arc weld on ute tray

also dont weld around battery & fuel tanks as they can explode ,take care

Paul, That is the essential information.

And there is no point in disconnecting the battery. More likely to do harm than good.

Disconnect battery or your up for an alternator. Common sense mate. Your putting high amp thru vehicle even thou it is close.

Disconnect battery.

Our if you don't your up for a new alternator and battery.

AT Alan B's expense.

ChristopherP
Sorry but am struggling to work out how current can go through alternator when both earth and electrode are both connected to item being welded on the "tray" of a ute.
"Common sense mate" statement makes me think that maybe current wants to travel through tray,rubber blocks,bolts and then through electrical system to alternator,
I honestly don't think so.
I have been welding on the back of my past 3 x utes over the last 18 years and have yet to have any electrical damage occur to ANY components on any of these vehicles.
Maybe it is my "Common sense mate" attitude of ALWAYS connecting the earth to the item being welded.
Regards
Paul

Sorry ChristopherP, it's not "Common sense mate", it's the physics of electrical engineering. If the welding earth clamp is connected to the piece being welded the welding current will flow from the electrode directly to the earth clamp via the workpiece..... it will not go running around looking for a path through your alternator or any other vehicle components.

But YOU do not need to worry anyway. No way are you going to pay out for a new alternator. I am going on record here that if you follow the "rules" outlined by me and destroy your alternator or anything else I WILL PAY FOR A REPLACEMENT. Now I am on record on that promise. Of course, you are going to have to demonstrate that you DID follow the rules and that the item was not previously faulty. OK?

Now, about your You-Beaut Surge Protector. Wonderful word, that "surge". Everybody who wants to put fear into you uses it in order to sell their product. The link you provided shows a contraption that seems to be intended to be connected across the terminals of a lead acid car battery. The accompanying text says that it contains a "heavy-duty varistor". A varistor is a passive electronic component that can be used to shunt over-voltages such as short-term spikes which may otherwise cause breakdown of electrical components such as semiconductors. They are not capable of safely handling sustained high currents as can be produced by activities such as welding. In any case, the impedance of a car battery is very low and much more capable of shunting low-energy spikes (or surges if you like) without harm to the battery or connected devices. But by all means use one of these things if it gives you a good feeling of security. It certainly will not do any harm except to your wallet.

Well we each have our own methods. I know most people are knowledgeable and cautious. I'm sorry if i misunderstood the question, but i prefer to err on the side of caution.

Whether you do or don't is up to you. I assisted a boilermaker weld some mounting points on a Lexus 4wd. The guy who owned said vehicle rang The dealer and they said the same as me. disconnect the negative side of the battery.

I will continue to disconnect my battery when i am welding anywhere on my vehilce or my friends.

I am sorry if i have upset more knowledgeable people.

Not upset mate, but very amused. LOL

No worries. No hard feelings. so when can we have a beer???

Next time im up that way we'll catch up and catch up.

The Saturated coast was my home for a number of years.

As you say, no worries Christopher. It's all just individual opinions anyway and if we didn't have differing opinions what else would we talk about?

And I'll take you up on that beer. Just MM me if your'e coming near the "Sunshine" LOL Coast and we'll share one or two.......... beers and yarns!

Will do!!!

cheers

Nick, If you follow good welding practice by having the welder earth lead solidly connected to the piece that you are welding you will have no stray currents to interfere with your vehicle electrics. Disconnecting the battery achieves nothing except you may need to reset your vehicle security code.......... if you can still find it!

Even with the battery disconnected your vehicle wiring is still fully connected from every circuit to the body via its earth return circuit. In point of fact, the battery provides a very low-impedance shunt path to earth for those circuits connected to the battery +ve and this is far more likely to protect against any stray voltages.

Those workshop mechanics and others who espouse battery disconnection do so because of myth belief not because of any electrical understanding. Trust me.

But if you feel more comfortable with disconnection, go ahead, it will do no harm. But be sure to remove the negative cable first to avoid shorting the positive battery terminal to chassis which WOULD do harm!

They use a special current surge protector.

surge protector.

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your mad if you don't. ever seen a battery explode due to over voltage/ amperage.

See FollowUp 4 above for my response to this device.

Frog look what your started ; Ithink the only way is to finish this is to get myth busters on to it .

Tony mc good point

Allan B i gess the myth might have come from days when the only electronics was the diode in alternator ?

as a good welder i all ways do as you say regards to welding .
I think you might be a electronic wizz , what about the 9v gajet that plugs into cig lighter to keep radio history re disconnect ?

p.s what the differance in welding from arcing your battery on chassis ??

good chatting with you

Yes Nick, I am an electrical engineer. The reason to attach the welder earth lead to the actual part being welded is like this: Suppose you weld on the bullbar but attach the welder earth to the chassis nearby instead of directly onto the bullbar. Quite possibly there may not be a perfect electrical connection between the bullbar and the chassis. On the bullbar you have a pair of spotties with one side of their lamps also connecting to the bullbar. Some of the welding current could find a path from the bullbar via the spotties into the vehicle electrical wiring to return to the chassis and thence to the welder. Disconnecting the battery would not necessarily prevent this but having the welding clamp on the bullbar would prevent it. There are wires connected to the body and chassis all over a vehicle so this sort of thing could happen on any part. Keeping the welder earth right on the part being welded is the only safe way and this is exactly what the exhaust mechanic and the body repair guys do.

The gadget plugged into the cigar socket (or clipped across the battery leads) is simply a small battery that maintains the 12v on the vehicle system to support the security and radio history whilst the vehicle battery is being replaced. It's a useful device.

My reference to taking precautions when disconnecting your battery positive was in regards to the risk of shorting the battery +ve to the body via say the spanner as a very large current would occur with personal risk. It is not related to welding except that is when you may be doing this action. The precaution applies at any time that you are connecting/disconnecting the battery +ve.

I second what Allan says!
Im a boilermaker welder and have done it this way for years and ever had a problem.

Cheers

Allan b i get what you are saying on putting the earth clamp on the job you are welding as i have been welding for many years 35 yrs plus my question is does it make any differance to the alternator if you were to get a spike if the battery is disconnected or connected........

Nick I don't see how you are going to get a "spike" applied to your alternator if you are welding elsewhere on the vehicle and using the work practices described above. Certainly it would not be possible to get a "spike" or indeed any other electrical event into the alternator if it was fully disconnected from ALL OTHER electrical connections. But note that simply lifting the +ve or in fact even both +ve and -ve battery clamps from the battery posts does not in fact isolate the alternator or anything else from the rest of the vehicle wiring or from the vehicle chassis and body which is what is being welded upon. It would in fact be necessary to locate and disconnect each and every earth connection at countless locations throughout the vehicle.

In point of fact, having the battery still connected to the alternator provides a very low impedance path shunting the alternator and other connected electrics and ensuring that the voltage on this network cannot rise above the nominal 12 volts.

Your doing a good job in this thread Allan - keep trying - I reckon I could write a paper on it being more risky to leave a high impedance circuit with aerial wires on it by disconnecting the battery - butwell we all know the earth is flat according to a poll taken in 1642

Thanks Allan for your answer ; i hope Frog not to BAMBOOZLED now

Now let talk about what damage your doing to your cruiser driving it through all that water!!!

If your not learning something new each day you might be dead !!!

Nick, I need to confess......... I wasn't really driving the Troopy through that water. I was actually being towed by M.V. Strait Magic but it was just out of the frame! LOL

Here she is:
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Ahhhh Robin, Why do I do this? Why do I open my mouth and then feel that I have to defend my position? Will I never learn? Why do I begin to doubt my own insight? Thank God you're there to put a hand on my arm in comfort!

whats the good of knowledge if you dont use it ?????

Oh I use it for sure Nick but I'm questioning the benefit of expressing it on a public forum where some people with absolutely no credentials on the subject will decry it based on their myth beliefs.

The trouble is that someone asks a question, I answer from an informed professional position, then several others without expertise refute me so I have to defend myself or look like a prawn! It then gets into a bun-fight and the Original Poster gets hopelessly confused. It all seems such a waste of time and effort.