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What MIG do I buy for working on the Z


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#21 menzcar

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Posted 19 July 2009 - 07:09 PM

For welding aluminium you need to buy a kit that incldes different rollers, a different lining, and a bottle of Argon. It will take a bit of practice to get it right. Warm up the ally slightly before welding, I use a heat gun.

#22 menzcar

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Posted 19 July 2009 - 07:10 PM

Oxy no good unless you are really clever. If you try it you will destroy your panel.

#23 zzzzed

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Posted 19 July 2009 - 07:12 PM

I recommend nothing smaller than a 180 amp,


I agree that a 180amp is an ideal size for home use, but i wouldn't say completely necessary.
I use a 135 amp cig at home and it welded up my rotisserie with excellent penetration.
i use a 250 amp cig at work on a regular bassis and i would actually prefer to use my 135 amp for thiner sheet metal

#24 zzzzed

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Posted 19 July 2009 - 07:14 PM

if you are welding alloy you have to also change to a nylon wound sheath for the softer alloy wire

#25 menzcar

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Posted 19 July 2009 - 07:22 PM

When I had some lessons the guy told me to always buy one that is 30% bigger than you need, because as you get better you tend to use more amps and use more grunt in your welding. Also have learnt with all tools that I buy that you should buy a grade higher than you need, and put less load on the tool. Except for cordless drills, the best one I've got was the cheapest.

#26 zzzzed

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Posted 19 July 2009 - 07:45 PM

when i had lessons i was  taught to use the less amp setting possible to reduce heat
i havnt had to turn my little bugger up full yet  ;)

#27 RBZ 260

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Posted 20 July 2009 - 12:20 PM

ive inherited my old mans 170amp mig thats approx 15years old.

use argoshiled light for the gas. do have different size rollers, inner sheet for 0.6, 0.8, 0.9 and 1mm

also welded stainless steel with it and fairly thick plates. look for Duty cycle % to be higher if going to be doing prolonged welding ie making your front fence or a gate. most are around 20% to 35% for non heavy industrial models.

mine is bulky unit but for car and around the home its good enough. though showing its age now im looking at upgrading soon. most prob will go for cigweld around 200A. personaly gasless are useless and i will never buy one. i guess going from gas to gasless needs some getting used to but so much easier with gas.

gas bottle rental is around 170 per year for E size bottle from BOC with 1 full charge for the first year. recharge is around $70-80.  should last you a fair bit depending on welding.

i use mine fairly regualarly one bottle is fine per year, but some years i did get up to to three refills.

also auto darkening visors are to me a MUST. makes the whole thing so much easier expecialy if u novice. not to say it will save your eyes.1 flash is all that is needed to have a very very sleepless and painfull nite.

it feels like somone filled your eyes with sand and rubbed it in. when u close eye lids feels like u running sandpaper accross them constantly. so if in for a torcher or have a third arm dont get one  8)

#28 menzcar

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Posted 20 July 2009 - 08:58 PM

Hi Mick, using least amps possible is a good option for welding thin sections such as panels, but for good penetration on thicker materials more amps the better. You can tell when you've got it right when the weld becomes part of the two surfaces being joined, instead of sitting on top. I try to aim for the most amps possible without blowing holes, as this gives a stronger weld, that requires a lot less grinding to prep for paint. when I'm in the zone there is often no grinding to be done at all, mind you I spend at least 6 hours welding per week, sometimes a lot more. But as long as the job is getting done and is working for you theres not much point debating the pro's and con's of how to set up your welder.
Cheers.
Pete.

#29 Kodie

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Posted 21 July 2009 - 01:17 PM

Thought I might drop into this thread.

Im doing a welding/machining/fitting (pretty much everything) course  (Trying to get out of mining) and at the moment im focusing on mig. Ive tried both gas and gasless and I would agree with most of the guys in this thread, gasless seem tedious and harder to perfect.

I would also have to agree with the auto darkening sheilds, after the first 3 days of welding with the normal helmet I cracked it and went and bought myself a auto darkening sheild. However I bought a cheap ebay model...... big mistake (what can i say, im a cheapskate). Pain ensued that night and a great deal of swearing! So the day after I went all out and bought myself an expensive one from BOC. Much better!

Anyways I would also have to agree with zzzzed on the less amps the better on car panels, my teachers and my fiances cousin both couldn't stress that enough to me. Then when I had a go on some cut up car panels it was ever so apparent when I went all maverick and tried to crank up the amps just to see what happened. HELLO! Even with tacks and clamps it warped to the crapper. So I suppose if you only want to weld up car panels and just the odd thing or two then a small cig transmig or something like that would do the job. Even if you wanted to do thicker gauge steel you can still bevel the edges and do multi passes?

I've had a play with arc and oxy welding and I reckon that if you tried that on a thin car panel without considerable experience you would mangle the panel and more than likely just keep blowing the metal away.

#30 reverendzed

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Posted 21 July 2009 - 01:31 PM

One last say and then I'll retreat as a gentleman from this conversation.  The guys who say a gasless Mig will not do the job probably haven't used one at any length or don't know how to weld.  By all means use gas if it's helping with your welding however to say that it is imperative to get a full penetration weld is at best erroneous information.
Rev.

#31 RB30X

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Posted 21 July 2009 - 02:17 PM

Gas sheilded welds certainly look better straight after, but if all you're doing is welding in a floor pan and you don't mind cleaning it up with a flap disc (best invention the world!) than painting over it then surely a gasless would do the job providing you're getting the penetration req.

#32 Zedback

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Posted 21 July 2009 - 04:10 PM

I'm going to follow reverendzed's lead and retreat.  Gas vs gasless has been discussed with some heat in many other forums as well.  I think universally professionals and anyone who regularly welds will go with gas and will consider gasless as useless. 

I'm not a professional and I do a few hours every 6 months or so doing nothing more than patching panels on my Z.  My gasless mig is adequate for the job and I don't mind having to clean up the mess.  It also cost me peanuts to get started with and make my own decision on which way to go.

#33 Scoota G

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Posted 21 July 2009 - 04:34 PM

Is anyone here actually qualified welder?

#34 RB30X

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Posted 21 July 2009 - 05:53 PM

probably less than those here who are qualified mechanics, yet have a look at us??

#35 V8Datto

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Posted 21 July 2009 - 06:02 PM

Gas vs gasless has been discussed with some heat in many other forums


I've done a tafe corse in arc welding, but I'd never own or run one, there horrid things

As for the gas and Mig's, with out the Argon bottle turned on I can't weld
It just doesn't work and makes a huge mess.

but reverendzed is right in saying that I'm one of thoes guys that's never used a gasless mig.

I'm sure they work great other wise they wouldn't make them. But saying that, they make Arc welders and I think there usless

#36 Kodie

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Posted 21 July 2009 - 06:54 PM

One last say and then I'll retreat as a gentleman from this conversation.  The guys who say a gasless Mig will not do the job probably haven't used one at any length or don't know how to weld.  By all means use gas if it's helping with your welding however to say that it is imperative to get a full penetration weld is at best erroneous information.
Rev.


Im going to change my last post to reflect this. They do the job but in comparison to gas they just seem tedious and are easy to make mistakes with. As far as I know and have seen when using them at my course you have a far greater chance of getting contaminanation into your weld (leading to rust), especially if your a novice like me :P t. On the other hand they are much cheaper :) Anyways im going to stop spouting crap as they both have there place.

I've done a tafe corse in arc welding, but I'd never own or run one, there horrid things

As for the gas and Mig's, with out the Argon bottle turned on I can't weld
It just doesn't work and makes a huge mess.


but reverendzed is right in saying that I'm one of thoes guys that's never used a gasless mig.

I'm sure they work great other wise they wouldn't make them. But saying that, they make Arc welders and I think there usless


Did the mig have gasless wire in it? The way you wrote that it seemed like you were talking about using a mig without gasless wire in it, in which case your weld would just about always be wrecked no?!

#37 Zeddophile

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Posted 21 July 2009 - 07:26 PM

Welding with the bottle turned off on a gas MIG is absolutely nothing like using a gasless MIG.  Gas MIGs use solid wire (incidentally its the same material as used in TIG filler rods, and can be used as such in a pinch!), and the gas flows out of the nozzle around the wire.  The wire used in gasless migs has a flux core, which acts somewhat like the coating on an electrode for arc welding (yes, that coating takes the place of gas in arc welding).  Hence you end up with the slag on top of the weld similar to arc welding, as instead of a smooth flow of gas around the arc and metal pool, the shielding elements are actually being thrown out from in the pool as the wire melts.  

Arc welding will do a fine job in the right hands and conditions, generally pretty clumsy for thin stuff as noted although it CAN be used.  More often used in serious construction work and shipbuilding.

A gasless mig will do fine for what you want to do, a little more cleanup than gas, but hey, the weld needs to be ground smooth in this situation anyway, right?

PERSONALLY, (having just spent bloody ages on the watch till I found my TIG welder), I'd be scouring classifieds and Ebay looking for a good brand secondhand gas unit, and running the little disposable bottles if you want to avoid gas bottle rental.  Out of what is currently on ebay, this http://cgi.ebay.com....:1|293:1|294:50 would be my first choice - I have used one a fair bit, and its a pretty decent unit which would cost twice as much to buy new.  Probably at the high end of what you want to spend (although it's around the 3 you posted earlier on), but right at the moment there actually isn't much else on there - last week there was a couple of extremely high quality MIGs up for stupidly low prices (and that's what I'd be waiting for).  I think from memory one was a Kemppi unit for under $800?  Don't be afraid to pick up an older unit if its from one of the good brands (Miller, Lincoln, Kemppi, Fronius, ESAB, BOC, and one or two others), as they will still weld smoother than a lot of the new cheapies.

Take for example my (estimated) ten year old Kemppi AC/DC TIG welder.  A fabricator mate came over to have a go, turned it on and flicked one or two switches to set it to AC, pumped the amps up a little, and laid down a perfect bead on a piece of aluminum plate.  First thing he said - "I love this welder.  Took me 3/4 of the day to set up my bloody chinese made inverter TIG to weld this smoothly."  

Freight isn't too bad either if you buy something interstate - I paid $105 from Sydney to Melbourne for mine, which I dimensioned as 100cm x 100cm x 40cm and 200kg.  Was actually a bit less than those dimension in the end (particularly weight, its more like 140kg).  That was using www.transdirect.com.au.

And while on the subject of TIG, converting your arc welder to run as one is not such a silly idea.... After all, with car panels you tend to only do little spots all round your patch, then let it cool and go again - its a pretty slow process anyhow, it wouldn't really be any slower with a TIG?  There was a conversion unit on Ebay last week for about $100....

Just my opinion, not to be transcribed down on stone tablets and quoted every Sunday morning.  However, if you are interested in looking at secondhand units, I can pass on a few tips which may help you pick a good unit no-one else will bid on (out of time at the moment).

#38 V8Datto

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Posted 21 July 2009 - 08:07 PM

Did the mig have gasless wire in it? The way you wrote that it seemed like you were talking about using a mig without gasless wire in it, in which case your weld would just about always be wrecked no?!


I have a BOC 200amp gas mig welder with normal wire and huge bottle of argon light shield.
If I forget to turn the bottle back on after taking a break or something it won't weld properly as expected and yes the weld would be "wrecked"

The gasless migs having a flux core wire means they should work perfectly fine

Thanks for the info too Zeddophile

#39 menzcar

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Posted 21 July 2009 - 08:10 PM

Hey reverendz,
tone down your remarks, your not retreating like a gentleman, your having a swipe. You should have been able to see from my post that I am an experienced welder. That is I have many years of experience brazing copper, brass, stainless and composites, welding thin, thick and heavy duty metals. And people pay me for my work. I wrote my reply to a guy who has little or no experience welding, a gasless mig for him will be a complete waste of time(that is, he will not get good welds, and it will be frustrating for some time). Nobody in the industry uses a gasless mig unless they have to, ie onsite welding in tricky situations. A good gasless mig for onsite welding is approx $4000. I have one which I use for welding reo bars in insitu-concrete walls at height, but always take my gas mig for the lower walls. Why would I recommend a gasless mig or an arc welder when I know that he is going to have a much better success with a good quality gas mig.
As for all the remarks on using the minimum amps - think about it. The idea of all welding is to match your amps and feed rate to the situation. If simply going for minimum amps then why not just buy a 1 amp mig. Because it wont do the job. You can call it the maximum or the minimum. Start high and adjust down until you get a good penetration without blowing holes - there you have your minumum. Start low and adjust up until you get good penetration - there you have your maximum. Same thing.
Does anyone have something intelligent to add, or does someone else want to test my knowledge of welding.
Peter.
BSc building technology.
BSc Toxicology.
Dip Horticulture.
Welding courses: Arc welding. Mig welding. Brazing, soldering.
12 years commercial experience.
I know all........(just kidding)


#40 V8Datto

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Posted 21 July 2009 - 08:21 PM

One thing that hasn't been noted yet is different brands of mig's have different amount of setting to control the power level (voltage).

When buying a mig welder for the first time all the buttons and nobs on the control panel mean nothing, untill someone explains what there all for.










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