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  1. #1
    Join Date
    Jun 2012
    Location
    melbourne
    Posts
    341

    Default A couple of faults.

    For four years I have been doing mostly TIG welding. in fact I didn't replace the Argon Co2 mix so for the last two years I have only been doing TIG. I quite often use the torch just with the button and I thought I was going quite fast because no messing about with foot pedals and the cable getting caught etc. When I'm actually welding, its not much slower than MIG, but there's still all the faffing around with stopping to get a new rod, cleaning it, putting your gloves back on etc. Anyway, i have been welding a fair bit recently and I just wanted to get things done so i bought a Ar/CO2 mix and tried the mig again. It turned out the mig was loads faster and so much easier, and you have a free hand to hold things. Having not used the mig for 2 years, my welding seemed a bit iffy. I thought it was just me. i seem to be losing my marbles as i get older and i wasn't sure if this was just another symptom, maybe I'm losing my motor skills too. Then i did a tack weld which you can see here. its all quite heavy gauge, the small part is 10mm steel, and I'm welding onto some 100x100SHS. The earth clamp is on the SHS. its actually broken off by the time i'm taking the photo but i held it in place so you could see it looked OK, it did stick a little. I know to point the flame at both sections to get some penetration but it just didn't work. It was a fairly big tack too, because it was heavy gauge stuff, so i was surprised at no pentration. This was my MIG at max setting so should be ~170 amp.
    20160928_111544.jpg

    If you read the american forums you'll know the pro's are very sceptical about small mig welders because they can give what looks like a good weld but have no penetration. particularly because their domestic supply is 110V so the diy migs are not very big at all.

    i bought my mig 16 years ago and i think it was 6 years old by then already. It looked as rough as it does now when i got it. Apparently worked in a car exhaust center. Its 170 amp, which is not too bad and shouldn't suffer the problems of small migs. In all that time, it has just run and run, can sit for years and then just run again. Its a transformer type of course, not a LSI chip in sight. Mega reliable. My Tig welder has stopped working twice in 4 years and my mig has always finished the job. i thoroughly recommend having a transformer MIg, especially since you regularly see CIG transmig 195 sell for $400 on ebay.
    20161030_120135.jpg

    Anyway, I thought it couldn't be my welder, so carried on, just taking more care to get penetration on each side of the weld. I was very disappointed in my welding though, i really had lost it. i had just replaced the plastic screen on my helmet too, maybe seeing too well was the problem! After a few hours my welder stopped welding. Three times in 16 years I've had to replace the motor fuse, so I checked that out but it was Ok. Turns out it had cut out due to being too hot, never had that before, but I had been using it a fair bit. I was really making use of the fact MIG is so fast and you don't need to keep stopping. In the process of searching for the fault however, I burnt my hand on the earth connector. It was roasting. On investigation, it was a really old cast brass earth clamp. That orange earth cable is 600amp stuff and had a huge brass clamp. No pictures, sorry. Turns out it had cracked almost right across the brass, so all the current was flowing through just a small bit of brass, causing a lot of heat and no doubt limiting the current.
    A new connector and everything is working perfect, and my welding is tons better. I reckon its worth checking how hot your earth clamp is getting because even if its just a poor connection and not the clamp itself, you must be losing some performance. If its hot, clean the earth point some more. Here's how the welds look now
    20161031_120629.jpg
    This was just verging on spray transfer mode. You can see how few splatters there are. 170 amp is borderline for spray transfer but it managed, just the occasional dip. I'm very pleased how this old welder can perform again.

    My other fault happened when my mig stopped working. I thought I'd just keep on going with the TIG to get the job done. Typical of my luck, I switched on the tig and it all lit up but was quiet. I saw some people complain about the fan noise on their welders but i find it very handy. For a start, I knew the fan wasn't working! I just left it and started checking out the mig, as it seemed the easier thing to fix to get the job done.
    I came back to the tig later and it still would switch on, and weld even, but just no fan. I wouldn't use it without the cooling so I opened it up. Mine is a generic chinese brand, but the same design as token tools and everlast. its a 250 amp tig/60 amp plasma thingy.
    20161030_120217.jpg
    If you've never taken one apart, go in from the back, don't try to take the front cover off. Its quite a fiddle to get it apart. I had a poke about inside but couldn't find anything wrong. When I powered it up, the fan was working. Put it back together and used it, all good. Next time I used it, it wouldn't start so i gave it a thump. Fan started so I used it that day no more probs. Next time, it wouldn't start again. Thump did no good. I poked a stick in to turn the blade of the fan round a few degrees (with the welder switched off, I don't recommend poking things into a 250 amp power supply if its switched on) Fan came on when I powered it up. ok so I havent fixed it but if it happens to you it might be worth trying to get the job done until you can fix it. Probably needs a new fan.

  2. #2
    Join Date
    Aug 2009
    Location
    Sydney, NSW, Australia
    Posts
    1,836

    Default

    You exhaust the fan sossity haha i think i have seen a similar mig to your on ebay from time to time, I'm much liking transformer machines over these inverter machines, the transformer machines weigh a ton but i find they are much smoother to weld with and less temperamental to slight changes

    i have a small DC inverter tig i will be using today its a nightmare to strike an arc most of the time maybe its my technique but on one job i ruined a whole powerhead on a outboard as i was scratch starting the torch grabbed let go than grabbed again melting a creator in a bolt mounting (i was heating the snapped bolt in aluminium block)

    it is a good little tig for what it is but i'd imagine a vintage 240v transformer tig would weld far superior

  3. #3
    Join Date
    Jun 2012
    Location
    melbourne
    Posts
    341

    Default

    Quote Originally Posted by gazza2009au View Post
    You exhaust the fan sossity haha i think i have seen a similar mig to your on ebay from time to time, I'm much liking transformer machines over these inverter machines, the transformer machines weigh a ton but i find they are much smoother to weld with and less temperamental to slight changes

    i have a small DC inverter tig i will be using today its a nightmare to strike an arc most of the time maybe its my technique but on one job i ruined a whole powerhead on a outboard as i was scratch starting the torch grabbed let go than grabbed again melting a creator in a bolt mounting (i was heating the snapped bolt in aluminium block)

    it is a good little tig for what it is but i'd imagine a vintage 240v transformer tig would weld far superior
    Someone was exhausted, I guess the fan was too. I was wearing an old jersey because otherwise its just old tshirts I've got and i needed the jersey for UV protection, but definitely not because i was cold. Still, beer tastes better when you are really dehydrated at the end of the day.

    I've never tried a transformer tig, but one of the mods on an American welding forum does incredibly beautiful welding and uses an old school welder with no fancy features at all. he uses a 2.4mm electrode for almost everything, even tiny stuff. I think at the end of the day, its the skill of the welder that makes a lot of difference though.

    i must admit the inverter stick welding is way better than the old ac buzz box transformer welders though, but thats because its DC instead of AC I think.
    You make a good point with striking an arc on the smaller TIG welders that don't have HF. If you know for sure you want to do tig welding, you are probably better getting a purpose built tig with HF, and AC while you are at it for that matter. I'm not sure but I think most of the dual purpose mig/tig don't have HF to start the arc? It always comes down to money though.

  4. #4
    Join Date
    Aug 2009
    Location
    Sydney, NSW, Australia
    Posts
    1,836

    Default

    Quote Originally Posted by sossity View Post
    Someone was exhausted, I guess the fan was too. I was wearing an old jersey because otherwise its just old tshirts I've got and i needed the jersey for UV protection, but definitely not because i was cold. Still, beer tastes better when you are really dehydrated at the end of the day.

    I've never tried a transformer tig, but one of the mods on an American welding forum does incredibly beautiful welding and uses an old school welder with no fancy features at all. he uses a 2.4mm electrode for almost everything, even tiny stuff. I think at the end of the day, its the skill of the welder that makes a lot of difference though.

    i must admit the inverter stick welding is way better than the old ac buzz box transformer welders though, but thats because its DC instead of AC I think.
    You make a good point with striking an arc on the smaller TIG welders that don't have HF. If you know for sure you want to do tig welding, you are probably better getting a purpose built tig with HF, and AC while you are at it for that matter. I'm not sure but I think most of the dual purpose mig/tig don't have HF to start the arc? It always comes down to money though.
    Anything that's is quality made welds far superior than the cheap Chinese welders, with my very first Chinese mig welder from Mishto on ebay it was meant to be a gas/gasless machine but really it was gas only mig i have never seen a gas only mig before this? no matter what setting it just would not weld fluxcore i think from memory it only had the one polarity for gas only too, it was about a $300 ebay Chinese welder was a nightmare i remember contacting the seller about it at the time and he or she replied "gas/gasless uses the same polarity" as iwas asking how to change the polarity

    when i first started to learn to tig weld the guys on this forum back on the woodworking forum mentioned i may have better luck upgrading from the 1.6mm tungsten to 2.4mm it made the world of difference as i was constantly burning up the 1.6mm

    my little Mechpro 140A arc welder just has the addition of a tig torch i run the gas from the bottle to the torch and it doesn't have HF but it fit my wallet at the time, if i had to purchase another one i would go for HF start but now i have a HF box haven't used it yet tho still unsure what polarity goes where would hate to wire it back the front and burn it out

    there was a CIGWeld AC/DC 3 phase machine on gumtree up the coast at Taree if anyone interested in reading this wants to purchase it, i was going to snap it up but a bit of a drive, being a 3 phase machine it can be rewired for 240v from what i read online i think a industrial machine like this would weld beautiful over a cheap welder i reckon

  5. #5
    Join Date
    Sep 2010
    Location
    Lebrina
    Posts
    1,910

    Default

    Very valid point regarding poor connections. i am totally frustrated by the so called "tradesmen" who will continue welding using a machine that has such poor connections that the insulation is melting off the cables, not to mention the marvellous surprise you get when you go to remove a near red hot earth clamp.
    As you found, good connections make a world of difference to welder performance.

  6. #6
    Join Date
    Feb 2012
    Location
    Sydney
    Posts
    67

    Default

    One of my welders is a Lincoln MIG 255 and I know in an instant if it hasn't got a good earth connection; it welds beautifully when it has. Sometimes I use an earth clamp to my steel welding table but often that's not as good as a direct earth on the piece itself.

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