baby mig still too hot

greetings,
I'm new-ish to mig welding and have a number of questions. I purchased
a smallish MIG machine, Decastar 135 by Deca (itallian). I bought it
'cause it was at a ridiculously good price and I can convert to gas
with ease. here's the 'but'...I'm rebuilding a Chevette and have to
weld on new sections of the body. I have yet to touch torch to body
yet and have just done a couple of small projects, but I find it too
hot for sheetmetal. It seems to just blow right through for the most
part.
its got 4 settings and obviously the variable wirefeed, but even at
the lowest setting its still spouting 55 amps and 14v. another
thing......It didn't come with a chart, so I'm forced to experiment
with the feed and heat every time I change metal thickness.
was initially worried that the damned thing wouldn't be powerful enough
if I ever wanted to do anything more industrial than brackets and body
work, but now I'm sorely tempted to return it or hunt around for a
"dimmer" (rheostat) I could wire into the lowest heat setting to give
me full control over the heat.
oh, and yea I'm still using flux core since I'm woking in my driveway
and trying to keep the cost down for the time being.
ideas? suggestions?
-m
Reply to
mkzero
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Hello -m, try using gas. For sheet steel, in my part of the globe (Australia), the suggested gas is Argoshield Light from BOC gases.
Here is a bit of reading from a UK web site.
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Quote from above website. "Argoshield Light is supplied in high pressure steel cylinders and is a mixture of argon with 5% carbon dioxide and 2% oxygen. Argoshield Light is designed for sheet and thin section MIG welding of mild steel, typically less than 4mm in thickness."
Use whatever that mixture is called in your part of the world.
Check your manual to make a polarity change when using gas. Torch is positive with respect to the lead that clamps to the work piece.
Since you are out in your driveway, If the weather is breezy/windy, wait for a dead calm day so that the shielding gas doesn't blow away from the torch tip when welding. Construct a wind break of some kind around yourself if conditions are a bit draughty.
Regards, John Crighton Sydney
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Reply to
John Crighton
The flux core wire is hotter than gas, also the solid wire can be thinner. If you go the MIG route (using gas) you will find better results on thin stuff.
Reply to
wayne mak
Get a spool of .026 hard wire and a tank of either C25 or argon. Put the flux core back on the shelf for the times you need lots of penetration or want to cut a car in half.
Flux core burns much much hotter than wire+gas. Its the nature of the beast.
Gunner
"If thy pride is sorely vexed when others disparage your offering, be as lamb's wool is to cold rain and the Gore-tex of Odin's raiment is to gullshit in the gale, for thy angst shall vex them not at all. Yea, they shall scorn thee all the more. Rejoice in sharing what you have to share without expectation of adoration, knowing that sharing your treasure does not diminish your treasure but enriches it."
- Onni 1:33
Reply to
Gunner
cheers guys, that helped. I've made up my mind to go all the way and get a bottl.
at least now I have an alternative to voiding the warranty with my electrical kludgery...for now :D
anyone have a chart or a 'rule of thumb' fomula for thicknes vs heat vs % feed rate?
-mark
Reply to
mkzero
In my experience the best rule of thumb is your own experience with your own unit. Feed rates are all arbitrary so between melting at the torch nozzle and ramming into the work is where you want to be. Practice just running beads along some scrap and you will get a feel for it as you slow it down and speed it up. Amps are a bit like horsepower, one manufacturers 80amps can be more like 65 on another unit. Having taught myself gas, then stick, then mig and finally tig over the last ten years I can say nothing beats some quiet time just running beads, then some butt welds etc, changing torch angle and arc length and it's boring but necessary to take notes of your settings if you don't do it that often. Start with less amps than you need and work up slowly. When things start to seem a bit frantic you've gone too far. Make sure as well that you are set up comfortably, somewhere to rest your arm makes a world of difference and mig welding outside requires that you shield yourself from any breeze. Don't take much to blow that gas jacket away and you'll be spitting and popping and blowing holes in everything. So pop down the scrapyard and get some panels to play on and also remember that rusted body panels, even just a bit, are VERY thin and VERY hard to weld. Have fun and good luck.
Scott
Reply to
comb
Hello mark, I must be feeling in a good mood tonight. I googled mig wire feed rate and found this for you
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a look at page one.
Hope all goes well after fitting the gas solenoid to your machine and changing the DC polarity to torch positive for the solid wire.
Regards John Crighton Sydney
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Reply to
John Crighton
thanks john, that's excellent. I tried to no avail to find something just like that but apparently my Google kung-fu is no good.
-mark Ottawa, Canada
Reply to
mkzero

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