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What size mig wire for rust repairs


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#1 jabba

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Posted 16 January 2006 - 09:05 PM

I got my mig welder last week and i was just wondering what sized wire is recommended for welding in repair panels, i used .9mm wire last time but im just wondering should i be using somthing else? Its a gas/gasless mig, i've just been using it gasless because im working outdoors. Also wheres the cheapest place to buy gasless wire, are there any cheap places on the 'net?

Thanks
Damien

#2 Pete

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Posted 16 January 2006 - 09:29 PM

For panel steel the ideal set-up would be a 0.6mm Argoshield gas set-up, If you have to use Gasless i think the smallest you can buy is 0.8mm in a flux cored wire.

If your used to gasless welding and you prefer it i guess theres not anything wrong with it, for me i prefer a Gas set-up, weld looks cleaner to me

#3 FastEHHolden

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Posted 16 January 2006 - 09:29 PM

gasless seems to burn hotter and doesn't do a gr8 job....but it can be done...I have been unable to find a cheap supply other than to buy a bulk roll and roll it on your spool with the aid of a lathe.

the thinner the better with the wire.

#4 racean69

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Posted 16 January 2006 - 10:34 PM

I would say go with the 0.6 solid wire(which is usually a gold colour) with Argoshield Light as your sheilding gas.
Only thing is you will need to get V type feed rollers to suit the solid wire(gas). That's provideing you have been using the grooved type feed rollers that suit the flux- core wire(gasless).

The solid wire will burn cooler due to the shielding gas providing a cooling effect simpley by it's presence around the weld pool and the fact that its smaller wire(0.6) there for requiring less heat to obtain penetration.

The flux-cored wire has no gas,(from an outside source anyway there is a gas present it is created by a chemical reaction and comes from the flux inside the wire when it's heated by the creation of a circuit when the arc is struck) to cool the weld pool and also the flux creates a slag on the top of the weld. This slag can get trapped under the weld and causes poor weld quality and appearance. And being larger dia req's more heat to burn.

Hope that all isn't to much of a rave.

PS... some welders will need to have there polarity swaped when changeing from flux-cored to solid wire.

#5 Yella-5000

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Posted 16 January 2006 - 11:11 PM

I use 0.9mm gas. If your using 0.9mm wire, don't try to do runs of any significance, lots of little runs, wait till orange goes, then go again, heat control is everything with panelwork, specially spotting in before welding.

#6 _Oldn64_

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Posted 17 January 2006 - 11:35 AM

Agree with Yella. Always do stitch welding. Take alots of time to stitch in your panel. And always do the opposite side of the previous weld. I will usually use 5mm stitches to graft the panel in. this will minimise the warpage. It is possible to do it with a gasless but the results will be easier to acheive with the gased versions. I also turn the voltage down to low so that the current is not so high when welding. this will by you some mroe time to stop the panels dissappearing.

When measuring the patch panel always cut smaller than your markings. that way you can trim the panel to suti not try and fill the panel after cutting too much.

Cheers

#7 jabba

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Posted 17 January 2006 - 08:56 PM

I dont know if i can justify the costs of gas bottle rentals etc for backyard repairs, also i dont have a wind proof area to work in. When i first started i was having alot of trouble with blowing holes in the metal, but once i started taking it easy with small tacks and waiting until the weld stoped glowing brightly before continuing i've had less problems. I think i might try .8mm wire next time. The quality of the welds shouldnt matter hugely for sheet metal work should it, its not structual and there going to be ground back anyway???


Thanks for all the replys, ill keep them in mind. I would switch to a gas setup but im just worried that ill spend a heep of money to find i cant weld because im outside.

<edit> im not sure about the rollers, i havent changed them from what came with the welder... should i have??

Changing the polarity is easy enough, theres a cord on the front you can move to pos or neg.

Thanks
Damien

Edited by jabba, 17 January 2006 - 08:57 PM.


#8 _Oldn64_

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Posted 17 January 2006 - 11:27 PM

If you are worried about the gas not staying when you are welding then you are either welding too far away or have not opened the gass tap properly. Most of the worlds bridges are welded on site (or used to be) These are therefore welded outside, and thus are fine.

Remember there are two techniques between the too as well.

Gasless you pull the welding pool where as with Gased ones you pull it. Always use a sweeping stroke and if you have a weld time indicator dial it in for 1 sec. This way you will give great tacks. Again weld opposite from the last and your warpage will almost be nil

Cheers

#9 jabba

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Posted 18 January 2006 - 06:49 AM

Hrmmm fair enough, ill make some phone calls and findout how much a gas setup will set me back :). Ill also try setting the spot timer to 1s and see how i go :D.

#10 Tiny

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Posted 18 January 2006 - 09:39 AM

Hey Jabba, I just purchased a mig welder to allow me to learnbefore i start to attack the torry.

We spoke with the guy at the store wehre we bought it and it is a professional welding supplier ( not just a store that sells welders too). He reccomended the following for auto work:

.8 wire with gas would be the best, thats what all the panels shops use that he sells to. If youve gotto use gasless, the wire ONLY comes in .8 but because its hollow to carry teh flux inside, the actually quantity of wire is more like the .6 wire. You should only need a U groove roller for aluminium wire we were told to use V groove for everything else ( the U groove stops the aluminium from deforming and stuffing up in your gun!)

You can take the roller off and look at it.. it should have the size and also the kind of groove stamped on it.. we have a .8 and 1.0 roller and its got another stamping like this" --v--" while the U roller's stamping is like this " --u--" its pretty obvious when you look at the roller :)

As tim has said, small stitches are the way to go... I dont use the timer.. you get good just by hearing what works :)

Good luck mate! i'm going to start learning ASAP myself!

Cheers.

#11 Tiny

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Posted 18 January 2006 - 09:40 AM

Pete and racean: Why do you say that the .6 wire is the way to go? Not as much filler? not so much heat? please explain ;)

Thanks!

#12 shanegtr

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Posted 18 January 2006 - 10:57 AM

8 wire with gas would be the best, thats what all the panels shops use that he sells to. If youve gotto use gasless, the wire ONLY comes in .8 but because its hollow to carry teh flux inside, the actually quantity of wire is more like the .6 wire.

Thats interesting. The other weekend when I was working on my cruiser I ran out of gas and had to change to gasless. I didnt notice any difference to the weld, just the end result isnt as clean as using the gas. I have found that the gas wire does seem to flow a bit better, but I dont think there is that much between the two

#13 Yella-5000

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Posted 18 January 2006 - 11:17 AM

Gas or gasless doesn't really matter, technique is the same, just cleaner welds with the gas, but like you say, most of the top gets ground off.

#14 Tiny

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Posted 18 January 2006 - 12:48 PM

ShaneGTR: Gasless wire is also known as flux core wire. What it is is hollow and contains a flux on the inside. As someone menitoned above, when this flux burns it creates the shielding gas that all welds need. That's now gasless wire works.

In very simple terms its like an inside out ARC rod... where the coating of the arc rod is what burns to give you your gas and shield the weld from oxygen and hydrogen in the atmosphere.

I tried welding with gasless at the course i went to, and i found it to be a little more difficult to use ( but thats a practice thing i'm sure!) and the weld looked terrible compared to a propper gas weld. As has been pointed out though, cause were grinding them back.. it shouldnt matter!

Thats just what ive been taught.. i would be extremely happy to be corrected and taught further by other people in the know!

Cheers!

#15 shanegtr

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Posted 18 January 2006 - 02:34 PM

Its interesting cause I never thought about how much wire would actually be in .8mm flux wire compared to .6mm soild. Makes sense but

#16 jabba

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Posted 18 January 2006 - 03:57 PM

Tiny, flux core wire also comes in .9mm. I bought .8mm wire this time, only .5kg roll because im really poor, i also bought a flap disk to clean it all up afterwards.

I was talking to the BOC gas dude that comes to work every other day to deliver medical gas and he said somthing like a d size bottle will cost around 80$ a year rental ( he may have been thinking hospital contract prices tho ) i forgot to ask how much to fill, ill ask him next time i see him.

I wanted to have another go at mig'n today but its raining :(. Tomorrow maybe hehe.

#17 Pete

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Posted 18 January 2006 - 05:15 PM

Pete and racean: Why do you say that the .6 wire is the way to go? Not as much filler? not so much heat? please explain


Majority of panel steel is only 0.6mm thick, earlier model cars have thicker steel but anything 30yr old and newer the sheetmetal is usually only 0.6mm.

A lot of guys will probably use 0.8mm - 0.9mm as its more multi-purpose for heavier stuff and you can also get away with using it on panel steel too. Nothing wrong with it at all but like Racean said earlier a gas set-up with 0.6mm gives a nice weld with good penetration and not a whole lot of build-up or need for a lot of amps thats why i prefer it.

All comes down to personal choice and what your more comfortable using, i've almost always used 0.6mm with gas, the new welder i've just bought has come with a 0.8mm flux cored wire roll so i gave it a go tacking together the restoration frame i've built for my mini project, i wasn't overly impressed with it but it still did the job.

#18 Tiny

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Posted 18 January 2006 - 08:48 PM

Jabba: I belive its about that oprice to hire the bottle for the year. Thing is... that only covers the first fill! Then they charge you for gas after that. if youve got a business you can claim it through.. then its well worthwhile!!

Pete: thanks for the info mate! I was going off what i was recommended by the welding shop.. I'm going to be doing LOTS of practice before i attempt anything permanent on the torana.. i'm still a newbie!

Thanks for the tip!

#19 Bart

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Posted 19 January 2006 - 07:42 PM

Any particular preference on the type of gas? Is MIGSHEILD M1 ok??

#20 racean69

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Posted 19 January 2006 - 09:59 PM

Never heard of MIGSHIELD M1 so I can't comment on that one.
But I am aware of the boc range and the best option from them(for panel work) is there gas called ARGOSHIELD LIGHT.
As with most welding(inert) gas it is amix of argon, CO2 and oxygen that is best suited to welding thin materials. From memory it has less CO2 which makes for a cooler weld pool.
Gas cost in my area is $87 for the gas (every time you exchange your bottle) and $125 a year rental. That's for a E size bottle. The gas cost aint so bad it's the rental thats the killer.

As for the roller types. ther are basicly 3 types the V, the U and the grooved or knurled type.
The V type is for hard/solid wires.
The U type for alli
The grooved/knurled type for flux cored wire (gassless), because of the "soft" type outer make up of the flux cored wire the tension on the drive roller is less, and the knurles actually drive/push the wire through the liner in your torch lead.
Roller tension is just a important as voltage, wire speed and gas flow in the quaility of your finished weld.

Just to confuse the issue a bit more there are also flux cored wires that require gas to weld with as well. I am currently useing 2.4mm flux cored wire with ARGOSHIELD 52 doing heavy fabrication work.

#21 Tiny

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Posted 19 January 2006 - 10:15 PM

Interesting Racean!!

Can i ask what tension settings are the way to go? That's something that we were never advised on!

Cheers!

#22 micksgtr

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Posted 22 January 2006 - 05:11 PM

Hi,
What size wire does your machine take?? 1kg or 5kg roll??? if your buying gasless the smallest you can buy is .8, However anything thats not .9mm will cause the price to rise. What state are you in and i can tell you where to get it from?? or you can buy it from me at wrok and i can have it to you anywhere in australia the next day. generally its not set about your machine settings, if you find that at no matter wat speed your wire feed is your getting like an on off arc, then tighten up your wire. Its a good idea to have your wire feed about half or a little less what your machine can handle. what machine has everyone bought that needs help?? or also if you need advice on buying a new machine let me no and i can help.
cheers

#23 jabba

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Posted 23 January 2006 - 01:22 PM

Hi,
What size wire does your machine take?? 1kg or 5kg roll??? if your buying gasless the smallest you can buy is .8, However anything thats not .9mm will cause the price to rise. What state are you in and i can tell you where to get it from?? or you can buy it from me at wrok and i can have it to you anywhere in australia the next day. generally its not set about your machine settings, if you find that at no matter wat speed your wire feed is your getting like an on off arc, then tighten up your wire. Its a good idea to have your wire feed about half or a little less what your machine can handle. what machine has everyone bought that needs help?? or also if you need advice on buying a new machine let me no and i can help.
cheers

My mig takes upto 5kg rolls. Im in NSW, cheapest i've found is around 100-110$ mark for 5kg's of .8 gasless. How much do you sell it for :).

#24 Com_VC

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Posted 23 January 2006 - 04:14 PM

what MIG Welders are you guys using?

I'm looking at getting one at the moment but not sure which to go for. Looking for something around 200 amps that takes 15kg spools.

#25 Tiny

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Posted 23 January 2006 - 04:24 PM

we just bought a unimig trade 240... havent actually zapped anything with it yet.. but was the best of all we looked at!




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