Is it worth me buying a pulse mig

[Bobley]

I've been tinkering with cars for years and only in the last year I've started welding. I've been to college and done C&G MIG part 1. Now I'm enrolled to do TIG part 2 (alloy). I was going to buy an ESAB Caddy or a Migatronic Pi200 and borrow my mates Sealey SuperMIG 180 but I really ought to get my own. I did fancy doing a bit of work on ali inlet manifolds and stainless exhausts in future hence the AC Tig but I've heard a few things about pulse MIG and MIG brazing..

Is it worth buying a good pulse MIG machine and just being happy to have a good all round machine? Is there any benefit to a pulse MIG for old car restos? (I'm thinking less heat during seam welding??). Or should I just go and buy a good 200Amp MIG and keep saving for the AC TIG in future?

Cheers

Bob

 

[Sparkey]

Strange....i always thought that you put in more heat when you're welding in pulse mode? (more experienced members of the forum: feel free to correct me when i'm wrong )
I'd say get the 200 amp mig and keep saving for the tig! But offcourse that's my opinion! The choice is up to you mate!

 

[Bobley]

Cheers for the reply. I think I've got my wires crossed or perhaps not phrased the question. I thought MIG brazing is the less intense process but I though you needed a pulse MIG to do that properly? The pulse MIG then also allows me to do high quality ali welds. I think the 2 machine approach is probably best, I just want to make sure that that is true and that I'm not missing out on anything by sticking to traditional MIG.

So ali and stainless aside what is the best MIG machine for welding this back together!!

 

[shenion]

A high-end pulse MIG can do controlled brazing that the heat input is controlled. weldequip or matt1978 would know more about these. I beleive the both have dealt with these intended for use on the new boron steels that need careful brazing as to not effect the temper of the metal.

Pulse MIG can also increase productivity as it can deposit metal faster and put in more heat. Can also use larger wire with less heat. Real useful to avoid globular transfer in the 160-200A range or for positional welding where spray-transfer might be difficult.

For ally, TIG is best. I'd get a decent MIG and leave the TIG for the aluminum and possibly stainless.

A lot depends on your budget.

 

[gordon stephenson]

I think what you need to know about pulsed mig, my understanding is that you can put more amps into the work for better penetration etc but it for such a short period controlled by the pulse electronics that the overall effect is less heat into the metal.

 

[matt1978]

Looking at your restoration project I would say a Pulse mig would be overkill. Most mig brazing is done in the short arc range anyway, not pulsed.

My advice would be to get yourself a good quality transformer mig which will come down to 15-20 amps.

 

[Sparkey]

A high-end pulse MIG can do controlled brazing that the heat input is controlled. weldequip or matt1978 would know more about these. I beleive the both have dealt with these intended for use on the new boron steels that need careful brazing as to not effect the temper of the metal.

Pulse MIG can also increase productivity as it can deposit metal faster and put in more heat. Can also use larger wire with less heat. Real useful to avoid globular transfer in the 160-200A range or for positional welding where spray-transfer might be difficult.

For ally, TIG is best. I'd get a decent MIG and leave the TIG for the aluminum and possibly stainless.

A lot depends on your budget.

What is globular transfer? (sorry, still some english terms i don't get!)
My experience is that pulsed mig is slower than normal welding...(exept maybe Matt's Twinpulse?)

 

[Paul.]

What is globular transfer? (sorry, still some english terms i don't get!)

Its the bit between Dip and spray, It used to have the grand title of dip to spray transition.

 

[Sparkey]

Its the bit between Dip and spray, It used to have the grand title of dip to spray transition.

Hmm, issit when it's like making blobs when you go too slow for spray but too fast for dip?

edit: sorry for hijacking your thread Bob!

 

[Paul.]

Hmm, issit when it's like making blobs when you go too slow for spray but too fast for dip?

Yep exactly that, have a read of this, it explains it quite well.

 

[matt1978]

Its when you don't have enough voltage to get into Spray arc, but you have too much voltage to remain in Dip transfer. Globular/Mixed arc is not nice to weld in, the arc is quite unstable and you get lots of spatter. The spatter is generally large and irregular in shape, also difficult to remove from the job.

 

[madkayaker]

then why use globular transfure?

 

[matt1978]

then why use globular transfure?

You wouldnt purposefully choose to weld in a mixed arc. It comes when the plate thickness you are welding dictates the amount of voltage and wire speed you need in order to weld it.

So if for example you wanted to weld some 5mm plate with a 1mm wire, you may well find that you are in mixed arc range and the plate thickness wont allow you to go up into spray arc (too hot) or turn it down into short arc (too cold). So you would then need to either drop down to 0.8mm wire and then you would be in spray arc or go up to 1.2mm and remain in dip transfer.

Beuty of Pulse welding is that you can weld all material thicknesses and current ranges with a 1.2mm wire for example with out any mixed/globular arcs.

 

[RapidResponse]

is mig brazing a procedure recognised for boron steels and APPROVED BY THE ASSOSIATION OF BRITISH INSURERS. Last time i brazed a sill on a triumph spitfire it got soundly failed at MOT. I know i should have let the Shutz dry, but hey.

 

[londonsean69]

is mig brazing a procedure recognised for boron steels and APPROVED BY THE ASSOSIATION OF BRITISH INSURERS. Last time i brazed a sill on a triumph spitfire it got soundly failed at MOT. I know i should have let the Shutz dry, but hey.

Is your Triumph Spitfire made from brazed boron steel???

IIRC a repair has to be to the same standard as original. Therefore, probably, your sills were welded, not brazed. Hence brazing being the cause of your failure.

I do stand to be corrected, but have a search on here for 'MOT sill repairs', it was discussed at quite some length a long time ago.

Sorry for the further thread hijack

Sean

 

[Weldingartisan]

I considered buying a pulse MIG last year, but after a good deal of research decided it was not for me right now. Although pulse machines are very effecient for production purposes, for a small fabrication shop like mine or a hobbyist I don't think you would get value for money or effeciency. I have about 10 commonly used filler wires for TIG and you can bet your bottom dollar as soon as I've set up for ally an urgent stainless or high alloy steel job will appear. No probem, just change the tungsten and pull out the right filler wire. Changing reels and gases each time would - for me anyway be quite a chore. W/A