Builds 1st FJ40, '76 - SMOKEY - Puttin’ her Back Together (4 Viewers)

[Weber Sarge]

Ok , that may be the whole problem , you're too focused on staying inside the puddle . Jody and others will point out to trace the very leading edge of the puddle instead -this is where you get penetration vs building on top of a cold weld . Without being there , it's too hard to tell if your travel speed is too fast or too slow - it could be either and almost betting now it's too slow . The sound is important - it should be a smooth and light frying sound with no sputtering .

Leave the cursive e's out for now , just use a straight drag motion . It would probably be a good idea to use some different metal - that may be high tensile steel you're using currently since it was from any type of blade setup . I'd imagine the steel you sourced for the project is just standard A36 carbon steel - need to practice on similar material .

Try increasing the wire speed a bit and stay focused on the leading edge instead of the center of the puddle - otherwise the puddle builds up ahead of the arc and you cannot penetrate deeply enough without using excessive heat input . Watch the gun angle closely - it's more important than one might think - almost as much as stick welding . Guys like Jody know how to cheat the gun angle a bit for video work - you need a higher angle to get the benefit of arc force for penetration . I'd love to hear more about how he's filming his videos - appears to have a very small high-res camera unit with an added arc shield of some sort , whatever it is they are some of the industry's best arc shots I've seen and especially on stick work .The guy is not only an artist , but knows very well how to explain things so folks can learn .

Sarge

 

[Vae Victus]

Makes sense. Well some of it.

When doing a straight drag or push on a lap joint, where do you focus the wire to ensure enough bite into the top, but penetrate the bottom piece?

I get when doing an "e" you would stitch in the top but focus more on the bottom, but a straight drag makes less sense.

I also understand now to trace the outside leading edge of the weld puddle - I was not grabbing enough new metal before.

Getting some good scrap today to practice on.

 

[Vae Victus]

Bucket-o-practice. A gentleman I've come to know who owns a welding company let me pick thru his scrap pile today. Now I have 30 lbs of practice material. He just gave it to me. Nice people are all around - you just have to look.

Also picked up some 0.035 rollers and wire. This may be part of the issue as well. Can raise the volts and slow the wire down a bit.

 

[Weber Sarge]

Bigger wire size will help a lot . On lap joints (not my preferred place to start practicing) you keep the main bead on the bottom plate and melt the top plate into the puddle . It's just a flick every other second or so . Also , gun angle really comes into play here as you want to angle the nozzle into the joint . You need to be practicing on flat butt joints first , lap joints are rarely ever used for anything . It's mostly tee and butt joints so work on the butts first . Once you get some base practice I'd suggest moving right into vertical up butt welds - it's solid practice for learning control on bead width and controlling the crown buildup . This becomes most important doing vertical tee joints . .
Sarge

 

[Weber Sarge]

BTW - nice bucket o'scrap .
Forgot to ask - have you checked the condition of your ground ??
Just to clarify - straight drag method will work in almost any situation - it's a matter of machine settings and travel speed . Puddle width is controlled with travel speed and bead height is basically determined by wire feed rate . I still prefer stick or tig for these reasons , I can fully control the puddle without filler rod if I like and depending upon filler size it determines how much I can or want to crown the bead or not crown it if wanted - just depends on what I'm doing . On lap joints , you'd really want a nice balance of travel speed vs wire feed rate to prevent undercutting the top piece . On tee joints , same thing for the most part to avoid undercutting the vertical piece . On vertical up it's a very tight balance to avoid having the weld "droop" or gob below the puddle . I can get some examples if you like ....but no mig here , lol .

Sarge

 

[Vae Victus]

So, first, the ground is one of the heave old style copper-alloy clamps with a strong spring. Plus I was grounded directly to the work piece in the newest samples (pictured below). I have not yet used the braided copper wire trick that Jody showed. I also have a mag mount ground clamp that I need to get a lug for so I can hook it up.

Next, I did the cut and polish method to inspect what I figured was a good weld. This was on the lap weld on 2 pieces of "good" steel, 3/16". The welder was 0.035 27+ volts, and about 320-340 ipm.

Here is the weld:

and here is the result of the lap weld cut. A cold weld:

So you are right - that weld is sitting right on top of the bottom layer. I couldn't believe it! As deeply as the vertical piece was melted away, the bottom piece was intact, plus there was porosity in the weld at the root. Wow.

I didn't photograph the butt weld, but needless to say, the weld did not penetrate even though was a 1/32 or so gap in it prior to welding due to a little roughness on one of the edges. It completely sat on top. I was able to break the butt weld with a 5# BFH (though it took a while and some hard hits). Not sure if a butt weld is supposed to bend 3/16 before it breaks, or not.

I need to go back, and crank up the heat, check the ground, and slow down the wire speed I guess. I was noticing the gun angle, and I was holding it at a little MORE than 45* when I did these welds, maybe closer to 55* - as the nozzle was covering up the puddle.

I was probably holding the gun a few degrees off of 0 for the wire vs the travel direction. The wire was probably pointing more toward the top plate in the lap weld rather than it pointing right to left down the direction of travel of the weld. This was probably bad too I'm guessing, but there was no one there to say "Don't do that".

Now - suggestions? I believe you now.

 

[Weber Sarge]

Just to be clear - I'm not out to humiliate anyone in any way , instead to teach and keep folks safe . If those welds had been on a structural part they would have failed - badly . What you show above is why I complain about someone going out and buying a cheap welder and try to build structural parts like bumpers , frame work , suspension , tire carriers and tow points or even a rotisserie . At least you are on the right page with a great power unit and wire feeder which is serious overkill for most users .

That said , wire speed needs to come down - yes . I'm starting to wonder how well your amperage output is working vs current voltage . I need to read up on your model (remind me again ? ) and see the current output chart . I'm used to old school transformer units that had an amperage range control and simple wire feed - as I said no mig here and I usually use tig or stick .

The butt weld - how did it look on the back side ? If you're hot enough it should burn clean through the plates , a really good setup and proper technique the welds will look equal on both sides in crown and almost the same in width . Properly welded steel will break near the weld but not the weld itself unless you stress it hard by bending repeatedly back and forth . Need to run a butt weld that is far too hot once so you understand where the limit is on power - make the steel literally fall apart and blow out , then turn it down a bit to achieve a correct bead profile .

On the lap weld , and again they are basically useless since they are not used in common weld joints , you must focus on the bottom plate and just touch into the top plate while focusing the gun angle into the joint . Regardless , when dragging the gun should be kept around 45* to the work and you can go up to 55* or so . More than that , you just build too much puddle and are left with no crown . It does look like you were trying to use a straight drag method and that's good for now . Using a slight weave pattern will help widen the puddle a bit and also can help some with penetration but the wire speed is way too high or your output is very weak from the machine .

Run a couple more short and simple butt welds and work on your settings - might help if I can see the front panel of your machine too . I assume you are running dcep process ? If the welder is set to dcen , that would be the whole issue with heat input ....

Sarge

 

[Vae Victus]

No, no Sarge I know you are not trying to make me look bad. I don't need help with that. Read on:

I just went out and pulled some additional practice pieces out. I actually pulled out the calipers b/c I wasn't sure what was what thickness. Turns out I've been doing all these runs on 1/4", not 3/16". Thus, yes, they are all cold, and hence no penetration. Sorry, rookie mistake.

I ran a couple of welds at 31v with 380-400 ipm on the 1/4" stuff and while there is still some spray transfer going on, it was certainly cutting deeper. I have a couple of 3/16" pieces and several 1/4" pieces to test on.

If I'm getting spray transfer at 31v on 1/4", can I just increase the wire speed, or is wire speed not a factor in when you begin to spray transfer?

I've been pushing the gun from right to left. Just read that perhaps I should pull it from left to right to stab deeper into the puddle. I'll try to remember to hold the gun closer to vertical (5-10* to the right) to push deeper. I'll also try to slow down and let more time for the wire to penetrate.

Here's the welder. Miller XMT 304 cc/cv, and a Miller S-22A wire feeder.

 

[Weber Sarge]

You may have to increase the wire speed some to balance out the heat input . Need to see some butt welds and I suggest beveling the plates a bit . Need pics of both sides, want to see how much heat input you're getting and width on the other side . Keep watching Jody and learn about gun angles paying most attention to nozzle distance and angle of attack . Pull or push depends on you, arguments as to which is better are as old as the process itself .

Have you verified you're running dcep ? Is the machine set to straight polarity or reverse ?
Sarge

 

[Vae Victus]

Ran some additional butt welds yesterday. Had another 3" of snow, so had some time off yesterday.

Yes, DCEP is confirmed. Ground is to (-) and weld gun lead is to (+).

Did some welds on 3/16" steel with 0.035 wire (I measured this time to be sure ). Ran the voltage up to as high as 32-33v, between 280-320 ipm. Ran it down to 23-25v as well.

Results (hi res, click to see larger). Top one is coldest (23v) others were 30-35v.

Ignore the bottom welds. The top 4-5 are the main tests.

I'm concerned that I'm not burning thru to the bottom, even with a slight bevel. I'm dragging L to R, holding the torch at about 10* off vertical.

I did a cut and polish but haven't finished polishing enough to see the welds.

 

[Weber Sarge]

Something is really wrong here - you're not getting hardly any penetration at that voltage and wire speed . Try turning down the wire , increase gun angle a little bit lower and stay ahead of the main bead a lot more - need to be on the leading edge of that puddle , not in the middle . I'm wondering if your power unit is getting full amperage or has a bad leg on one side of the input that is restricting it's output . Like I said , not totally used to using voltage vs amps for an output setting - need to see if Miller has a conversion chart .

I assume you are using 220v , pretty much have to with the XMT anyway . I know you had to repair a board , was it anything associated with the power section ? At 35v , it should blow large holes through 3/16" steel nearly regardless of wire speed - should be running extremely hot but it isn't . The only other thing I can think of is it's running in Constant Current mode versus Constant Voltage mode - which is what is needed for mig work .

Maybe I'll track down the user manual for the XMT - need to do some reading as I'm way more used to stick and tig work .
Sarge

 

[Weber Sarge]

Just read through the manual for the XMT's , seems it has to be set for remote feeder and automatically runs in CV mode so that should be covered .
What gauge is the ground cable ? Checked for corrosion or burning at the welder plugs/cables ? Trying to figure out why you are losing raw power output - the XMT should be able to fry that steel and it isn't . I hope the short circuit issue it incurred didn't wipe out part of the power board on the step-up side as that can happen and it's the most expensive part of an inverter machine .

Just for fun , got a stick cable and stinger around ? I'd be curious to see if she can still stick weld or not properly ....?

Sarge

 

[Vae Victus]

I think I have a couple of sticks around. I'll try that.

It is putting out enough power to vaporize the wire. I'll run it up to 35v and see what I can do on some 1/8". I'm sure it'll blow thru it. Should I speed up or slow down the wire speed to test this?

I've not really slowed down enough to see if it burns thru.

It's in CV mode? Hmmmm. So when I adjust the voltage, it stays constant and the amperage adjusts based on what? Always wondered how that works.

 

[Weber Sarge]

Something is wrong or wired incorrectly - the welding calculator is calling for around 21-24 volts with 75/25 gas mix and 360-380ipm on .035" wire for 3/16" steel . Amperage range is 180-190 also . At that power , it should easily weld all the way through 3/16" steel and it's not even close .
Either you're moving way too slow or something is wrong with the machine , I'd suggest having a second pair of experienced eyes on it if you can ....mostly checking machine settings .

Miller's welding calculator online -
http://www.millerwelds.com/resources/calculators/mig_solid_amperage_calculator.php

Sarge

 

[Vae Victus]

After consulting with some other folks on WelderWeb.com, and watching several more how to vids, I finally figured out it's my technique not the welder.

I said to hell with it and started in the rotisserie. I got the two main stands done tonight with a little grinding left to do.

I cannot weld uphill. Jody on WeldingTipsandTricks.com makes it look so easy. Ha!

But, here are my good welds. The others are so ugly they'd break the camera so they aren't being shown.

 

[Weber Sarge]

Only about 3-4 of what you are showing will hold , maybe . When starting another weld against an existing one , grind a notch to start into so you don't have a cold overlap spot at the intersection . Welding uphill is a skill , just need to practice - a lot . Do not leave huge tacks in place , instead use small tacks and weld right through them and speed up momentarily to keep a correct bead profile and burn it in the right way . The gusset in that inside corner is fairly good , otherwise not too sure I'd trust it to hold weight without failure and hate to harp on this stuff - gotta make it safe !

Turn the wire speed down low enough to stop stacking weld beads on top of the steel , just above a stutter point is what you need . Use that bucket of steel you have and set up some vertical passes and practice , it's not that hard and just takes time . Impatience kills , grasshopper .....wish I were closer .

Sarge

 

[Vae Victus]

I hear ya. I'll keep working. Yes, that was one big tack - good tip regarding the notch, I'll do that in the future. Most of my tacks were smaller, but that one didn't hold and I went back over it instead of grinding and doing again.

It's warmer today, so I can keep working. I'll do a little practice before continuing.

The other thing I saw some videos on and then experienced was warping due to thermal expansion and contraction. The long 72" main tube warped on the first support I did because I did all the welds along the bottom side at the same time. The tube curved about 1" from end to end. On the second side, I waited in between welds, alternated sides, and did some of the upper welds on the 45* supports in between. This helped reduce the warping quite a bit. However the second side did still warp about 1/4". If you notice, there are no welds on the bottom side except one for the short side tube that has the nut welded in - nothing to help counter the heating along the top side.

Can you heat the side opposite your welds with a torch prior to beginning to counter the effect? Perhaps there is a more logical order to do the welds. Can you quench the welds with water?

 

[djcfj40]

Just wanted to chime in and say thanks...
I'm learning a lot. Jody's videos are amazing.
I,ve always been uncomfortable with my welding skills,just dont do enough of it to get good.
Reading your posts have been very helpful.
Is'nt that what this forum is all about. People with the same interests helping each other..
Sarge, you are truly a master of your craft.
Vae, Can't thank you enough for documenting this Great Project !!!

 

[Vae Victus]

I'm very appreciative of the opportunity to do this with all the assistance of this forum. I never feel alone!

Thanks for saying it's helping. Sometimes I feel like this is just a narcissistic rant that is driving folks crazy.

 

[Crescent Wrench]

Awesome work VV, now head down ass up and lay some bead.