the with another--(should have just replaced the nozzels!)
So it seems that others are having this same problem--and Bernard--if your monitoring this website---listen up. Their is a problem with your nozzels.
You can lessen the worm holes also by using 75% argon 23% CO2 and 2% oxygen it is a hotter running gas thus lettin you lower your volts a few notches and run a lil higher wire speed with a wire try it out. wire welding should have minimal spatter anyhow have you used elephant snot once an hour can help too but it makes a mess every where. I run only Lincoln machines with digital read out and I rarely ever have a splatter problem. Once you find that combo of numbers that work it should sound like a jet airplane haulin tail.
I have a centerfire 400amp gun and have been running short arc uphills and overheads on 3/8 plate without even changing the tip. it actually seems to collect less spatter than the tweco I use at work, not to mention I am able to run lower gas than with the tweco. I am running .035 er70s-6 (cheap) wire at 17.8v (as the feeder reads) and 230 wire speed for uphills.the power source reads about 4v higher once arc is struck? I guess thats normal? anyway I have used about half a 33lb. spool so far without problems. Although I do not use nozzle dip either. If you are using dip, maybe it is dripping onto the nozzle holes and making it clump up?
If I have any future problems I will repost.
