Repairing rust on a panel.

For pinholes I think lead would be the best solution. If you wanted to be meticulous about it, cutting out a larger section back to good metal then welding in a patch may be better. I had a similar repair done on pinhole in a door twenty years ago - the door is still good today.

Not within my skills I'm afraid. Perhaps more so on such an obvious place on a nearly flat panel.

I'll give the lead a go. I take it it's pretty well the same stuff as plumber's solder?

It's not going to be what you want to hear, but for several reasons the best way to repair this is with plastic filler.

Chris

A coating of Hydrochloric acid (Spirits of salts) will kill any rust cheaply

The original was repaired by the body shop some 5 years ago. Started bubbling about a year ago and is now disgusting. They took all the original paint off too before repairing. They also filled in a hole in the wing where an aerial was. That too is showing now.

They said they'd used some newish (polyester?) filler - much better than the usual 'Cataloy' type stuff.

if it was not sandblasted first on both sides then that will happen.

Polyester filler is good stuff, reasonably flexible and easy to rub down but it is no good at all for stopping rust.

The only sure way to gain longevity from ingrained rust is to have the area sand blasted, it would be worth purchasing a sand blast kit like the one recently sold from ALDI for about a tenner which comes complete with sand but you'd need a compressor to use it. This method is the only sure way to remove rust from within the metal itself.

After adequate keying you then use the polyester filler directly over the bare steel, rub this down smooth which must by done dry and then immediately prime with any of the suitable cellulose or acrylic vehicle paints available before applying the finishing colour coat.

BTW what is your car colour?

Stephen.

No , plumbers solder is lead free .

If it truely is only a pin hole then a mig or tig welder will fill it without any problem

Any bigger than a pin you will need to get it patch welded anyway

Acid pickling is the way "new" cars are done (not sandblasting). For top quality, "Industrial" steelwork is always sandblasted.

That's because it's the cheapest way to do it.

An old technology that Practical Classics rediscovered recently is metal spraying using an oxy acetylene system. They recommended Zinc spraying, but the same technique can be used for steel. It's not cheap, but it can be used to build up the sheet to the original thickness in the original material.

I've seen it successfully used on crankshafts using the appropriate material in the "spray gun"

It may be now for potable water. But you can still used leaded stuff for heating, etc.

It might do in the hands of a skilled operator. I'm not. I'd just make the hole bigger. ;-)

It is just a pin hole and the surrounds on both sides are fine. I'm wondering if it was a fault in the steel.

Since the area is so small I've been using a selection of diamond burrs in a Dremel type tool. I've no space for a compressor. Actually quite successful - on the frame which had more surface rust, I removed the paint with a flap wheel then used the burrs to clean up the pits. Removes less metal than grinding away with something larger.

Plain black. The respray is in water based.

Not if its exposed or is accessable .

They certainly dont like it in the new heating systems , they run alot hotter and because of the galvanic action.

Like how? The temperatures on the water circuits of a modern condensing boiler are *lower* than that of the non condensing boilers previously used.

Flow temperatures have dropped from 80deg C to about 70 and return temperatures from 60 deg C to around 45 -55

Eh?

Actually, a condensing boiler runs cooler than older types. That's why rads may have to be increased in size.

And what is different with 'galvanic action'?

Indeed. I've also no idea what he means by 'galvanic action'. Lead solder is still the best for electric connections. Lead free has caused all sorts of problems.

Basically, lead free would be used for precisely nothing - apart from H&S considerations.

What's important for a condensing boiler in order for the claimed efficiencies to be achieved is to have a high differential between flow and return temperatures. To this end, flow temps are often actually higher, 82deg C in the case of my installation.

Chris

"Dave Plowman (News)" wrote: [snip]

Exactly, there has been some disinformation in this thread. That apart, if you can get hold of it, the correct "lead" to use is plumbers' metal - solid sticks or bars of solder without flux. I'd use Fry's flux for the job and practice on something non important - possibly by drilling a hole and "fixing" that until I was confident.