StratfordShark

Thanks Geoff - sounds admirably fastidious to use the steam cleaner! Will get on with other mechanical stuff (new shocks) after treating this rust patch but will consider doing the steam clean in future, especially if I get a lift.

Daniel Dudley

Time to get a subscription to Practical Classics and a Clarke mig welder ! A night course in auto body repair will have you cutting out small sections and letting in new metal in no time.

I have had a mig for at least 15 years, and although I don't use it a lot nowadays, I was able to rebuild a front shock tower on a Fiat Abarth replica last summer for pennies in the evening hours. Once you get started, it's pretty easy, but I did take a night course at a trade school. Tin snips and an angle grinder are about all the tools you need, although a hammer and a few dollies are quite handy.

StratfordShark

Well I took a wire brush on a drill to the rust patch, and lo and behold I now have a hole where the bubbling was worst!

How do people go about fixing this kind of thing short of welding in new metal (and if you do the latter, isn't the new section very obvious?).

Ian928

A competent auto repair welder will have no problems to repair that! They cut out the bad area and weld in a new metal plate with exactly the same size, grind the welds down and hide the repair with a thin coat of filler (or if you prefer it, tin). Just be sure that they surface treat the repaired area properly (epoxy primer on both sides of the panel) before filler and paint.

WallyP

Patch:
Remove loose rust, grind area with 36 disk, treat with rust converter. Fiberglass patch, good body filler, prime, paint on both sides, undercoat inside.

Fix:
Cut area, weld in patch panel, grind, straighten, fill, prime and paint both sides, undercoat inside.

Done properly, either method will last for years, be impossible or difficult to see on casual examination. The metal patch can be (but rarely is) done so that only a suspicious expert can find it.

Patch can be done pretty well at home. Fix requires expert help, special tools.

CanAmJohn

It might work out cheaper and better to get the car to a good body shop and let them sort it, they will match the paint well too.

StratfordShark

Thanks guys - I really no nothing about bodywork so good to know there are common patches/fixes. I'm not good with 'craft' skills so will be taking this to bodyshop once I finish some of the mechanical projects I have on (suspension and brakes mainly).