Experience with Inductance control, AL/Stainless on MM251 or MM350P? W/Out Spool-Gun?

[Teeps]

Question is two fold, on experiences and opinions.

1.) have you welded aluminum well, without using a spoolgun on either the mm251 or mm350p? Any major draw backs to this? Costs compared to Spoolgun?

2.) Value of inductance or pulsing capability on Mig GMAW, with Welding on different metals, espec. 6061, and 308L, chromemoly(probably has to be tig'ed)?

Before the end of the year, I'm determined to make an investment in a 220 volt welder.
Unfortunately in the long run, I will need both a Mig and a Tig.

I will probably get a loan for $2k, and spend 1000-1500 up front $$$$. So 3000 +/- is my budget, (have to spend quite a bit on electrical service upgrades as well, which is leaving things really tight for me.

However, I think a good mig welder might be able to keep me going on projects for quite some time while I save for an Ac/dc tig machine.

I consider the mm251 to be my minimum amperage requirement for thicker stainless, especially spray transfer.

Since I won't have a Tig machine for a while longer. I'm wondering if the MM350P might be a better choice.

My questions is on the value of the inductance control, and the pulse ability.

Does pulse help on aluminum or stainless?

I've read in the Mig book, and seen on the door charts that different inductance is more beneficial for stainless steel. And different inductance ranges are shown for steel, and aluminum as well.

My goal of course is proper welds, also with good appearance (which will no doubt require much development on the operator side as well ) and schooling is in the plans.

Since I was thinking on spending in the 3000 range.
Linde has a sale on right now on MM251's for 1679.00 (I guess they get an additional 5% margin from Miller right now, until the end of the year)

The MM251, would end up around 2800 with spoolgun + tax out the door, I'm guessing. I'm going to have them get some quotes together for me....

However, if aluminum is doable without the spoolgun (which I guess I could get later, after the welder is paid off). I might be able to squeeze the MM350P into the budget for $3300 - ish.

Now that I think about this, it will be even more than that, since I would need a spare mig gun with liner for aluminum, and maybe different drive rolls?

So now this might be more like $3700.00 - 4000.00 ? Which may still be worth the extra current capacity, for stainless, and the added control over inductance.

Hmm, that has me wondering about cost of the mm251, w/ AL mig gun and liner + a dyn200dx.

$4450.00 ish maybe.... Sigh.

So I guess the only downside to going with the mm251 and dyn200dx, instead of an mm350p, is that I will not be able to weld anything over .2" thickness while still having control over inductance, or having a pulse option. I think I will be ok with this. I think 98% of the exotic metals I may have to weld will be 1/4" or thinner, mostly tubing. I may end up with projects on Aluminum, and Stainless that will be thicker, (AL cyl head repair, etc), hopefully inducance control wouldn't be absolutely necessary for thos instances.

Well thanks for your insight on these questions, anything else I should be considering here?

Thanks in advance,

Don

[wrench3047]

(AL cyl head repair, etc), 

I can't remember if I read on this site or another, but what I read said you need a minium of 250amps. I don't know if the advantanced features of the dynasty are going to do it. Now that I think about it I think the link was on this site somewhere, maybe someone can find it or put input in on the dynasty AL cly head repair idea. Don't have any input about your mig questions except I've used the MM251 at work and I liked it. hehe

[Alex]

Al/Stainless w/wo spoolgun

Don,
I have a MM251 and I weld aluminum with a second gun w/ teflon liner. I know a lot of others use a spoolgun. I just can't get used to them. I feel like I have much better control using the same type gun I use on mild steel. For me, the changeover is quick and easy. Turn off the valve on the C10, swap out the drive rollers and wire, plug in the dedicated aluminum gun, run the wire in, and turn on the valve on the Ar. Takes about 5-6 minutes. I am not in the habit of swapping back and forth more than once a day, so its no big deal. Pulsing is great for really thin stuff but not absolutely necessary. If I welded anything thicker than 0.375, I'd be real tempted to go for the MM350P. Also, with the MM350P you can plug in a Python push/pull gun without having to add the push/pull module, its all internal.

[Teeps]

Thanks for the advice guys,

Yeah, I'm waiting for a quote from the Linde guy, we'll see what he says.

Alex,

I'm doubting I'd regret owning the mm350p, but having to wait to pay it off until I can get a dynasty might hinder me a bit.

What is the advantage of a push pull over all else? Ability to do aluminum with better control of the wire, with less feed problems? More accurate wire feed speed/control of weld current?

[wrench3047]

the push/pull allows you to have a longer torch without having to keep it completely straight to avoid feeding problems. So yes help with AL feeding problems.

[Danny]

Teeps,

For cylinder head repair TIG is the way to go. One characteristic of the wire feed process is that it tends to have cold starts. So, at the start of a weld, there can potentially be a lack of fusion or at best very shallow fusion between the basemetal and the weld metal. More then likely though a lack of fusion at the start is going to your most common occurence. TIG on the other hand starts out by creating a molten puddle first then adding filler to it. So if done properly, a TIG weld bead should have complete fusion with the basemetal along its entire length.

As far as, GMAW of stainless steel goes, since SS dissipates heat so slowly, it actually requires less current then mild steel for the same material thickness.

I think you are over rating the need for inductance control. It of course has some benefit, however, in my experience machines like the MM 210 or MM 251 perform very well as designed on steel, SS, or aluminum. I would personally much rather have a standard 250+ amp GMAW unit and a good quality AC/DC GTAW unit, then just a 300+ amp GMAW unit that offers you pulse and an inductance control.

I work in the food processing industry, so I weld a fair amount of 304L SS ranging in thickness from 20 ga. - 1/2". Anyway none of the machine that i use to weld SS contain an inductance control, and i am quite capable of producing quality welds using these units. I guess my biggest secret would be the fact that i use a 308L Si filler wire. The high silicon content in this wire makes the weld puddle wetout similar to a steel weld, so you don t have the peaking issue that can be a problem with a 308L filler wire. I 'll attach a few sample SS welds most are just on scrap that i used to dial the machine in on.

[migmaniac70]

****, When i grow up i want to be like Dan! To **** with Mike.

[wrench3047]

TIG is the right way to repair a cly head but because of the thickness you need a good deal of amperage and the dynasty 200 might not be big enough.

[Teeps]

Thanks guys,

and thank you Dan.

I have seen that last "Latch" picture before, very nice welds!!!!
Thanks for the advice on the Silicone wire, I picked up some of this myself to do some exhaust tubing, I'm glad to know it works well for you. (not that I'll be able to pull off quite the same beads you can exhibit... wow!!!)

I was really on the fence on the value of the extra amperage and the inductance control for my application, thanks for your insight on the right way to go. If it's possible to pull off quality welds without the inductance, then I'll probably pass on the mm350p. I can use my little 120v mig when pulse comes into play anyway.

I'm going to try and swing the mm251 at minimum, and maybe the dyn200, doesn't look like I'll be doing any cylinder head repair with the dyn200, as the current probably won't be hot enough.

Then again, I can aways try some pre-heat and pure helium or something.

[Danny]

****, When i grow up i want to be like Dan! To **** with Mike.

Heck, I wish I was Dan 10 years ago , Back then I was a pretty darn good stick welder. Nowadays, I'm no where near the same level -way out of practice. TIG and MIG are all that my job require me to use.