www.robowars.org

RoboWars Australia Forum Index -> Technical Chat

what eBay welder?
Goto page 1, 2, 3, 4, 5, 6, 7, 8, 9  Next

Post new topic   Reply to topic
  Author    Thread
miles&Jules
Experienced Roboteer


Joined: 19 May 2010
Posts: 3959
Location: ipswich QLD


 Reply with quote  
what eBay welder?

Hi gang...a mig welder is our M&J wish list of stuff, but we may be able to scrap together some funds for one....so what are people using and recommend?

Want one that can do steel and Ali so we need an ac mig right?...and we don't have 3phase or 15 amp points so we need 10amp plug....the local aluminium shop sells gas so we can get that locally.

this any good?
http://www.ebay.com.au/itm/New-250A-Gas-Mig-Mag-welder-for-Aluminium-Metal-/262146441497?hash=item3d09254119:m:m53UKuXMDCVfSSQr6UuWEvQ
_________________
Miles Blow - Julie Pitts
www.mulesfilm.com.au
www.wombokforest.com.au

-Pickasso- Vivid Sportsman champion 2015

Post Wed Nov 18, 2015 12:46 am 
 View user's profile Send private message Send e-mail Visit poster's website
Nick
Experienced Roboteer


Joined: 16 Jun 2004
Posts: 11745
Location: Sydney, NSW


 Reply with quote  

That welder description says all the right things for ali and steel - what the build quality is like is anyone's guess. The main thing you need for aluminium welding is the Teflon hand piece liner so that the wire doesn't snag and a good wire feeder, which that welder has.

My advice is to get a 2nd hand piece just for aluminium as changing the liner is usually fussy and will wear the liner out. The welder has a standard connector, so you can use hand pieces from other manufacturers. Use 1mm aluminium wire if possible, the thinner stuff is much more likely to snag up in the rollers.
_________________
Australian 2015 Featherweight champion
UK 2016 Gladiator champion

Post Wed Nov 18, 2015 6:50 am 
 View user's profile Send private message
Nick
Experienced Roboteer


Joined: 16 Jun 2004
Posts: 11745
Location: Sydney, NSW


 Reply with quote  

Another thing to look for is the duty cycle, this means the amount of time you can weld VS the time the machine needs to cool down. It is usually measured over a 5 minute period as a percentage - that welder has a 20% duty cycle so you can weld for about 1 minute in every 5 without overheating it. its measured at full power so at lower power you can probably weld at 50% duty cycle or more.
_________________
Australian 2015 Featherweight champion
UK 2016 Gladiator champion

Post Wed Nov 18, 2015 7:07 am 
 View user's profile Send private message
DumHed
Experienced Roboteer


Joined: 29 Jun 2004
Posts: 1219
Location: Sydney


 Reply with quote  

I would forget about MIG, and go TIG.

Once you're used to it you'll never want to touch a MIG again Smile
_________________
The Engine Whisperer - fixer of things

Post Wed Nov 18, 2015 9:59 am 
 View user's profile Send private message Visit poster's website MSN Messenger ICQ Number
Glen
Experienced Roboteer


Joined: 16 Jun 2004
Posts: 9467
Location: Where you least expect


 Reply with quote  

What do you wanna do with it? I wouldn't get a mig for anything other than lots and lots of heavy fabrication.

Dumhed and I have a super nice MIG here at work and have never used it lol. They just aren't that useful for most things vs TIG.
_________________
www.demon50s.com - Minimoto parts
http://www.youtube.com/user/HyzerGlen - Videoooozzz

Post Wed Nov 18, 2015 2:19 pm 
 View user's profile Send private message Send e-mail Visit poster's website MSN Messenger
Valen
Experienced Roboteer


Joined: 07 Jul 2004
Posts: 4425
Location: Sydney


 Reply with quote  

mig is good if you are doing lots of the same stuff, because you can destroy a few parts to get your settings right, tig you can add heat without adding metal.

Everybody hates on tig for being hard to do but really it's not that bad. The only real downside to me is its not as forgiving in terms of cleanliness. TIG stuff has to be perfectly clean or it'll just explode with porosity and it won't get better if you keep welding lol.
The only thing we don't have is a foot pedal, for the kind of stuff we wind up doing that'd be so much handy ;->
_________________
Mechanical engineers build weapons, civil engineers build targets

Post Wed Nov 18, 2015 2:51 pm 
 View user's profile Send private message Visit poster's website AIM Address Yahoo Messenger MSN Messenger ICQ Number
Don
Experienced Roboteer


Joined: 21 Feb 2010
Posts: 355
Location: Gladstone, Queesland


 Reply with quote  

I would have to disagree with the Mig destroying a few parts to get settings right comment.
One thing I would look out for with the cheaper brands, It can be harder to get spares for.
As for which one is the better they all have there pros and cons

Tigs: are more versatile for smaller jobs and different materials.
Migs: are slightly easer to use/and less surface preparation is needed.And can tackle the lager and more repetitive jobs.
Stick: great for outdoors or limited room or working at heights,also are one of the strongest welds

as for the 15amp plug, I had a 10amp male to 15amp female made up and it works a treat

Post Wed Nov 18, 2015 6:12 pm 
 View user's profile Send private message MSN Messenger
miles&Jules
Experienced Roboteer


Joined: 19 May 2010
Posts: 3959
Location: ipswich QLD


 Reply with quote  

Genius guys....does with mig or tig use less gas? So big is a bit like brazing where you feed it in and mig it squirts out the metal from the trigger.?

Good thinking about spares to.... and duty cycle..will look into it.
_________________
Miles Blow - Julie Pitts
www.mulesfilm.com.au
www.wombokforest.com.au

-Pickasso- Vivid Sportsman champion 2015

Post Wed Nov 18, 2015 9:58 pm 
 View user's profile Send private message Send e-mail Visit poster's website
Glen
Experienced Roboteer


Joined: 16 Jun 2004
Posts: 9467
Location: Where you least expect


 Reply with quote  

Mig can be gasless, but its horrible. Avoid like the plague unless you have to weld outside in a hurricane or something.

Got some more time to type now so here's my assessment, take it with a grain of salt Smile

Mig is good for heavy fab - making trailers, big framework, or when you need to make lots and lots of parts quick. Once you learn how to use the machine, setting the wirespeed and voltage is easy enough.

But you only get one go to make it look nice, not too hard when you get good at it but very few seem to be, Its as messy as a stick welder (spatter and smoke and sparks n shit go everywhere) plus tacking up delicate stuff is a pain in the ass cause unlike a tig, the wire has to touch the part to get started so that normally knocks the part away.

Very easy to get a cold weld on a mig too, were the weld sits on the joint without fusing into the metal.

Aluminium on the MIG is straight up horrible in my experience. Doing it via short arc (the normal way with steel) works and looks okay but its not strong at all. Spray arc is very strong and not that hard but can only do thicker metal and holy balls is it messy. I tried it a few times and smoked out the whole workshop Laughing

Also have to use a different gas (pure argon vs the argon mix for steel) for the aluminium too.

Swapping the torches and wire spools gets old fast, trust me you'll do it once then probably never again.

Now - TIG. Tig is like soldering on steroids. The torch has an electrode that doesn't get eaten away (in theory!) and you dip the filler rod in with your hand, like solder.

Biggest advantage for me is you can tack things up very delicately cause there's not much force on the part given nothing touches it, and can go back and reweld anything that came out bad as you don't have to use the filler.

Aluminium welding while tricky, is much nicer than with the mig and easier to set up for - don't need to change gas and wire spools etc. Just grab a different filler rod.

Personally the learning curve is less steep. People think mig is easier to learn but IMHO spraying bird shit weld at something and half sticking two parts together doesn't mean you know how to do it. Getting a strong TIG weld is easier once you got shown or told the raw basics.

Also much cleaner and just nicer to use - no spatter and silent (ac mode for ali gets pretty loud though). Don't have to armour up to weld anything, just throw a hoody on and weld away at 2am in your boxers lol, that's how half of decimator got done Smile

Disadvantages are tungstens are expensive, however they last a LONG time, gas is expensive ($460 to buy the bottle and $160 for a refill which lasts me about a year and a half) plus a little bit slower. Unless you are making 200x of something that's moot.

Like Don says, they all have their uses. It all boils down to the sort of work you see yourself doing.
_________________
www.demon50s.com - Minimoto parts
http://www.youtube.com/user/HyzerGlen - Videoooozzz


Last edited by Glen on Thu Nov 19, 2015 9:53 am; edited 1 time in total

Post Wed Nov 18, 2015 10:30 pm 
 View user's profile Send private message Send e-mail Visit poster's website MSN Messenger
Spockie-Tech
Site Admin


Joined: 31 May 2004
Posts: 3160
Location: Melbourne, Australia


 Reply with quote  

+1 for Glen comments.

I used a friends MIG a lot, then bought myself a DC HF Start TIG welder + Plasma Cutter) (now looking to upgrade to AC for Ally when the budget allows).

The TIG is much *slower to weld lots of stuff together, you wouldnt try to build a trailer or a heap of angle-iron shelves or anything with TIG, but since nearly all TIGS also do Arc/Stick welding mode, I just switch to stick mode if I have to glue any large amount of big steel chunks together quickly.

And Stick welding is great for burning through nearly *any crap on the steel construction without giving a damn. The stick rod coating is a flux as well as a shield and floats any crud in the weld pool to the top to be chipped off when it solidifies. So paint, mill scale, small amounts of oil/grease, you just burn on through it. The gas shielding in Mig and Tig *doesnt act like a flux, so you have to get all the crud out of the way first.

Migs arent *quite as fussy as Tig cleanliness wise, but if you want *quality welds, they require nearly as much pre-weld cleaning of your parts for good adhesion.

So while its a bit smokier and messier than Mig, I think Arc is better (in some ways) than Mig for fast, low precision building of big heavy stuff. You dont have to constantly stop and clean the gun either, which often clags up and jams with Migs. You do have to keep stopping and changing the Rod of course though, so its probably much the same overall speed wise.

Also as Glen once said, while Migs dont make quite as much smoke as sticks do, they still throw out an incredible amount of sparks, which will set anything within a meter or so of you on fire, including you. You get almost as much spatter/BB's as a stick weld all around your Mig welds too.

Tig is slow and fussy (joint prep), but neat, clean, quiet and precise. But the ability to easily switch to stick for quick, messy, smokey/sparky, bulk welding means a Tig is really a 2-process machine. (If not a 3 process if its a Plasma cutter as well, which many are).

Migs are sort of in the middle.. The fast one handed "Hot Glue Gun" aspect of them is nice, but the sparks, jam ups, joint cleaning, spatter, etc are annoying, they dont offer the same precision clean/quiet work as a Tig and a Mig is always only a Mig (unless you buy a $5k multiprocess machine) so you dont have the ability to switch to Arc mode (which is also useful when you dont want to burn gas, or have run out)

I think Gary uses a Mig for nearly everything, but hes been using them as a day job for years, so its probably 2nd nature to him Smile

*edit, hah, Glen updated his post while I was typing this and already said pretty much everything I Did.
_________________
Great minds discuss ideas. Average minds discuss events. Small minds discuss people

Post Thu Nov 19, 2015 9:37 am 
 View user's profile Send private message Send e-mail Visit poster's website MSN Messenger
Valen
Experienced Roboteer


Joined: 07 Jul 2004
Posts: 4425
Location: Sydney


 Reply with quote  

on the tungsten consumption, we got a handful when we got the machine, a few years later we got a few more, then at a random hardware store I saw a box of them for $4 a tungsten, so I got 2 boxes (of 10) they are still mostly unused.

The only other thing we have though is we got a little like 100W bench grinder that's on the welding trolley that only gets used for tungsten. So when you grind it you don't contaminate it.
_________________
Mechanical engineers build weapons, civil engineers build targets

Post Thu Nov 19, 2015 9:59 am 
 View user's profile Send private message Visit poster's website AIM Address Yahoo Messenger MSN Messenger ICQ Number
Glen
Experienced Roboteer


Joined: 16 Jun 2004
Posts: 9467
Location: Where you least expect


 Reply with quote  

quote:
Originally posted by Valen:
on the tungsten consumption, we got a handful when we got the machine, a few years later we got a few more, then at a random hardware store I saw a box of them for $4 a tungsten, so I got 2 boxes (of 10) they are still mostly unused.




Yes sorry for the sneaky edit there Brett, felt the need to splurge all those thoughts on welding for a while haha,
_________________
www.demon50s.com - Minimoto parts
http://www.youtube.com/user/HyzerGlen - Videoooozzz

Post Thu Nov 19, 2015 10:03 am 
 View user's profile Send private message Send e-mail Visit poster's website MSN Messenger
DumHed
Experienced Roboteer


Joined: 29 Jun 2004
Posts: 1219
Location: Sydney


 Reply with quote  

I would also add that a cheap TIG welder works fine, and since there are no mechanical moving parts involved, they tend to be pretty reliable.

A MIG needs a lot of precision mechanical parts for the wire feed, torch, etc and a cheap one will not be great.

Even expensive ones are not super consistent.


As for gas usage, a MIG will be using 3 - 10 times as much gas depending on your settings.
With TIG you can get away with amazingly low gas flow if there's no breeze and things are set up well.
_________________
The Engine Whisperer - fixer of things

Post Thu Nov 19, 2015 10:28 am 
 View user's profile Send private message Visit poster's website MSN Messenger ICQ Number
Rotwang
Experienced Roboteer


Joined: 15 Jun 2004
Posts: 1576
Location: Vic


 Reply with quote  

Depends on how serious you are about welding aluminum. I agree with Glen: I only did it once after buying my first mig with the extras.

So aluminum means ac tig and argon gas which costs more than mig gas per bottle as for me a given weld is quicker with a mig than a tig the actual LPM VRS $Pweld figure is ?

As for aliminum you really need a foot pedal or thumb wheel to have any hope of not turning the job into a molten blob.

The problem with a lot of migs is that they wonít throttle back far enough. Not a deal breaker for bot building but for car body work they are too hot on there lowest setting.

Brettís correct in that I use the mig for almost everything, Tig is too slow.

Another use for the tig is un coated bronze if you havenít got oxy acetylene or similar.

So my vote forget the aluminum and get a mig. Inverter ones are nice.

http://www.ebay.com.au/itm/MIG-TIG-MMA-Welder-Inverter-Welding-Machine-220-Amp-NEW-3-IN-1-ARC-Gas-Portable-/271841569906?hash=item3f4b052c72:g:hQsAAOSw~bFWMOM-

compare the weight!
_________________
Satisfaction is proportional to effort and results.

Post Thu Nov 19, 2015 8:04 pm 
 View user's profile Send private message
DumHed
Experienced Roboteer


Joined: 29 Jun 2004
Posts: 1219
Location: Sydney


 Reply with quote  

If you forget aluminium though you can get a ~$200 TIG, which will also stick weld.

I don't think welding speed is a big problem with robot building - but certainly if you're going to need to build a lot of big metal stuff it'll be faster (but uglier) with a MIG.
_________________
The Engine Whisperer - fixer of things

Post Fri Nov 20, 2015 7:14 am 
 View user's profile Send private message Visit poster's website MSN Messenger ICQ Number
  Display posts from previous:      

Forum Jump:
Jump to:  

Post new topic   Reply to topic
Page 1 of 9

Goto page 1, 2, 3, 4, 5, 6, 7, 8, 9  Next

Forum Rules:
You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum

 

Last Thread | Next Thread  >
Powered by phpBB: © 2001 phpBB Group
millenniumFalcon Template By Vereor.