Fix tiny rust spot

irlrobins

Hey all,

Noticed a tiny rust spot on the bonnet of my 06 VW Golf today. Probably caused by a stone chip or other road debris. Chip is prob 5 mm by 2 mm but I'd like to treat it before it got worse.

What's the best approach? Simple touch of matching paint from motor shop?

R

Hal1

A touch up pen will only mask the rust and stonechip. The rust will only spread over time so best to treat it at the early stages.

I would treat the rust firstly. Mask off the area and and loosen the rust with some 800 wet & dry sandpaper. Apply some Krust (small pen size bottle available in halfords). Depending on the depth of the crater it might need some filler. I've used Holts knifing putty and it works very well for small jobs. It goes off in a few minutes.

Wet sand back to a smooth surface with 1200 sandpaper. Then primer, touch up paint (you cars colour), and finally laquer. The results will only be as good as your prep work.

fasttalkerchat

Hal1 wrote: »

A touch up pen will only mask the rust and stonechip. The rust will only spread over time so best to treat it at the early stages.

I would treat the rust firstly. Mask off the area and and loosen the rust with some 800 wet & dry sandpaper. Apply some Krust (small pen size bottle available in halfords). Depending on the depth of the crater it might need some filler. I've used Holts knifing putty and it works very well for small jobs. It goes off in a few minutes.

Wet sand back to a smooth surface with 1200 sandpaper. Then primer, touch up paint (you cars colour), and finally laquer. The results will only be as good as your prep work.

This, plus sand after each layer of primer and each layer of paint. You want to get at least 3 of each... weather permitting.

String

If its just a tiny rust sport wouldn't scratching the rust away and then dabbing it with some sort of rust treatment to chemically change it be enough?

irlrobins

I was about to ask the same. Call me lazy but that seems a lot of work for a rust spot that so small.

fasttalkerchat

irlrobins wrote: »

I was about to ask the same. Call me lazy but that seems a lot of work for a rust spot that so small.

For an 06 Golf i think its worthwhile.
Up to the OP really. If you paint over it you will have no problems for a year or so.

Hal1

Sure there are plenty of stone chip kits you can buy that would mask the chip, but ideally you would want to treat the rust. The guide I wrote above would ensure the rust would not return.

dharn

i would expect 90 % of people who tried the above job for a stone chip would probably make it look worse ( sand, prime, sand again paint , lacquer )

fasttalkerchat

dharn wrote: »

i would expect 90 % of people who tried the above job for a stone chip would probably make it look worse ( sand, prime, sand again paint , lacquer )

I thought it was quite simple. just put some tape arounf the patch so you dont damage surrounding paintwork. I was impressed with the result from the halfords 3 pen set.

irlrobins

dharn wrote: »

i would expect 90 % of people who tried the above job for a stone chip would probably make it look worse ( sand, prime, sand again paint , lacquer )

Yeah, that's my fear. I'd rather pay someone to do it right first time.

dharn

the point i was making was that for the average stone chip, size of match head or less ,touch in pen should be fine , some guy was talking about sanding,priming,paining, laqureing, that sounded like a bad idea to me

Owen

Not to mention the terrible idea of putting tape around the repair area *shudder*

Hal1

What's the problem with using tape to prevent overspray? It should be ok once you give light pases between each coat. It won't leave an outline then.

fasttalkerchat

Owen wrote: »

Not to mention the terrible idea of putting tape around the repair area *shudder*

?? How would you do it?

GaryIrv93

http://www.howtogetridofstuff.com/household/how-to-get-rid-of-car-rust-spots/

challengemaster

Hal1 wrote: »

What's the problem with using tape to prevent overspray? It should be ok once you give light pases between each coat. It won't leave an outline then.

The problem is you wouldn't be spraying anything in the first place, you're only making work for yourself with such a small area. Very fine brush and building up layers, same as you would for a regular stone chip just with some more prep to get rid of the rust.

dharn

Hal1 wrote: »

What's the problem with using tape to prevent overspray? It should be ok once you give light pases between each coat. It won't leave an outline then.

why would you spray a stone chip ???

Owen

Hal1 wrote: »

What's the problem with using tape to prevent overspray? It should be ok once you give light pases between each coat. It won't leave an outline then.

Tape will give you a hard defined edge. I'm in the middle of repainting a bumper someone had a go of themselves using that sort of advice, you can clearly see the parallelogram of the new paint where the owner taped off the repair area. I now have much more work to correct what would have originally been a simple repair.

You don't spray stone chips/small rust spots. There is no quick fix. You either respray the panel in its entirety, or you use a cosmetic fix like a paint pen. The paint pen won't fix the rust, or the crater around the paint, just put colour on it, it'll still be visible from a meter away. The day someone comes up with a solution for stone chips that actually works they'll make their fortune.

Hal1

dharn wrote: »

why would you spray a stone chip ???

A touch up pen would be better in this situation for a stone chip. Rust spreads, I was just suggesting a method to prevent it from bubbling back . Although after reading Owen's post I can see how my method is flawed. Thanks .

fasttalkerchat

Owen wrote: »

Tape will give you a hard defined edge. I'm in the middle of repainting a bumper someone had a go of themselves using that sort of advice, you can clearly see the parallelogram of the new paint where the owner taped off the repair area. I now have much more work to correct what would have originally been a simple repair.

You don't spray stone chips/small rust spots. There is no quick fix. You either respray the panel in its entirety, or you use a cosmetic fix like a paint pen. The paint pen won't fix the rust, or the crater around the paint, just put colour on it, it'll still be visible from a meter away. The day someone comes up with a solution for stone chips that actually works they'll make their fortune.

Ah okay I see now, the tape is for when you are sanding so you don't scratch the surrounding paintwork. Don't spray either.

Owen

No tape, no sanding. Just don't go at it. It'll end up a mess, even I wouldn't do it. Either spray the whole bonnet, or don't go at it.

fasttalkerchat

Owen wrote: »

No tape, no sanding. Just don't go at it. It'll end up a mess, even I wouldn't do it. Either spray the whole bonnet, or don't go at it.

Each to their own but his chip is 5 mm by 2 mm. Thats too big to leave because it was rust and flake. I had a bigger one and i spent a week sanding and using the halfords 3 pen set and did a perfect job. If it doesn't work out you could respray after.

Maybe I'm too much of a perfectionist.

Owen

In all my time here I've seen bad advice given out and I've tried to disuade people from having a go when clearly they've never practised on scrap panels to build their skill level, or if they're listening to 20 different people with 20 different approaches - this shows they clearly don't have the skill level. Some people refuse the advice, and decide to have a go themselves promising photos of the job when it's done after.

In all my time here (Apart from Alloys) I've never seen anyone put up a photo of the bodywork they've done themselves. And I'd be 99% certain that it's as a result of making a monumental f*ckup and having to pay someone to do the job making it more expensive & time consuming than just getting it done the right way the first time.

irlrobins

Like I said, I'm happy to pay someone to get it right first time than me making a pig ears of it. I had thought of just touching it up but as some people had pointed out I'd probably just be hiding the damage and the rust could still spread under it.

dahamsta

Owen, do you have a particular procedure for doing stone chips? I have an OEM BMW kit that wasn't cheap, but it's sat on my hall table since I got it because any time I've gone looking for howtos I've come across horribly complicated procedures like the above. Is it really just a case of dab it on as carefully as you can, and deal with the rust when it actually becomes an issue?

challengemaster

dahamsta wrote: »

Owen, do you have a particular procedure for doing stone chips? I have an OEM BMW kit that wasn't cheap, but it's sat on my hall table since I got it because any time I've gone looking for howtos I've come across horribly complicated procedures like the above. Is it really just a case of dab it on as carefully as you can, and deal with the rust when it actually becomes an issue?

If there's rust there it already is an issue, just not a major one. If you cover over it and leave it to spread, all you'll end up doing down the line is having to cut out a large piece of metal and weld in a replacement. Covering over it is only stopping you from seeing the damage

fasttalkerchat

fasttalkerchat wrote: »

Each to their own but his chip is 5 mm by 2 mm. Thats too big to leave because it was rust and flake. I had a bigger one and i spent a week sanding and using the halfords 3 pen set and did a perfect job. If it doesn't work out you could respray after..........

Perfect with a Halfords 3 pen set? I find that very hard to believe.

trixyben

is there a treatment or what is the best treatment to get rid of the rust?

I have a small chip above rear whell arch thats going to need attention soon

Owen

dahamsta wrote: »

Owen, do you have a particular procedure for doing stone chips? I have an OEM BMW kit that wasn't cheap, but it's sat on my hall table since I got it because any time I've gone looking for howtos I've come across horribly complicated procedures like the above. Is it really just a case of dab it on as carefully as you can, and deal with the rust when it actually becomes an issue?

Pretty much unfortunately. There is one system which sort of half works, Sprayless Scratch Repair but it's not a long term solution. It's a resin which is mixed up to match the pigmentation of the paint on the car, smeared in to the chips so there's a bit too much, then machine polished flat.

It's still a visible repair as nothing can remove the circular outline of the stone chip, and in time power washers will remove it, but it does a reasonably good job of masking the damage. It's not something I do BTW before you ask

dahamsta

That's what I thought, and it doesn't bother me. Sure who has the time and money to fix every little chip as it happens! Thanks Owen.

kevin65

No need for drama with small rust spots. Just use a small craft knife with a sharp point to carefully remove loose pieces of paint and rust. If spot is very small, use the knife to carefully scratch out the remaining rust. If you go using sandpaper, you need to be careful or you end up damaging the srroundng surface. With all rust and loos paint removed, clean the surface. You could use a little bit of warm water and wash up liquid, wiping with a squeezed out cloth, rinse the cloth and then wipe again. If you have something like IPA, just give it a quick wipe. Give the spot a coat of rust primer paint with a small artists brush, making sure you only paint the surface of the spot. This should dry to be slightly below level of surrounding paint. Follow up with top coat and lacquer, the touch up kits from the manufacturer will give you the best match. Leave for a couple of weeks for paint to fully cure and then use some 2000 grit wet and dry to lightly sand the spot followed with some scratch removal polish and then a good coat of wax.
It will never be invisible when you look along the surface, but much better than rust!

Nonoperational

I agree with Owen. It's very very hard to get a good result on stone chips. My car is black and filling them very carefully with a Halfords black pen definitely improves them. It is obviously not perfect but it's an improvement especially for larger chips.

There are a few approaches that seem to work to a certain extent. I thought this was a very good job http://www.detailingworld.co.uk/forum/showthread.php?t=20127
This is a fairly professional job though and not something most people would have the skill to do.

There's also a product called Dr Colour Chip that seems to give OK results. http://www.detailingworld.co.uk/forum/showthread.php?t=77128

At the end of the day a respray is the gold standard...

Tigger

people belived the paintdoctor more when he was called paint doctor
Owen just dosen't have the same ring:P

if a person wants to try stuff they really should (as Owen says) practice on scrap to learn or at least realise that its too hard

Owen

kevin65 wrote: »

No need for drama with small rust spots. Just use a small craft knife with a sharp point to carefully remove loose pieces of paint and rust. If spot is very small, use the knife to carefully scratch out the remaining rust. If you go using sandpaper, you need to be careful or you end up damaging the srroundng surface. With all rust and loos paint removed, clean the surface. You could use a little bit of warm water and wash up liquid, wiping with a squeezed out cloth, rinse the cloth and then wipe again. If you have something like IPA, just give it a quick wipe. Give the spot a coat of rust primer paint with a small artists brush, making sure you only paint the surface of the spot. This should dry to be slightly below level of surrounding paint. Follow up with top coat and lacquer, the touch up kits from the manufacturer will give you the best match. Leave for a couple of weeks for paint to fully cure and then use some 2000 grit wet and dry to lightly sand the spot followed with some scratch removal polish and then a good coat of wax.
It will never be invisible when you look along the surface, but much better than rust!

This is terrible, and incorrect advice. Why paint needs weeks to cure is beyond me. You cannot blend lacquer on a flat panel like a bonnet without substantial experience, and even then you wouldn't use 2000 paper or polishing compound, and ... even then there's only certain areas you can paint if you're blending. Bonnets aren't designed to be blown in.

dahamsta

And you certainly can't remove all traces of rust with a craft knife. It's not called tinworm for nothing.

kevin65

Owen wrote: »

This is terrible, and incorrect advice. Why paint needs weeks to cure is beyond me. You cannot blend lacquer on a flat panel like a bonnet without substantial experience, and even then you wouldn't use 2000 paper or polishing compound, and ... even then there's only certain areas you can paint if you're blending. Bonnets aren't designed to be blown in.

You don't seem to have read my post correctly. Where did I mention anything about 'blowing in'? I'm not talking about spraying sections of paint, I'm talking about fixing very small rust spots, such as those from stone chips! I have used this method successfully for years on my cars and my wife's cars. As I said in my post, it won't be 100% perfect, but will give a very good result. And yes, touch up paint does need at least a week to fully cure under typical Irish ambient temperatures before sanding. Different to spraying in a booth obviously! You should read a post correctly before shooting it down.

kevin65

dahamsta wrote: »

And you certainly can't remove all traces of rust with a craft knife. It's not called tinworm for nothing.

For small spots of surface rust, yes you can. There is a difference between surface rust and rust that has pereforated a panel. I have done it successfully many times for surface rust spots. Have you ever tried it?

dahamsta

I haven't, because I know how oxidation works -- what you see and remove is just the tip of the iceberg. If you really want to remove the rust, and halt the oxidation process, you'll need a lot more than a craft knife. Again, it's called tinworm for a reason. What you're doing is patching over, which is what I'll be doing too. But it's not removing "all" rust. Like Arnie, it'll be back.

Owen

kevin65 wrote: »

And yes, touch up paint does need at least a week to fully cure under typical Irish ambient temperatures before sanding.

As a spray painter - that's b*llocks. Even the cheapest crappiest aerosol will be cured in 8 hours these days without assistance. The mere fact that you're talking about sanding after the paint has dried (After a week no less) reinforces the fact that your technique is flawed. You shouldn't be giving advice like this to a person on a forum - they may well follow it and have it turn the minor stone chip on their car into a golf ball sized blemish.

Dahamsta has properly corrected you on the treatment of rust, which under no circumstances could ever be removed with a craft knife. It's hilarious to even suggest it could. All you'll do is remove the surface visible rust - the tip of the iceberg, the chemical reaction underneath is the real enemy and you've taken no steps to address that whatsover.

If you'd like to be shown properly how to paint without needing to sand or wait a week for paint to cure, I'll gladly demo it for you some day. I genuinely mean that, and not in an aggressive way.

kevin65

Owen wrote: »

As a spray painter - that's b*llocks. Even the cheapest crappiest aerosol will be cured in 8 hours these days without assistance. The mere fact that you're talking about sanding after the paint has dried (After a week no less) reinforces the fact that your technique is flawed. You shouldn't be giving advice like this to a person on a forum - they may well follow it and have it turn the minor stone chip on their car into a golf ball sized blemish.

Dahamsta has properly corrected you on the treatment of rust, which under no circumstances could ever be removed with a craft knife. It's hilarious to even suggest it could. All you'll do is remove the surface visible rust - the tip of the iceberg, the chemical reaction underneath is the real enemy and you've taken no steps to address that whatsover.

If you'd like to be shown properly how to paint without needing to sand or wait a week for paint to cure, I'll gladly demo it for you some day. I genuinely mean that, and not in an aggressive way.

Not in an agressive way? Well, you tone is coming across as agressive to me. As I said earlier, I am talking about a solution for light surface rust spots such as thos from stone chips, not rust perforations and has worked successfully for me for the last 20 years. But since you see yourself as the local know-it-all on this topic, I'll leave it to you. The floor is yours...