Blackline MIG 200 setup issues flare / burn back

[Fultonius]

Hi Folks,

Our tRusty old T4 failed its MOT on rust, rust and more rust.

I recently did a night class to learn metalwork, we did MIG, TIG, Plasma cutting, Oxy etc. The van failed the MOT 3/4 through the course, so I quickly wrapped up my "project" (a 3-legged plant stand) and focussed the last 2 weeks on stitch welding 1mm sheet metal with the MIG. While it wasn't pretty, I was managing to get full penetration and overlap on the spots and when ground flush there were only "many" pits and voids, rather than it being totally detatched haha!

I spent a bit of time looking for, checking out and narrowly missing out on second hand Clarke 135s etc. and decided life was too short and ordered a new Blackline 200, thinking that they 1) get good reviews on here and 2) should be a nice simple baseline to start from, so any "issues" would be down to technique and not because it's a crusty old second hand welder and 3) 1 year warranty.

So, I messed around with some 2-3mm steel, doing some runs, welding old bolts to it etc. Seemed easy enough to get settings to work, wire fed smooth and welds look ok.

I then cut some pieces of my 1mm sheet (plain mild steel) that I bought for the van repair and this was where trouble started.

I had accidentally bought Hobbyweld 15 instead of 5, so went back and got that swapped. Hoping that was my issue sorted, I cracked on with some more practice.

Issues:

Even when I have the voltage down very low (less than 1/10) I keep getting insanely hot flare ups. So bad that it seems to flash-vapourise the top sheet of 1mm steel (was practicing overlapping welds). The mig wire turns into flying little blobs of molten steel and plugs the tip. I've tried upping the feed to the point of getting pushed back from the weld by the wire and then backing off a bit. Sometimes this helps, but then every once in a while it just goes nuts again.

When things are going ok, it settles down and creates a weld pool and I can control the arc. It seems like I'm on a bit low a setting as I'm getting very protruded beads and not a lot of penetration, but if I up the voltage even a tiny bit I go back into flare time!

What to do?

I'm not really sure what's going on. I've done a lot of googling about burn-back etc. and it seems like my wire feed rate it ok, tension ok (if I grip the wire the feed slips but only with decent pinch force), and i don't notice any obvious stuttering of slowing down of the feed (I had wondered if my weedy garage power supply was dropping voltage when the arc was kicking in - the supply wire is too thin and I should really get it upped to 4m2 - bloody cowboys that installed it before we moved in.

I've tried new tips and it still sometimes happens first pull of the trigger.

Setup: 0.8mm wire, 0.8mm tips, 12-14L/m gas, hobbyweld 5%. Voltage about 1/10 and speed 2.8-3 / 10.

What I've tried:

I thought it could be a bad ground, so I checked the earth point in the welder and torqued it (it was fine). I cleaned up another bit of the frame of the van and made sure I had a really good earth.

I've run some beads on some thick bar with the settings higher and managed ok looking welds. Even attached an old screw to it and couldn't hammer it off for love nor money, so the welder CAN work fine, it's just frustratingly inconsistent.

Here are some examples:

1st weld, ok:

First attempts on thin steel, short runs, spots and some seam stitch - a total mess, blasting huge holes (Hobbyweld 15) etc:

Close up of one of the bad flare-ups (note, settings were 1/10 Volts, around 2.5-3/10 speed (hobbyweld 15):

 

[Fultonius]

Split into 2 posts as I went over the 10000 character limits:
Some examples of the flare-ups and weird "splat welds". In the purple you can see I was trying to do a plug weld and it just melted the **** out of the edge of the top sheet. In the yellow I persevered despite is flashing and flaring and spitting blobs all over, again, the top sheet melted away, the cavity was smoking and the welds are just shallow splats. All on voltage 1/10.... The below pics were all after switching to hobbyweld 5.

Loads of "Pidgeon Poop" (what I think you lot call it) when trying to fill small voids in my stitch welds, I think I'd upped the feed rate at this point. Clearly not getting enough heat in and just mounding it up, ready for grinding off again... This stuff is all getting cut out as I found a ton more rust and need a full replacement outrigger, so we'll just count that as "practice".

Note - this was flap disked to bare steel, then zinc primered (weld through apparently) I scraped back some of the primer in the weld zone to help the process, but maybe I should have fully buffed it back off?

I guess what I would like to know is:

- Has anyone seen weird flare ups like this before? When it happens, there seems to be a TONNE of heat generated in a tiny amount of time - smoke coming out from the hollow section like I've run a seam weld too long, little droplets of molten metal flying all over the place, all within 0.5s of pulling the trigger. I've tried persisting to see if it settles and it just seems to create a mini flame thrower...

- Could this be an issue with the machine? Or is it all technique, prep and settings?

- What can I try?

I'll go and grab a photo of the better welds on the thicker steel.

 

[MoreWellie]

Setup: 0.8mm wire, 0.8mm tips, 12-14L/m gas, hobbyweld 5%. Voltage about 1/10 and speed 2.8-3 / 10.

from my experience weld thru primer makes things more difficult rather than easier so I would not put this on at this stage
I would reduce your gas flow to about 5-6l and try running spots (stitching) along clean metal not on an edge
power comes from wire speed so I would try different settings between say 5 and 7, personal experience says that gives me a decent result
you could try upping the voltage to 2/10 as spots are naturally colder
start with about 2 seconds on, 2 seconds off, vary the time between the spots (to work out what is best) and make them partially overlap
see what happens with that

 

[Misterg]

The mig wire turns into flying little blobs of molten steel and plugs the tip.

Are you trying to weld outdoors?

That sounds like what happens when a draught blows the gas coverage away. You could try increasing the gas flow.

 

[Fultonius]

Are you trying to weld outdoors?

That sounds like what happens when a draught blows the gas coverage away. You could try increasing the gas flow.

Yeah, but on a totally windless day. I'm going to spend some time in the garage tomorrow just welding lines on new steel and see if I can get some consistency.

 

[roofman]

VW used a galvanised treatment on its body panels...very hard to remove it with grinding, this could be causing the flare ups you describe..plus are you sure your wire feed is consistent? check the feed rollers are nice and snug on the wire.

 

[Fultonius]

VW used a galvanised treatment on its body panels...very hard to remove it with grinding, this could be causing the flare ups you describe..plus are you sure your wire feed is consistent? check the feed rollers are nice and snug on the wire.

Good point, I'll keep that in mind. It was also happening on the 1mm ungalv mild steel sheet though, so I'm not sur it's only that.

 

[roofman]

Also are the leads set up for gasless? these multifunction machines need the polarity to be right, the torch needs to be negative when welding gasless

 

[Fultonius]

Also are the leads set up for gasless? these multifunction machines need the polarity to be right, the torch needs to be negative when welding gasless

It's set up for gas (torch busbar link to +ve, earth lead in -ve).

 

[arther dailey]

I think @8ob has one of these , he might be able to tell you what he sets his at for given thickness if he has time , as busy man

 

[Fultonius]

I've been doing some more testing this morning, I might go back and see if I can set up a camera to film the workpiece and the display at the same time.

I got my OH to film the displays on the welder to see what it thinks is going on. First time round it kind of ran ok and didn't melt the **** out of everything. Peak voltage was about 40V and current was jumping around between 20A and 50A, but kind of averaging around 30A. Clip

Short Clip on Youtube137A, 60.2V

I checked the voltage at the breaker in the garage and it dropped to 218V from 230V when welding (it's got a run of 1.5mm^2 for 30m to the house breaker - planning to upgrade soon!), but I have another 20m+ of 4mm^2 extension from the wall mounted 32A socket to the welder (I didn't fancy cutting my reel of SWA just now as I was going to order a nicer 10m piece of rubber 4mm2 cable instead). I'm guessing that means the voltage will be another 4v lower, so 214v at the welder - just out of spec....

 

[8ob]

I've been doing some more testing this morning, I might go back and see if I can set up a camera to film what's going on.

I got my OH to film the displays on the welder to see what it thinks is going on. First time round it kind of ran ok and didn't melt the **** out of everything. Peak volktage was about 40V and current was jumping around between 20A and 50A, but kind of averaging around 30A. Clip

Short Clip on Youtube137A, 60.2V

from the review I did a few years ago, both on .6mm wire

Rusty 1mm sheet to the edge of some 3mm angle

And a bit of thinwall box on some 3mm angle. none of it cleaned up.

 

[Fultonius]

Thanks Bob, it was your review that had me convinced it would be suitable. I had ordered an Uptime but, they didn't have stock until May.

 

[eddie49]

Some random comments:

- since the machine is new, have you tried contacting Rally Design for advice?
- if there is a fault in the machine, it could be an intermittent failure in the voltage or current feedback circuit, which is supposed to stabilise the output of the inverter.
- are you able to borrow a Eurotorch in order to test with a different one?
- for a flow of 12 to 14 l/min of argon mix gas, there sure is a lot of brown staining ( = loss of gas coverage ). Maybe your torch angle is wrong, or too far away?
- are you certain that your new 1mm sheet metal is plain uncoated mild steel, not Zintec, not galvanised?
- as well as checking the tension on the pressure roller, have you looked at the spindle brake for the wire spool?
- when you "checked the earth point in the welder", does that mean you removed the casing? You could retighten all the bolted connections on the busbars, heavy cables, thick PCB tracks, Eurotorch brass block, and back of the Dinse sockets. Also check correct seating of the multi-wire cable harness plugs. You may find a thick wire going through the centre of a plastic spool ( like a Polo mint ) - that's the current feedback transformer.
- get some 1.6mm Arc electrodes and test the welder in MMA ( Arc ) mode at 35 Amps.
- regarding your garage mains power supply, most of the power used in the instant the arc starts comes from the 500 - 2,000 microFarad's worth of capacitors on the DC bus in the inverter power source.

Many of the pictures and sounds indicate poor technique, but some imply a faulty machine. I would suggest stopping work on the van itself and concentrating on just laying straight beads on thin sheet on the workbench. Then try lap welds, and cutting slots in the sheet with a Junior hacksaw or thin cutting disc and welding them back up.

 

[moleb]

I have the same welder and I use it with .6 wire on anything less than 1mm. For .8mm sheet, I set mine to around 2 on the wire speed and 3 on the volts. It does suffer from inconsistent initial strikes when stitching though but that's not a problem on 1mm and above.
Is your gas flow OK? Check it at the torch with a pea shooter as some of your welds above look a little 'gasless'. Also, check the basics like wire feed tension and new tip etc. Check Urchfab and Weldingtipsandtricks, both have MIG basics vids which are helpful reminders.

 

[Fultonius]

Really appreciate all the feedback guys.

Eddie - I'm planning to go back to RallyDesign, but I wanted to elminate as many possible human errors as possible before jumping to "stupid machine". I've seen way too many cases (both me and others) blaming tools, machines etc. before figuring out what the issue is. Stupid human before stupid machine.


First I'll run through these questions, then add some more info form today's testing:

Some random comments:

- since the machine is new, have you tried contacting Rally Design for advice?
- if there is a fault in the machine, it could be an intermittent failure in the voltage or current feedback circuit, which is supposed to stabilise the output of the inverter.

I do feel there's possibly something odd going on with getting stabilisation. It's very intermittent with no change to settings, material or technique - see more later.

- are you able to borrow a Eurotorch in order to test with a different one?
- for a flow of 12 to 14 l/min of argon mix gas, there sure is a lot of brown staining ( = loss of gas coverage ). Maybe your torch angle is wrong, or too far away?

I was wondering if I've been starting with too little gap between the mig wire and workpiece, hence arc starting before it's had a chance to set up decent shielding? I noticed today that if I started with a short wire, torch further away and then moved in momentarily after pulling the trigger, it set up the arc more quickly and consistently.

- are you certain that your new 1mm sheet metal is plain uncoated mild steel, not Zintec, not galvanised?

Yep, as it's starting to rust a bit due to damp air....

- as well as checking the tension on the pressure roller, have you looked at the spindle brake for the wire spool?

Yeah. I'm not 100% sure as I'm inexperienced, but it seems to be adding a bit of drag but not much. Wire feed generally seems very stable.

- when you "checked the earth point in the welder", does that mean you removed the casing? You could retighten all the bolted connections on the busbars, heavy cables, thick PCB tracks, Eurotorch brass block, and back of the Dinse sockets. Also check correct seating of the multi-wire cable harness plugs. You may find a thick wire going through the centre of a plastic spool ( like a Polo mint ) - that's the current feedback transformer.

Ah, no, haven't had the full case off, just the bits accessible from behind the wire feed.

- get some 1.6mm Arc electrodes and test the welder in MMA ( Arc ) mode at 35 Amps.
- regarding your garage mains power supply, most of the power used in the instant the arc starts comes from the 500 - 2,000 microFarad's worth of capacitors on the DC bus in the inverter power source.

Interesting, makes sense.

Many of the pictures and sounds indicate poor technique, but some imply a faulty machine. I would suggest stopping work on the van itself and concentrating on just laying straight beads on thin sheet on the workbench. Then try lap welds, and cutting slots in the sheet with a Junior hacksaw or thin cutting disc and welding them back up.

Here's what I found later today.

I decided to see if I could just get it working reliably on thick steel so ground back some old bits of the van and got laying. Ended up with the Mig V on 4 and Speed on 5 and could get a reliable arc start and nice steady continuous runs of bead.

Looking much better.

I then transferred over to the 1mm plate. Managed to do loads of wee spot welds that had good penetration, started and stopped well - basically running like I expect it to:

I thought I'd taken a photo of the reverse, but lets just say there was full penetration.

I then did some slotted lines using a thin angle grinder blade (1.5mm or so?)

Pre-grinding, bit of brushing:

Quite a wide gap, so had to start on one side and move across. Should probably start with thinner gaps as per Eddie's recc.

Reverse:

 

[Fultonius]

pt 2:

Front side after grinding (note, I know I was impatient and put too much heat into it, but managed only to blow one or twin wee holes):

Corner fillet weld:

For all of the above my settings were:

Gas: 12L/m
Mig-V: 4
Wire Speed: 5

Technique-wise, it seems like I can reduce the chance (but not eliminate) of flare ups if I (as mentioned above) start with the torch about 1" away, with the mig wire cut short, then pull trigger and ease in to the workpiece. Some times it just does spots absolutely no bother and other times it flares but I'm now able to catch it before it melts right back to the tip.

I can't quite fathom how it's working better on a much higher setting...

I'll keep playing with practice metal for a while. I need to order a new outrigger for the van anyway, so there's going to be a bit of delay. Could really do with a metal top for my bench too. Carpenter's bench ain't ideal!

As I said, really appreciate all the feedback and don't want this to sound like Blackline bashing! Most likely it's not the culprit...

 

[Misterg]

start with the torch about 1" away

That sounds like a hell of a long way away! I'd normally clip the wire to about 10mm and start with it barely clear of the work.

Did you try increasing your gas flow? To me, your beads in the first picture look like they need more gas coverage. How are you measuring gas flow? (In pre-internet days, I used to release the wire feed roller, pull the trigger & adjust the gas until I could feel a very gentle breeze on my cheek with the torch held about an inch from my face.) Might be worth getting a peashooter gauge if you haven't got one.

Sorry to say it, but, to me, the welds on the slots indicate a pidgeon with a severe digestive disorder (technique rather than tools). If you can practice and build on the beads in the first picture, I think your results will improve a lot.

Only a hobby welder, so take it FWIW!

 

[Fultonius]

Re: Gas flow - I'm just going off the hobbyweld (Startech?) regulator gauge. I'll see about picking up a pea-shooter style.

 

[Bravheart]

FWIW have the same box but don’t make a living from it so just my thoughts.
Gas, forget the peashooter for now just make sure the bottles open and the gauge has plenty flow. Mine had a leak so changed the connectors on the box.
Its a 4m welding cable so make sure it’s as straight as possible and not kinked or damaged. Check the spool brake and wire tensioner as above but also check you’ve got the right drive wheel and its clean and not damaged, some wheels have the opposite groove and some the adjacent groove stamped on the side just double check your using the right one. Also that the wire is feeding off the spool straight and not upside down.
I would get some new clean 0.6 wire to try and keep the wire speed down it may be too high for thin stuff, have you seen the advice top left of screen.

MIG Settings Calculator

Estimates the range of mild steel thicknesses you can weld with each setting on your MIG welder.

www.mig-welding.co.uk

edit. Finally get an experienced welder to try it or another hand lance or take your scrap bits and try on another welder to rule out box problems.