I learnt to gas weld 50+ years ago and got to a stage where I was happy enough with the results. I have had a dabble at TIG and find it difficult.

Dave,

I recently bought a decent Miller inverter TIG welder STH 160. It is a light but high quality unit.

I found that even a few amps change in current can make a difference. I found that electrically it is very good.

Unfortunately the control system was obviously designed by an electronic engineer who wants to make everything as small as possible with as few controls as possible. This has meant that I still cannot use (program) the pulse setting. I need an eleven year old to show me how to set it up! What we want is big fat switches.

I am experiencing a problems in avoiding pin holes even in a good quality run. Bit of a problem as my next job is to make a petrol tank for a run up rig for the 27 litre Meteor tank engine.

TIG welders are expensive but do a fabulous job in my opinion.

John

it is difficult at first, but it takes practice, like all welding, and it gets easier. It pays to adjust your welding helmet till you can see as clearly as is absolutely possible, because you need to have a clear view of the puddle, and also to follow the gap you are welding (something that I fail on), my tig is an old school transformer, so no foot pedal, but it is ac/dc and was only £150. It pays to rest your wrists on something, sit down at the job, and concentrate on the puddle. Absolute cleanliness, even on steel is essential, as is a nice clean pointy tungsten. With TIG, you need to be very picky, you cant just point and shoot like you can with mig, and you cant burn your way through dirt, rust and grease like you can with gas and stick

I am also trying to learn to use a TIG welder. I started off using the MIG auto dimming helmet but was struggling to see what I was doing. Brought a Parweld True Colour vizor and this transforms things. I can now see the weld puddle. The other thing I did was by a x2 cheat lens to fit in the vizor. This increases the size of what you are looking at significantly. I wish I had bought the x2.5 now.

Trouble is I have not picked the welder up for a couple of months. I had intended to try and use for a few hours every week. I want eventually to be able to TIG ali.

Colin

It may seem paradoxical, but excessive heat build-up in the body of the work is often the result of using too little current. More current, faster traverse and a helping of reckless abandon may prove better. A foot control makes life so much easier – but you do have to control an extra limb… Also, use a gas lens to economise on gas and get a better view of the electrode, which can stick out more.

Once Covid is under control I will have a search for the Hinkley training facility. I am only about 25/30 miles away and would love to improve.

Very True!

Three important things in TIG welding – ( and a fourth..)

• Correct current setting – Experiment on similar thickness materials to get it right first.

Don't let the test pieces get too hot while 'testing' as that will mask the correct current setting –

Body weld Position.

Esp when learning, seat yourself at the weld table, use arm rests, be comfortable, rest the weld hand lower wrist on a block of wood placing the tungsten at a comfortable height over the weld line – mock-swipe the weld line so when welding with helmet on visibility you 'naturally' follow the line. Important as it helps you get a feel for the flow of the tungsten over the material – A poor hand position may move in an arc, away from the line, or may swoop the tungsten up or down, dipping into the puddle or increasing the arc length and current, making holes.

• Visibility.

For beginners, use a decent auto-darkening helmet. If you can't see the weld line in non-dark mode or see the line right ahead of the arc in darkened mode, its set to dark. To start, keep the weld line in view, with the weld pool approaching your view – when experienced you can TIG away from your view, with a hidden weld line – needed in some workpiece orientations..

It is imperative that the weld puddle is CLEARLY visible – often maltreatment of the helmet results in lots of fine scratches on the lens cover – Don't grab the nearest rag, or tissue/towel and with vigour clean the lens with a circular wipe pattern! Now when the arc strikes, the view is lost in lots of little starburst patterns, with a very bright hazy area at the puddle….

Magnification of view is a great aid to steadying the hand – try it – with normal eye view, get up close to a human hair and try cut the end off with a scalpel – note the hand shakes, etc. Now do that under a microscope – suddenly the knife tip is rock steady…

So if you are jittering the tungsten around the puddle, and digging the weld wire everywhere else, get close up, put on some 2 or 3X magnifiers and get to maybe 10 or 15cm of the weld.

• A 4th item is relevant when welding aluminium –

Aluminium requires AC current to ensure proper surface oxide removal during welding.

The joint MUST BE a very good fit – small gaps can be closed, – 0.2 – 0.4mm not more, and NOT at the start of the weld point! If you try the latter, the two halves of the joint will melt and peel away from each other – if you are good you can quickly bridge the gap with melt from the feed wire – if not, you ruin the part.

Aluminium requires LOTS more current due to its thermal performance. Starting cold, can require up to 2 to 3x the current needed to do mild steel of the same. And its the start of the Ali weld job that normally messes you up – the heat just conducts away to fast, so you up the current, and halfway through the job start melting big holes in the job as the job has heated up a lot.

Heat is your friend in this – pre-heat the Ali job first- Gas torch, oven, whatever –

To start, the parts must be VERY clean around the weld area – use a stainless steel wire brush ( one reserved ONLY for this – don't use it on the Morris's brakes and wash in petrol and use it on your weld..).Then wipe down with a damp ( NOT wet) CLEAN cloth with a solvent like acetone. Now, don't touch with bare fingers, or with the dirty weld gloves, at least not on the weld areas!

Now, if going to pre- heat – first mock-fitup and get the position right, get your weld position right, weld flow direction sorted, etc. The put the bits in the oven, or heat in place with a torch, etc – the old trick of some soap on a free spot, turns black(ish) when hot enough – works ok. THEN when hot, a quick wire brush over the weld area to get rid of the new oxide helped along by the heat, and you are ready to go.

When you weld, if you dip into the puddle, STOP – don't try to fudge your way along – it will only get worse. Re-grind that tungsten, ball it, CLEAN the weld with the brush, or if bad, a file ( NOT USED ON STEEL/BRASS etc!) and start again.

This may all seem onerous, but welding Ali is quite unforgiving. Once you get the knack you will quickly learn what you can forego in all the above processes and the weld is easy..

TIG is not hard – like everything we do, just needs a little practice and some common sense – and a bit of study!

Joe

Edited By Joseph Noci 1 on 31/12/2020 11:48:31

Spot on Joe, there is much wisdom in this post.

What is often not known is that aluminium when cut, ground or machined ALMOST INSTANTLY forms an insoluable oxide in air, it is this oxide film that makes aluminium much use at all, as chemically it is a very reactive metal. So if it is not cleaned IMMEDIATLEY before welding trouble can be expected.

Since the consequences can be catastrophic I will repeat the following !!! NEVER grind aluminium AND iron on the same machine without cleaning all dust out of the guard BEFORE and AFTER use. You will create a chemical fire at some 3000*C commercially known as the THERMIT process. ME carried a report on an accident of this sort many years ago, but with many newcomers to the hobby and this not being an obvious hazard I feel it should be raised regularly. Keep safe Noel

SORRY FOLKS ! THINGS RUNNING SLOW THOUGHT IT HAD NOT BEEN SENT.

Edited By noel shelley on 31/12/2020 13:37:04

Training is really useful with welding. I managed to get City&Guilds levels 1&2 in TIG and MMA (Stick) at Northampton College. The first because of a redundancy deal, where the company paid for 'retraining' when I took VR from the IT department, The rest from some of the redundancy payout.

4 hours one-on-one for £80 sounds excellent value for money. Even more so if they can start up where you left off if you want to go further.

Just think what You would learn after an hours talk with John now.