TIG Welders

[greasemonkey]

Hi All
I have been looking at getting myself a new welder and have been looking at the range of TIG welders on the market and the wide range of prices. Assuming that I dont want to weld Aluminium what sort of current rating should I aim at for a maximum of 6mm mild steel and 1.5mm stainless. Also how do I equate electrode diameter to material thickness. Any advice you may have would be gratefully recieved.
thanks

Andy

[SteveW]

Andy,

I went over this same route a couple of months back and after not quite enough research went for the Clarke 150 from Machine Mart (MM). This is an inverter type so is very light, 6.5kgs but able to go from 15 to 130 amps DC and use rods up to 3.2mm. Also being able to do alloy would have been great but it just doubles the initial costs and then some. There was some very useful articles in MEW a few months back on this.

As TIG was also on the list I also bought the Arc and TIG kits. The final push was one of MM's no VAT on Clarke kit days and I saved a packet.

I needed the Arc kit because the Clarke 150 doesn't come with much and I also needed a shield. In this case the example supplied is a fairly poor example of the hand held type. This is OK for MMA as it provides something for your other hand to do. Previously I've found the hinged head masks truly a pain because their design is never quite cleaver enough to be actually useful and either stay up or down when you need them to. I think I'll be putting an LCD auto type on the list very soon once the hole in the bank balance closes up a bit. The TIG technique is very similar to gas welding, torch in one hand filler in the other. Yes you can just fuse the edges without filler. Anyway, you really do need either a third hand or a magic LCD hat.

The TIG kit is a bit cleaver except it comes with a regulator for a big bottle of Argon. This is fine if you have both the space and the throughput to warrant having a big bottle with its intendant supply issues. So far I haven't pursued this avenue yet. I found that B&Q do the small (tiny) bottles each specific to a particular metal (alloy, Ssteel & Msteel) at just under eight quid a go. They also do a regulator for them at fourteen and a bit quid. This should get me over the hump of getting the hang of it all.

Also the arc is much brighter with TIG and the MM supplied shield doesn't provide the recommended level of tint by a factor or two although is OK for MMA.

I went for the Clarke150 because it was small, light, was DC and had a usefully wide current range. However, it's not until your get it home that you find a) no included mains plug and b) it needs up to 23 amps which is why there's no plug. This means a special plumbed in high current connection and there's a limit to how long any extension lead can be.

Have I used it yet? Well no. A lot is going wrong in my life at present but I am almost ready for when things look up.

Anyway I hope the above is of help.

[greasemonkey]

Hi Steve
You have answered a lot of my question, thanks very much. I was tempted by the Clarke 150 but think that I can possibly get a better deal on a 130A Sealey unit. I shall have to make sure that it comes with a 3 pin plug though as hard wiring it in will be a pain, I want mine to be portable.
I am still not sure how you equate rod diameter to current and material thickness so if anyone can shed some light on this I would be grateful. My local motor factors supplies gas in returnable bottles. They are not much larger than the disposable style but are about 1/3 the price. I would have to investigate any other options. Um, good point about the face mask thats going to increase the bill a bit.
The reason I want the TIG capability is that I have never got on with MIG welding and if it wasnt for having to store 'unfriendly' gases at home then I go for gas welding as it is somthing I'vve always felt quite comfortable with.
Hope things get better for you soon, thanks for the advice.

Andy

[Jo]

I still stand by my old stick welder. No fancy gas bottles to buy and it does most of the welding jobs needed around the shed. My neighbour has a tig and I have never felt the urge... except that he can do stainless welding for my superheaters: - nice lad!

The main problem with all of the hobby kits is the grotty earthing clamp: throw it away and fit a decent one.

(P.S I've also got a mig and OxyAcetylene gathering dust)

[ron]

Hi Andy
I've had a lot of experience of MIG and I found TIG more difficult, although to be fair I haven't persevered [wasn't my kit].
One thing I would recommend if you haven't got one, is these auto darkening helmets, they have come down to a reasonable price now and I wish I could have had one years ago when I was doing a lot more welding! they make life a lot easier.
I rent a bottle of Argoshield from BOC, getting a bit pricey [£50/year] but still a lot cheaper and more controllable than these throwaway ones.
Ron

[Phil Sutton]

For MIG welding I used to use CO2 bottle from my friendly local pub owner(in the days when I used to have a local),then found that I could get similar bottles from a local soft drinks firm.They used to run out at about £10 a throw,inc VAT.That was about 5 years ago,and before I wore the welder out . ::)Suppose I might invest in another sometime.
Have you tried the local library to see if there are any books in there about welding?Ours is pretty good at getting books for you at 75p a time.Good value I think,especially if you can photocopy any bits you need and then return the book.

Phil

[Steambuff]

Hi,
I think that one of the variables to consider would be that of the type of welded joints that you will be making i.e. butt, vee or overlap etc. I think it might well be a case of pracrtice makes perfect, what might be an ideal setting for one person might not be ideal for you, as you can appreciate the feed rate of the filler rod also has an effect on deciding the dia of rod.


Steambuff

[chris vine]

Hi,

I spent some time trying to perfect stick welding with a little SIP air cooled arc welder. After no success I bought a little Oxford oil cooled one. This was far better and produced good welds even at my hands.

However when I tried a really large industrial welder the results were amazing by comparison and so easy too. It was explained that this was because the voltage of the big machines is much higher and although it is the current which produces the heat to melt the metal, it is the voltage which throws the arc and makes the lenght less critical.

Of course the power required by the machine is the product of the current and the voltage so clearly the cheap machines will tend to have a low voltage, especially as the average buyer does not go further than looking at the current.

It occurs to me that there may be the same situation with MIG and TIG welders but I don't know.

Chris.

[greasemonkey]

Hi Everyone
Thanks for all the advice offered above, a lot of points have been raised that I hadnt thought about. I think I need to do bit more research before opening the wallet, I will let you all know how I get on.
thanks

Andy

[SteveW]

Andy,

Just found some detail on rod size/current/material thickness from the back of a packet of Clarke rods (source acknowledged).

Rod Current Material
1.6mm 25-50 amps 1.1-.16mm
2.0mm 50-75 1.6-2.5
2.5mm 75-105 2.5- 4.0
3.25mm 105-135 4.0-4.8mm

Re thickness of material thicker metal (i.e. edges) will require some form of preparation, you need to get weld right into the joint so expect the joint to be either 'V' or 'J' prep'ed. Thicker material will need multiple passes. The problems here is ensuring that you don't embed any slag into subsequent weld beads.

The point above about voltage is very important. Not enough jolts and you don't get a good spark. A good connection to a low impedance source is essential, no long leads. In the case of the Clarke 150 Inverter it offers 90 plus volts open circuit which must drop quite a bit on a 135 amp load which is why it needs 23 amps at 230 volts. All the cheaper (economy) welders with 13amps supply connections have to be limited on oc volts.

Years ago I did a City & Guilds Welding Course and got to use industrial graded three phase kit. It was a joy to use.

[greasemonkey]

Hi Steve
Thats the info I was looking for! Going by that 130 amps is only just going to be capable of welding 5mm steel in a single pass but I dont think that a higher caoacity machine will still be capable of beign plugged in to a 3 pin socket. Thanks for the help.
Andy

[SteveW]

Andy,

You have to be a bit careful when you're whacking 130 amps in to a bit of steel else it'll distort big-time. You need to spread the heat out along the joint at least to start with. Weld a bit leave a bit etc. When the weld metal cools it pulls like you won't believe.