mig or tig

[Farmer DaveParticipant @farmerdave]

I am thinking about buying a small welder suitable for welding aluminium sheet/plate to form crankcases and other parts for model engines. I have not much knowledge of either Mig or Tig with or without gas.Can anybody help what would you recommend.

Regards Farmer Dave

Edited By Farmer Dave on 05/07/2014 21:50:22

[Farmer DaveParticipant @farmerdave]

[stan pearson 1Participant @stanpearson1]

Dave

I have used both and there is a difference, Mig is like Arc welding but with a continues wire instead of rods if you use this on steel you will need ARGON SHIELD if on Aluminium you will need pure Argon Tig is like gas welding but with electric arc and you use a rod as in gas welding, both are good at what they do. If you welding Aluminium and Stainless Tig is the best its not so good on mild steel.

Hope this helps

Stan

[Bob Brown 1Participant @bobbrown1]

If you are thinking of aluminium then the best option is TIG but it needs practice and not all people find it easy to master. You can weld aluminium with MIG but the results are no way near as good as TIG.

You will need gas no if's or buts and a 50/50 argon/helium mix is probably a good start also AC although it is possible to weld aluminium with DC, AC helps clean the weld. On that note welding aluminium needs to be clean really clean and the use of acetone to remove all traces of oil and grease followed by the layer of oxide with a stainless wire brush. Welding electrode choices are quite extensive and selection is down to material being welded.

As steel welding is best done with DC it is probably better to get a AC/DC welder which gives you the best of both worlds.

I would practice getting the position of the rod and torch correct and feeding the rod before you power up the welder. Practice makes perfect and the key is welding in a comfortable position where ever possible and more practice.

Bob

PS: TIG will weld steel as well if not better than MIG and that is the view of a mate who used to work at the welding institute where a lot of these processes originated. Model Copper and steel boilers are TIG welded all be it by coded welders.

Edited By Bob Brown 1 on 05/07/2014 22:42:31

[Oompa LumpaParticipant @oompalumpa34302]

Tig will not work well without Argon and frankly if you are buying one of those (or rather, thinking about buying) toy DIY Tig sets, save your money. You will be better off buying a proper second hand Tig set that will actually do the job. I have used ally wire in a Mig but Tig beats it every time for finesse. If you want to put plenty on and machine it down, Mig might work.

Question is, how good are you at welding right now and do you have the time and inclination to practice?

graham.

[Oompa LumpaParticipant @oompalumpa34302]

So there you have it. Three of us posted within thirty seconds of each other and to my amazement, we are all in agreement. Choose any one of the answers above and there you have it.

graham
still amazed!

[WALLACEParticipant @wallace]

Add a foot control for ally as well. You need a bit of extra heat to start off with then knock it down to avoid what you’re welding turning into a puddle….

Don’t ask.

W.

[Clive FosterParticipant @clivefoster55965]

Best bet is to sign up for a welding course to learn both MIG and TIG properly on industrial class machines.

Then you will both know what to do and be able to make an informed choice of used or lower end new machine. Trying to learn ally TIG on your own is hard. A low end machine needs higher skills to compensate for its limitations and any affordable industrial quality machine will be past the flush of youth so may well be faulty or in need of a good go through. Industrial machines have considerable set-up flexibility which is great when you know what you are doing but its all to easy for a beginner to get it all wrong. The absolute worst thing you can do with TIG is to develop an incorrect technique which gets sort of OK results from a wrongly set-up machine.

Clive

[MuzzerParticipant @muzzer]

I'd agree with Graham and others – get a decent (used?) professional machine with a foot pedal, AC and DC output (ie not just DC) and HF (ie not scratch start). As ever, the hobby equipment is harder to use then the Real Thing.

I read loads of books and watched plenty of the Youtube training videos – there are some really good ones. Admittedly I also did several weeks welding training years ago (remember the MSC Training Centres?). I can now manage passably with both TIG and MIG but it's one of those things where the more you challenge yourself and practice, the better you get.

MIG is like a tube of glue that won't stop flowing, so unless you get it right first time, you have to grind it back. You also have a minimum current (translates to minimum material thickness) unlike TIG which can be controlled almost down to zero. I used to think that with TIG you could weld anything but in fact some metals have lots of impurities – try welding copper water pipe which is riddled with oxygen and bubbles with the stuff when you try to weld it.

Technique and joint preparation are critical, particularly for TIG. For a work of art, I reckon nothing can beat a well executed TIG weld. I never said I was an artist!

Murray

[Bob Brown 1Participant @bobbrown1]

Another major problem is going to be power supply, a lot of the "industrial" machines are likely to be three phase although they tend to only use two phases and due to power requirements it will not be possible to run these machines from a single phase supply and a converter. Single phase machines require quite a large power supply 16amp + and although you can get machines that run of a 13 amp plug they are not really up to much.

A lot of the better quality single phase machines will need between 16 to 32 amp supply.

On top of this is cost, you are looking at £1000.00 plus for the machine, new or second hand as the AC function and HF start all tend to push the price up. Then there is gas, dependant on what you weld and the quality of the weld you require will affect the gas you use, gas is not that expensive but bottle rental can push the cost up.

If as I suspect you are only looking to weld small parts and not very often where the machine sits idle for 99.99% of the year then it is an investment that does not add up, it is probably better to find someone who has the kit and can do the job for you.

Bob

[FatgadgiParticipant @fatgadgi]

Dave – my personal experience, for what it's worth …….

I agree with most of the above – you really need TIG for aluminium and you need pure Argon gas and AC/DC. The AC bit costs more money than just DC, but is necessary for aluminium.

TIG welding is probably the most versatile welding option, in terms of materials that you can weld, available, but it's also probably the most difficult to learn (and expensive to run). MIG on the other hand is not that good for aluminium, but it's a doddle to learn.

I class myself as a good self taught amateur when it come to stick and gas welding and bought a Chinese TIG set 3 years ago. It was around the £650 mark and I have to say I have had no problems with it and I've been very pleased. The company is UK based and buys Chinese welders and sells them on, but carries spares and has back-up in the UK, which I thought was a good compromise. The unit also stick welds very well and I find that I now use the TIG in this mode for steel rather than use my old transformer unit.

I considered second hand "proper" makes, which has been my philosophy for most of my machines, but whilst I would expect them to perform better and for a lifetime, the size and weight put me off – the Chinese one is all electronic and can be lifted with one hand and has features to help start and control the weld that are not normally on the older machines.

After playing around using a full bottle of gas (which lasts less time than you might think) I found that I was getting the hang of it – some welds were very good, some welds were functional but looked childish. Occasionally I still blow a hole through the piece if I do not concentrate properly – one day I'll get the foot pedal which will help a lot.

Cheers – Will

[ronan walshParticipant @ronanwalsh98054]

A really good welding set that can be had for reasonable cost is the chinese made r-tech. Don't let the chinese put you off, these are very good machines and the uk agent has a no quibble warranty where if something goes wrong (never anything major i hear) then he will put it right. Also you do really need ac for aluminium, you can use pulsed dc but with ac and the correct gas you can get lovely clean "stack of pennies" type welds.

Have a look on the mig welding uk forum and also doubleboosts channel on youtube.

Edited By ronan walsh on 06/07/2014 10:29:42

[Robin KingParticipant @robinking15611]

Dave,

All good advice thus far. Forgive the assumption but I assume you're not a welder by profession so with the best will in the world you're not going to learn much more from posts/reading alone. You can learn by the 'try it and see' process but the best way is as Clive posted earlier – on a course, and getting hands on tuition is essential if you are going to make the best use of whatever kit you buy and the experience you gain will stand you in good stead when buying equipment. Aluminium welding is something you need to be shown how to do and then practice, practice, practice; if you have an instructor there who can point out the rights and wrongs then you will be well on the way to at least understanding what is going on (and why it's gone wrong!). On the course I attended our instructor encouraged us to take in individual project pieces which he then used as a basis for demo's, resulting in a lot of high grade welded pieces tracking back to my workshop

[jaCK HobsonParticipant @jackhobson50760]

I've been in the same dilemma for a couple of years (so far solved by spending the available cash on other tools).

AC TIG is a complicated machine. If you want UK support in case it goes wrong then it is going to cost £1000: http://www.weldequip.com/tecarc-206i-acdc.htm Half that cost if you take a gamble on a new machine from ebay. If cost isn't an issue then I'd have go straight for TIG

If someone has not done welding before then I would recommend a £50 (cheapest you can find) starter 'stick' set and try welding some mild steel. I've had mine for 8 years and it performs a useful function. It is a good learning tool as more expensive sets are much easier to use. Treat the £50 as a lesson rather than capital expense.

[Involute CurveParticipant @involutecurve]

I have both MIG and Tig, for Ali I use pretty much extensively Tig, but for my motorbike petrol and oil tanks I also use gas welding with flux on some seams, because you get a more pliable weld for subsequent forming, in this case I use strips of the parent metal as rods.
I did have a very expensive £2000 + tig set that I bought new in 2003 this went faulty last year, whilst it was away getting repaired, I borrowed a Chinese tig set that cost £420 new off ebay, when the original tig set came back from repair, I sold it and bought one of the Chinese ones, with enough change to buy another two!! its much smaller weights a tenth of the American one and has more functions, it came with a pedal but I prefer to use torch control and utilise the slope up slope down function and or pulse to control my current within a preset range, in addition to Ali I use it for Titanium, cleanliness a well shaped tungsten, short arc length and getting into a comfortable position is the key to good neat welding, and lots and lots of practice, oh and don't even think about Tig welding without a good gas lens.

[FatgadgiParticipant @fatgadgi]

Yep, mine came from r-tech as well – Will

[John McNamaraParticipant @johnmcnamara74883]

Hi Farmer Dave

If you want to see TIG welding done by an expert this is a good site to watch, Its a bit addictive watching Keith Fenner so watch out….. You will have to browse a bit he does not weld in every video.

As a jobber he covers a lot of light engineering subjects. All done with older manual machinery, except for CNC plasma cutting (I wish).

**LINK**

Or his YouTube home page

**LINK**

Regards
John

[ronan walshParticipant @ronanwalsh98054]

Pure aluminium is actually pretty easy to weld, its when the metal has old oil or grease absorbed into the pores of the metal , or when the ali contains zinc or something it gets messy and frustrating. Believe me ,i used to work in a fabricators/welding shop where all sorts of work was brought in. To be asked to weld something in new clean ali was a welcome relief.

[Bob Brown 1Participant @bobbrown1]

Not all aluminium alloys are equal, some are easier to weld than others and some are impossible like 7075 amongst others in the 7xxx series also some of the 2xxx series but not all of them.

Clean and oil free is essential.

Do not forget some of the heat treated alloys like 6082 T6 (tricky to weld) will no longer have the same strength once welded unless it is re treated.

Edited By Bob Brown 1 on 06/07/2014 20:15:04

[Farmer DaveParticipant @farmerdave]

Thanks for all your thoughts and advice, it would seem that to get a decent machine I would need to spend £800/£900 and need some help & training. I think I'll stick with my usual method of pins/rivets and filler or get a pro to do it for me. My hands are not that steady anyway.

Regards Farmer Dave

[Oompa LumpaParticipant @oompalumpa34302]

It would seem I am going to be looking closely at some of the Chinese sets. And if they are lightweight as Shaun says – having no reason to doubt him – I like that, the smaller the better for me.

graham.

[stan pearson 1Participant @stanpearson1]

When I served my time in the late 50s it was ether Electric arc or gas, I was shown a useful trick when welding pure Ally light a candle run the Ally over the flame when you heat with welding torch the black soot goes light grey stick your rod in and weld.

Stan

[Involute CurveParticipant @involutecurve]

Posted by Oompa Lumpa on 06/07/2014 22:18:36:

It would seem I am going to be looking closely at some of the Chinese sets. And if they are lightweight as Shaun says – having no reason to doubt him – I like that, the smaller the better for me.

graham.

Try mine Graham next time your in the area, I was amazed how good it is, holds a nice arc and loads of functions. the torch as supplied was useless but its easilly sorted with new lens and pot, my mate who's a coded welder reckons its a good set, you can pick it up with one hand and walk with it, and it runs upto 200amps AC/DC also it has a btter Alloy cleaning action the the Miller had.

[ronan walshParticipant @ronanwalsh98054]

Some of the chinese plants, r-tech for instance have siemen electronic components, not something made in a sweat shop in a back lane in the back of beyond. Something else to know is a lot of the american welding plants with some prestigious names are made in china or italy, and only assembled in america.

[Author]

Posts