Welding on car

[is200 Newbie]

I have got to the point where I am starting to put an exhaust together - I can do a lot of the welding off the car in my garage but at some point I will need to get under it to do a spot weld to a piece I know is a bit iffy.

I am a welding "virgin" and at the moment its ending up looking like rice pudding !! I will practise a lot more before starting but does anyone have any tips regarding welding something attached to a car, especially this one with all the electronics on it. I have been told to disconnect the negative Battery lead before starting and all will be ok ?

Any advice would be helpful.

[madasahatter]

Im not an expert but disconnecting the earth is a good idea. Welding is an art in itself. Is it a mig welder? Do you not know anybody who can do this for you.

[normski2]

Don't know if this still applies. On the occasions I did have some work done on works vans I would always disconnect the leads from the alternator too.....just in case.

[is200 Newbie]

Its a mig welder and yes, it is an art. Playing with the settings last weekend it was looking a lot better when I had enough but a way to go yet I think but I am nothing but persistant.!!

Thanks for the top regarding alternator lead - every precaution helps.

[toffee_pie]

tbh, dont think welding an exhaust is for the novice, too much to go wrong.! 

[mk_lon]

Hey IS200 newbie, I thought I would check in - how did it all go? 

I take it you had enough of the aftermarket exhaust system you had fitted we were speaking about a while ago. 

[Verbout]

I used to weld in the early '80s, stick welding in the maintenance workshops. Was quite good at it, it's just perseverance.

Practicing on scrap metal got me to the stage where I could weld stainless steel food grade pipe work with no problem. Also did brazing using silver solder, not too good at, but passable.

Never had a go at tig or mig welding but would love to.

Just keep at it, it suddenly clicks.

[is200 Newbie]

21 hours ago, mk_lon said:

Hey IS200 newbie, I thought I would check in - how did it all go? 

I take it you had enough of the aftermarket exhaust system you had fitted we were speaking about a while ago. 

Not had a chance to fit yet - have all the parts even the hangers for the exhaust but not had a chance to take the boxes off my car yet properly which is where I will start. Need some space in the garage and that's proving hard to do at the moment as not long turfed the front garden and done a wall so there's all sorts of rubble and garden bits in there at the moment.

I have managed to weld up the second box that needed flipping over to match the opposite side. I am using rover MG V6 boxes as they fit very well but are twin boxes and the input pipes need bending. Will cut and weld up to the correct angle for these then fit to existing to ensure they are quiet.

So when done I will have two twin boxes on the car - have gone for an IS200 resonator so this will give me a replacement for the whole system that was originally replaced with the stainless one. The SS resonator is shot but the boxes are in very good condition. I had fitted the rover boxes on the car a few months ago as they are and initial experience was that they are quiet but could not drive the car due to the piping needing modding - need to alter the pipes first before anything and fit to the car to make sure they are as quiet as I expect..

But so far so good. - cost so far is £86 for the parts, all new. Will need exhaust tips and maybe when I come to do it another length of exhaust pipe but cost should be under £100 if it all works. Better that £3000. Also, I will need to put a bumper spoiler on the rear to hide the cut I will need to make in the bumper so add another £150 to the cost. Still good and it keeps me busy !!

Picture below is of the two boxes before cutting / turning around and turning inside out then welding back up, you can see that if I was to use as they are then they would not match. Don't have a picture yet of the box welded up - will take some pics when I start - the box on the right is the passenger side and the left one is the driver side and they fit very well.

[is200 Newbie]

20 hours ago, Verbout said:

I used to weld in the early '80s, stick welding in the maintenance workshops. Was quite good at it, it's just perseverance.

Practicing on scrap metal got me to the stage where I could weld stainless steel food grade pipe work with no problem. Also did brazing using silver solder, not too good at, but passable.

Never had a go at tig or mig welding but would love to.

Just keep at it, it suddenly clicks.

I have bought a Mig welder - electric only - suits my needs. Welding is new to me so still practising but had a good result when I welded an exhaust flange to my lads astra exhaust a few weeks ago (something to practise on !!) ... found that the wire feed was too tight making the weld wire quite jumpy when feeding the weld so not feeding right. When I fixed this it was very good welding (beginners luck) - I believe Mig creates a mess but once cleaned up its ok. I will be grinding the welds back to tidy them up anyway so as long as its a good weld I should be ok.

I have some scrap metal and some extra reels of wire so have a chance to practise before I do the exhaust. - Don't think it will take long once started because its all there. just need to get a bit of space !! 

[steve2006]

MIG tip, the throw away gas bottles are expensive, if you have a friendly pub landlord see if he will sell you a full CO2 gas bottle and regulator, with occasional use it will last for years.

Also the large drums of wire work out cheaper than the small ones.

Finally don't ever strike an arc without the mask up, arc eye from personal experience is like having had your eye balls sandblasted and the effects do not appear until later.

[Verbout]

Ive still got scars on my feet when chipped slag went down my boots, and they're a swine to get off with a burning cinder melting your skin

Newbie, do you use it gasless with coated wire?

[is200 Newbie]

Its a gasless welder - can only use it via mains electric.

I am using fluxcored 0.9mm fed wire - works for what I am doing. Found pushing the weld along is the easiest way for me after I figured out the feed of the wire. Got the mask and struck it a few times with the shield up while getting used to it but its a learning curve.