Every wire feeder in our shop, right now, has the contact tip either flush with the gas nozzle or is in past the nozzle by about 1/8", and MOST of our welders can see what they are doing. I don't remember what you are using but we are using FCAW with 100% CO2.
When we have spatter problems, it is usually because of improper technique for the actual parameters being used. Usually the
electrode angle is wrong , more than 15 degrees from 90, and the electrode extension (stickout) is too long.
CHGuilford

ZebraFive,
I am not sure if I can help, but I'd like to get the subject back on track with your question as I understood it.

The short nozzle certainly wont effect the current or the weld in any way electrically. I'm not sure of the practical effect it has on the gas protecting the electrode, weld puddle and HAZ, but it must alter that envelope in some small way. I do believe the short nozzle will stay clean longer in a spatter-filled environment although I wouldn't bet on the difference being a practical benefit; I just don't know as I never compared the three configurations with that kind of critical eye. I imagine the short nozzle would also tend to require a bit higher rate of gas flow as well.

Correct me if I am wrong, but I understand by your question you would like to discuss the accuracy and implications of thse presumptions with respect to weld characteristics and discontinuities.

Delta out

Your question is vage however in FCAW I use nothing but a thread protecter over my contact tip and the better you can see the better the weld.But it sounds like you are using a sheilding gas,I do not know enough about your case are you dule shelding or miging?pardon my spelling and are you using a gas lense.Electrical stick out and angle make a huge driffrence in spatter try making these simple adjustments.Are you using constant or variable voltage and remember after the machine gets up to working tempature it will need to be tuned in again.

At the very least having the tip stick out that far is wasting shielding gas. At worst they will have excessive porosity and irregular bead contour. The scenario that will most likely play out is the gas will be turned up to compensate for the poor coverage, a strong venturi effect will pull the atmosphere into the weld puddle and it will become contaminated. The degree of contamination will be directly proportional to the cfm being applied, which will be determined by the amount of stickout. If they are getting excessive spatter, take each machine and set it to what I call "book settings" or manufacturers suggested settings for the wire size, gas being used, process you desire (short arc, spray, etc.) and size plate being welded, you can then tweak each machine from there. Do you have welding procedures? These can often help you keep your welders and machines within approved parameters. I appreciate your confidence in me, I will do my best to ensure it is not misplaced.

Mike Sherman
Shermans Welding

visit www.weldreality.com for the answers to this question
post this question on his weld questions and you will get all that FACTS you need.
There is all of the GMAW/FCAW information you need to answer this and all other "operations" type questions on that site. You can show these FACTS to the weld manager that way.

It sounds like you have a comon problem that most companies have when short arc welding. The contract tip should be only 1/8" outside the nozzle because anything else could cause porosity. If your welders have trouble seeing the joint, a smaller diameter nozzle should be used. The biggest problem that causes spatter in welding is an incorrect voltage setting. Voltage is arc lenght, and WFS is amperage. If the voltage is too low in the short-arc mode, the wire is running into the molten puddle and causes spatter during the dead short and arcing process (up to 120 times a second). If the voltage is too high, the wire is staying outside the puddle and slightly in the Globular mode. This will cause spatter due to the droplet splashing into the molten puddle.

Spatter is welding wire that does not stay in the puddle. I have seen 7% of the wire lost to spatter. This results in extra clean up and possibly poor welds due to incorrect welding parameters. Listen to the arc, and try to get a crisp frying sound (like frying bacon). This will give the best voltage for short-arc welding (16 to 20 volts). Make sure that your welders keep the wire stickout between 1/4" and 3/8". If it gets longer, you will lose voltage in the arc because of resistance in the welding wire. If you are welding on galzanized material, it is very difficult to completely eliminate spatter. Most applications can be adjusted so that no spatter will appear on the part.
MLM

Your problem is not a new one and alot of weld shops today struggle with this on a daliy basis. There are alot of factors to take into consideration when welding in the short arc mode. I work for a gas manufacturing company and my job is to work with companies to solve your type of problem and to increase productivty. Please drop me a note at campbeach@aol.com with your phone number and I would be glad to give you a call and discuss it with you. I cover the Northeast so I may not be able to stop in but still may be able to help.

Thanks

Bob