Welding advice - Repairing rust holes

[BlackSupra]

I have just had my project car media blasted and had the rust blasted away, this has left a number of holes in the bodywork and i was wondering what type of welding technique / welder type (mig? tig?) i should be looking at to repair the holes.

Being a classic car, i want to minimise the pannel cutting, so wanted to get some advice on the approach to take.

Images below are of luggage compartment under the fuel tank and floor meeting door sill.

[MR22ZZ]

is this the sort of thing where lead rubbing would work best?

But then there is the challenge of finding someone who 1) can 2) is willing to do the work for you 3)..... 4) Profit

[lexsmaz]

In my opinion either mig or tig is fine, but you obviously need to actually cut out the rusted section & weld in panels to replace it, if you were to try & weld up those holes the holes would just spread as the metal would be super thin around it & it would just blow through .. I cant piture where the second picture is on the car, but you mention it comes up to the sill so its definately structual & should not be just covered up / lead wiped etc as there would be no strength in it ..

Depending on how old or rare the car is, you could go to a wreckers & cut at the bit that matches your car on a donor car & then weld it in & rust treat it & seal it up ..

[Eusto]

Are you welding yourself? If you are and don't have any experience, Tig isn't really an option. Mig should be fine if you practice a little bit. Like Lexsmaz says above you will have to cut out all the rust. Cut a new piece to fit and weld in and grind down. The better you get at welding the less grinding you'll have to do!

[airfireman1]

The only way to get rid of rust is to cut it out and replace it with good metal. Even if it is a classic car, if the rust repairs are done properly it should not affect the value. The above statements are true the more practice the better the finish and the better the quality of the welder the better the job.

[BLK_20v]

is it running? lead wiping could be done, but youve gotta make sure the rust is dead first... is the car drivable?

[timbosaurus]

Don't know why you'd bother leadwiping. It's a way of covering up rust, just like bog... Only more difficult.

Cut the rust out (all the way back till you've got 100% perfect metal), make a patch (either from another car or fabricate one from sheet), then weld it in using mig or tig.

Mig is quick and easy, but leaves a much harder and brittle weld. You have to grind it back smooth, and can't planish it smooth or bend it.

tig takes more patience, bit the weld ends up being mild steel, so behave more like the original panel, meaning you can panel beat, planish, file, etc over and around the welds.

[dnegative]

Chop it out and put in new steel, the only proper way.

You could braze over it but it wont be easy

[Hen]

If you cut it out and weld new metal in make sure you remove ALL the rust. I've had plenty of times before where I've been TIGing a piece in and hit a section with a little hidden rust and it flares up causing a shitty weld and much swearing.