Welding - Safety Precautions?

[kwakdonut]

Hi all,

following my pre-MOT check of my car, I noticed a crack in my exhaust, running about 2" round one of the pipes that exists the cat. It's not leaking and passed the MOT with no problems but I don't want it to get any worse.

I am proficient enough to weld it and I intend to do it in situ as the access is more than enough.

But apart from disconnecting both batteries, are there any other safety precautions I should take in regards to the car, am thinking W211 electronics etc!

Thanks in advance
Tony

 

[chris846]

gas weld or electric weld?
The main thing to think about is that exhausts usually have a habit of being a lot more rotten that they appear - they can be paper thin when the crack first starts to appear, and this can make welding difficult: the thin metal just disappears once you start to apply heat.
Without seeing the job, I'd recommend you remove the exhaust. You can make a much better repair, plus you've no worries about starting a fire or zapping electrics.
If the idea of removing the exhaust is daunting, well, it'll have to come off sometime if you're going to keep the car (maybe sooner than you think if it's started to fail) - might as well do it at your own dictation!

 

[nigel cross]

Watch out for the fuel pipe,I know someone who didn't and by the time he got to a fire extinguisher it was too late

 

[Druk]

I've been told...disconnect the alternator. That might be 'old wives tale'

 

[dog68]

Don't wear contact lenses.

 

[kwakdonut]

I've been told...disconnect the alternator. That might be 'old wives tale'

I believed that disconnecting the batter(ies) generally isolates the alternator.

I was intending to disconnect both batteries at both positive and negative terminals.

Anyone else add weight to Druk's suggestion?

 

[kwakdonut]

gas weld or electric weld?
The main thing to think about is that exhausts usually have a habit of being a lot more rotten that they appear - they can be paper thin when the crack first starts to appear, and this can make welding difficult: the thin metal just disappears once you start to apply heat.
Without seeing the job, I'd recommend you remove the exhaust. You can make a much better repair, plus you've no worries about starting a fire or zapping electrics.
If the idea of removing the exhaust is daunting, well, it'll have to come off sometime if you're going to keep the car (maybe sooner than you think if it's started to fail) - might as well do it at your own dictation!

It's a MIG welder. The exhaust still appears very strong, it's obviously taken a whack and the original weld has started to crack. I was hoping to run a bead over it to secure it back up.

I don't really want to removed the exhaust unless I absolutely have to!

Thanks for the advice

 

[kwakdonut]

Don't wear contact lenses.

Have perfect vision so no problems there!!

 

[oldcro]

I'd be inclined to remove the exhaust as otherwise you're putting a high amperage through the car. Fry the electronics and a hole in the exhaust will be the least of your problems.

 

[SilverSaloon]

I'd be inclined to remove the exhaust as otherwise you're putting a high amperage through the car. Fry the electronics and a hole in the exhaust will be the least of your problems.

overkill IMO. I recently welded the exhaust on the Alfa. I disconnected the battery and went with it.

no problems for me.

 

[kwakdonut]

I am wary as this is a pre-facelift 211!!

 

[Howard]

Is a 211 not a little bit more 'electronic' than an Alfa Derek ?

 

[SilverSaloon]

i read somewhere before about surge protection devices prior to welding.... may be worth looking into.

put the earth clamp onto the exhaust itself, not onto the car's body

 

[kwakdonut]

i read somewhere before about surge protection devices prior to welding.... may be worth looking into.

put the earth clamp onto the exhaust itself, not onto the car's body

I would do that anyway lol. As my first post said, I am a reasonably competent welder but was unsure about how my MB would react to being Tazer'd!!

 

[shorty]

Just disconnect the batterys , the car will be fine . In work we cut them in half , then weld in a middle section . Theres never been a problem with the electrics . In fact with some of the cars we forrgot to disconnect the small battery , the was now ill effects on the car .
Where working on some 212s now and one of these has had some welding done with the battery connected , though the car is still fine .

 

[Miley Tipton]

hi,

I am new to this forum, and want to enhance my knowledge related to Tools and Techniques in the automobiles field.
Me and my father works in a Garage, so we have a little knowledge about this, because I do welding, soldering, and other works to help my dad.
Major points to keep in mind while doing welding are
1. USe safety glasses to protect your eyes
2. Use hand gloves to protect yourself from heat.
3. Check pressure guages properly
4. maintain proper angle between welding rod and welding instrumnet.
5. Avoid silky clothes, which catch fire easily.

else welding is not very difficult process if person take proper preventive measure.