Fixing Stone Chips


Warning.

You attempt this at your own risk, I will not be liable for you following this guide.

Background:

It’s inevitable that at some point no matter how careful you are there will be stone chips. If they don’t smash into your windscreen then they will take little chunks out of your cherished and much-loved paint job.  The chips were not visible straight away, but when the paint was waxed, the telltale white spot appeared in the paint.

This is a tiny chip I know, but to a classic car owner, it’s the size of a satellite dish!

Equipment:

Colour matched paint, toothpick or similar pointed wood, scalpel (optional), masking tape (optional), various fine grades of wet & dry sandpaper, clear lacquer (optional), good torch, detailing brush, clean lint-free cloth, 100% isopropyl alcohol, a little pot to hold the paint.

Various grades of wet and dry need to be fine as we are not going to sand the clear coat off the coloured base paint. So I have the following grit variations; 1500, 2000, 2500, 3000, 5000 & 8000. I may well skip a couple of grades when I get to that step. The grades are slightly different colours and clearly marked up on the back of each sheet. Keep them clean as you don’t want any debris or contaminates on the sheets. So I keep them in a sealable plastic bag, or document wallet would be ideal.

Grades 1500grit to 8000grit left to right.

Costs:

One litre of Isopropyl Alcohol £5, set of detailing brushes £5, paint £??, lint-free paper cloth £2, toothpick (tub) £1, scalpel £5, masking tape or post-it note, £0.50 But all you really need is the paint, the cleaning alcohol and the sandpaper.

Process:

Locate the stone chips and mark them. I first saw this tip at the Shelby American factory in Las Vegas. The cars would be checked and they would highlight any damaged paint with masking tape (or post it note) section just above the damaged area.

You can always remove the tape and replace it once you have finished working in the area.

Clean the area to remove any wax or grease already on the paintwork. This will give the touch-up paint the best chance to cure properly. Using the Isopropyl squirted onto the area take the lint-free cloth to clean thoroughly. The surface area will be cleaned, but I found that some of the wax could still in the chipped area. For this, the small detailing brush, (or cotton bud) came in handy to work the alcohol into the chip itself. The bristles need to do the work, so a gentle work in is required. The alcohol will evaporate very quickly so keep an eye on the alcohol applied. This brush was a little big, an artists brush would have been better, but it doesn’t matter as you are only cleaning the area.

With the area cleaned we need to prepare the paint applicator. Some recommend a toothpick, I like a slightly longer wooden burger skewer. There are even some that will use masking tape rolled to a point to apply the paint. I find that method is a little flimsy for me, but it’s just as effective. Whatever gives you a fine working point will be good.

Depending on the size of the chip will depend on the point required for the filling. I use the scalpel to sharpen the pick to a point and get some fresh wood to soak the paint up a little and hold it onto the pick. The bigger the point the potential to hold a larger droplet, but there is more chance of things to go wrong, such as a run.

I like to use a small mixer bowl, small yoghurt pot or top of a rattle can work just as well. Making sure the inside of the container whatever your choice is clean goes without saying. For the paint’s application there are two options depending on your preferred method, first is the traditional method just the paint or a newer idea of a little lacquer mixed with the paint.

1) Place a little of the colour matched, ready mixed paint as per manufacturers recommendations into the pot.

2) Mix the main colour paint three parts bar coat coloured paint to one part topcoat lacquer for the shine. Spray a tiny amount of lacquer into the cap on one side, so it’s a liquid and then add a small amount of the colour paint to the opposite side, that way you can mix the two as you need.

Locate the chip to be worked on and dip the tip of the pick into the paint, just enough to hold a tiny droplet on the tip of the pick. Using a good light or the bright torch illuminate the working area. The first little drop is applied into the chip itself. You can always practice on something else until you feel confident to try it on the proper paintwork.

Touch the tip into the middle of the chip. The idea is to create a tiny high spot that fills the chip or build up the paint to at least the height of the original paint depth. When you come to sand down you should get a flat surface and not a little dip. Depending on the depth and size of the chip I like to do a base fill first, then come back a few minutes later to add another little fill droplet. You can try a larger droplet, but you could create a run if you put too much on. It’s easier to add a little at a time rather than making work for yourself trying to clean it up later. Depending on where the chip depends on the approach, the horizontal surface is a lot easier than the vertical one that risks the paint running.

The pic here is as close as I could get with raised paint droplet areas.

Leave the paint to dry for a least a few days.

I left my fills for a complete week before I even attempted to work the paint. When you come back in a few days, you will be pleased that you marked up the areas with tape. If you try to sand too early, you will pull the paint out the chip. Also with the paint cured it will be better when you come to polish, seal and wax finish.

The next step requires some patience and delicacy. Going mad with the sanding could remove to much paint or will require more polishing later.

I use a small pencil rubber for stone chips with the sandpaper wrapped around it. I marked up the back of the sandpaper with grit grade as to make sure I knew what it was. Placing the rubber on the sandpaper you can get the size you need to cut into strips.

The paper wraps around the rubber multiple times and will allow for plenty of fresh paper as you need it. The runner has long and short sides to use as you need for the area. The rubber will adapt slightly to the surface you are working on.

As this is a wet & dry paper I found that a small spray bottle with water in it is ideal to wet the area. As the alcohol has removed the wax layers the water should stay on the paint. Spraying the paper before use is also a good way to get started. Depending on the type of paint you have, (hard or soft) will depend on the grade of the paper you should start with. Use a fine grit or grade first as you can always go more aggressive if you need to. I started with 2000grit.

Spray the area and the sandpaper with water with these little 30ml spray bottles which are perfect for the job and cost virtually nothing to buy.

Keeping the paper as flat to the surface as possible start with gentle rubbing for a few seconds and check the area. Wipe away the water and sandpaper residue and you should see a cloudy patch where you have been sanding.

Feel the surface and see where else you need to continue. Reapply more water, turn to a fresh piece of sandpaper and repeat. The cloudy patch is where the paper has taken the very top sheen off the clearcoat, this will be corrected later. Once you have checked the area and the high spot of the paint droplet is almost smooth, swap the sandpaper over to the next grade, 2500grit then 3000grit which should be fine or 5000grit as required. This will remove any sanding marks from the previous sandpaper grade. The sanding marks are incredibly fine at this grade of papers and virtually indistinguishable. This will also help with the final paint correction later on.

Below is another area treated, the white paste is from the glass paper and not the paint. When the paste was removed the smooth surface is shown.

Remember, little and often. 

You are not trying to get to the base coat, light even pressure. Once you have achieved your smooth surface and used the finer grades of paper it’s time to correct the paintwork.

You will need to use a compound polish, there are many on the market, Meguiar’s Compound, Auto Finesse Tripple etc. Use whichever is your preference. There are again a couple of options here.

1) Machine polish. This will give the best results providing you can get to the area of course. In my case, the chip was in a curved area.

2) Hand polish. This is by far the longest method to achieve top quality results. Due to the location of my chip on the rear quarter panel I didn’t want to use the machine polish in this area.

So I used my Auto Finesse Handi Puck and the polishing pad attached to it.

Apply the polish of choice as per the manufacturer’s instructions. Continue to polish until the cloudy area from the sanding has been removed. Little and often, patience is the key. The results in the following pictures are the polished areas.

As we have now finished the polishing the area we will need to protect the area by reapplying layers of wax. You could apply glaze before the wax depending on the overall finish of your paintwork. I used some Dat Wax as a base because it’s a good oily product and of course it was blue which would blend into the painted area. Apply your personal preference for this wax stage according to your wax manufactures instructions.

With the areas waxed the results should be virtually invisible.

Results:

The overall finish depends on the time and effort you are prepared to put into it.

You really should practice on something first. Get an old car piece of paintwork and practice on that first. If you sand too hard you will make it worse, possibly a professional spray in. Get it right and you will have perfect paintwork again. The colour of your car and colour match will define how good the overall finished job will turn out.

Difficulty:  8 out of 10

The reason this job gets an 8 is the potential to cause untold damage. Patience is a must. You rush it, you ruin it. The sanding is a critical part of the process, start lightly and check all the time until you understand how the paint feels with the sandpaper, do a few passes clean and check. Repeat as required. The tighter you make the initial paint drop into the chip, the easier it will become to blend in. Flicking paint about will mean lots of cleaning up and polishing you didn’t need to do.

The quality of your sandpaper and grit grade choices depends on the paintwork. Start with the fine if you have to and then you could go more aggressive for the worse parts if you are not progressing. Then come back with progressively finer papers until it’s totally smooth.

Conclusion:

If in doubt don’t chance it. I won’t be held responsible for you ruining your paintwork. You will need patience, time, a steady hand and confidence. The reward is a great looking paint job again.

Be careful.

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