[jb02]

I have a HH140 that I am primarily interested in using for autobody restoration. I'd like to be able to do butt welds but am fighting with edge blow through using repeated short tack welds. I am using .023 solid core wire with 25% ArCO2 gas set to ~20 flow rate.I am working primarily with 18ga metal patches. Hoping that some of the more experienced welders here can answer some of my questions:

I have difficulty seing the weld in-process once my heelmet auto-darkens. It is an adjustable darkening Hobart helmet. What shade and sensitivity is recommended at minimum for safety purposes?

I have been primarily practicing using a #2 amperage setting and between 20-30 wire feed speed. Is this within a reasonable range

Should contact tip be even with tip of nozzle or slightly forward.

What is recommended stick out from tip prior to initiating weld and how close should wire be to work surface?

For making short repeated tack weld for heat control...do I need to trim the wire after each shot. I always seems to have a small ball on the tip of the wire after each tack.

I have watch the Beginner T&T mig welding video's on this YT channel... but they really are not targeted for thin gauge metal welding. Any other video's that people can recommend?

JB

I have been holding the gun head at a slight angle so I have visibiliuty of the wire-to-work field. Is this correct or should I try a more perpendiciulr to work position?

How tight a fit do I want at the join seam between pieces when starting.

[Spartan]

I'd say 10 is a pretty standard starting shade. For lower amperage stuff I occasionally drop down to a 9, and sometimes an 8 for TIG at 15-20 amps or so, but that is fairly uncommon for me. It is technically safe at all shades because all of the UV and IR light is being filtered out, but it can strain your eyes if it is to bright. If you're seeing spots after a weld, then bump it up a half shade or so at a time until you are no longer seeing spots and that should be the sweet spot for that process. If you are still having trouble seeing the puddle at a 9 or so, it may just mean it is time for a better helmet...if you can't see the puddle, you won't be able to make good welds.

The contact tip can be even or slightly forward...it's really just personal preference in my opinion. Sometimes the tip is even recessed a tiny bit. Slightly forward is my preference. Or I should say was my preference, I don't MIG much anymore.

Wire should be trimmed nearly flush with the tip, and it is always best to trim it before each weld. It'll give you a more reliable and cleaner start that way, but I imagine most everyone is guilty of not always following that best practice.

Slight torch angles are perfectly fine. I try to keep it at about 20 degrees or less.

You want as tight a fit as possible, especially while you are learning. Welding over gaps can be challenging, especially with MIG. If the gaps are too big you can end up shooting the wire right through it and end up burning back and creating a mess in general once the wire does eventually short-out. Gaps are weldable with MIG, but not ideal while you are still trying to learn the basics.

As for the settings, the problem with welders like that is the settings on the dials are somewhat arbitrary. Best to go by the chart and then make adjustments from there until you get that nice sizzle sound and an adequate puddle. If you don't have a chart on that machine, try to find one for it online. You can also take your own wire speed measurements with a stop watch and a tape measure and post them somewhere on your machine to have true inches per minute values for each of the arbitrary dial values.

[Oscar]

I have been primarily practicing using a #2 amperage setting and between 20-30 wire feed speed. Is this within a reasonable range

I'm not familiar with your machine, but settings aside, you should be focusing on the weld puddle and the size/characteristic of the resultant bead. Are you getting the bead size you want? Is it too convex or too flat? You need to learn what different WFS and different Voltages do to your weld bead profile. Also keep in mind that travel speed affects the final outcome as well.

Should contact tip be even with tip of nozzle or slightly forward.

That depends on the parts/consumables that are available/you have purchased. Different MIG guns are set up differently. For the most part, they either have the tip recessed about 1/8" or are flush (for low-medium duty welders in the 100-250A class). Some might have it protruding but I haven't seen to many like that. None of them are wrong, just different for different preferences.

What is recommended stick out from tip prior to initiating weld and how close should wire be to work surface?

For low-amperage welding I would shoot for no more than 3/16" of wire sticking out from the tip. If your CTWD ends up being too long because the wire itself is sticking out too far, then the amperage at the puddle decreases due to resistive heating of the wire length, and then you get a ropey bead. Remember, it's not about how close the wire is to the work, it's the CTWD that matter, because once you hit the trigger, the wire will advance and there will be no such thing as how close the wire is to the work, as it will be short-circuiting. It's all about CTWD in this regard.

For making short repeated tack weld for heat control...do I need to trim the wire after each shot. I always seems to have a small ball on the tip of the wire after each tack.

yes, snip it off. Sometimes depending on the machine, if you are holding too much of a CTWD the ball on the end of the wire becomes excessively large, leading to the situation you are describing. It can sometimes be minimized by holding a close CTWD, but really it all depends on the machine. It may be that it is unavoidable with your machine.

I have watch the Beginner T&T mig welding video's on this YT channel... but they really are not targeted for thin gauge metal welding. Any other video's that people can recommend?

I haven't seen to many, but even if you could find them, they may not apply to you. For example, my MIGs have lots and lots of settings to all but guarantee success on thin sheet metal. Would they help you? Not at all. I have all digital synergic control with fully adjustable start speed %, start speed time, inductance, burn-back, pinch, and probably a few other things. In the end it comes down to creating the puddle you need. You need to deposit a certain amount of metal, with a certain amount of penetration, with a certain amount of convexity to the bead crown. This is where you need to play with WFS/V/Travel speed, CTWD, gun/wire angle with your specific set-up.

II have been holding the gun head at a slight angle so I have visibiliuty of the wire-to-work field. Is this correct or should I try a more perpendiciulr to work position?

How tight a fit do I want at the join seam between pieces when starting.

A slight angle is normal to increase visibility. Just don't go to crazy. No more than about 10°. IMO, zero-gap is ideal, or very very close to zero-gap.

[sbaker56]

18g with .023 and gas isn't too bad but you've still got to keep a few things in mind you really wouldn't be on thicker stuff. You'll want to be traveling way faster than you probably naturally will want to and even then only in 1-2 inch welds, the heat will catch up to you after a few inches and what was originally just right for settings will start uncontrollably blowing through. Because you don't have infinitely variable voltage think of your CTWD as your fine heat control after your voltage setting gets you into the ball park. I have a HH210 and if I can't avoid blowing through regardless of travel speed the first thing I do is experiment with increasing my CTWD on a piece of scrap. If it's still a problem at 3/8 then what you want to do is drop your voltage down one setting, and start off with your CTWD as close as reasonably possible, which is usually somewhere in the range of 1/8-3/16 and increase it again if need be. That's much more reliable than adjusting wire speed in most cases for me.

What you don't want to do is change 3-4 variables at once when you realize your settings or stickout is off.

[225256]

Watch this video to see how one of the best adjusts a machine that has tap settings with no accurate readout of wfs or volts.

https://www.youtube.com/watch?v=sZuq4XQTHVs

[CopperCulprit]

I have a HH140 that I am primarily interested in using for autobody restoration. I'd like to be able to do
welding machines butt welds but am fighting with edge blow through using repeated short tack welds. I am using .023 solid core wire with 25% ArCO2 gas set to ~20 flow rate.I am working primarily with 18ga metal patches. Hoping that some of the more experienced welders here can answer some of my questions:

I have difficulty seing the weld in-process once my heelmet auto-darkens. It is an adjustable darkening Hobart helmet. What shade and sensitivity is recommended at minimum for safety purposes?

I have been primarily practicing using a #2 amperage setting and between 20-30 wire feed speed. Is this within a reasonable range

Should contact tip be even with tip of nozzle or slightly forward.

What is recommended stick out from tip prior to initiating weld and how close should wire be to work surface?

For making short repeated tack weld for heat control...do I need to trim the wire after each shot. I always seems to have a small ball on the tip of the wire after each tack.

I have watch the Beginner T&T mig welding video's on this YT channel... but they really are not targeted for thin gauge metal welding. Any other video's that people can recommend?

JB

I have been holding the gun head at a slight angle so I have visibiliuty of the wire-to-work field. Is this correct or should I try a more perpendiciulr to work position?

How tight a fit do I want at the join seam between pieces when starting.

I was wondering if holding it in a angle mainly works for the different types of joints, cause it suppose creates a better fit. However I've just been holding it at a slightly lower than 45 degree angle

[Oscar]

I was wondering if holding it in a angle mainly works for the different types of joints, cause it suppose creates a better fit. However I've just been holding it at a slightly lower than 45 degree angle

Sometimes you have to. The main thing to be cognizant is: are you achieving the desired & proper bead/puddle characteristics? If so, then you're doing it right. If you are not achieving the proper bead-puddle profile/wet-in/penetration, then you're practicing incorrect technique for that specific scenario. Sorry but there are so many variables that there is no "yes/no" answer to your question". You have to know how to weld in order to determine if your weld is good or not. It just simply takes time. Add in destructive testing and macro-etching, and your knowledge of welding increases 10x in the same amount of time practicing.