I need to mig one of the pipes going into my back box, small split.

Normally I'd just take the battery leads off but on the FF not so sure ?

2003 4.4, obviously lots of ECUs to break.

Really can't be bothered to drop the whole exhaust for an inch of weld unless absolutely necessary.

So, any anecdotal stories either way?  2003 4.4 Adriatic Blue FF

Disconnect the battery and leave for an hour before welding sir... Never had an issue and have welded countless 322’s sir

Thank you kindly Craig.

Job for the morning  2003 4.4 Adriatic Blue FF

And try and get your earth clamp as close to where your welding, without getting in your way, as this also reduces the path that the current has to flow and reduces the risk of it frying any ECU's Yesterday I couldn't spell Engineer... Today I are one!
Inventor of the 'Guide-o-Matic automatic wheel alignment tool'
Former long term L322 owner, Up/Down graded to a Classic Tractor!

It's a good idea to earth both sides of the weld with a jump lead. That way the welder wont earth the other half of the weld through the Lambda sensors and ECU.

I didn't bother disconnecting the battery or alternator when i did mine a couple of months ago, it all seems fine still, no harm in doing it to be on the safe side though.

The exhausts are stainless, so use stainless wire to do a proper job, but normal mild steel wire will still do it if it's all you have.

Are the pipes on the early cars stainless? I thought they were mild steel sir Im pretty sure they only went to stainless systems post 2009 models...

Stainless steel is a pig to weld with a standard Mig welder, I would caution against it. When you see those wonderful shots of stainless being welded with a Mig and it looks sooooo smoooooth, it's a very expensive high frequency Mig welder that's being used, the same for ali

Stainless steel will weld perfectly alright with mild steel wire, and give you a easier time welding with a better result. But the weld will rust, all be it surface, and the stainless around the weld will be stained. So unless you have a Bling Mobile and your going to show it off, I personally would not bother. Also you will have to use pure Argon gas as opposed to a mix or CO2, which will involve more expense along with the stupidly high cost of the stainless wire.

Then you have to get the right stainless wire for the material that your welding as different grades of stainless steel require different grades of wire, then you will have to purge all the oxygen from the area that's going to be welded, as this also effects the finish. So unless it's on show and needs to be perfect, save yourself no end of hassle and just use the standard Mig wire and Argon Mix gas and it will behave just like normal steel

Oh and I forgot that if you do weld stainless steel with stainless wire and the correct gas the welded area will have to be annealed as the welding process causes the welded area to become very brittle, and prone to cracking and off we go again  Yesterday I couldn't spell Engineer... Today I are one!
Inventor of the 'Guide-o-Matic automatic wheel alignment tool'
Former long term L322 owner, Up/Down graded to a Classic Tractor!

Well, using argon mix because it's what I have, stainless wire, again it's what's in the mig at the minute, never caused me a problem using on mild steel before.

Not getting too excited about the weld, no crack and leaks will suffice.

I will use a jump lead to earth either side though, can't hurt anything and no extra hassle at least.

As you can gather it didn't get done today yet anyway  2003 4.4 Adriatic Blue FF

Cam-Tech-Craig wrote:

Are the pipes on the early cars stainless? I thought they were mild steel sir Im pretty sure they only went to stainless systems post 2009 models...

Quote:

Stainless steel will weld perfectly alright with mild steel wire, and give you a easier time welding with a better result. But the weld will rust, all be it surface, and the stainless around the weld will be stained

Yeah fair comment, and most of the Range Rover's exhaust is pretty well hidden anyway. I just happened to have some stainless wire when i did mine, came out ok, maybe i was just lucky.

Using stainless wire on mild steel and mild steel wire on stainless should have the same outcome, but I'm only guessing now. Using the wrong grade stainless wire on stainless steel is a disaster, as is using the wrong gas, it will cause porosity in the weld, and can also cause the weld to crack And then there's the staining that will also happen, dark brown / black mess that is a pita to shift. A pal of mine tried to weld some 304 with 316 wire and pure argon, didn't end well Unfortunately as stainless steel is an alloy unless you are 100% certain of the grade it's very hit and miss as to whether it will be a or ending.

The same goes for aluminium there are hundreds of different alloys and it's a mine field as to what to weld them with. Basically get the wrong type of filler or welding wire and you'll be in a world of hurt. A18 grade wire for mild steel is also known as universal because it's very forgiving and mixes with most steels without any fuss  Yesterday I couldn't spell Engineer... Today I are one!
Inventor of the 'Guide-o-Matic automatic wheel alignment tool'
Former long term L322 owner, Up/Down graded to a Classic Tractor!

As i said, i was probably just lucky with mine.

I did try welding some ally once, made all the right noises, but just wouldn't take at all.

Being pedantic though, all steels are alloys (normally of iron and carbon) not just stainless, but i agree with the point you make about some being more forgiving when it comes to mixing with others.

The trouble with alli is there is a fine line between weld and blob You've got to try and keep and amps down, the wire speed up and go like the clappers, otherwise it just burns back on one side and not join together, which results in a lot of and In fact if you do it right then you start high and slow to get it going then reduce the amps and increase the wire feed, can't do that on my Mig's, not even the BOC one

It is a bit easier with a TIG, but there is a steep learning curve there and the kit to do alli is expensive, but I will say that it's a lot more forgiving than a Mig. If you ever see one of those this is how we make a super car documentations, have a listen to the welders, they don't crackle like a standard Mig, instead there is a high pitched hum, They are running at least at 400 Hz, maybe higher. Have you seen the cost of a high frequency welder ? It's cheaper to buy the car  Yesterday I couldn't spell Engineer... Today I are one!
Inventor of the 'Guide-o-Matic automatic wheel alignment tool'
Former long term L322 owner, Up/Down graded to a Classic Tractor!

Well mine defo isn't stainless, maybe someone fitted a later system to yours Zirconblue as I've not seen one on an early one yet...

Never had any bother welding stainless with mild wire, if it's a decent weld it will hold... don't use CO2 for anything these days, tends to make very brittle welds IMHO, use Argon for everything, get a nicer weld and better penetration...

Never had any bother frying ECU's either, without fancy earth straps and never waited for longer than 5mins after disconnecting battery (didn't know you should Craig )... also have to admit to not bothering on several occasions and not had any bother... maybe I've just been lucky though... Pete

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The hours wait is lunch time He didn't think to start earlier I would have thought that once the battery was disconnected everything was pretty much isolated, especially if you keep the weld area to a minimum ie, don't earth at the front bumper and start welding the rear

FYI Argon / 5% Co2 mix is the best thing for steel, not pure Argon, which is normally used with a TIG on stainless and ally. I did try an Argon / Co2 / Oxygen mix once, worked well with surface rust, but I'd recommend a good wire brush and get the cheaper stuff  Yesterday I couldn't spell Engineer... Today I are one!
Inventor of the 'Guide-o-Matic automatic wheel alignment tool'
Former long term L322 owner, Up/Down graded to a Classic Tractor!