Need some input from the group...

Fighting problems with excessive porosity and spatter on my little Lincoln SP-175. Running 0.030" solid core with 75/25 gas on mild carbon steel. To get anywhere near a reasonable looking bead, I have to run about 28lbs of gas, which is about double what it should be. A little research has led me to a possible issue with the tip recess: mine is currently flush with the nozzle. Can anyone tell me their experiences with tip recess on their MIG machines?

It is very possible the guages are off, and I've got an appointment with the local welding supply shop to have them checked later this week... And yes, as originally stated, I fully understand that 28cfh is waaaaaay too much. I'm basically pulling my hair out because I cannot seam to lay a decent bead with this machine!!

Check to make sure you don't have splatter blocking the holes for the shield gas? Also make sure you don't have a kink in gun liner. I was welding yesterday when I noticed a poor arc and porosity...I thought I was out of gas. Nope. I was not paying attention and had looped the line and the gas line was being restricted. I unlooped the line and cleaned the tip. G2G.

No kinks, I'm always VERY careful with that because I've seen too many squirt guns damaged that way... As for the other, I just checked and cleaned everything, installed a new tip and all. Very next bead looked just like the one before all the cleaning and replacement... It truly acts as though it's not getting good shielding gas to it, even though my flow is rediculously high (according to the gauges at least) and I'm inside with no wind or anything to rob it :(

Have you pulled the gun completely apart and cleaned out the holes in the gas diffuser or did you just change the contact tip? Spatter from doing a lot of overhead can fall down and block the diffuser holes after a while.

Have you checked the line going from the cylinder to the machine for obstructions?

Is the gas solenoid on the machine starting to go bad?

Is it possible you got a bad cylinder of shielding gas?

It is entirely possible that the gas line or gas solenoid are leaking inside the machine, and the gas flow going to the welder is not what is comming out of the gun.

alot of good info provided to you here.....

28 is just about double as you predicted.

checking flow coming out of nozzle/tip with no wire speed. stick the gun under water (use a drinking glass from the house)......

whether or not the tip is positive past the nozzle tip doesn't matter a whole
lot unless it's like 1/2 past, then maybe......

--Sherpa

Should make a breeze if you point it at a piece of paper with the wire feed disconected. Adjust the knob at the regulator to view any change in output. and listen for leaks as you restrict the output with a rag.

Gas should be good, as this is actually the third bottle I've tried it use...

Diffuser nozzles were cleaned, not just a new tip...

No leaks anywhere in the system, I've testing every connection and every inch of line multiple times...

I'm really suspecting the solenoid and/or the guages. I appreciate everyone's input, and I'll post up the results of the warranty inspection later this week.

Make absolutely sure that your connections to the electrode and clamp are correct at the machine. If you're using solid wire then it should be set up dcep...meaning the whip should be hooked to the + lug and the ground to the -.

Make absolutely sure that your connections to the electrode and clamp are correct at the machine. If you're using solid wire then it should be set up dcep...meaning the whip should be hooked to the + lug and the ground to the -.

check polarity as stated above are you by any chance welding galvanized metal that needs to be cleaned b4 welding Ed

Make absolutely sure that your connections to the electrode and clamp are correct at the machine. If you're using solid wire then it should be set up dcep...meaning the whip should be hooked to the + lug and the ground to the -.

That's where I'm putting my money.

ok take and pull a little wire off of the spool and look at it very close. If a welder sits for long lengths of time the cheapass wire we get now will start to rust. It's hard to see but this happened to me not that long ago. if you spot rust you must pay off a few layers and discard. I would pull your gun off of the machine and pull the wire out and squirt brake cleaner into the liner to rinse the shit out of it. when it starts to run clean on the other end, then take and blow compressed air through it to dry it out. when I bought my welder new many years ago this old fella that worked at the welding shop told me that secret. he said if you will do this ocationally you will never need to buy a new liner. and umm yes he was right 20 years later and prolly 50 reels of wire later it still works as good as day one.