Rust Treatment

[ChrisHParticipant @chrish]

I am sure, well as far as I can be these days, the little grey cells being as they are now, that there was an article on Rust Treatment in MEW a while back, but I am blowed if I can recall when. Can anyone point me in the right direction please?

Had the digital issues section had a search function I wouldn't need to ask, but I guess adding a search function there would involve a fair bit of software writing/updating at a not inconsiderable cost!

My end-of-life crisis car has developed a small rust patch which needs treating, hence the query.

Chris

[ChrisHParticipant @chrish]

[mechman48Participant @mechman48]

Depending on how big the patch is.. remove surface rust with wire brush / emery cloth, apply Jennolite / D rust / Ku rust or similar propriety rust neutraliser from Halfords ( usual disclaimer ).. let it dry, rub down lightly again, any embedded rust will have turned to a black oxide ready for primer coat, fill in any deep scratches, rub down with wet & dry, let it dry completely, apply primer / matching top coat.. wet & dry again, another top coat. Halfords will make up an exact match for your colour if you give them the manufacturers colour code.. did it on my last car.. an exact match!

I'm not a car mechanic / bodywork specialist so can only offer advice as to how I've done it in the past, no doubt there will be plenty of posts as to how to do it correctly… but FWIW..

George.

p.s. I also cleaned any road detritus from behind the affected panel /patch down to bare metal as well & gave that a coating of the anti rust gel too, then gave that a top coat spray followed by a coating of Waxoil or similar.. belt & braces scenario, rust does eat from both sides.. .

[Russell EberhardtParticipant @russelleberhardt48058]

Yes, Jenolite (or any other brand containing phosphoric acid) works well. It converts the rust into a phosphate which is quite inert. The instructioons may tell you that you don't need to rub down but ignore that if you want a good finish.

Russell.

[Neil WyattModerator @neilwyatt]

Issue 216 had a feature on RUST by Dave Fenner.

Neil

[Phil WhitleyParticipant @philwhitley94135]

Hi Chris, Beware!! can you tell me what car it is, and where the rust is, or even post up a picture? If this is ONLY stone chip damage, and you know the metal underneath is sound, as the others have said, anything with phosphoric acid in it will remove it, then use a product like "Davids" zinc rich primer or similar.

If however the rust first appeared as bubbling in the paint it is almost certainly rust which has come right through the metal of the panel, or an earlier repair which has not been done properly, and will require either a welded in repair, or filling with a reinforced matt and resin type filler after all the rust has been neutralised and treated or removed. Don't wish to be negative about this, but going out to spend a few minutes fixing some rust then coming back with a long face and a hole in your pride and joy is not a good way to spend your Sunday! I spent a large(too large!) part of my life rebuilding rusty motor cars and have welded everything from an Aston Martin DBS V8 to a Citroen 2CV.

Phil

[KWILParticipant @kwil]

As Phil says

"after all the rust has been neutralised and treated or removed", just because it has turned to black phosphate on the surface do not believe it has done the same to the bottom of the rust pit, get down to clean metal you can see, then you can be sure.

Agree most strongly on use of a rich zinc primer to protect the bare metal before applying the next paint coats.

Edited By KWIL on 15/02/2015 13:33:33

[Swarf, Mostly!Participant @swarfmostly]

Hi there, all,

I'd like to add a caution regarding 'get down to clean metal'.

If you are too gung-ho with the wire brush, what appears to be 'clean metal' appears quite soon. However, this is often an illusion! The 'bristles' of the wire brush are much harder than the mild steel being treated. Thus, the brushing action smears the steel and closes it over the tops of the pits, leaving these largely untouched and still rusty but inaccessible to the Jenolite or other anti-rust treatment. That shiny burnished surface is a snare and a delusion! Those rusty pits will break out again disappointingly soon!

My own preference is to use an abrasive disk and to stop once any loose material has been removed. There needs to be some rust still evident for the Jenolite work on. Also, the instructions on the Jenolite container do not recommend zinc-rich paint as the next stage.  For zinc coating (i.e. galvanising) to work, there must be galvanic (i.e. electrical) contact between the particles of zinc and the steel – nobody has yet expained to me how that requirement can be satisfied when the zinc particles are insulated from the steel and from each other by the binder/carrier components of the paint???

As Phil has posted, what I have written does not apply if the rust is coming right through the thickness of the base material.

Best regards,

Swarf, Mostly!

 

Edited By Swarf, Mostly! on 15/02/2015 15:31:28

[WALLACEParticipant @wallace]

If you have a compressor, I’d use a small sandblasting gun. In my experience ( Lancia – need I say more ?! ), rust killers just slifhtly prolong the time for it to bubble through again – sandblasting kills it dead. It also gives a good finish for primer to adhere to.

Unfortunately, it usually uncovers a lot more rust than you were expecting – and if you’re a but too enthusiastic, can blow holes in rust weakened panels…

W.

[ChrisHParticipant @chrish]

Thanks to all who have commented, and to Neil for saying which copy of MEW I need to look at.

However, I have looked more closely at the problem and have concluded that what is really required is to bite the bullet and get her into a body shop for a proper welded repair with the affected area cut-out and replaced ASAP.  What appeared as a wee rust spot came to reveal on scraping back a cunning repair that has lasted at least a few years but is now wanting fixing properly. It has been previously filled and painted but now the rust is blowing the filler off. If I do anything there it will be a very short term cop out to try and ensure further damage is minimumised before a proper job Is done. By the way Phil, the car is a Eunos MX5, Mk1 from 1996 and the area is in way of the outside of the nearside sill at the rear, immediately before the wheel arch.

As the car is well loved and I want to keep her for a long time it will pay me to get her sorted sooner rather than later, so a search for a good but reasonable body shop local to me is on! The MX5 is not particularly quick comparative to modern cars, but just great fun to drive, I always have an ear to ear smile when driving her so she is worth spending money on. Now, where do I find some stash of money……?

Chris

 

Edited By ChrisH on 15/02/2015 21:59:15

[Dave HalfordParticipant @davehalford22513]

Chris

Ask them to butt weld the plate, if they start talking about joddlers go somewhere else. More expensive but you only do it once not twice.

Any kind of lap joint gives a nice condensation trap on the side you cant paint and welded steel rusts faster.

You'll sometimes see a line of tiny bubbles all around a lapped/joddled repair on older classics.

PS Check your sill drains

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