Floor Welding Advice Please

[piglet14 0]

We have 2 small holes under the rear seats and 1 less small in the boot, I also have to investigate an area under the bonnet in front of the strut.

The owner is doing welding at college and I'm good at grinding the arse out of things.

We have a borrowed MIG with a large gas bottle and a roll of 0.6 wire.

 

My questions are, what plate thickness/type?

And should plates cover the holes overlapping or be a precise fit in the hole?

 

If the plates cover with an overlap doesn't that create a new rust trap between the old body and the new plate if both are bare metal?

 

I have some 1mm Galv mild steel sheet, is Galv plate OK for MIG?

 

Thanks

[Pugleyrich 37 1 Cars]

I can't help on thickness as I've not welded mine myself. I do know that overlapping is not good as they create a trap as you've described.

I recently took my car for a small patch in the floor. I was disappointed to find it had been welded over the hole. I had the garage put it up on the ramp and grind the excess old metal off until it was flush. Didn't take 5 minutes.

[arbor 2]

I've always used 0.8 wire and cut the patch/hole back to decent metal then make a template to fit the hole. Plating over the hole seems lazy, bit of patience to get the template right with approx. 1mm gap to allow decent weld penetration is the way to go.

 

Wouldn't suggest galvanised steel it vaporises the zinc and gives off fumes which aren't great. The thickness is fine but try and find mild steel, I get mine from local agricultural building suppliers or agri fabricators, mostly off cuts but cheap as chips and done right will last for years. Good luck.

[toolie72 67 1 Cars]

If you cut floor to get rust out then make template for a butt fit-this does two things 1-looks better and minimises water trap 2 mot tester will think-good job

I used to use 1.6 mm steel on sunbeams, escorts etc but 1.2 would be fine on floor-I've seen some rotten 205s in scrappies and they've all gone there

Galvanised steel is a no no in your garage-you will feel very very ill-it is poisonous-take it from an a@@e that's done it!!

[boldy205 75]

Weld through zink primer is always good to keep corrosion down

[piglet14 0]

The aerosol stuff? Doesn't make it difficult to weld then?

[Emmy Seize 8]

Just do as suggested above. Cut out the rust, then create a patch to butt-weld in. Do not apply any primer before welding.

 

Personally, I prefer red oxide primer over zink coat as you can filler and paint it over without headaches.

[boldy205 75]

The weld through specific primer is designed to do just that. Never made my welds any worse.

[petert 586]

Not sure of what your product is called over there, but we call it zinc anneal. ie annealed mild steel sheet which has a thin coating of zinc. It's very easy to weld. Not to be confused with fully galvanized steel, which has a much thicker coating of zinc and has been work hardened by the cold rolling process.

[welshpug 1,657]

the most common name ive heard is zintec, just ask your

local factors for repair sheets, they'll know what you mean, it'll be stocked in two gauges usually.