Wednesday, May 21, 2008

How to Repair Chips and Scratches - Properly

Scratches and chips on the paintwork of your car can be an eye-sore and can have a detrimental affect on the resale value of your car. To properly repair chips and scratches on the paintwork of your car you need to get together the following items to do the job:

  • Touchup or color matched paint
  • Compatible primer
  • Organic cleaner
  • Solvent
  • 3M Imperial Hand Glaze
  • Sanding Block 2000 grit
  • Car wash
  • 600 grit wet/dry sandpaper
  • Round un-dyed wooden toothpicks
  • Large lightweight cardboard boxes (large shoe box or bigger)
  • Several 100% cotton towels
  • New pencils with unused erasers
  • Rubber glue
  • Several heavy clean plastic cups
  • Roll of quality masking tape

Paint chip repair is a learned skill and should be practiced on an area of the car that is not readily visible. Don't try repairing the larger panels such as the hood first.

Test all cleaners or solvents on the paint prior to usage. Apply a little cleaner or solvent to a cloth and rub it onto a patch on the car not clearly visible. If you do not get any color on the rag, then the cleaner/solvent should be safe for the paint. If you do get color on the rag, then you need to try another solvent.

REPAIR STEPS:

Step 1

At least 24 hours before you want to start, use the rubber glue to attach small 600 grit sandpaper circles (the diameter of the eraser) onto several new pencils. The eraser must be unused and flat on top.

Step 2

Wash the car with a quality car wash and dry thoroughly.

Step 3

Paint chips are generally of two different types. The worst case has exposed the bare metal, while the less severe has left the original primer paint still intact. Clean the area of the chip thoroughly with a degreaser. If there is rust on the exposed metal, clean off with the pencil eraser. Use a toothpick to gently probe the area and make sure that the edges of the chip are secure and not waiting to fall off and ruin your work.

This is an optional step! If you do not feel comfortable with sanding or your paint is one of the new clear-coated finishes, you should jump to step number 5.

Take the new pencil/sandpaper tool you made earlier and dip it into clean water and put a few drops of water on the chip area.
*SLIGHTLY* rough up the chip and a small portion of the surrounding paint. Lightly turning the pencil will rough up an area the diameter of the eraser and this should be more than enough. Keep the roughed up area as small as possible, the object is to give the new paint approximately 1 mm of old paint to "grab" around the perimeter of the chip and not dig scratches.

Step 4

Move onto the next chip and repeat the above. Depending upon the amount of time available, you may wish to tackle 10-20 chips at one time. Try to stay within the area that may be covered by your box(es).

Step 5

When finished sanding all your chips you are tackling at this time apply a small amount of Alcohol or Enamel Reducer to a rag and wipe each chip and surrounding area to remove any sanding dust and grease/oils. Use additional solvent and new area of the rag for each chip. Allow to dry (these are highly volatile and will evaporate quickly with no residue).

Step 6

If the original primer is intact, and "pencil sanding" does not disturb the primer, then skip the next step and go directly to painting
(step 9).

Step 7

Make sure that the chip and surrounding area is clean. If not, reclean with the organic cleaner, Alcohol or Enamel Reducer. Pour or spray a small amount of primer into a clean plastic cup. Dip the point of a wooden toothpick into the primer to get a thin coating on the first 1-2 mm of the toothpick. If there is a blob on the end, gently scrape it back into the cup. Place the tip of the toothpick against the center of the chip and allow capillary action to literally flow a *THIN* coat of the primer into the depression of the chip.

Move onto the next prepared chip.

If you have finished priming all your prepared chips before two hours are up, cover with a box, taped down with masking tape. The key is to allow the first coat of primer to dry at least two hours.

Dispose of your cup and start with a fresh cup and toothpick. Apply another thin coat of primer to each repair that needs primer. Priming is completed when no metal is visible and the level of the primer is below the level of the surrounding paint. This is important! Cover and allow dry for two hours or until dry.

Step 8

Apply a small amount of Alcohol or Enamel Reducer to a rag and wipe the chip and surrounding area to remove any sanding dust and grease/oils. Allow to dry. Repeat for all the chips you intend to repair.

Step 9

If you are using a touchup, shake the bottle thoroughly. If you are using color-matched paint, mix thoroughly and pour a small amount into a clean plastic cup.

Step 10

Dip the point of a new toothpick into the paint to get a thin coating on the first 1-2 mm of the toothpick. If there is a blob on the end, gently scrape it back into the bottle. Place the tip of the toothpick against the center of the chip and allow capillary action to literally flow the paint into the depression of the chip. Repeat for each chip. The key is not to use too much paint. Do not re-dip the toothpick. Use only the amount that will flow from one dip.

Step 11

Cover with your paint box and allow to dry 2 hours and repeat 8-12 times till the depression is filled with paint and bulges slightly upward and covers the roughed up area with a thin coating of paint. The first 2-3 coats may not completely hide the primer. This is fine because you have many more coats to go.

Step 12

The paint application is completed when the new paint bulges slightly upward (a fraction of a millimeter) and had covered the roughed up area with a thin coat of new paint. Allow the paint to dry for at least a week.

Step 13

The touchup paint has been applied to the surface and allowed to dry for at least 1 week, and resembles a minute mound on the flat plane of the existing paint.

The object is to remove the mound and make the surface of the paint one continuous flat plane. The Finesse Block offers the ability to gently remove only the high spot of the repair. Unlike sandpaper or polish on a rag, the five usable sides of the block are flat and act like a "wood plane" to remove only the elevated areas of the repair. The 2000 grit will not leave scratches.

Step 14

Soak the Finesse Block in clean water for 24 hours prior to use. Put a small drop of car wash on the chip repair. This acts as a lubricant for the sanding block. Then gently "plane" the high spot on the paint. "Plane" in one direction (usually back to front - drawing the block towards me). If the block dries out, re-wet and continue use.

When the new and existing paints are blended (smoothed to the flat plane) to your satisfaction, clean the area using a quality car wash and lots of water and then use a quality glaze to restore the high gloss finish. I prefer 3M Imperial Hand Glaze. Don't use a machine on your car.

Step 15

When applying either a glaze or a wax, apply to your soft cotton cloth or applicator pad and work in one direction only. Circles are many times the cause of "swirl marks." A front-to-back, back-to-front motion (the way the air flows over the car) will help minimize swirl marks or at least make them less visible. Buff out with a soft cotton cloth. If it looks good, wax with a quality hard wax and you are done.

Step 16

Tip for applying wax. If you are using a quality Carnauba based wax, try applying it with your fingers instead of a pad or cloth. Hold your fingers together and use your fingertips as an applicator pad. The tactile feedback from your fingers will tell you when the wax has been worked into the paint. If grit should lodge under your fingers, you will know immediately and not grind it into the paint. A pad will not allow this tactile feedback.

A circular motion of the pad will make a 360-degree swirl mark. All marks on paint are most visible at a 90 degree viewing angle. Thus the front-to-back marks are most visible from the sides, whereas a circle stands out from any viewing angle.

By Bill Bailey

1 comment:

fairings said...

interesting article, i never knew about this until now