15amp welding ?

[gavuk]

One of the selling points of the Portamig range is its low start amps,being a co2 user I've never used the lowest settings on my own welders,so i'm interested in seeing examples of low amps welding.Will it allow you to weld a patch on a car for instance without ,backstepping ,or weld runs longer than 1/2"-1" without stopping ?......what do you use below 30amps for?...please post some pics and show me what I'm missing ..

 

[malcolm]

CO2 doesn't maintain the arc on low settings on any welder that claims less than 30 amps minimum (Portamig included). You just end up with a high build and no penetration.

With argon/CO2 mix you can lay a continuous bead on a 0.8mm butt joint on the bench even with the old 20 amp minimum Portamig. I managed a 0.3mm butt joint with pulse technique. But for those thicknesses I'll tend not to want to do long welds as the metal just distorts.

Was under a car the other day working out of position on a weld that I couldn't see without having the torch at a hideous angle, using the thin metal technique on minimum setting for a badly prepared 0.8mm butt joint. Turned out neat. That's more of an advantage than the low amps to me.

 

[gavuk]

I've always made good progress using "the thin metal technique" using co2 and 0.8mm wire ,and of course i've chased a few holes .....and cursed myself for not removing enough metal to clear the rust...I've used argon mix at work and in disposables but for home use co2 is ok for the mot work I normally undertake....Thanks for the reply Malc ,the question arose from another post camparing the parweld and portamig,never having used either,I couldn't say the lower amperage of 15amps on the portamig was a huge bonus or not ? I think thin metal technique is as important for distortion free welding of thin metal as welders that go lower than 30amps

 

[malcolm]

You've probably got a decent rig at home. My SIP 130 wire feed takes a full 2 seconds to get to speed making it useless at thin metal technique. Decent rig is the trick regardless of new/ second hand, wire and gas type etc (though the latter make things easier).

Planning to write something up about distortion - I've been experimenting with it. Metal pulls together after welding. With the sills on my ultra-cool Renault 5 I did the seam weld before even tacking anything else. Metal moved and went wrinkly but didn't cause any bother - straightened it before welding the other bits.

 

[gavuk]

Running a thermal arc fabricator 180amp,which didn't get good reviews in the past here due to duty cycle ,but even my old sealey 130amp was good for thin metal technique....never owned a welder with stitch or spot timers although I've used them years ago,and so far no issues with either torch or pcb's due to manual pulsing ,or alluminium windings ....learnt gas years ago at college when tacking up we set the gap to taper open from the start point and angled both plates down from the weldline ,amazing to see it contract and level up by the end of the run ...look forward to reading your findings on distortion

 

[BillJ]

I understood the 15A setting was more intended for MIG brazing. I'd have thought 15A would be on the borderline of being able to melt 0.6mm steel wire effectively.

 

[Ian D]

I think my mig is min 25 amps, but i allways run it quite abit higher than that.
You run the risk of burn through, which does happen but you get a good weld, there is a bit of a knack to it.

 

[gavuk]

I understood the 15A setting was more intended for MIG brazing. I'd have thought 15A would be on the borderline of being able to melt 0.6mm steel wire effectively.

good point ,never tried mig brazing

 

[bunnymofo]

sorry fpr my dumbness, but whats mig brazing ?

 

[gavuk]

Looky here Bunny ,used on modern boron steel vehicles.....mig brazing

 

[brookie456]

One of the selling points of the Portamig range is its low start amps,being a co2 user I've never used the lowest settings on my own welders,so i'm interested in seeing examples of low amps welding.Will it allow you to weld a patch on a car for instance without ,backstepping ,or weld runs longer than 1/2"-1" without stopping ?......what do you use below 30amps for?...please post some pics and show me what I'm missing ..

Hi Gav, no it's not the cure-all on old bodywork (damn!). Have taken some shim stock from work and run a good 8" with no problem and minimal distortion, but car stuff is still hit-and-miss due to variable thickness, more technique than just machine setting. Great on consistent material, but I'm back to 0.8mm wire on 1 above minimum on the Portamig using CO2/Argon mix - great machine though, would love to give brazing a shot! Hope the Harrison is up and running?

 

[gavuk]

Harrison is fine ,many thanks ,got the metric gear train as well now........glad its not just me above minimum settings either