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Jul 15, 2009 18:38:18 GMT
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;D My mate's incident showered him in acid, it literally exploded apparently with shrapnel everywhere. Being mask'd up his eyes and mush escaped the acid rain...
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'66 Amazon <-> '94 LS400 <-> '86 Suzuki 1135 EFE
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purplevanman
Posted a lot
Way too orangey for crows
Posts: 3,830
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Jul 15, 2009 18:38:42 GMT
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some I do some i don't, I wouldn't weld next to a battery cuz of the gases. My theory is my earth clamp is always next to the spot I am welding and the current will not go all the way round the car before finding my clamp. Never had a problem but I am not saying there won't be  Customers cars are a bit more important |
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Welder, fabricator, general resto work
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Jul 15, 2009 18:40:57 GMT
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naturally.. don't create sparks anywhere near a battery!
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75 Range Rover 2 door 82 Range Rover 4 door
84 Range Rover 4 door 78 Datsun 120Y 2 door
78 Datsun 620 Pickup 81 Datsun Urvan E23 86 Datsun Vanette van
98 Electric Citroen Berlingo 00 Electric Peugeot Partner 02 Electric Citroen Berlingo
04 Berlingo Multispace petrol 07 Land Rover 130 15 Nissan E-NV200 15 Fiat Ducato
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BiAS
Club Retro Rides Member
Insert witty comment here
Posts: 2,231
Club RR Member Number: 147
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Jul 15, 2009 18:54:31 GMT
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Modern stuff is more prone to damage from not disconnecting the battery.
I've damaged stereos, amps and electronic ignition modules before I learnt my lesson and got a battery saver. My mate did a 500SEC ignition ecu whilst welding, nearly a £1000 for a replacement off Mercedes! (he got one s/h for about £400) Luckily I learnt my lesson before welding anything with airbags or ecu's.
The saver works by absorbing any spikes. The way I always figured it happened is that you are putting a spike of dc voltage into the negative side of the cars circuit, the battery is a link to the positive side of the anything with a circuit board in the car.
I think on older stuff there's only really the alternator/dynamo to ruin so there's a lower risk of damage.
Stretched handbrake cables isn't a myth BTW, ask anyone who's worked for a Kia dealer and had to replace the cables on the Sedonas!
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(car+wheels)-rideheight=WIN
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Jul 15, 2009 20:17:03 GMT
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I'm in the its rare but it CAN happen club.. and paricularly if it's a customers car where a problem could get expensive, messy andtroublesome if you don't. And the answer is quite simple, if the battery is disconnected, you don't have a circuit. the alt is not connected. I suspect the semiconductor damage is through back emf and lenz effect in the wiring as a secondary to the (being welded on) shell. Doesn't take much to kill silicon... ever worked with CMOS? you have to wear a grounding strap so your fingers don't zap them  |
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To get a standard A40 this low, you'd have to dig a hole to put it in |
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Jul 15, 2009 20:19:30 GMT
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MY FRIENDS FIRM WERE WORKING[WELDING] ON A BRAND NEW LORRY WITH ONE OF THOSE SURGE PROTECTORS ON THE BATTERY AND IT STILL-UNFORTUNATLY-BLEW THE LORRY COMPUTOR.COST 5K TO PUT RIGHT.
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Jul 15, 2009 20:34:52 GMT
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Interesting point, but if it were an inductance issue , disconnecting the battery would intesify it not reduce it, as somone else pointed out. Surge protector does make a little bit of sense at least.
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75 Range Rover 2 door 82 Range Rover 4 door
84 Range Rover 4 door 78 Datsun 120Y 2 door
78 Datsun 620 Pickup 81 Datsun Urvan E23 86 Datsun Vanette van
98 Electric Citroen Berlingo 00 Electric Peugeot Partner 02 Electric Citroen Berlingo
04 Berlingo Multispace petrol 07 Land Rover 130 15 Nissan E-NV200 15 Fiat Ducato
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Jul 15, 2009 20:41:35 GMT
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yeah, but think about flyback - as you cut off the arc, it goes up the shell, through the earth, and battery (back to front) and out thru the positives as a surge, and 99% of alternators have their diodes permantly connected to B+ and not switched. Disconnect one batt terminal, it can't do that.
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To get a standard A40 this low, you'd have to dig a hole to put it in |
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Jul 15, 2009 22:04:25 GMT
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I thought this was to protect sensitive components, mainly the ECU? I do it, because I'll only kick myself when it 'happens'.
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Jul 15, 2009 22:10:56 GMT
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I think the magnetic field (or whatever) from welding can induce a voltage in nearby wiring and fry electronic conponents such as ECU's e.t.c. Many people suggest removing them before welding.
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1987 Maestro 1.6 HL perkins diesel conversion 1986 Audi 100 Avant 1800cc on LPG 1979 Allegro Series 2 special 4 door 1500cc with vynil roof. IN BITS. HERITAGE ISSUES.  |
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rtlkyuubi
Posted a lot
Low and Slow
Posts: 2,922
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Jul 15, 2009 22:21:00 GMT
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I always remove the battery before I weld. And especially on new cars with the amount of ecu curse word. Also at work disconnecting the battery before welding is reliegion as it can blow the ZBR unit (engine ecu) and they cost ££££
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Jul 15, 2009 23:15:41 GMT
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surely putting a voltage down the body would be live a live neutral reverse which could kill things? that was my theory...
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DutyFreeSaviour
Europe
Back For More heartbreak and disappointment.....
Posts: 2,944
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I've learned a shed load on this - love this place  On the disconnecting thing - I've usually stripped out most of the damn car before I get around to welding at all  Smaller jobs I'd disconnect - just 'cos it's the way I was schooled by pops. |
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Back from the dead..... kind of
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