Rust! Any tips for DIY removal?

[storm_warning 0]

The winter has been harsh to my car's body and after it's first wash in months and l o t s of rust spots have popped up :(

 

I have nowhere near enough money to get it done by a bodyshop, so I'm forced with doing it myself. I am fully aware I won't get a great finish, but whatever I get must be better than the rust itself, so does anyone here have any top tips for rust removal/treatment and in-the-garden paint touch-ups? Biggest spot is about the size of a 50p coin and a couple of long strips of rust on the trailing side of both front wheel arches, but mainly they're small spots along the seals, but highly noticeable.

 

It's Mystic Blue, if it makes a difference?

[Kevin Bacon 5]

Yeah best thing to do is tidy up the areas as best you can until you can afford to get it done professionally. That's what I do.

 

Trouble is, each repair just bubbles up again every winter, so it really is a band aid fix, but VW metal is very good on the whole, so providing you patch it up reasonably well, it shouldn't spread any further than the initial patch size.

 

I would sand it back as aggressively as possible, dig out all traces of rust as possible and that will mean eating into unaffected paint to kill the "spiders legs" unfortunately. Then I would bypass "KU rust" and all those crappy ineffective treatments and pick up a copy of classic car or something. In the back of that mag will be a few adverts for PROPER rust treatments. I've yet to do that myself, but having done this for the past 6 years, the stuff you get in Halfords won't last more than a year, 2 tops.

 

Then when treated, all you can do is get the level back up again with fillers and things, paint, cut back, paint, cut back, etc etc until you're happy.

[davidwort 0]

One of the big problems with rust removal and patching up is that steel seems to absorb moisture, so if you simply sand back and immediately re-paint the rust forms again under the paint, cracks the paint and lets more moisture in.

I've found the best way is to de-rust in the summer, try to strip the area in the sunshine and leave it in the sun for a while, or even heat gently with a hair dryer and then treat and re-paint.

This isn't going to last forever as primer bonding and top coat cracking can still be a problem when doing pateches over a few mm in size, but it seems to work as well as anything.

The longest lasting repair I made on a rear arch I scraped, and then stupidly allowed rust to form on, was actually painting smooth-rite straight onto the metal, leaving for weeks to cure and then spraying a matched top-coat can over the top, but matching a small patch in colour is very hit and miss and metallics will never look right, at least solids can be cut right back.

[iow_corrado_g60 0]

im interested in ppl's answers too this and am in exactly the same position.

 

 

I've been looking about quite a bit and this places seems to have alot of good stuff but ive heard a good few reviews about the por stuff!

 

http://www.frost.co.uk/result_search.as ... 3godzUAxdA

 

 

Kev what do you sand back with wet and dry 800 grit or the like???

[iow_corrado_g60 0]

has anyone used this

 

http://www.frost.co.uk/item_Detail.asp? ... e=Eastwood Rust Dissolver (946ml) US Quart&catID=28&frostCat=Rust&frostSubCat=Eastwood&subCatID=32

[Kevin Bacon 5]

I've found the best way is to de-rust in the summer, try to strip the area in the sunshine and leave it in the sun for a while, or even heat gently with a hair dryer and then treat and re-paint.

 

Absolutely! I forgot to mention that. If I have to rust repair in the winter, I warm the entire panel (in an enclosed garage) that needs painting first, to avoid localised temperature differences, which can promote moisture build up.

Summer is best though as you say.

 

Low_Corrado_g60, that's the kind of stuff I'm talking about mate :) KURust stuff just turns rust blue and nothing else. It's rubbish.

The only way to "cure" rust is to remove it altogether, mechanically, or chemically, not just paint over it as per Kurust, LOL! :lol:

 

As for sanding, you need some aggressive to hoik all the rust out if doing it mechanically. A flap wheel on a drill for instance..... you want to see bright steel before going back in there with paint! Then you want finer grades when it comes to feathering in your repair to the surrounding paint.

[corradophil 3]

You need to remove every last little bit of rust. Blasting is best, but not really a suitable thing for you.

 

Another good way to remove it is using rotary wire brush attachments in an electric drill - be warned though, it can he hard to control the positioning of it accurately.

 

In the past, I have succesfully used a dremmel with various grinding stones and small wire brush attachments to completely remove rust spots. I have also used white smoothrite as a primer.

 

Rust can come from both sides of the panel, in which case you may end up with a hole. This is most likely on rear wheel arches, or anywhere which is double skinned.

[Kevin Bacon 5]

Yeah agree with all that /\

 

Prevention is wise too, so every year I get underneath with the 5 litre pot of black waxoyl and get busy. I leave the lid off the waxoyl for 2 weeks and periodically stir it first though, otherwise it goes on too thin and gets washed off the first puddle you drive through. You want it to go on like a thick tar, then it won't get washed off so easily.

[storm_warning 0]

Awesome responses, thank you all! Realy don't want to wait until the weather's nice and hot to de-embarrass my car 8) My friend has a heat gun, maybe I can ensure moisture free rust removal by using that?

 

One more question, after removing rust and re-painting the area (you can tell I am new to this) how do you go about blending the new paint into the existing surrounding paintwork? Is it a matter of lots of cutting back using fine grade wet paper? Does this apply to the laquer, too? Again, I am not expecting to perform miracles, just having a car coloured spot is better than a rust coloured spot!!

[corradophil 3]

If they are small rust spots, I assume you will be touching them in with a paint brush, not spraying.

 

Keep the repairs as small as possible. Once touched in leave the paint to harden. If it was me I'd leave it for a week.

 

If you have a high spot this can be carefully dressed back using 1200 or 1500 wet and dry. Be very carefull to only rub the lacquer you have put on. It is very easy to rub the through the surrounding paint leaving you with more repair work to be done.

 

The aim is to build up the colour so it is just lower than the surrounding factory finished paint. Then apply lacquer to the base coat and build it up to the finished level. It is likely that the lacquer you put on will sit high, so this needs to be dressed back as described above. Below I've illustrated the effect you will probably get. It is usefull to use something as a rubbing block when dressing the lacquer back because this will allow it to be rubbed to a flat finish - not uneven and rounded because your finger tip will distort to the shape of the lacquer.

 

-------- Uneven lacquer to be dressed back

------ -------------

--------------------------------------------------------------------------- Lacquer

 

--------------------------------------------------------------------------- Base coat (colour)

 

---------------------------------------------------------------------------- Primer

 

______________________________________________________ Metal

 

 

Perfecting this process may take a few goes - so you should find a descrete repair to start with, and get it right before starting the others. Once you are happy with the repair, you wil be left with a dull patch where you dressed it back, need to polish this with a compouns such as Farecla G3. If you don't have this T-Cut will work too.

 

Hopefully this will help you with the theory, but you will need to be patient and allow plenty of time to practice it.

 

It is unlikely that you will get a perfect finish, but you should be able to tidy and protect the areas which have rusted, and it should look better than rust, plus it should not cost much.

[davidwort 0]

Awesome responses, thank you all! Realy don't want to wait until the weather's nice and hot to de-embarrass my car 8) My friend has a heat gun, maybe I can ensure moisture free rust removal by using that?

 

they get ****ing hot and are intended for paint stripping :lol: seriously, I'd use a hair dryer, tescos probably do one for about 3 quid these days :)

[AlexDG 0]

Rather late reply, but thought I would revive this one because I have been trying something new (to me)...

 

Malt vinegar - yes really!

 

Over the last 24 hours I have been soaking an original suspension strut off a 1980 924 (so nearly 30 years of corrosion) in a couple of litres of cheapo malt vinegar and the majority of the rust has dissolved!

 

Even though I knew the chemistry was sound I was not entirely convinced it would work as effectively as it has done. There are some bits that are more heavily pitted so I have left it in soaking for another 24 hours, but I have to say the results are quite amazing, very little effort and cheap (though not particularly quick and it makes the garage pong a little - some reason I have a craving for chips...).

 

I will take some before and after pictures when I do the next strut.

 

OK so malt vinegar is no good for panels, but I am guessing a sauce of some description with a similar acidic quality applied to a rusty panel and covered in cling film (to stop it drying out) could well work, I will try it out when I have finished the more immediate job of rebuilding the suspension on the 924.