[RamboBaby]

My buddy's 800cc atv broke where the engine mounts to the transmission housing. I keep reading to use 4043 which is good because I have plenty of it on hand but I don't wanna screw this up by using the wrong filler. I have plenty of power on tap at 250 amps and in advanced pulse mode it welds with the equivalent of 310 amps. This stuff is about 1/2" thick so I'm gonna give it some preheat.
I do not have any helium. Were also gonna shore this thing up so that it doesnt have to handle all of the stress on the right side of the machine.
I've got my machine dialed in like this: 250 amps, advanced pulse mode @10 pilulses per second, 50% on time, 100 background current (background is DC in advanced pulse mode for deeper penetration), 30hz for more heat, 40% cleaning action. 1/8" thoriated tungsten, #7 cup with gas lense. This setting instantly puddles about 1/8" deep into aluminum that is 1/4" thick. I am accustomed to welding thick to thin. This scenario is very much like welding thick to thin. I don't think I'll need all that heat but I will know for sure by tomorrow afternoon.
Any advice would be greatly appreciated because I have never welded a casting. Filler selection and weld thickness are what I'm most concerned with because I don't want it to break again.
How much gas flow would be appropriate in this situation? It is my understanding that castings fare better with higher gas flow but I do not know how much is necessary. I typically run with 15cfh on a gas lense for most applications.
Also, how much reinforcement should I add to the weld? This is obviously a high stress part.

[dave powelson]

If the DC background can be on, without any pulsing, do so.
You'll need max. heat input. Pulsing reduces heat input.

Can and should preheat with the torch, even if separately warming
part up first-which helps. Play the torch up and down the cracked area
to be tacked...to get it close to 'heat', while blowing off internal
contamination-brush that off, then go back for real tacks. You'll want and need to see
slight casting melt--before even thinking about adding filler.
As the heat builds up in the casting, the wetting/fusion becomes easier.

If casting is wholly filthy internally, 'Massive focused heat succeeds where all other methods-fail.'
Even if the filler has to be jammed in below a puddle with lots of floating trash on the top...
..sorta like bump welding anodized.

Running an upwards of 90% unbalanced to get beaucoup heat....if you need to.
Lower the AC freq. is, the more heat, but the arc is much less stiff and vice versa. (Dynasties can compensate
for that, via wave form, independent EN/EP amplitude...maybe your machine can as well.)

Fit and tack both sides, etc. tight up to the break.
Then sequentially carbide groove out bevels in the crack and weld out.
The tight crack, initial fitting/tacking and the bevels for full or close
to full pen welds that actually back groove into the opposite side welded
out for strength.

If that break out is for a dowel pin, you'll need to study the fit, etc. of that, hopefully before
starting the repair. A temporary thru bolt and nut to clamp tight might help.
Before a wrought or cast piece breaks....it bends and distorts....fitting the stretched crack areas
together, doesn't necessarily make a part that 'fits'. Due to this, sometimes part or a lot of the cracked
area is ground/carbide burred away--to get correct broken part placement, relative to the bolting/dowel
pin functions.

[RamboBaby]

It fits pretty good because it was bolted to a backing plate. Three bolts sheared and the one that was left broke the casting instead of shearing. This particular bolt is actually the exact same stud that holds the wheels onto the hub.
It has to be pulse for me to get the deepest penetration. The high side is alternating current while the low side is DC. The DC side is what allows it to penetrate deeper. I have the machine set for 50% on time (AC) at 250 amps and 100% background current (DC). If I nail the peddle with it set up like this the arc is extremely violent and will blow out a small piece of 1/4" aluminum. I have to roll the power on because of that. I can set it as low as 20 hertz. This is the first time that I have tried to crank out maximum power from this machine and it's hard to believe that this little thing has this much force behind it. I can burn completely through a piece of 1/4" aluminum in about ten seconds.
Were going to put the bolts back in and secure it to the mounting plate before tacking so that it doesn't distort.
Thanks for your reply.

[sedanman]

I think you're a little confused on the science involved. If you are welding on ac, then it's all always ac. The high side of the wave is electrode positive and the low side is electrode negative. The switching is what defines it as alternating current. Pulse would decrease overall heat as this is basically turning the current on and off. On the other hand, lowering the frequency can help with adding heat.

[Poland308]

Some machines I believe are capable of bouncing back and forth between ac welding and DC welding.

[Kevin_Holbrook]

i think you will be better off building the entire corner back up with weld

[MosquitoMoto]

i think you will be better off building the entire corner back up with weld

+1.

I reckon I'd be building up a new corner with weld.

I've had good results with both 5356 and 5183 on cast. I understand that 5183 is meant to be the 'go to' rod for cast, but I am no expert.



Kym

[RamboBaby]

I think you're a little confused on the science involved. If you are welding on ac, then it's all always ac. The high side of the wave is electrode positive and the low side is electrode negative. The switching is what defines it as alternating current. Pulse would decrease overall heat as this is basically turning the current on and off. On the other hand, lowering the frequency can help with adding heat.

No I am not confused about it. It's the high side of the pulse that's AC. Backend of the pulse is DC negative. You can read about it here:
http://www.everlastgenerators.com/blog/ ... e-part-2-2
Building it up would be Ideal but the stud is a wheel stud and is countersinked because there is no room on the side that the engine sits on. It is a round head that locks into the pocket with spline teeth. If I just built it up then it would have to be machined and I don't have that capability. I'll mention it to him but I'm just trying to give the guy what he is asking for. It looks to me like it broke because someone rolled it backwards.

[dirtmidget33]

I weld on a lot of Polaris engine blocks, transmissions and rear ends. For filler I use the 4043 and 4943 these work great on the Polaris stuff. I have been phasing out my 4043 and using more of the 4943. I especially been using 4943 for mounts or areas that need a lot of build up do to 4943 not needing dilution of base metal for strength like the 4043 needs. The AGL can be a pain to clean out of transmissions but acetone does remove it. Here is some links to a repair I put up on forum on a Polaris block repair. I don't use pulse or helium sometimes preheat it depends on part. In the links I give cleaning description I use and what porosity sort of looks like when junk bubbles out of the castings on these.


http://forum.weldingtipsandtricks.com/v ... 799#p66799


http://forum.weldingtipsandtricks.com/v ... 818#p66818


http://forum.weldingtipsandtricks.com/v ... 827#p66827

Good luck. I haven't been on forum in awile

P.s. I would just build up the corner with weld material using 4943 preferably then drill holes after machining it flat. To do the stud you can press the stud in the aluminum on a press or draw it in with a nut to cut splines with the stud. Just have to have the hole the correct size for splines so you dont have a lot of matierial to go threw and use lube so it will press in easy. In can be done just take your time if need be knock it out after it goes in some clean debris out re lube and try again.

[sedanman]

Then l must have been lied to all of these years. I was told that when electricity swapped polarity that was the definition of alternating current.

[exnailpounder]

i think you will be better off building the entire corner back up with weld

Agree 100%...unless you can get full penetration on the break of that tab, it will only break again. Build up a new one.

[RamboBaby]

i think you will be better off building the entire corner back up with weld

Agree 100%...unless you can get full penetration on the break of that tab, it will only break again. Build up a new one.

OK, the "Aye's" have it for corner buildup.....I'll let him know and also let him read this thread for verification. The hole on the transmission mounting ear has to line up with the engine mounting plate and it has to be countersinked with an end mill because the stud head needs to be flush with the ear on the transmission as well. I'm not competent in that regard so I guess he's gonna have to visit a machine shop.

I especially been using 4943 for mounts or areas that need a lot of build up do to 4943 not needing dilution of base metal for strength like the 4043 needs.

That was my main concern. 4943 it is.....thank you!

Then l must have been lied to all of these years. I was told that when electricity swapped polarity that was the definition of alternating current.

Well, if you read the link that I posted for you previously then you will not be confused any longer.

[sedanman]

No thanks Mr Jones, l don't like KoolAid.

[RamboBaby]

No thanks Mr Jones, l don't like KoolAid.

Why don't you just stay out of this thread. You're not wanted here.

[sedanman]

You don't want me here, I'm heartbroken. But im staying so deal with it.

[Kevin_Holbrook]

You don't want me here, I'm heartbroken. But im staying so deal with it.

21. TIG Pulse Mode Selector
Pulse OFF
Standard Pulse
Advanced AC Pulse
The unit features two pulse modes. The standard mode is available in AC and DC modes. The
Advanced AC mode, works only in AC. Pulse is used to control heat input on metals by puls-
ing amperage between a high (Peak) and low (Base or background) amp value. The high amp
stage is represented as Welding Amps. The low amp stage is represented as Pulse Amps. The
Advanced AC pulse pulses between AC and DC
–
polarity to control heat input on thin alumi-
num. In advanced mode, AC is assigned the welding amps stage of the pulse, and DC
–
is
assigned the pulse amps stage of the pulse. Both the standard and Advanced pulse modes
have the same features of pulse time on, pulse frequency and pulse amps. Other than chang-
ing the polarity in Advanced AC pulse mode, the two pulses are similar in adjustment.



i don't know what this looks like on a scope ,but i think this is what he's talking about ( disable hf before connecting any type of scope , meter ect )

[sedanman]

If you have a balanced square wave ac arc, 50% of the time you have electrode positive and 50% of the time you have electrode negative. If you only looked at one tiy bit of the wave form you could say you had dc electrode positive or dc electrode negative. You could also say that any square wave switched between ac and dc depending on how much of the wave you were looki g at. If the polarity changes between positive and negative it is by definition alternating current. Let's agree that a full wave starts and ends at zero volts and has both a positive and negative peak.

[RamboBaby]

If you have a balanced square wave ac arc, 50% of the time you have electrode positive and 50% of the time you have electrode negative. If you only looked at one tiy bit of the wave form you could say you had dc electrode positive or dc electrode negative. You could also say that any square wave switched between ac and dc depending on how much of the wave you were looki g at. If the polarity changes between positive and negative it is by definition alternating current. Let's agree that a full wave starts and ends at zero volts and has both a positive and negative peak.

You can send the boy to school and give him some books but you can't make him learn to read. Just because you are ignorant and don't want to read the link doesn't mean that you need to be coddled. It does, however, mean that you are making yourself look even more stupid every time you submit another post to this thread.
Inverter welders also do not have a zero point in advanced square mode. That's why they weld so much hotter than square wave transformers when using the same amperage.

[sedanman]

Listen, l am not calling you names. Alternating current has a zero point. You CANNOT have ac with passig through zero. It does jot matter what produced the ac wave. Without zero it isn't ac. Everlast is not the end all be all authority on alternating current. They most likely describe it the way they do to make it easier for YOU to grasp what's going on. I'm ok. And I'm not going away

[Oscar]

Listen, l am not calling you names. Alternating current has a zero point. You CANNOT have ac with passig through zero. It does jot matter what produced the ac wave. Without zero it isn't ac. Everlast is not the end all be all authority on alternating current. They most likely describe it the way they do to make it easier for YOU to grasp what's going on. I'm ok. And I'm not going away

Sorry, but with all due respect, he is right and you're the one that is actually confused---not about what you know, but about this specific machine. You're confused as to what that machine can actually produce. You are right in your description of an AC waveform, but that is not what he is talking about. His machine can actually pulse/switch/whatever you want to call it between an AC waveform, and then to DCEN, and then back to AC, all on it's own by way of operator settings. It is actually part of the machine's abilities. Note that we're not dissecting an individual AC wave into it's EN/EP constituents, either. The name given to this ability by the mfg is called "Advanced AC Pulse". One moment in time [defined by a specific machine setting], there is an AC arc between the tungsten and the workpiece, then another moment in time [also defined by a specific machine setting] it has instantly switched over to DCEN between the tungsten and workpiece at a lower amperage level for a set amount of time, then back to AC at the higher amperage level, ad infinitum. That is the pulsing action that he is describing. It's not that you were lied to before, it's just that before this ability likely didn't even exist in consumer-level machines.

[sedanman]

Oscar, If the ac wave retuns to zero and then there are complete dc negative pulses that also return to zero then l concede that this machine does switch between ac and dc. If it does not return to zero then it's still a wildly manipulated ac wave. The op maitains that inverters don't have zero. I really need to see a plot of this. All will note that l stated l THOUGHT the op was confused, l did not resort to name calling.

[Oscar]

Oscar, If the ac wave retuns to zero and then there are complete dc negative pulses that also return to zero then l concede that this machine does switch between ac and dc. If it does not return to zero then it's still a wildly manipulated ac wave. The op maitains that inverters don't have zero. I really need to see a plot of this. All will note that l stated l THOUGHT the op was confused, l did not resort to name calling.

The whole zero-point crossing is irrelevant. A modern inverter-based welding machine has IGBTs switching at up to 20 kHz+ frequencies (source: Lincoln Electric Co.). It has enough switching-speed that it can stop an AC waveform dead in it's tracks at any point during the wave-cycle and instantaneously [for all practical purposes] spit out a flat DC output, negative or positive. it does not have to stop, kill the AC wave, reset to 0V, then say, "Ok, now for this DC output...". It happens blindingly fast, that for a human brain,these kind of logic-controls are instantaneous taking no time at all. You have to think about these kinds of things at micro-processor-like speeds; for an inverter switching at 20 kHz+, "watching" an AC welding arc switch back-and-forth at even a "high" AC welding frequency of 200Hz, likely takes an eternity because the monitor/controller is "thinking" so much faster than the action it is monitoring/controlling.

The absolute simplest way to put it, IMO, is like this:

1. Imagine you are welding on a 200A AC arc (freq can be anything you desire).
2. The [hypothetical] welding machine you are using has a simple push-button to switch back to DCEN.
3. This [hypothetical] welding machine does not care if you press the AC/DC button right as you are carrying on with your AC welding arc. It will do as it is "told", and as quickly as it is told to do so.
4. While you are welding in AC, your "friend" goes over to the machine, presses the AC/DC button (thus reverting it to DCEN), and immediately rotates the amperage control knob so it reads 100A.
5. Now, you (without doing anything yourself), have a DCEN arc at your TIG torch.
6. couple seconds later, your friend presses the AC/DC button to revert it back to AC, and immediately cranks up the knob to 200A.
7. Keeps doing this over and over again, at regular intervals, for as long as you are welding.

What you see from your perspective at the tig torch, is (naturally) you see an AC arc, then a DCEN arc at a lower amperage, then back to AC at your original amperage, ad infinitum. This is exactly what the microprocessor is doing with the user-defined parameters for Advanced AC Pulse in the welding machine in question. This is exactly what is in the link that Rambobaby posted.

But for the sake of knowledge, Rambobaby is ALSO confused. WIth his settings of 250AC/100DCEN, it is not providing more penetration than the AC wave alone as he thinks, because for the increased penetration to take place, the DCEN values have to be set HIGH (not low) compared to the AC wave. If he would also re-read the link he provided, he would see this as well.

So everyone's confused!


Not the best video in the world, but you can actually hear the machine constantly switch between AC and DCEN. The AC arc has a "buzz", while the DCEN is quiet as usual. Fast-forward to 1:35
xndfIdvtpdo

[RamboBaby]

Did I post 100amps background current? My bad if I did! It's set to 100% background current. In this case the DCEN is much hotter than the ac which is set to 60%EN/40%EP. I gotta have cleaning action on this casting and even with 40% cleaning it's actually only cleaning 20% of the time due to 50% on time. In my case the AC side of the pulse is actually the cold side although I don't believe that the surface of the sun is much hotter than that "cold" side.

[Oscar]

100% background current does make much more sense to get the deeper penetration aspect of it.

[sedanman]

Oscar, thank you for taking the time to explain this properly. I am learning something from this and it appears l was wrong.