Welding frames

[D project]

May be a silly question,but do you need to disconnect the electrics before doing welding on a frame. Or is it okay to leave everything in place?

[caps 999]

yes dissconnect all wiring

[D project]

Thanks, disconnect or remove everything.Coil stator etc?

[caps 999]

un plug the loom so it wont earth out anywhere

[TT5 Matt]

just disconnect will do not unless its in the way or could get burnt,its just in case theres a voltage feedback that finds its way into the electrics.when i worked underground at the local mines where would weld things back on the diesel loader's without even turning off the motor and disconnecting the alternator and never loss one yet

[Ji Gantor]

Hi D Project,
What bike is it?
Does it have Electronic ignition or points?
What are you welding on the frame?
What method of welding are you going to use?

Ji

[D project]

Hi Ji , RM 250 1983 with electronic ignition. The bolt hole that holds the brake arm on the frame is worn and needs building up with weld. I have a mig welder.
Thanks D.

[GMC]

I was a bit scared to look at this thread, seemed a bit like Deja Vu

I will usually disconnect a battery before welding but have never bothered disconnecting anything else.
Even batteries can be fine with welding while connected but I have this fear of Murphy’s Law.
What you need to watch for is where you put the earth in relation to what you’re welding. If welding the frame then make sure you have the earth securely on an unpainted part of the frame.
If you were to put the earth on the swingarm then the arc would travel through the swingarm bearings thus rooting them by arcing the rollers together.
If you put the earth on a painted bit of the frame it may burn through but if the earth clamp rests against wiring or throttle cable then the arc will travel through the wiring until it finds the frame. The amperage will completely stuff any components in seconds, before you even realize you have a bad earth.
If the arc was to travel through a cable it would wander down to the carby possibly welding the needle to the jet and also stuffing the cable.
It will only ever do this if there is opportunity for the arc to travel somewhere else to complete the circuit
I have wasted a few rulers over the years, even the odd tape measure too as they have been resting on something I have been tacking and the arc has traveled through them to the job, burning chunks out of the ruler.
I will usually use a footpeg for the earth clamp for a frame as it’s easy to make sure nothing is touching.
The other thing to look out for is splatter. A TIG doesn’t splatter but on the odd occasion you can get a piece of molten metal globule drop down.
The chances of these globules or splatter finding you plastics are directly proportional to the cost and availability of said plastics.

An old school welder’s trick is to use a piece of copper bar to hold behind your weld. If repairing a hole for instance then clamp or secure the bar behind the bracket you’re fixing. The weld won’t take to the copper and it will leave a flat area on the weld when you remove the copper. This is good for stopping the weld running through the hole and all over the place reducing clean up afterwards

[Hoony]

The chances of these globules or splatter finding you plastics are directly proportional to the cost and availability of said plastics.

The above is what is known as GMC's law

[GMC]

The chances of these globules or splatter finding you plastics are directly proportional to the cost and availability of said plastics.

The above is what is known as GMC's law

Have you seen me at work

[firko]

An old school welder’s trick is to use a piece of copper bar to hold behind your weld. If repairing a hole for instance then clamp or secure the bar behind the bracket you’re fixing. The weld won’t take to the copper and it will leave a flat area on the weld when you remove the copper. This is good for stopping the weld running through the hole and all over the place reducing clean up afterwards

That was the first thing my first apprentice master, legendary pioneer tig welder and pub brawler/womaniser/Labor party identity old Tony Mulvihill taught me back in the sixties when he was trying to teach me to weld. Believe it or not I've still got the same three pieces of copper I used for my welding projects when I was a apprentice. Still got all the T squares, G clamps and hammer I made as well. Some things are sacred in my man cave, these are just some of them

[mx250]

May be a silly question,but do you need to disconnect the electrics before doing welding on a frame. Or is it okay to leave everything in place?

Of course its ok, reconect every thing ,leave tank on but drain half of fuel. To extinguish any falling spatter, do job while standing in pool of water. Hold tightly with left hand while using right hand to complete earth to a lightning  rod in opproaching storm. Everything should fuse together nicely.
PS: Old Boy says, “Hurry up”.  He desperately needs one more unused half a brain to divide up for the new Irish montesa ridders works team. 

Looks like those God bothering Monty riders have kick sand in ya face........again - hey Boyo .

(P.S. you should go straight to Hell for your Welding advice . Sounds to me like you are drumming up business - things must be a little slow.  Can't you whip up an anti-christ or two, maybe start a religious war or three .)

[Ji Gantor]

Hi D Project.
I would recommend the same as Matt and GMC.
God Boy has raised a valid issue, Drain all fuel before welding just in case.
Electronics can become tricky as mother boards do fry.
I have been down at my local exhaust fitters and seen electronics fried when the welder paid no attention to this matter.
That said I have seen a few welders welding frames that have electronic ignitions without disconnecting anything without damage to said electronics.
To be safe disconnect battery like what Geoff said.
I would disconnect the CDI and coil so these two items are not earthing.
As Geoff said MIG will produce spatter, you can spray cooking oil over parts of the bike you don't want to become spattered. MIG builds holes very well but TIG also performs well. If your MIG is gasless (and of course this is not MIG but manual welding) you will have to clean the flux off between runs.
If you had used Oxy welding you would not have to disconnect any electrical wires.

Ji

[Slakewell]

Two points but mostly solid advice so far.
1) Electricity is like everything else in life will always travel the shortest distance between two points.
Always put the earth clamp as close as possible to the place you are welding. I normally will use vice grips then put the earth on those.
2) Aluminium dose the same job as Copper ( use at least 5mm upwards)

[GMC]

I blew up a battery once with the Oxy.
I had my car battery on the charger and so had removed the little plugs on top so it didn’t build up pressure.
While I was waiting for it to charge up so I could go out ( I had forgotten to park the HD on a hill the night before) I decided I would weld up that little crack in the front panel that’s part of the bonnet latch.
All was going well until the oxy gave one of those little pops as they do.
From what I can gather afterwards, one of those hot specs from the Oxy popping must have gone down one of the battery holes.
forkin blew shit out of the battery and covered me and the car in acid.
Scratch one battery, jeans and T shirt