Thread: Chinese TIG welder Comparison

Pete - having seen the schematics for these welders, what do you reckon the weakest point in the chain is? I.E if you pushed it what would break? Are the overload protections circuits robust enough to prevent frying or could they fail?

Originally Posted by 19brendan81

Pete - having seen the schematics for these welders, what do you reckon the weakest point in the chain is? I.E if you pushed it what would break? Are the overload protections circuits robust enough to prevent frying or could they fail?

Oh sorry mate, if only it was so easy Unless there was a major design flaw it's unlikely one would pick up an obvious weak point just by looking at the schematics. It tends to be more about the quality of the components used, and even then it can be very difficult to just look at something and say "oh that brand is rubbish, that will fail for sure". What tends to happen is that when a product is released a weak point will emerge over time and thousands of units, so if you're in the game of selling or repairing them you get to know, or the word may even get around the pro industry. Electronics are on the whole VERY reliable and often failures are purely random.

Having said all that, if you think of it, not as a box of electronics, but say a high performance motor in a car you probably won't go too wrong. One of the biggest enemies to electronics is heat, just like a car. A major difference between seemingly similar welders is the duty cycle they're capable of, that is how long they can run at a specified current output compared to how long they need to be on standby. A welder designed for professional use doesn't earn money sitting there idling away so it may be specified as 60% duty cycle at maximum output. On the other hand a DIY type welder could be only 20%. If you want the welder to last and you do a lot of very high current welding towards its capacity respect that duty cycle. You may think you're getting away with it only to find the unit doesn't last too long in the long term. Think of it maybe like towing a very heavy trailer through hilly country; going up a hill you could have your foot flat, but you don't want to do that to your motor all day! If you need something to do that, buy a bigger car to haul that capacity up the hills easier.

Incidentally, while on the subject of heat, the fans are there for a reason, so with any electronics if it comes with a fan or cooling vents make sure they can do their job effectively.

As far as the protection circuits, yes they're fitted but you shouldn't be triggering them all the time and expect your machine to last. Just like seatbelts or airbags they are there for PROTECTION. In a motor think of it as the rev limiter, sure you could rev the engine to the limiter every time you change gears (and I seriously think some women do, 2.5 microseconds after they release the ignition key ) but unless you're racing the car why would you do that? Clearly the engine won't last long if you're flogging it so hard and electronics are no different in general (of course depending on just how much "protection" they offer in the design; how high that rev limiter is set).

The bottom line is just because a welder says 200A does it mean you should, or even can, operate it at 199A every time you turn it on. If you do a lot of 200A welding you should probably buy a 350A welder. Sadly it's one of those areas that you may think you've got away with it but wonder why your kit never seems to last.

Hopefully that's of some interest.

Pete

Edit: I would just like to emphasise once again that I'm not pretending to be any sort of welder expert, far FAR from it. However most of the above is applicable to any sort of electronic device, and in particular industrial electronics, and I'm simply relating what I know about electronics to what I can see here in this field.

Thanks Pete. Helpful post.

Hi Brendan

Have you had the opportunity to try your welder with aluminum and if so how well did it work -- and I guess how is it performing in general - any problems?

Graeme

Yeah I have. I finally got hold of some aluminium and had a good crack at it. I played around with various settings and have kept the results. I couldnt photograph it in the garage as it was dark and the flash was playing havoc with the shot due to the reflective metal. Its a matter of dragging them outside into the shade and photoing them there I reckon. Then ill show everyone.

In summary though it performed admirably. I've had it for about 6 months now and have gone through half an E sized bottle of argon. Everything works as expected.

Brendan

Thanks Brendan
I build bicycle frames and I would like to be able to tig them but eight grand for a Miller is beyond my budget so I am glad there seems to be a satisfactory cheaper alternative. I realise you probably have not kept an eye on the market since you bought your machine but if you have do you thing you would still purchase the same unit or have better things become available from the same or similar people who have a shop type outlet ?
Thanks Graeme

In terms of shop type outlet im pretty sure Token are still the best value for money. There are many other blokes on the web such as bob the welder and national welding supplies who will do chinese welders, but they are more expensive than Token. the mob in WA, Weldsmart I think, have a pretty good product range. Id be tempted to give one of their welders a go.

How thick is the tube you use for bike frames? My welder only goes down to 30amps on AC, but will go as low as 5 amps on DC.

Bike frame a usually very thin -- main tubes are normally around 1 mm but often less depending on the type of alloy steel used but some components like the crank housing can be more like 2.5 mm so you end up joining a 0.7 mm seat tube to the 2.5 crank housing. I have not TIG welded for some years but if memory serves me I only ever used AC for Alum so 30 amps would probably be OK since the Alum tubes are always much thicker - more like 1.2 - 1.6 mm -- not that i can remember what sort of amperage I used to use to weld Alum stuff like that when I was doing it.
Graeme

Sweet. 30amps would be fine if the alloy tube is 1.2 or 1.6. It would be pushing it if the tube was .8 or so though. However, if your using steel then you would be fine wtih my welder. Ive gone down to approx half a mil with mine, used 10amps.

Thanks for the info -- I likes the look of the machines from WA but I am more attracted to buying something from Wyong where I can drive there and talk to someone. Its less than an hours drive and life experience tells me that if you have problems, being able to deal with someone face to face usually gets you a more satisfactory result. Probably means I am old and cynical but thats life.
Graeme

Thats probably the biggest selling point of the machine, his shop in wyong. It gives a lot of people confidence in the brand. Its a bit different to buying from a warehouse/onseller, and evidently punters are prepared to pay a fair bit more to deal in person.

Silverwater Welding and Hare and Forbes sell Unimig TIG machines and they are both in Sydney.

Finally posted up some sample welds.....here they are.

https://www.woodworkforums.com/f160/a...amples-109998/

Brendan

I have an ALLMAX 200amp AC/DC TIG from MAGNUM on EBAY.MAGNUM had a different name when I bought mine,as it was a couple of years ago,Mine has all the features as Token tools machine,,,,Well I would say they are identical,mine has a Toshiba MOSFET.
I have to just but in and say it would have to be the best TIG and STICK machine I have used in a very long time.!!
I used a mates miller 2-3 weeks ago and felt that mine was much easier to use with many more settings avaliable..
Just my 2 cents worth.
Matt