advice because keep blowing holes.

[l2daintree@hotmail.co.uk]

trying to fix the tin worm on my cappuccino, and because the metal is so thin i keep blowing holes into the metal. its making my welds look poo..
does anyone have any tips. i am using 0.6 wire and tip on lowest setting with a snap-on 130 welder. car looks a state now. whenever i go to weld the old metal just melts away so i end up making a smaller hole bigger.

 

[dstealth]

What gas are you using? If you're using 'pure' CO2, it will burn hotter than CO2/argon mix which is what you should be using.

Also, if its wafer thin, rusty metal less than 0.8 ish, I wouldn't be MIGging it anyway.

 

[peterd51]

Hi,

finding solid clean metal is an 'art' on some cars...

One method I used on a rotten Fiesta was to cut a strip of mild steel, about 1/2" wide and lay it across the top of the floor above the line where I was joining the patch on from underneath....

as it burnt through the floor it joined onto the new bit above in odd places. Then knowing I'd got a reasonable thickness of plate underneath I finished off with a seam weld on the strip above the floor.

Regards
Peter

 

[zardoz]

Dont try and do any continuous welds, use the stitch method, where you just weld half an inch then move along a few inches and weld another half an inch, etc etc. This gives the metal time to cool and you wont blow holes in it. If its REALLY thin you may have to weld a quarter inch at a time, no more that a tack really (oh yes you should tack your joins first i forgot to say at the begining)It may look crap but as long as it is a proper weld and holding the metal together, who cares. If its somewhere that is on show then you can sand the weld down with a flap disc (not a grinding disc) and even do a skim of filler if needed.

There are ways of taking the heat away quickly from a weld of thin metal, these usually involve clamping long plates of copper behind the weld, dunno if i'd recomend for a beginner, but if you prepared to give it a go you might get it to work. Depends on how critical the weld is to get correct first time i suppose ?

 

[deltabravo]

Hello, you should really be using oxy-acet' for a car in that condition, considering you say you are a novice. Mig or stick welding is fine when you have a bit more experience under your belt. I know how hard it is to try not to blow away the welds when you are learning the trade, I remember how ****** off I used to get when I was learning to weld some 40 years ago, so I do know the feeling. As already suggested, I would spot/tack weld the joins and gradually join up the tacks until you have a nearly straight weld and then carefully over-weld the tacks and join them altogether in a straight run of weld. It will take practice and patience but will come out as a neat, sound joint. Use a slow wire feed and not too many amps for tacking, once its joined, go to the next tack. I hope this helps you out, good luck and patience, Bob.

 

[l2daintree@hotmail.co.uk]

thanks everyone, i am going to atempt it today just need to buy some more gas co2 argon mix. i found that it was less likely to blow when i had the wire speed mega slow, so i think i will keep doing this. god welding is so hard. and i kinda wish i did take it to somewhere to get done but i really wanted to learn myself and just bought all the kit.
oh well

 

[COMP]

get more pics for us

 

[Sean]

From experience of welding 2cvs where the original metal can be as thin as 0.5

1 any rust pits, oil or paint will cause it to blow

2 weld the car to the patch ie have the patch behind the welding area

3 clamp it good and tight so the heat is absorbed into the good metal patch

4 make a chill bar and spoons from flattened out copper piping

5 your only really going to get a tack, so buzz a good tack move the torch a mm then buzz again. As you get it you see the hot spot appear, stop momentarily move torch wait till hot spot fades then buzz again becomes quite quick after a bit and if you use the copper behind the work you can achieve a good penitration and fewer holes.

Sean

oh and is that repair piece galv? needs cleaning off if it is.

 

[zardoz]

From experience of welding 2cvs where the original metal can be as thin as 0.5

oh and is that repair piece galv? needs cleaning off if it is.

yes i was gonna mention that. You shouldnt really weld galv to non galv. You CAN do it, but its not really reccomended, as the galvinized coating has to be throughly ground off well back from the edge, (as it will yield a deadly poisonous smokey gas) and looking at that piece you have in your hand that means all over on both sides as its on the samm side.