How to Fix 7 of the Most Common Types of DIY Paint Job Problems

How to Fix 7 of the Most Common Types of DIY Paint Job Problems

A DIY paint job can look great when the prep, spraying technique, and products are right. But even a small mistake — dirty surface, wrong reducer speed, poor gun setup, heavy coats, or rushing dry times — can create problems in the final finish.

The good news is that most common paint defects can be fixed. Some can be corrected by sanding and buffing. Others require sanding the area smooth and repainting. Below are seven of the most common DIY automotive paint problems, their causes, how to fix them, and which products can help prevent them next time.

 

1. Orange Peels

Description: A finish with a rough, bumpy surface, similar to an orange peel.

Common Causes:

Orange peel results from poor leveling of the paint or clearcoat. Possible causes can include applying coats too dry, spraying from too large a distance, using an incorrect speed of reducer, poor air pressure, improper setup of the gun, and applying too thin coats.

How to Fix It:

If the orange peel is in the clearcoat and there is enough clear on the panel, it can usually be corrected by wet sanding and buffing. Start with a fine grit, then work your way finer before polishing.

If the texture is heavy or the clearcoat is too thin, the better fix is to sand the surface smooth and apply more clearcoat.

Helpful Products:

For jobs where the clearcoat needs to flow out better, use the correct reducer and clearcoat setup for the temperature. Products like:

 

2. Fish Eyes

Description: Small round craters or circles in the paint or clearcoat where the coating pulls away from the surface.

Common Causes:

Fish eyes are usually caused by contamination. This can come from wax, grease, silicone, oil, old detailing products, dirty air lines, or even touching the panel with your hands after cleaning it.

How to Fix It:

Let the area dry or cure. Do not keep spraying heavy coats over the problem. Once dry, sand the affected area smooth, clean it very well, and recoat.

If the fish eyes are in the clearcoat, you may be able to sand and re-clear the panel. If they are severe or spread across the panel, the job may need to be sanded back and redone.

Helpful Products:

 

3. Runs and Sags

Description: Thick drips or heavy areas where paint or clearcoat has flowed downward on the panel.

Common Causes:

Runs happen when too much material is applied at once. This can come from spraying too close, moving too slowly, using too much fluid, applying coats too heavily, or not giving enough flash time between coats. A reducer or activator that is too slow for the temperature can also make runs more likely.

How to Fix It:

Let the run fully cure before touching it. Do not try to wipe it while it is wet. Once cured, carefully level the run with sandpaper or a small sanding block, then wet sand and polish the area.

For large runs, the panel may need to be sanded and re-cleared.

Helpful Products:

  • Use the correct clearcoat and activator speed for your conditions. 
  • MC270 Production Clear with the proper hardener,
  • along with the correct MR reducer, can help the material lay out properly without staying wet too long.

 

4. Dry Spray

Description: A rough, dusty, or grainy finish. The paint may look like it landed on the surface, but it did not melt together smoothly.

Common Causes:

Dry spray happens when the material starts drying before it fully lands and levels on the panel. Common causes include spraying too far away, moving too fast, using too much air pressure, spraying in hot weather, or using a reducer that is too fast.

How to Fix It:

If dry spray is in the clearcoat and there is enough clear on the panel, it can often be wet sanded and polished. If it is in the basecoat, the area may need to be sanded smooth and recoated before clear is applied.

Helpful Products:

  • In warmer conditions, a slower reducer may help the paint flow better.

 

5. Poor Coverage or Uneven Color

Description: The color looks patchy, streaky, blotchy, or see-through. Some areas may look darker or lighter than others.

Common Causes:

Poor coverage can happen when not enough coats are applied, the basecoat is mixed incorrectly, the spray pattern is uneven, or the wrong primer/sealer color is used underneath. Some colors naturally cover worse than others, especially reds, yellows, pearls, metallics, and some bright colors.

How to Fix It:

If the clearcoat has not been applied yet, allow the basecoat to flash and apply more coats until the color is even.

If the panel has already been cleared and the color is still uneven, the panel usually needs to be sanded and repainted.

Helpful Products:

 

6. Sand Scratches Showing Through

Description: Visible sanding marks, scratches, repair edges, or rings showing under the paint or clearcoat.

Common Causes:

This usually happens when the surface was painted before the scratches were sanded fine enough. Deep scratches from coarse sandpaper can show through primer, basecoat, and clearcoat. It can also happen when primer edges or body filler edges are not feathered out smoothly.

How to Fix It:

If the scratches are showing through the finished paint, the best fix is to sand the area smooth, reprime if needed, block it properly, and repaint.

If the scratches are only light marks in the clearcoat, wet sanding and polishing may correct them.

Helpful Products:

 

7. Dull Clearcoat or Low Gloss

Description: The clearcoat looks flat, hazy, cloudy, or less glossy than expected.

Common Causes:

Low gloss can happen when the clearcoat is sprayed too dry, mixed incorrectly, applied too thin, or sprayed with the wrong activator for the temperature. It can also happen if the clear is buffed too soon or if the surface was contaminated before spraying.

How to Fix It:

If there is enough clearcoat on the panel, let it cure, then wet sand and buff. Start with fine sandpaper, refine the scratches, then use compound and polish to bring the gloss back.

If the clearcoat is too thin, rough, or uneven, the better fix may be to sand and re-clear the panel.

Helpful Products:

 

Final Notes

Most paint problems come down to a few basic things: prep, cleanliness, spray technique, temperature, and using the right products together.

Before spraying, make sure the panel is clean, sanded correctly, and ready for paint. Choose the right primer, reducer, activator, basecoat, and clearcoat for the job. Take your time between coats and do not rush the flash times.

AutoColorOnline carries the main products needed for DIY automotive paint work, including basecoat kits, full paint kits, primers, reducers, activators, clearcoats, sandpaper, masking supplies, tack cloths, and buffing products.

A good finish starts before the paint ever hits the panel.

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