Having trouble welding repair section into car

[Can'tWeld]

Hi all,

This is my first car repair, so go easy on me. I'm currently patching up the steps and floor on my Nissan Serena from a bad case of rot. The problem I have is that on one side of the patch the original (despite taking it back to shiny) is so thin that I keep blowing holes. I've tried turning the power down and all I get is sputter.

I've been (trying to use) the stitch welding method but it's just not working right. Can anyone venture any tips?

Note that I've only welded one side so far, the other bits are just tacked in for now. I gave up for tonight when I realised it's not quite turning out how I hoped.

I know that on part of that weld my wirespeed was too high and I've ended up with bits of wire everywhere.

Can someone give me some tips? Do I need to take out the bit on the left as well? As I said I cleaned it up but it's pretty thin. It looks a pain to reconstruct so I'd rather not cut it out if I can avoid it.

Cheers.

 

[michael1703]

the bit on the left should weld but will be tricky

you need to put more heat into the fresh steel, instead of welding the two pieces 50/50 you want a 60-70% more of the heat in the good bit

the wire speed is high as you say, the weld is very porous through not enough gas or wind blowing the gas away

another thing, does your shroud give sufficient cover of the tip? some hobby migs have very rough fitment of the shroud onto the torch leaving the tip protruding from the shroud

 

[michael1703]

p.s. the bottom bit looks promising, should get a nice weld on the bottom

 

[the snooper]

i dont think the original steel is that good either and will probably made the less experienced welder have a hard time you coul also try closing the gaps up where the plates meet

 

[Sean]

well apart from the wire speed, set up, earth and shielding gas etc...which will come with practice and more practice

that bit of metal on the right, beside the door seal, is just too rusty and weak to weld to

some of the gaps will cause you problems

sorry
Sean

 

[volition82]

Not going to lie to you that is rough, won't ever pass an mot with that level of welding. My advice would be to get two bits of new steel the same thickness (as the car) and set up the welder on that. If it is welding well on the good material then if you have problems on the car it will be caused by rust, paint, technique etc. The method of welding (if you can call it that) i've found that works best for cars is to do a spot and just as it is cooling move forward and spot again. I've just finished welding a patch on my van and the metal was in a lot better condition than yours, I was a 3g coded welder in mig and I was also using a butters welder(with co2) and it still looked like sh*t, nothing I would ever be proud of.

It's just the way it is with repairing cars, they are hard work and the welds look rubbish. Agree with sean the pillar looks to rotten to use and should be replaced, wouldn't want to have a crash in a car with rot like that. Also remember to move the welds about to limit heat distortion.

 

[Can'tWeld]

Hmm, looks like the bottom of the pillar needs to come out then.

Cheers everyone.

 

[the snooper]

you should also not that the piece with the arrow is whats left of the piece you are replacing and will possibly be rusty inbetween i would remove that strip as it serves no purpose

 

[Faaluke]

Are you welding directly to rust?

What surface prep have you done?

 

[elebub]

Volition82 is spot on, and its some comfort to know a coded welder has trouble. It's not only the front of the metal that got to be sound but the other side. Sounds pretty obvious but when you are welding a patch over a cavity it gets difficult to assess the state of the metal but you have to make sure the inside edges are as clean as the outside and if its dodgy cut it back some more. I have found out by bitter experience if you don't get back to sound metal you are on a hiding to nothing.
Good luck and hang on in there - you know it's worth it.

 

[Can'tWeld]

Question... is it OK to cut out the rusted part of the C pillar and weld a patch on? I think my problem is mostly bad prep, but also because I'm trying to weld to something that's rusted to hell. If done properly, is it safe to patch that part?

 

[lexi]

Got to be careful as that C section is structure. If you had more experience you could do it but not sure at your stage. Get metal shiny. Try to get more spot or stitch on it all.

Then turn power up a bit and work where you have put weld on to "spread" that out. short bursts with the extra power.

Don't be disheartened. That is not strictly welding per se. It is much more difficult.

Hitch on here HATES doing stuff like that and he is welding for a living

Would also add that if you have a poor machine it will make it doubly difficult.

 

[Can'tWeld]

Thanks for the tips all.

Tommorrow I'll have a go at patching the same spot on the other side of the car (there is a lot more good metal there to weld to so it should be easier to get some practice in).

Should probably also switch to 0.6 wire as well - those welds I did with 0.8 which probably explains the blow through.

Thanks again. I'll let you know how I get on.

(I'm not even keeping this car now, I'm just going to patch it up and then sell it cheap in a few months - it all seems a massive effort when there's not much reward involved )

Forgot to add, my machine is a rather rusty old Clarke 150TE, so not too bad (probably in the realms of mid-range hobby migs). The wire feed is a bit errattic though, which doesn't help matters...

 

[Alfaman]

Hi,

hope you get better results with clean metal on the other side. Get a good close fit up on the patch panels, and you'll be less likely to blow through as well.

Erratic wire feed will cause you no end of problems!

Don't take this the wrong way chap, but if I bought a 2nd hand car and then lifted the carpet to see that standard of welding, I wouldn't be very happy.

 

[Can'tWeld]

Wrong end of the stick! I'm not selling anything with that standard of work on it. What I've done there - I'll cut it out and start again. All I'm doing by patching the other side is trying to get some experience on better metal first before I try to weld the tinfoil.

I'm just in two minds about whether to do it; the car isn't worth much but I'd like to get something for it, which I'm more likely to if I patch the obvious holes first. The other option is to break it for parts...

 

[Alfaman]

Wrong end of the stick! I'm not selling anything with that standard of work on it.

Fair enough m8!

My advice would be to get two bits of new steel the same thickness (as the car) and set up the welder on that

Volition is right, if you've got plenty of offcuts then that's the way to go Good luck!